Staphylococcus aureus infections

Pictures

Picture	Title	Caption	Copyright
Title Symptoms Caption S. aureus-caused inter-digital pouch lameness in a sheep. Animals affected usually find it difficult to walk except following surgical intervention. Copyright ©G.O. Egwu	Symptoms	S. aureus-caused inter-digital pouch lameness in a sheep. Animals affected usually find it difficult to walk except following surgical intervention.	©G.O. Egwu
Title Symptoms Caption S. aureus subacute mastitis in a ewe. Though milk appeared apparently normal, more than 150 colonies of S. aureus were isolated from the right half of the udder on Mannitol salt agar plate. Copyright ©G.O. Egwu	Symptoms	S. aureus subacute mastitis in a ewe. Though milk appeared apparently normal, more than 150 colonies of S. aureus were isolated from the right half of the udder on Mannitol salt agar plate.	©G.O. Egwu
Title Symptoms Caption S. aureus-associated keratoconjunctivitis in sheep. Notice that the conjunctivae and cornea are very inflamed. Pannus (migration of conjunctival vessels) have already migrated into the cornea. The sequel of this, following secondary bacterial infection, is corneal ulceration and permanent blindness. Copyright ©G.O. Egwu	Symptoms	S. aureus-associated keratoconjunctivitis in sheep. Notice that the conjunctivae and cornea are very inflamed. Pannus (migration of conjunctival vessels) have already migrated into the cornea. The sequel of this, following secondary bacterial infection, is corneal ulceration and permanent blindness.	©G.O. Egwu
Title Pathology Caption Vegetative endocarditis of 12 months old layer caused by Staphylococcus aureus and Streptococcus faecalis. Copyright ©Sri Poernomo	Pathology	Vegetative endocarditis of 12 months old layer caused by Staphylococcus aureus and Streptococcus faecalis.	©Sri Poernomo
Title Symptoms Caption Dermatitis (gangrene) caused by Staphylococcus aureus in fowls.|Dermatitis (gangrene) caused by Staphylococcus aureus. Copyright ©©Sri Poernomo	Symptoms	Dermatitis (gangrene) caused by Staphylococcus aureus in fowls.|Dermatitis (gangrene) caused by Staphylococcus aureus.	©©Sri Poernomo

Identity

Preferred Scientific Name

• Staphylococcus aureus infections

International Common Names

• English: agalatiae mastitis-metritis syndrome; avian staphylococcal infections; bacterial chondronecrosis with osteomyelitis in broiler chickens; bacterial endocarditis in ruminants; bovine actinobaccillosis; comb necrosis in layer breeder chickens; enzootic calf pneumonia; folliculitis of sheep; gangrenous dermatitis of chickens and turkeys; goat mastitis due to staphylococcus aureus; impetigo of sheep; mammary abscess in pigs; mastitis; mastitis in ewes due to miscellaneous bacteria; ovine and bovine infectious keratoconjunctivitis; ovine interdigital pouch lameness; purulent osteomyelitis; pyoderma of sheep; scalded skin disease; septicemia of lambs or kids, tick pyemia; staphylococcal dermatitis; staphylococcal dermatitis in birds; staphylococcal dermatitis in cattle, impetigo, folliculitis; staphylococcal dermatitis, folliculitis, furunculosis, impetigo, of sheep; staphylococcal dermatitis, folliculitis, impetigo, of sheep; staphylococcal mastitis; staphylococcal, staphylococcus aureus, mastitis in cows; staphylococcus aureus mastitis in ewes; Staphylococcus aureus-induced septicaemia; staphylococcus infections in birds

Local Common Names

• Norway: hva; mastitt

Overview

History

The early classical historical, but un-referenced, description of Micrococcus (Staphylococcus) was recorded by Merchant and Parker (1967). These authors stated that micrococci were first discovered, in pus, by Ogston in 1881, who then divided the organism (Micrococcus) into two other groups namely Staphylococci and Streptococci respectively in 1883.

Merchant and Parker (1967) further stated that in 1884, these organisms (Staphylococci and streptococci) were first cultivated in artificial medium. During this process two species of Staphylococci, Staphylococcus pyogenes aureus and Staphylococcus pyogenes albus emerged.

Scientists have demonstrated the relationship of these cocci organisms to human infections following experimental self-inoculations.

Taxonomy and Nomenclature

Migula, in 1895, officially assigned three organisms (two staphylococci and one streptococci) to the genus Micrococcus and they were then named Micrococcus aureus, albus and citreus respectively in 1900. Further nomenclature of staphylococci into chromogenic strains such as S. pyogenes albus (a non-pigmented variety), a golden form, and an intermediate yellowish variety of S. pyogenes citreus, was observed to be merely a physiological characteristic that was readily lost during primary and sub-cultures. Transformation in historical nomenclature occurred then, when Buchanan, in 1911, used the genus name Micrococcus for the group and later Staphylococcus in 1917.

The first well defined systematic classification of these genera was by Bergey in (1948), who maintained the genus name Micrococcus; and in the 1957 edition classified them in the genus Staphylococcus and family Micrococcaceae consisting of four genera, Planococcus, Stomatococcus, Micrococcus and Staphylococcus. Bergey has since classified Staphylococcus in the family Staphylococcaceae. More than nineteen species of the genus Staphylococcus are recognized and four groups are clearly distinct, based on deoxyribonucleic acid (DNA:DNA) hybridization analysis. These four groups are S. epidermidis, S. saprophyticus, S. simulans and S. sciuri. Of the large number of staphylococcal species, only three (S. aureus, S. epidermidis and S. saprophyticus) are commonly associated with some human and animal diseases. However, S. aureus, amongst the staphylococcal species is one of the most important causative pathogens in a variety of human and animal diseases.

Association of S. aureus with animal diseases

One of the most economically important diseases caused by S. aureus in dairy animals is mastitis. This is commonly defined as an inflammation of the mammary gland accompanied by physical, chemical, pathological and bacteriological changes in the milk and glandular tissues (Blood and Radostits, 1989; Ameh et al., 1993; Oliver et al., 1999; Apolo et al., 1999; Fitz-Patrick, 2000). S. aureus mastitis in cattle, sheep and goats has serious financial and milk production implications for intensive herds and flocks in the diary industry (Elecko, 1998; Smith et al., 1998; Saratis et al., 1998; Barkema et al., 1999; Sears and Smith, 1999).

In an extensive system of production, multiparous ewes have been shown to have higher milk somatic cell counts compared with primiparous ewes (Lafi et al., 1994). In another study, S. aureus was reported to be the dominant pathogen in clinical cases of mastitis from 145 different breeds of Nigerian goats, as well as from 173 quarter milk samples collected from 297 dairy cows, maintained extensively in Egypt (Shoukry and Shabana, 1997).

The eradication of S. aureus from extensive dairy herds or flocks is more difficult than in intensive systems due to a non-adherence to mastitis control guidelines (Zurzul, 1994). Persistence of this organism in affected udders results in poor milk production, low condition scores, culling and preponderance of resistant strains in affected animals (Elecko, 1998; Zecconi and Piccinini, 1999; Tyagunenko et al., 1999; Costa et al., 2000). It can also lead to zoonotic transmissions from milk to man (Blood and Radostits, 1989; Oboegbulem and Fidelis, 1996).

S. aureus has also been incriminated, or shown to be associated with a variety of human and animal diseases. It has been reported as causing a generalized scalded skin disease in lambs, resembling ‘scalded skin syndrome’ of man. The characteristic lesions of this disease include exfoliation with deep ulcerations in the affected areas (Scott and Murphy, 1997; Yeruham et al., 1999).

Other infections caused by S. aureus and reported in pigs, include purulent osteomyelitis with lesions located at the costo-chrondral junction of affected pigs (Jensen et al., 1999). This disease has been experimentally reproduced when eight calves were intramedullarly infused with a haemolytic strain of S. aureus. This induced traumatic osteomyelitis shown by arteriographic and radiographic analysis. The analysis clearly indicated areas marked by an increased sprouting of osteomyelitic arterial networks around the meta-tarsal bones (Das et al., 1998). Similar microscopic osteo-myelitic lesions have also been observed in experimentally infected goats (Hoque, 1997; Singh et al., 1998).

Staphylococcal dermatitis in some domestic animal species is associated with three bacterial species, S. aureus, S. hyicus and S. epidermidis. S. aureus induced septicaemia has also been reported in chickens and lambs (Pyrah et al., 1994; Rasmaswamy et al., 1997; Fisher et al., 1998). Other important diseases associated with S. aureus in domestic animals which have serious implications in intensive and extensive husbandry systems includes agalactiae mastitis-metritis syndrome in cows and pigs. This is characterized by a purulent uterine discharge (Aerts et al., 1995; Esmat and Badr, 1996). Other equally important diseases implicated or associated with S. aureus in domestic animals are: ovine interdigital pouch lameness (Egwu et al., 1994), bovine actinobaccillosis (Mondodori et al., 1994), abcessation (Sharma et al., 1994), porcine gastroenteritis (Ayoade et al., 1990) and ovine/bovine infectious keratoconjunctivitis (Egwu et al., 1989; Egwu, 1992; Egwu et al., 1993; Chhabra et al., 1996; Takele et al., 2000).

The ability of S. aureus to produce these diseases in domestic animals, is due to elaboration of cytolytic, sphingomyelinase, leukocidic, demonecrotic and entero-toxins (A-E). These include enzymes such as hyaluronidase, nucleases, penicillinase, sphingomylinase, coagulases and the production of ‘slime’, which is known to aid attachment, inversion and multiplication of the organism (Baselga, 1994).

Drastic reduction and elimination of S. aureus-induced diseases, particularly mastitis, should involve good management. This includes good housing, sanitation, maintenance of milking equipment, routine monitoring and surveillance, composite and bulk milk testing, milker's hygiene, accurate timing and strategic treatment or chemotherapy of all diseases induced or associated with S. aureus. These measures are important to ensure the production of good quality milk and profitability. More importantly they are ensuring the consumption of high quality milk as one of our essential dietary components, with reduced chances of contracting diseases such as tuberculosis, streptococcal sore throat, staphylococcal entero-toxin and brucellosis. These are all of zoonotic importance, and are commonly associated with inadequate food safety or hygiene.

Hosts/Species Affected

Vectors and Intermediate Hosts

No vectors or intermediate hosts are needed for the development or transmission of S. aureus, and perhaps other staphylococcal organisms. Moreover, no literature exists to date reporting any significant role vectors or intermediate hosts may play in the transmission of staphylococcal diseases.

Hosts

There is a wide host range for infections caused by S. aureus and other important specific diseases caused by this species. Nevertheless, host susceptibility is dependent on a number of factors.

Survival of the causal organism in different climatic and geographical locations may depict differences in invasiveness, virulence, pathogenicity and therapeutic variations as observed with this species (Blood and Radostits, 1989; El-Sukhon, 1995; Bansel et al., 1995; Mackie et al., 1998; Zadoks et al., 2000; Larsen et al., 2000).

Host specific influences, such as whether the animal is at the primiparous or multiparous state, can influence the colonisation, distribution and transmission of S. aureus in all clinical stages of mastitis (Blood and Radostits, 1989; Pyorala et al., 1994; Simpson et al., 1995; Poornima and Updhye, 1995; Boscos et al., 1996; Vural et al., 1999).

The age of the female animal is also an important consideration in the susceptibility to mastitis, as the number of pregnancies can affect intramammary infections (Blood and Radostits, 1989; Vural et al., 1999). Some inherited genetic characteristics, or resistance conferred by the host in retarding the entry and penetration of S. aureus into tissues of the udder, can be reflected in the anatomical conformation. This includes the size of the udder, shape, length of the teat and the openings of the teat sphincter (Blood and Radostits, 1989; Saratis et al., 1998; Aliyu et al., 1999).

Variations in the breed susceptibility of dairy animals to mastitis and other staphylococcal infections have been reported (Blood and Radostits, 1989; Egwu et al., 1995a; Boscos et al., 1996). Extensive dairy husbandry and semi-intensive systems, particularly in tropical countries during the time of scarce pasture grazing, result in various injuries of the teat. These injuries include abrasions, perforations of the udder and dog bites resulting in jagged and lacerated wounds, which enhance fast entry of the causal mastitis organisms (Smith and Roquisnsky 1977; Ameh et al., 1993, Lafi et al., 1998).

Host immunity may involve the ability of the animal to mount an effective systemic and local immune response. This is an important aspect of the host susceptibility to infection. Production of antibodies to specific immunogenic epitopes of S. aureus and cellular immune responses could determine the ability of the host to ward-off previous or recent infections by S. aureus and other staphylococcal diseases (Blood and Radostits, 1989; Park et al., 1999; Hayakawa et al., 2000; Rivas et al., 2000; Riolett et al., 2000).

Distribution

Staphylococcus aureus and the diseases this organism causes, or is associated with, occur worldwide in all continents and countries of the world. Surveys of various incriminated infections and diseases have shown remarkable similarity in epidemiology of S. aureus and its associated diseases (Blood and Radostits, 1989; Ameh et al., 1993; Oliver et al., 1999).

Although the distribution and occurrence of S. aureus and its diseases as shown on the map, the geographical spread is not exhaustive. The organism is widespread in countries where intensive and extensive livestock rearing are prominent (Smith et al., 1998; Blood and Radostits, 1989; Barkema et al., 1999).

Distribution Table

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Pathology

Gross pathology

Gross and histopathological changes are common features that are associated with mastitis infected glands. Gross lesions are usually obvious following palpation of the infected udder and can be either a result of pronounced or massive swellings. The udder is usually enlarged to approximately twice its normal size, with other associated signs which are discussed in the disease course text (Blood and Radostits, 1984; Egwu et al., 1994; Ameh et al., 1996; Fabre et al., 1997). Necrotizing gangrenous lesions are a common feature associated with mastitis caused by S. aureus, Clostridium perfringens and Escherichia coli (Blood and Radostits, 1989; Ameh et al., 1994). The affected gland shows marked necrosis of the parenchymal epithelium coupled with foci of epithelial erosions, and ulcerations of the ductal system and surrounding skin (Blood and Radostits, 1989; Ameh et al., 1994; Cifrain et al., 1995, Jones, 1998).

Though necropsy procedures are usually not common in animals that have died of gangrenous and other clinical forms of mastitis, further examination of histopathological changes in affected animals are important in order to ascertain the extent of tissue damage.

Histopathology

Lesions observed through histopathology, include accumulation of large numbers of PMNs and other inflammatory cell cytokines (Sanchez et al., 1994; Shoshani et al., 1995; Leitner et al., 2000). Histologically, the inter-lobular duct’s epithelium, in the infected mammary gland, has been displaced by bits of necrotic debris and bacterial clumps. These ducts (interlobular) are necrotic with fibrinous thrombi, and sometimes the vascular walls of the inter-lobular stroma exhibit thrombosis (Shibahara and Nkamura, 1999; Leitner et al., 2000).

Marked accumulation of PMNs, which is sometimes not reflected in the grossly affected gland, is the basis of sub-acute diagnosis of mastitis using the California, Wisconsin and other somatic cell counts (Lam et al., 1996; Hulsen, 1997). This histopathological change, though not diagnostic for S. aureus-induced mastitis, could reveal the causative agent of the mastitis pathogen if backed by a laboratory culture of the collected samples.

Diagnosis

History of Persistent Mastitis

This forms an integral part of the diagnostic tool of staphylococcal mastitis. A history of recurring and persistent mastitis in a flock or herd probably involves S. aureus as the sole or one of the multi-causative agents. This is because S. aureus can produce resistance to most anti-bacterials, as a result of production of beta-lactamase or penicillinase, allowing the organism to persist in the tissues of the udder (Allen et al., 1994; Simko and Bartko, 1996; Schlegelova and Sediva, 1999) following prolonged antibiotic treatment with unsuitable antibiotics.

Diagnosis based on history can be carried out either during on farm investigations/visits or by the use of questionnaires. Questions asked are usually based on the number of animals affected in the flock or herd, morbidity and mortality, breed, recurring cases, milk yield etc. Response to antibiotic treatments, cure rates and hygiene practices should form the bed-rock of using history as a diagnostic tool during epidemiological investigations.

Clinical Signs

The gross clinical signs manifested in affected animals with mastitis are very obvious, even when accompanied by systemic infections. Since many clinical forms of the disease have been described by many authors (Blood and Radostits, 1989; Deutz et al., 1995; Ameh et al., 1996; Fabre et al., 1997), most farmers can recognize affected animals with mastitis grossly or following assistance by veterinarians. Early recognition of these forms of mastitis allows urgent and prompt action for the affected animal, including initiation of treatment where necessary.

Laboratory Diagnosis

Laboratory diagnosis forms another very important component for confirmatory diagnosis of S. aureus mastitis and related diseases. The colony morphology on simple laboratory media may be fundamental in ascribing the agent S.aureus as a causal organism from cultured samples, particularly for sheep and ox-blood agar plates, due to the production of alpha or beta haemolysis. Laboratory cultures of milk from individual quarter, half, composite or bulk tanks, can be used to enable isolation of the organism (Hogenveen et al., 1997; Leitner et al., 2000). Cows, ewes, does and other animals with sub-clinical mastitis, may pose serious diagnostic problem(s) to the inexperienced farmer. Somatic cell and bacterial counts are then needed to make an accurate diagnosis (Blood and Radostits, 1989; Simpson et al., 1995; Hulsen, 1997; Lam et al., 1996) based on the degree of inflammatory PMNs and the number of leukocyte cells detectable on a graded scale.

Bacterial counts of more than 200 are used as a baseline for positive samples (Blood and Radostits, 1989). Somatic cell counts (PMNs) greater than 250,000/ml in milk are suggestive of an inflammatory process (Blood and Radostits, 1989; Beloti et al., 1997; Barkema et al., 1997; Allore et al., 1998; Bauldry et al., 1999). Examination of milk using the milk cup, in the laboratory or by the pen-side of the affected animal, is important for enabling the farmer, veterinarian or technologist to assess the milk quality, by examining the consistency and colour of the milk. Also important is the combined use of somatic cell count and N-acetyl-beta-D-glucosaminidase (Ngase) enzyme in discriminating the quarters with or without mastitis (Faingold et al., 1995; Pyorala and Pyorala, 1997). Experience and practice with any of these procedures highlighted will assist in the diagnosis and recognition of mastitic milk.

Serology

Mastitis caused by S. aureus is increasing in importance throughout the world. Since intensification of dairy farming, even in some tropical countries, the disease is gaining recognition, and therefore the control and eradication of mastitis should be of utmost priority to the dairy farmer. Early diagnosis of this disease using more reliable, specific and sensitive laboratory diagnostic tools, is gaining acceptance for rapid prevention and initiation of chemotherapeutic measures. Strains of S. aureus may vary in their geographical origin and antibiotic sensitivity patterns, as well as in their phage or ribotypes (Aarestrup et al., 1995; Adesiyun, 1995; Yoshida et al., 1997; Raimundo et al., 1999). Furthermore, diverse geographical isolates of S. aureus can be characterized by using genomic finger printing of isolates from milk. In one such study, 137 S. aureus isolates were categorized into 20 distinct DNA finger printing profiles, which were further amplified by PCR at 506, 770, 784 and 2479 bp regions (Kim et al., 1999). Also the use of genes expressed by S. aureus have been amplified using PCR on milk samples (Khan et al., 1988; Lammers et al., 2000; Tisala et al., 2000). Example genes used are the ‘nuc gene’ or those screened from the mutant library (Lac Z mutants), including those from the 165-235 ribosomal RNA spacer sequences. Other combined diagnostic techniques incorporating laboratory culture, somatic cell counts and enzyme linked immunosorbent assays have been described for the diagnosis of S. aureus mastitis in dairy cows (Hicks et al., 1994; Fox and Adams, 2000). Some other laboratory sensitive methods for the diagnosis of diseases caused by S. aureus, include the use of pulse field gel electrophoresis for identification of isolates (Mc Cullagh et al., 1998; Dalamitra et al., 1998) and other simple laboratory enzyme-based methods for milk samples (Faingold et al., 1995; Pyorala and Pyorala, 1997).

Immunology

Systemic and local immune responses are provoked during intra-mammary infection with S. aureus. The immunoglobulins involved in body fluids or milk during humoral immunity are IgG1, IgG2, IgG3, IgA and IgMs (Guidry et al., 1994; Leitner et al., 2000). As a result of possession of different antigenic components on the surface of S. aureus, antibodies are usually directed against these surface antigenic sites, and to the different toxins elaborated by these organisms (Baldi et al., 1994; Quinones and Demo, 1997; Jones, 1998).

Cellular immunity also plays a functional protective role in S. aureus mastitis and other staphylococcal diseases. Specific recruitment of mammary neutrophils and leukocyte or lymphocyte sub-populations following vaccination with type-5 capsular polysaccharide (Cp5) antigen and whole cells of S. aureus, have been reported in experimental studies (Herbelin et al., 1995; Almeida et al., 1997; Waller and Colditz, 1999). Nevertheless, altered immune reactions such as type I hypersensitivity reactions following inoculation of S. aureus have been reported in an experimental goat (Schofield et al., 1997). This shows that immunology to this disease can be protective, but can sometimes be accompanied by altered states of immunological reactions, which can be damaging to the affected host.

List of Symptoms/Signs

Disease Course

Pathogenesis

S. aureus induces disease by either toxin production (Cifrian et al., 1996; Quinones and Demo, 1997; Jones 1998), or by direct invasion and destruction of tissues (Kang et al., 1996; Quinones and Demo, 1997).

Other staphylococcal species can invoke disease by proliferation of the causative agent in conjunction with some virulent toxins and/or associated enzymes produced by these organisms (Blood and Radostits, 1989; Baselga, 1994; Bezek and Hull, 1995; Ichikawa 1996). Amongst the numerous diseases caused by S. aureus, mastitis is of a high priority in dairy animals. This disease (mastitis) can be classified as per-acute, sub-acute, acute and chronic (Blood and Radostits, 1989; Simpson et al., 1995; Topolko and Benice, 1997) forms or clinical stages.

The disease process is dependent on the ability of the organism (S. aureus) to survive in the vicinity of the dairy animal, and its ability to confer resistance on a variety of disinfectants and antibiotics used in the farm (Boddie and Nickelson, 1997).

The strain variation of S. aureus accounts for the degree of pathogenicity (Bansal et al., 1995; Hermans et al., 2000). However, the size of the inoculum, stage of lactation, injuries on the teat and elaboration of toxins and enzymes will determine the type of mastitis and pathology induced in the hosts (Sultra and Poutrel, 1994; Bansal et al., 1995; Ameh et al., 1993; Quinones and Demo, 1997; Fitzgerald et al., 2000). In spite of these aforementioned factors, the adherence of S. aureus to the epithelial cells of the mammary gland, is the first process required for the initiation of pathogenesis (Katic et al., 1996).

Clinical Forms of Mastitis

Per-acute

This occurs most frequently during infections of early lactation (Blood and Radostits, 1989). It is sometimes accompanied by gangrene of the udder, due to the necrotizing action of the alpha toxins (Cifrain et al. 1995; Jones 1998). Per-acute mastitis usually occurs during the first few days of lactation and is accompanied by a severe temperature elevation to 41 - 42^°C, tachycardia, pronounced depression, absence of rumen motility and muscular weakness (Blood and Radostits, 1989). The affected quarter or half of the animal is swollen and hard. There is subcutaneous emphysema, blister formation and gangrene in some affected cases. These inflammatory processes can subside within a few days, and the infected gland is then replaced by proliferation of connective tissue, marked by blockage and atrophy of the ductal area.

Sub-acute

The sub-acute form of S. aureus mastitis is transient and mimics the clinical signs of either the acute or chronic forms, or both. The milk may show some degree of infection as evidenced by blood clots (Blood and Radostits, 1989; Petrovic et al., 1997) with an elevation of the leukocyte counts (Lam et al., 1996). The California mastitis test (CMT) is routinely used on individual, composite and bulk milk samples (Simpson et al., 1995; Leitner et al., 2000) to detect levels of polymorphonuclear cells (PMNs). The temperature of the affected animal may or may not become elevated (Blood and Radostits, 1989; Egwu et al., 1994; Rapoport et al., 1994).

Acute

The acute form of mastitis is characterised by a visible enlargement of the udder. There are marked changes in the milk observed, such as evidence of blot clots, fibrin, watery consistency, lobules and coloration. The temperature of the animal is elevated and the enlarged udder is painful on palpation. The affected animal is weak, comatose and sometimes becomes recumbent in unfavourable situations (Ameh et al., 1996; Fabre et al., 1997). Other associated signs include dullness, anorexia, inappetence and general malaise. Milk quality and production are reduced drastically (Wilson et al., 1997). This form is clinically recognizable by the farmer and provides an opportunity for reporting such cases urgently to the veterinarian or other appropriate authorities.

Chronic

If an animal is suffering from the chronic form of mastitis, the functional capacity of the udder is compromized. There is atrophy or shrinkage of the udder and milk production is also drastically reduced. The glandular tissue becomes fibrosed, and sometimes the ducts are blocked with difficulty in milk letdown through the teat sphincter (Shoshani et al., 1995). Most causal agents persist in the udder during this stage and with appropriate treatment, recovery from this clinical form of mastitis is high (Deutz et al., 1995). Farmers usually try to maintain patency of the teat canal by making use of teat cannulas. Total milking out by farmers or veterinarians can assist in the successful application of chemotherapy at this stage.

Epidemiology

The staphylococcal species, with particular reference to S. aureus and associated diseases, are ubiquitous worldwide and affect a whole range of domestic and wild animals (Blood and Radostits, 1989; Oliver et al., 1999; Smith 1999).

S. aureus is always a dominant causal agent of mastitis (Smith et al., 1998; Elecko, 1998; Oliver et al., 1999) and is also highly predisposed to many organs of animal and human hosts, thereby causing different diseases (Egwu et al., 1989; Mondodori et al., 1994; Esmat and Badr, 1996; Ramaswamy et al., 1997; Takele and Zerihun, 2000).

Direct replication (cell division) of S. aureus is by binary fission and intermediate hosts or vectors are not necessary in the development of this organism. However, it is interesting to note that tick-pyaemia of lambs, characterized by elaboration of neuro-toxins, as a result of tick bites on the definitive host (lambs) is enhanced by S. aureus (Clarkson and Faull, 1985; Blood and Radostits, 1989). The obvious lesions resulting from these septicaemic staphylococcal infections are lameness, abcessation of vital organs, unthriftiness and general weakness of affected lambs. Experimentally, ixodes ricinus ticks acting as intermediate hosts infected with S. aureus have also reproduced typical lesions of tick pyaemia (Webster and Mitchell, 1986). The disease (tick pyaemia) has been reported as occurring naturally and concurrently with other diseases of domestic animals such as, enterotoxaemia, tick-borne fever, louping ill and lamb dysentry (Clarkson and Faull, 1985; Blood and Radostits, 1989).

Incubation Period and Transmission

The primary barrier protecting against the entry of S. aureus into the mammary gland is the teat sphincter. When the pathogen (S. aureus) overcomes this barrier, if not washed out by the physical act of milking, the bacteria multiplies, invades and proliferates in the udder tissue (Das and Khanna, 1994; Sultra and Poutrel, 1994).

Considerable variation occurs amongst susceptible animals, between infection and appearance of clinical signs. The incubation period may be for 3 - 4 days following infection of the teat (Blood and Radostits, 1989; Fox et al., 1995), with inflammatory processes coming into action 3 - 5 days later. These processes however, depend on the virulence, host immune mechanisms and weight of infecting pathogen. These factors also determine the degree of pathology and type of mastitis produced (Blood and Radostits, 1989; Das and Khanna, 1994; Sutra and Poutrel, 1994; Bansel et al., 1995).

Direct and indirect transmission of S. aureus, are usually the main avenues of disseminating an infection. Usually, mammary gland infection occurs via the teat canal and/or environment (Blood and Radostits, 1989; Bansal et al., 1995; Bouchard et al., 1996; Kosev et al., 1996). It can also occur through other unhygienic measures such as, housing, defects in milking machines and management factors (Demchonko, 1994; Vasil, 1994; Refsdal, 1996; Fox et al., 1995; Benda 1998; Barkema et al., 1999). Other inter-alia factors include: the use of clean milking towels for pre and post cleaning of mammary teats, clean calving pens, unhygienic housing condition, improper adjustments of milking machine, dirty teat cups or the use of unclean hands during hand milking. The importance of all factors mentioned cannot be overemphasized in their respective roles in the transmission of mastitis pathogens.

S. aureus is known to co-exist with many other bacterial pathogens occurring in the environment and other animal sites (Poorima and Updhye, 1995; Poorima and Upadhye, 1995; Huan and Huan, 1996; Yanni, 1999). However, the ability of S. aureus to persist in the tissue of the udder makes it somewhat more ameliorable to treatment, compared to other organism such as Escherichia coli, Streptococcus dysagalactiae, S. uberis and Pseudomonas aeruginosa that are all found in the environment (Sultra and Poutrel, 1994).

Since S. aureus is ubiquitous in distribution and is also involved in many other animal diseases, contact transmission, aerosol transmission, wounds and abrasions on the body surface play an important role in the transmission of S. aureus (El-Sukhon 1995; Poorima and Upadhye 1995; Yanni, 1999; Moller et al., 2000). They also play a role in other induced diseases such as mastitis-metritis syndrome, abcessation, gastroenteritis, septicaemia, osteomyelitis and urinary infections, including respiratory and environmentally acquired infections. Dissemination of the organism from one organ to the other is also possible, depending on the invasiveness or multiplication of the organism in the host tissues.

Impact: Economic

Economic impact of Mastitis

Mastitis caused by Staphylococcus aureus, is a major disease for the dairy industry to contend with, if productivity and health of the animals are to be ensured.

Generally in most affected animals, losses occurring from fatalities amongst dairy herds are very minimal compared to those resulting from milk production (Blood and Radostits, 1989; Deutz et al., 1995). Affected cows with sub-clinical mastitis have been shown to produce low birth weight calves (Dominigues et al., 1996). This may pose very serious economic costs and returns in rearing the dairy calves.

Contaminated milk has transmitted some zoonotic bacteria to man, when the milk has not been properly pasteurized before human consumption. Such diseases caused by this transmission include tuberculosis, streptococcal sore throat, brucellosis and staphylococcal food poisoning (Blood and Radostits, 1989; Mousing et al., 1997; Hernandez and Baca, 1998). Most of these diseases are becoming devastating in most developing countries and some are emerging as diseases in parts of the developed world.

Economic effects resulting from quarter or udder half infections of the mammary gland are drastically reduced milk yield, monetary returns and profit to the dairy farmer. This is dependant on the stage of lactation and time of infection (Shoshani et al., 1995; Deutz et al., 1995; Ameh et al., 1996; Fabre et al., 1997). Infection of cows during the dry period could reduce milk yield by up to 11%, whereas those occurring at late lactation could reduce percentage yield by up to 48% (Blood and Radostit, 1989; Deutz et al., 1995). This constitutes tremendous economic waste and financial returns to the dairy farmer.

The prevalence of specific mastitis pathogens such as S. aureus varies from herd to herd. In a high prevalence herd, conservative economic milk losses resulting from S. aureus mastitis on a ‘cow basis’, could be in excess of US $90-250, particularly in large dairy herds (Blood and Radostits, 1989).

Quarters or halves of udders from animals infected with S. aureus, alone or in combination with other mastitis pathogens, can result in low or poor quality milk and market sales (Shoshani et al., 1995; Lam et al., 1996; Fabre et al., 1997). Losses emanating from premature culling as a result of unthriftiness or poor condition of acutely or chronically affected animals, could seriously undermine the productivity of the dairy farm as well as monetary returns (Deutz et al., 1995; Dominigues et al., 1996; Moclerson et al., 2000).

The greatest economic losses for dairy farms with mastitis are usually associated with the costs of veterinary medicine and care, particularly in those herds with acute or chronic forms of the disease. The use of pre-dipping disinfectants, intra-mammary antibiotics and other systemic antibiotics can impact large economic losses in monetary terms to the dairy farmers. This is especially the case, if these are carried out routinely in the process of trying to eliminate persistent and recalcitrant strains of S. aureus on a dairy farm.

Apart from those practices aimed at reducing intra-mammary infections, there are other diagnostic costs incurred by the farmer. These include routine somatic milk counts on individual, composite and bulk milk samples and the increased labour costs for this. There are obvious advantages in monitoring levels of milk infection, but it does create an extra cost.

Other Economic Impact of S. aureus Associated or Induced Diseases

Other losses occurring from S. aureus induced or associated diseases, include blindness in small and large ruminants. This could be temporary or permanent blindness as observed in sheep, goats and cattle suffering from ovine, caprine and bovine kerato-conjunctivitis (Egwu et al., 1989; Al-Gaabary et al., 1998; Takele and Zerihun, 2000). Affected animals with this acute or chronic ocular disease are unthrifty, off-feed, emaciated and generally lose sight of their environment. It is not clearly known what role S. aureus plays in initiating the disease or exacerbating the disease condition, but its frequent association with the disease process is likely to indicate a possible role of toxins and enzymes, and other ocular inflammatory mediators in the disease process. Corneal ulceration (see picture) which is usually purulent, or scarification on the cornea following healing, has been reported to be associated with S. aureus following natural and experimental infections (Egwu et al., 1989; Egwu and Faull, 1991, Egwu and Faull, 1993).

Tick pyaemia causes the early death of lambs, particularly those with good traits that make them potential replacements for breeding ewes. Losses from this disease could be as a result of septicaemia, lameness, arthritis and disseminated abscessation of vital organs (Clarkson and Faull, 1985; Webster and Mitchell, 1986).

Zoonoses and Food Safety

There is an important public health aspect of S. aureus infections. Staphylococcal food poisoning is becoming important in the milk and meat industry (Blood and Radostits, 1989; Mousing et al., 1997; Hernandez and Baca, 1998). Nosocomial (hospital acquired) infections are common sources of acquiring S. aureus. The need for pasteurization of milk before consumption, and the sterilization of prosthetic surgical equipment before open surgery must also be ensured. Many other pathogens of zoonotic importance apart from S. aureus are involved in ‘mastitides’ (Blood and Radostits, 1989). These include Mycobacterium spp. (El-Haenaeey et al., 1994; Klinger and Rosenthal, 1997), and commonly incriminated species of this genera (mycobacterium) include: M. bovis, M. fortuitum, M. smegmatis, all of which are commonly acquired from contaminated milk and its products. Infections can also be obtained from infections of the hosts or from contaminated unhygienic preparations of milk and meat products (El-Haenaeey et al., 1994; Klinger and Rosenthal, 1997). Clostridium perfringens type A, Bacillus spp., Campylobacter jejuni, and Brucella abortus and milletensis are also commonly acquired pathogens from improperly pasteurized milk and its products (Egwu et al., 1994; Huan and Huan 1996; Waage et al., 1999).

The isolation of S. aureus from local milk products (nono) or local yoghurts, even at low pH has been reported by Egwu et al. (1995b). Consumers should therefore ensure that milk and meat products are wholesome before taking them to market, to ensure freedom from some of these zoonotic diseases. This is particularly important in developing countries where consumption of local milk products is popular.

Disease Treatment

Consideration for the treatment of S. aureus induced diseases should involve the target sites involved in the disease process. These sites include the udder, respiratory tract, eyes, bones and skin where the diseases are manifested. Priority is however ascribed to S. aureus mastitis, as it stands out prominently because of the economics involved in controlling the disease. Treatment should aim at combating or controlling the severity of mastitis through chemotherapy, with the use of the right antibiotics following adequate sensitivity tests or anti-biogrammes (Sandgren and Ekman, 1996).

Antibiotics

A number of first generation antibiotics including penicillins, streptomycin, cloxacillin, penicillin/streptomycin combination and nitrofurazone, have been used at various doses and regimens for the treatment of S. aureus mastitis (Blood and Radostits, 1989; Owens et al., 1997; Egwu et al., 1994; Dhabele et al., 1997; Schlegelova and Sediva, 1999).

The intramammary and/or systemic routes are usually employed during the chemotherapy of mastitis (Egwu et al., 1994; Pyorala and Pyorala, 1994; Dhabele et al., 1997; Owens et al., 1997).

Most drugs used in the treatment of S. aureus mastitis tend to be more sensitive in vitro than in vivo (Egwu et al., 1994; Owens et al., 1994; Dhabele et al., 1997), following experience from laboratory and field investigations.

The increasing incidence of S. aureus resistance following mastitis treatment has resulted in inefficacy treatment in the use of antibiotics (Allen et al., 1994; Simko and Bartes, 1996; Schlegelova and Sediva, 1999).

There is a need for antibiotic sensitivity testing prior to treatment of mastitis to determine the best drug of choice (Cruz et al., 1997; Kumajock et al., 1999). This should involve serum blood concentrations of the drug of choice, minimum inhibitory concentration studies and disk sensitivity antibiotic testing (Owens et al., 1994; Egwu et al., 1994; Allen et al., 1994; Simko and Bartes, 1996), so as to allow the veterinarian to select the best antibiotics.

Ethnoveterinary Practice

Ethnoveterinary practice has not assumed any significance in recent times for the treatment of mastitis and other related diseases. However, the efficacy of this method of treatment has not been properly assessed in line with current antibiotic usage. This practice in nomadic pastoralism could offer some benefits to the nomadic farmer, who may find costs of modern antibiotic treatment very exorbitant. Some of these practices may be handed from generation to generation in the family line.

Chemotherapy of Other S. aureus Diseases

Infections like osteomyelitis, keratoconjunctivitis, and staphylococcal dermatitis can be treated with oxytetracycline, erythromycin, demofloxacin and other suitable antibiotics (Egwu, 1992; Egwu and Faull, 1993; Al-Gaabary et al., 1998).

The commonly used drugs, dose, adverse reactions and possible emergence of resistant strains in the disease treatment table.

Prevention and Control

Farm Level Control

The pathogenic importance of S. aureus in mastitis and other related infections necessitates the need for its control, eradication and prevention in affected dairy herds (Tichaecek, 1999). Though complete eradication of S. aureus may, to some extent, appear inconceivable or unachievable, the need for continuous monitoring and surveillance in affected dairy herds or flocks cannot be overemphasized.

A holistic approach is therefore needed to achieve a meaningful eradication programme of mastitis that will maximize profitability in the dairy industry.

Awareness of farmers

To raise farmer awareness, there should be an on-farm discussion by veterinarians, animal scientists and dairy epidemiologists, with dairy farmers on the need to be constantly aware of and control this important disease (mastitis). The importance of the ability to recognize the clinical signs of mastitis and the performance of simple routine tests on milk by the farmers, cannot be underestimated. Some of these facets of awareness in the control of mastitis have been previously documented (Majic et al., 1994; Brown et al., 1998). There is a need for farmers to partake in all aspects of the on-farm control measures if the weight of the infecting organisms and elimination of the causal agents are to be achieved in the dairy farm.

Husbandry Practices

Management is important in the control of S. aureus mastitis. The components of this aspect of management include housing, movement of livestock, in-house sanitation of cow cubicles, pens and milking parlours, as well as milking procedures and general hygiene of the milker and premises (Vasil, 1994; Benda, 1998; Barkema et al., 1999).

It is a recognized fact, that the dairy industry is well developed in more temperate than tropical countries. In the latter countries, nomadism and transhumance practices that are tied to the extensive and semi-intensive husbandry have compromized some of the enumerated measures (Smith et al., 1998; Ameh et al., 1993; Aliyu et al., 1999). These practices, rather than enhancing control have worsened it, because animals are usually herded together, eat and drink together and generally disseminate and contract infections.

Housing

It is a known fact, that the construction of dairy houses in temperate region is of a higher quality standard than those in the tropics, where milking animals are always on the move and sedentary herds or flocks are rarely found. Even where dairy farm houses exist, in-house milking equipment and other infrastructures may vary from farm to farm. The hygienic conditions of this equipment and the degree of disinfection in the dairy houses, may account for the prevalence of S. aureus on these farms (Blood and Radostits, 1989; Poorima and Updhye, 1995; Barkema et al., 1999).

The site or location of the house, as well as the nature (wooden or concrete) can significantly affect the prevalence of mastitis pathogens (Poorima and Updhye, 1995; Barkema et al., 1999).

The bedding material used, such as wet sawdust has been shown to easily predispose to mastitis compared to dry shavings and straw (Blood and Radostits, 1989).

Milking parlour/milking cow

The milking parlour should be routinely disinfected and overcrowding during milking minimized. The mammary gland of the milking cow should be washed with a mild disinfectant containing mild and suitable antiseptics. This should include the use of creams and solutions on teat sores, which constitute a common source for entry of bacterial pathogens (Blood and Radostits, 1989; Saratis et al., 1998; Aliyu et al., 1999). Practising pre- and post-dipping of the teat can reduce the incidence of mastitis in the herd, for example the use of 0.25% or 0.5% solutions of providone iodine (hydrochloride) and iodine.

Milking machines

There is no doubt that milking machines constitute an essential component of the infrastructures required in the dairy industry. However, the misuse of these machines has resulted in increased subclinical and clinical mastitis (Vasil, 1994; Refsdall, 1996; Barkema et al., 1999).

Therefore, for good herd health surveillance in dairy farms, examination of the milking machines to detect faults related to vacuum pressure, milk cup pressures, vacuum capacity, pulsation rate, air bleeds and the milking vacuum at the teat-cup to ascertain no blockage of air vents should be carried out. These measures must be ensured in order to meet standards of specification prior to milking (Blood and Radostits, 1989; Fox, 1997; Barkema et al., 1999).

It is however, important to state that some modern technological advancements in the design of milking machines have incorporated automatic milk cup deflectors, which divert refluxed milk from the pipeline, and also automatic milk cup removers to prevent milk accumulation in the cups and reflux into the tanks.

Restriction of Animal Movement

There is a need to restrict movement of dairy herds to neighbouring paddocks. It is important to minimize or prevent contact of affected animals with clean herds. Nevertheless, the practicability of this practice in pastoral nomadism is far from reality (Mech, 1975; Williamson and Payne, 1978; Gefu, 1982). Strict government laws on livestock movement, quarantine and free market livestock trades should be enforced in all their ramifications to prevent S. aureus mastitis epidemics. National and international policy programmes on livestock movement should ensure that animals with clean bills of health should be allowed to cross international boundaries. There should also be a need for dairy monitoring boards, required to censor infected herds/flocks by examination of milk through testing by somatic cell counts of individual, composite, herd, or bulk milk (Blood and Radostits, 1989; Lam, 1996; Hogeveen et al., 1997; Leitner et al., 2000). This process of testing, backed up with culture, can also detect some other serious mastitis causing pathogens, which may be exotic in the importing country.

Culling

Routine monitoring and surveillance of dairy herds and infected milk allows easy identification of animals suffering from mastitis. This ensures that the affected animals are culled from the herd, enabling the dairy farmer to institute good mastitis control measures. Identified animals that are sick with mastitis should be treated and the farmer should ensure that such animals are routinely removed and treated before allowing them back into the herd. This culling process ensures that certain mastitis pathogens not ameliorable to treatment are kept under check.

Vaccines

The use of vaccines for the control of staphylococcal mastitis has not been well documented and its efficacy is not well ascertained. Vaccines prepared using whole cells of S. aureus, sub-units, anti-toxins or targeted against specific anti-inflammatory cells may be promising, if such vaccines are able to invoke protective anti-body levels. Nevertheless, varying degrees of success have been reported in the field following experimental trials on various species of animals (Nordhaug et al., 1994a, b; Fitzpatrick, 2000; Virtala and Nevalainen, 2000).

Although many S. aureus component vaccines are still undergoing experimental field trials, the likely past and future problems, and efficacy on the use of such vaccines has been previously highlighted (Faria et al., 2000; Fitzpatrick 2000).

The vaccines listed in the table are not exhaustive, the potential acceptability of each vaccine and ability to confer immunity in vaccinated animals remains properly assessed (Han-HongRyul et al., 2000; Virtala and Nevalainen, 2000). It is however, important to note that there is yet to be any effective marketable S. aureus vaccine. The potential for producing S. aureus sub-unit vaccines in the present age of deoxyribonucleic acid recombinant research is great, provided such genetically engineered vaccines targeted against immunogenic epitopes can also cross-protect against similarly related pathogenic bacterial organisms causing mastitis.

It is also important that apart from mastitis induced by S. aureus, no available vaccines exist for immuno-prophylaxis of other diseases caused by or associated with S. aureus. Research into these types of vaccine, for other staphylococcal-induced disease, is still in its infancy, but it is hoped that following experimental trials and field success this type of vaccine will become available.

References

Aarestrup FM, Jensen NE, 1997. Prevalence and duration of intramammary infection in Danish heifers during the peripartum period. Journal of Dairy Science, 80(2):307-312; 28 ref

Aarestrup FM, Wegener HC, Rosdahl VT, 1995. A comparative study of Staphylococcus aureus strains isolated from bovine subclinical mastitis during 1952-1956 and 1992. Acta Veterinaria Scandinavica, 36(2):237-243; 24 ref

Adesiyun AA, 1995. Characteristics of Staphylococcus aureus strains isolated from bovine mastitic milk: bacteriophage and antimicrobial agent susceptibility, and enterotoxigenicity. Journal of Veterinary Medicine. Series B, 42(3):129-139; 46 ref

Adesiyun AA, Webb LA, Romain HT, 1997. Relatedness of Staphylococcus aureus strains isolated from milk and human handlers in dairy farms in Trinidad. Journal of Veterinary Medicine. Series B, 44(9):551-560; 26 ref

Aerts MML, Beers HJ, Herben PJ, 1995. Comparative activity of nafcillin, oxacillin and cloxacillin on mastitis/metritis pathogens. Sensitivity of microbiological milk residue tests. Symposium on residues of antimicrobial drugs and other inhibitors in milk. Kiel, Germany, 28-31 August 1995., 39-40; 2 ref

Alam MGS, Ahmed JU, Rahman MB, Rahman MM, 1995. Occurrence of bacterial flora in the genital tract of female buffaloes. Bangladesh Veterinary Journal, 29(1/4):71-74; 9 ref

Al-Gaabary MH, Ammar KM, 1998. Infectious bovine keratoconjunctivitis, IBK., in Egyptian buffaloes. Eighth Scientific Congress, Faculty of Veterinary Medicine, Assiut University, 15-17 November, 1998., 654-667; 19 ref

Ali-Vehmas T, Vikerpuur M, Sandholm M, 1994. Lactoperoxidase antagonizes anti-staphylococcal activity of cell-wall destabilizing antibiotics. Indigenous antimicrobial agents of milk: recent developments., 164-174; 16 ref

Aliyu MM, Egwu GO, Ameh JA, Gadzama YH, 1999. Biometrics of mammary gland of mastitic and non mastitic ewes in Nigeria. Nigerian Veterinary Journal, 20(2):75-84; 23 ref

Allen JL, Cowan ME, Cockroft PM, 1994. A comparison of three semi-selective media for the isolation of methicillin-resistant Staphylococcus aureus. Journal of Medical Microbiology, 40(2):98-101; 14 ref

Allen KL, Molan PC, 1997. The sensitivity of mastitis-causing bacteria to the antibacterial activity of honey. New Zealand Journal of Agricultural Research, 40(4):537-540; 19 ref

Allore HG, Wilson DJ, Erb HN, Oltenacu PA, 1998. Selecting linear-score distributions for modelling milk-culture results. Preventive Veterinary Medicine, 33(1/4):11-29; 21 ref

Almeida RA, Matthews KR, Oliver SP, 1997. Eukaryotic and prokaryotic cell functions required for invasion of Staphylococcus aureus into bovine mammary epithelial cells. Journal of Veterinary Medicine. Series B, 44(3):139-145; 23 ref

Ameh JA, Addo PB, Abekeye JO, Gyang EO, 1996. Prevalence of clinical mastitis and of intramammary infections in Nigerian sheep. Bulletin of Animal Health and Production in Africa, 44(2):117-119; 14 ref

Ameh JA, Addo PB, Adekeye JO, Gyang EO, 1993. Prevalence of clinical mastitis and of intramammary infections in Nigerian goats. Preventive Veterinary Medicine, 17(1/2):41-46; 9 ref

Ameh JA, Addo PB, Adekeye JO, Gyang EO, Teddek LB, Abubakar Y, 1994. Gangrenous caprine coliform mastitis. Small Ruminant Research, 13(3):307-309; 14 ref

Ameh JA, Edgbe-Nwiyi T, Zaria LT, 1999. Prevalence of bovine mastitis in Maiduguri Borno State, Nigeria. Veterinarski Arhiv, 69(2):87-95; 27 ref

Anyam AA, Adekeye JO, 1995. Bacterial flora associated with mastitis in sheep and goats in Zaria (Nigeria) area. Bulletin of Animal Health and Production in Africa, 43(3):163-166; 11 ref

Apolo, A., Bellizzi, T., Lima, D. de, Burgueno, M., 1999. Subclinical mastitis in dairy sheep in Uruguay. In: Milking and milk production of dairy sheep and goats. Proceedings of the Sixth International Symposium on the Milking of Small Ruminants, Athens, Greece, 26 September-1 October, 1998 [Milking and milk production of dairy sheep and goats. Proceedings of the Sixth International Symposium on the Milking of Small Ruminants, Athens, Greece, 26 September-1 October, 1998], [ed. by Barillet, F., Zervas, N. P.]. Wageningen, Netherlands: Wageningen Pers. 168-170.

Arvind Kumar, Katoch RC, 1997. Microbial flora of infertile dairy animals in Himachal Pradesh. Indian Journal of Animal Sciences, 67(4):288-289; 14 ref

Asai T, Niwa K, Jinnouti T, Mori M, Suzuki G, 1996. Enterotoxigenicity of Staphylococcus aureus isolates from bulk and individual cow milks. Journal of the Japan Veterinary Medical Association, 49(9):666-668; 9 ref

Ayoade GO, Oladosu LA, Adebambo OA, 1999. Intensive pig production in Nigeria: incidence and causes of preweaning mortality. International Journal of Animal Sciences, 14(1):31-34; 15 ref

Baird-Parker AC, 1963. A classification of Micrococci based on physiological and biochemical tests. Journal of General Microbiology, 30:409-427

Baldi L, Guarino A, Fenizia D, Franciscis Gde, Gentile A, 1994. Identification of antibodies against the Stafilococcus aureus [Staphylococcus aureus] in water buffalo by fluorescence activated cell sorting. Proceedings, 4th World Buffalo Congress, Sao Paulo, Brazil, 27-30 June 1994. Volume 3., 449; 3 ref

Bansal BK, Singh KB, Uppal SK, Nauriyal DC, 1995. Post-milking teat dipping in prevention of intramammary infections under natural exposure to mastitis pathogens. Indian Journal of Animal Sciences, 65(8):860-863; 11 ref

Barillet F, Zervas NP, 1999. Milking and milk production of dairy sheep and goats. Proceedings of the Sixth International Symposium on the Milking of Small Ruminants, Athens, Greece, 26 September-1 October, 1998. Milking and milk production of dairy sheep and goats. Proceedings of the Sixth International Symposium on the Milking of Small Ruminants, Athens, Greece, 26 September-1 October, 1998., 571 pp.; [EAAP Publication No. 95]; many ref

Barkema HW, Schukken YH, Lam TJGM, Beiboer ML, Benedictus G, Brand A, 1999. Management practices associated with the incidence rate of clinical mastitis. Journal of Dairy Science, 82(8):1643-1654; 48 ref

Baselga R, Albizu I, Amorena B, 1994. Staphylococcus aureus capsule and slime as virulence factors in ruminant mastitis. A review. Veterinary Microbiology, 39(3/4):195-204; many ref

Beloti V, Müller EE, Freitas JCde, Mettifogo E, 1997. Study of subclinical mastitis in dairy herds in the north of Paraná, Brazil. Semina (Londrina), 18(1):45-53; 42 ref

Benda P, 1997. The effect of pipeline milking equipment on the incidence of the main mastitis pathogens (Staphylococcus aureus, Streptococcus agalactiae) in samples of milk from tanks. Vyzkum v Chovu Skotu, 39(1):16-20; 12 ref

Bergey DH, 1948. Staphylococci. In: Krieg NR, Holt J, eds. Bergey's Manual of Determinative Bacterilogy, Vol. 2. Baltimore, USA: Williams and Wilkins

Bergey DH, 1957. In: Krieg NR, John HOH, eds. Manual of Determinative bacteriology, edition 7. Baltimore, USA: Williams and Wilkins Co

Bergey, DH, 1983. Manual of determinative bacteriology, edition 8. Baltimore, USA: Williams and Wilkins Co

Bersot LS, Oliveira LATde, Franco RM, Carvalho JCAP, 1998. Bacteriological evaluation of pork (loin cuts) on sale in Niterói and Sao GonÇalo, Rio de Janeiro State, Brazil. Revista brasileira de Ciência Veterinária, 5(1):3-7; 15 ref

Bertolatti D, Hannelly T, Bishop M, French E, Marendoli M, 1996. Staphylococcus aureus in Western Australian poultry. International Journal of Environmental Health Research, 6(4):277-287; 18 ref

Bezek DM, Hull BL, 1995. Peracute gangrenous mastitis and cheilitis associated with enterotoxin-secreting Staphylococcus aureus in a goat. Canadian Veterinary Journal, 36(2):106-107; 10 ref

Bilic V, Habrun B, Humski A, 1999. Sensitivity of bacteria isolated from pigs. Praxis Veterinaria (Zagreb), 47(1/2):39-46; 16 ref

Binta MG, Mushi EZ, Adom EK, 1995. The impact of infectious bursal disease in Botswana. Zimbabwe Veterinary Journal, 26(3/4):110.115; 5 ref

Black A, 1997. Bacterial and parasitic diseases of New Zealand poultry. Surveillance (Wellington), 24(4):3-5; 36 ref

Blood DC, Radostits OM, 1989. Veterinary Medicine, ELBVS edition, London, UK: Bailliere Tindal, 501-550

Boddie RL, Nickerson SC, 1997. Evaluation of two iodophor teat germicides: activity against Staphylococcus aureus and Streptococcus agalactiae. Journal of Dairy Science, 80(8):1846-1850; 10 ref

Boscos C, Stefanakis A, Alexopoulos C, Samartzi F, 1996. Prevalence of subclinical mastitis and influence of breed, parity, stage of lactation and mammary bacteriological status on Coulter Counter Counts and California Mastitis Test in the milk of Saanen and autochthonous Greek goats. Small Ruminant Research, 21(2):139-147; 41 ref

Bouchard é, Guillemette JM, Bigras-Poulin M, DuTremblay D, 1996. Mastitis and its control. The principal cause: infectious bacteria. Producteur de Lait Québécois, 16(5):23-25

Brentrup H, 1998. Udder infections in first-calf heifers. Occurrence, importance and prevention. Tierärztliche Umschau, 53(1):15-16, 18; 15 ref

Brown DF, Ardaya VD, Ribera CH, Cuellar GAM, Kerby PJ, 1998. Mastitis control programme in the developing dairy industry of tropical lowland Bolivia. Tropical Animal Health and Production, 30(1):3-11; 21 ref

Busch K, Hajsig D, 1995. Effectiveness of chlorhexidine gluconate (PLIVASEPT DV) on Staphylococcus aureus strains isolated from bovine and ovine mastitis. Praxis Veterinaria (Zagreb), 43(1/2):101-103

Calva RB, Cortés FR, Aja-Guardiola S, 1994. A study of mastitis in dairy cows in the temperate areas in Mexico. Proceedings 18th World Buiatrics Congress: 26th Congress of the Italian Association of Buiatrics, Bologna, Italy, August 29-September 2, 1994. Volume 1., 721-723; 8 ref

Calvinho LF, Zurbriggen MA, Canavesio VR, 1997. Experimental infection of the bovine mammary gland with a vaccine strain of Staphylococcus aureus. Veterinaria Argentina, 14(135):300.306; 18 ref

Carman M, Gardner E, 1997. Trends in bovine mastitis and sensitivity patterns 1976-1995. Surveillance (Wellington), 24(4):13-15; 1 ref

Chaffer M, Leitner G, Winkler M, Glickman A, Krifucks O, Ezra E, Saran A, 1999. Coagulase-negative staphylococci and mammary gland infections in cows. Journal of Veterinary Medicine. Series B, 46(10):707-712; 17 ref

Chao MR, Wu FM, Chen MC, Vinther K, 1994. The periparturient excretion pattern of haemolytic bacteria from sows in Taiwan. Proceedings: The 13th International Pig Veterinary Society Congress, Bangkok, Thailand, 26-30 June 1994., 214

Chen-Sujen, Wang-ChingHo, Chen SJ, Wang CH, 2000. The contamination status of bacteria and fungi in the chicken hatcheries of Taiwan. Journal of the Chinese Society of Veterinary Science, 26:103-109

Chhabra RK, Dhablania DC, Sharma DK, 1996. Studies on some oculopathies with reference to organisms and their sensitivity in animals. Indian Journal of Comparative Microbiology, Immunology and Infectious Diseases, 17(2):179-180; 5 ref

Cifrain E, Guidry AJ, O'Brien CN, Marquardt WW, 1995. Effects of alpha toxin and capular exopolysaccharide on adherence of S. aureus to cultured teat, ductal and secretory mammary epithelial cell. Research in Veterinary Science, 58:20-25

Clarkson MJ, Faull WB, 1985. Notes for the sheep clinician. Notes for the sheep clinician., Edition 2:126 + viipp

Contreras A, Corrales JC, Sierra D, Marco J, 1995. Prevalence and aetiology of non-clinical intramammary infection in Murciano-Granadina goats. Small Ruminant Research, 17(1):71-78; 38 ref

Costa EO, Benites NR, Guerra JL, Melville PA, 2000. Antimicrobial susceptibility of Staphylococcus spp. isolated from mammary parenchymas of slaughtered dairy cows. Journal of Veterinary Medicine. Series B, 47(2):99-103; 17 ref

Cowan ST, 1962. An Introduction to chaos, or the classification of micrococci and staphylcocci. Journal of Applied Bacteriology, 25:324-340

Cruz AD, Magalhaes Lopes CAde, Modolo JR, Gottschalk AF, 1997. Comparative "in vitro" study on the susceptibility and emergence of mutants resistant to danofloxacin and ciprofloxacin among Staphylococcus aureus isolated from bovine mastitis. Revista de Microbiologia, 28(1):61-64; 21 ref

Dalamitra S, Fenlon DR, Thomson-Carter F, Allan EJ, 1998. A study of the epidemiology of Staphylococcus aureus in the cow using pulsed field gel electrophoresis. British Mastitis Conference 1998., 84-86

Das AK, Singh AP, Chawla SK, 1998. Experimental bovine osteomyelitis: an arteriographic study. Indian Journal of Veterinary Surgery, 19(2):93-95; 11 ref

Das SC, Khanna PN, 1994. Factors influencing shedding of Staphylococcus aureus in milch cows. Cheiron, 23(5):210-214; 5 ref

Demchenko AG, 1994. Microorganisms in milk, their isolation and identification. Problemy Veterinarnoi Sanitari i Ekologii, 94:76-79; 9 ref

Deutz A, Obritzhauser W, Köfer J, 1998. Prevalence of penicillinase-forming strains of staphylococci mastitis. Tierärztliche Umschau, 53(10):597-598, 600-601; 17 ref

Deutz A, Schuh M, Planner G, Fuchs K, 1995. Loss of milk caused by chronic mastitis in ewes and results of treatment. Wiener Tierärztliche Monatsschrift, 82(11):346-350; 23 ref

Dhabale RB, Sharma NC, Kumar AA, 1996. Microbial and therapeutic studies in repeat breeder cattle. Indian Journal of Veterinary Research, 5(2):55-59; 9 ref

Domingues PF, Longoni H, Rocha GPda, Júnior JR, Curi PR, Neves IR, 1996. Effect of subclinical mastitis on body weight of Nelore calves. Revista Brasileira de Medicina Veterinária, 18(3):102-105; 8 ref

Egwu GO, 1992. In vitro antibiotic sensitivity of Mycoplasma conjunctivae and some bacterial species causing ovine infectious kerato-conjunctivitis. Small Ruminant Research, 7(1):85-92; 19 ref

Egwu GO, Adamu SS, Ameh JA, Onyeyili PA, Abana SP, Chaudhri SUR, Rabo JS, 1994. Retrospective, clinicopathological and microbiological studies of interdigital pouch lameness in sheep in an arid zone of Nigeria. Bulletin of Animal Health and Production in Africa, 42(1):5-11; 17 ref

Egwu GO, Ameh JA, Aliyu MM, Mohammed FD, 1999. Caprine mycoplasmal mastitis in Nigeria. Veterinarski Arhiv, 69(5):241-250; 31 ref

Egwu GO, Faull WB, 1991. Humoral immune responses in lambs following ocular experimental infection with a pure cloned culture of Mycoplasma conjunctivae.. Bulletin of Animal Health and Production in Africa, 39(3):333-337; 12 ref

Egwu GO, Faull WB, 1993. Clinico-serological studies of ovine infectious keratoconjunctivitis in adult ewes experimentally infected with Mycoplasma conjunctivae and/or Staphylococcus aureus. Small Ruminant Research, 12(2):171-183; 29 ref

Egwu GO, Faull WB, Bradbury JM, Clarkson MJ, 1989. Ovine infectious keratoconjunctivitis: a microbiological study of clinically unaffected and affected sheep's eye with special reference to Mycoplasma conjunctivae.. Veterinary Record, 125(10):253-256; 33 ref

Egwu GO, Onyeyili PA, Ameh JA, Sulaimon S, 1995. Prevalence of - lactamase producing staphylococci recovered from fermented milk products. West African Journal of Biological Sciences, 2(182):90-98

Egwu GO, Onyeyili PA, Chibuzo GA, Ameh JA, 1995. Improved productivity of goats and utilisation of goat milk in Nigeria. Small Ruminant Research, 16(3):195-201; 68 ref

Egwu GO, Zaria LT, Onyeyili PA, Ambali AG, Adamu SS, Birdling M, 1994. Studies on the microbiological flora of caprine mastitis and antibiotic inhibitory concentrations in Nigeria. Small Ruminant Research, 14(3):233-239; 35 ref

Elbers ARW, Miltenburg JD, Lange Dde, Crauwels APP, Barkema HW, Schukken YH, 1998. Risk factors for clinical mastitis in a random sample of dairy herds from the southern part of the Netherlands. Journal of Dairy Science, 81(2):420-426; 34 ref

Elecko J, 1998. Mastitis in goats of different breeds over a 5-year study. Slovensky Veterinársky Casopis, 23(4):200-205; 10 ref

El-Haenaeey EY, Mahmoud OM, Haroun EM, 1994. Bacterial isolates from the respiratory tract of cattle and their zoonotic importance in Al-Qasseem, Saudi Arabia. Veterinary Medical Journal Giza, 42(1(B)):189-196; 24 ref

El-Idrissi AH, Benkirane A, Zardoune M, 1994. Investigations on subclinical mastitis in goat dairy herds in Morocco. Revue d'élevage et de Médecine Vétérinaire des Pays Tropicaux, 47(3):285-287; 14 ref

El-Sayed AA, Abdalla AE, Fadelmula A, 1996. Isolation of bacteria and fungi from bovine abortions in Sudan. Sudan Journal of Veterinary Research, 14:29-33

El-Sukhon SN, 1995. Virulence factors in bacterial isolates from pneumonic sheep lungs in Northern Jordan. Assiut Veterinary Medical Journal, 33(66):102-109; 17 ref

Erskine RJ, Sears PM, Bartlett PC, Gage CR, 1998. Efficacy of postmilking disinfection with benzyl alcohol versus iodophor in the prevention of new intramammary infections in lactating cows. Journal of Dairy Science, 81(1):116-120; 9 ref

Esmat M, Badr A, 1996. Some studies on mastitis-metritis agalactia syndrome in cows. Veterinary Medical Journal Giza, 44(2A):303-309; 16 ref

Fabre JM, Morvan H, Lebreux B, Houffschmitt P, Berthelot X, 1997. Estimation of the frequency of pathogens causing mastitis in France. Part 1. Clinical mastitis. Bulletin des G.T.V., No. 3:17-23; 19 ref

Faingold D, Ham Mvan, Winkler M, Glickman A, Leitner G, Saran A, 1995. The impact of Staphylococcus aureus udder infection on the milk somatic cell count and NAGase [N-acetyl--D-glucosaminidase] activity in an Israeli dairy herd. Proceedings of the Third IDF International Mastitis Seminar Tel-Aviv, Israel, 28 May - 1 June 1995. Book 1., s-3,40-42; 7 ref

Faria, J. E. de, Pinto, M. S., Dale, R., Zamperlini, B., 2000. Vaccination influence on Staphylococcal infection level of the mammary gland in dairy cows submitted to natural challenge. (Influência da vacinação sobre o nível de infecção estafilocócica da glândula mamária de vacas leiteiras submetidas a desafios naturais). Revista Brasileira de Ciência Veterinária, 7(2), 104-108.

Fatihu MY, 1997. Bacterial flora of urinary bladder of cattle in Zaria, Nigeria. Revue d'élevage et de Médecine Vétérinaire des Pays Tropicaux, 50(3):204-206; 15 ref

Fenlon DR, Logue DN, Gunn J, Wilson J, 1995. A study of mastitis bacteria and herd management practices to identify their relationship to high somatic cell counts in bulk tank milk. British Veterinary Journal, 151(1):17-25; 15 ref

Ferraro L, Scaramelli A, Troya H, 1999. Prevalence of subclinical bovine mastitis in Venezuela and evaluation of the California mastitis test (CMT). Revista Cientifica, Facultad de Ciencias Veterinarias, Universidad del Zulia, 9(2):81-90; 66 ref

Fisher ME, Trampel DW, Griffith-RW, 1998. Post-mortem detection of acute septiceamia in broilers. Avian Diseases, 42(3):352-461

Fitzgerald JR, Hartigan PJ, Meaney WJ, Smyth CJ, 2000. Molecular population and virulence factor analysis of Staphylococcus aureus from bovine intramammary infection. Journal of Applied Microbiology, 88(6):1028-1037; 24 ref

Fitzgerald JR, Smyth CJ, Hartigan PJ, Meaney WJ, Kapur V, 1996. Analysis of diversity of Staphylococcus aureus isolates from bovine mastitis using DNA restriction fragment length polymorphisms of rRNA genes. Mastitis Newsletter, No. 21:29; [Newsletters of the International Dairy Federation No. 144]

Fitzpatrick JL, 2000. Staphylococcus aureus mastitis: past problems, future risks. Cattle Practice, 8(3):273-277; 24 ref

Flamand L, 1995. Herd supervision procedure is a useful weapon against mastitis. Report of the 5th half-yearly Mastitis Panel meeting, Weesp, Netherlands, 10 May 1995. Tijdschrift voor Diergeneeskunde, 120(19):571-572

Fox LK, Adams DS, 2000. The ability of the enzyme-linked immunosorbent assay to detect antibodies against Staphylococcus aureus in milk following experimental intramammary infection. Journal of Veterinary Medicine, Series B, 47(7):517-526

Fox LK, Saran A, Soback S, 1995. Colonisation of S. aureus on chapped teat skin. In: Proceedings of the Third IDF International Mastitis Seminar Tel-Aviv, 28th May 1995, 6:51-55

Gefu JO, 1982. Socio-economic characteristics of goat producers and their husbandry practices in Northern Nigeria. In: Proceedings of International Conference on Goat Production and Disease, Tucson, USA, 422-427

Geornaras I, Jesus AEde, Zyl Evan, Holy Avon, 1997. Bacterial populations of different sample types from carcasses in the dirty area of a South African poultry abattoir. Journal of Food Protection, 60(5):551-554; 17 ref

Godkin A, Kelton D, Alves D, Lissemore K, Leslie K, Smart N, Church C, Meadows P, 1999. Biosecurity practices to limit spread of Staphylococcus aureus on Ontario sentinel dairy farms. Proceedings of the Thirty-Second Annual Conference American Association of Bovine Practitioners, Nashville, Tennessee, USA, 23-26 September, 1999., 254-255

GonÇalves RMS, Franco RM, 1998. Determination of the bacterial content of type 'B' and 'C' pasteurized milk sold in the city of Rio de Janeiro, Brazil. Higiene Alimentar, 12(53):61-65; 24 ref

Graaf Tde, Romero Zuniga JJ, Caballero M, Dwinger RH, 1997. Microbiological quality aspects of cow's milk at a smallholder cooperative in Turrialba, Costa Rica. Revue d'élevage et de Médecine Vétérinaire des Pays Tropicaux, 50(1):57-64; 31 ref

Guidry A, Fattom A, Petel A, O'Brien C, 1997. The prevalence of capsular serotypes amongst Staphyloceccus aureus isolates from cows with mastitis in the United States. Veterinary Microbiology, 59(1):53-58

Guidry AJ, O'Brien CN, Oliver SP, Dowlen HH, Douglass LW, 1994. Effect of whole Staphylococcus aureus and mode of immunization on bovine opsonizing antibodies to capsule. Journal of Dairy Science, 77(10):2965-2974; 62 ref

Guillemette JM, Bouchard é, Bigras-Poulin M, 1996. Mastitis and its control. Increases in somatic cell count. Producteur de Lait Québécois, 16(6):24, 26-27; 1 ref

Habrun B, Bilic V, Humski A, 1997. Bacterial diseases of pigs in large agglomerations in Croatia in 1996. Veterinarski dani 1997, Cavtat, Croatia, 15-18 October 1997. Zbornik radova., 183-189; 6 ref

Han-HongRyul, Park-Hee Myung, Han HR, Park HM, 2000. Efficacy of bovine staphylococcal mastitis vaccine composed of alpha toxin, capsular polysaccharide and fibronectin buiding protein in lactating cows and heifers. Korean Journal of Veterinary Clinical Medicine, 17(1):152-158

Hayakawa, Y., Akagi, M., Hayashi, M., Shimano, T., Komae, H., Funaki, O., Kaidoh, T., Takeuchi, S., 2000. Antibody response to toxic shock syndrome toxin-1 of Staphylococcus aureus in dairy cows. Veterinary Microbiology, 72(3/4), 321-327. doi: 10.1016/S0378-1135(99)00198-4

Heidimli HH, Uaar M, 1999. Efficacy of amoxicillin + clavulanic acid for treatment of clinical and sub-clinical mastitis. Hayvancilik-Arastirma-Dergisi, 9(1-2):65-70

Herbelin C, Gilbert F, Poutrel B, 1995. Specific recruitment of mammary neutrophils and bactericidal activity of milk from cows immunized with Staphylococcus aureus type 5 capsular polysaccharide (CP 5) and toxin. Proceedings of the Third IDF International Mastitis Seminar Tel-Aviv, Israel, 28 May - 1 June 1995. Book 1., s-1,79-81; 3 ref

Hermans, K., Herdt, P. de, Devriese, L. A., Godard, C., Haesebrouck, F., 2000. Colonisation of rabbits with Staphylococcus aureus after experimental infection with high and low virulence strains. Veterinary Microbiology, 72(3/4), 277-284. doi: 10.1016/S0378-1135(99)00179-0

Hernández J, Baca D, 1998. Effect of tuberculosis on milk production in dairy cows. Journal of the American Veterinary Medical Association, 213(6):851-854; 20 ref

Hicks CR, Eberhart RJ, Sischo WM, 1994. Comparison of microbiologic culture, an enzyme-linked immunosorbent assay, and determination of somatic cell count for diagnosing Staphylococcus aureus mastitis in dairy cows. Journal of the American Veterinary Medical Association, 204(2):255-260; 16 ref

Hogan JS, Smith KL, Todhunter DA, Schoenberger PS, 1997. Efficacy of a barrier teat dip containing 0.55% chlorhexidine for prevention of bovine mastitis. Special Circular - Ohio Agricultural Research and Development Center, No. 156:105

Hogeveen H, Sampimon OC, 1997. Relationship between individual somatic cell count and bacteriology: a detailed study on a low bulk milk somatic cell count farm. Society for Veterinary Epidemiology and Preventive Medicine. Proceedings University College, Chester, UK 9th, 10th and 11th April l997., 258-267; 17 ref

Honkanen-Buzalski T, Myllys V, Kulkas L, 1996. Prevalence of bovine mastitis in Finland. Suomen Eläinlääkärilehti, 102(4):191-197; 9 ref

Hoque M, 1997. Post-traumatic osteomyelitis: its incidence in fracture cases and experimental studies in goats. Indian Journal of Veterinary Surgery, 18(1):46

Huan XinLian, 1996. Detection of pathogens of dairy cow mastitis in Jinan, Shandong. Chinese Journal of Veterinary Medicine, 22(2):12

Hulsen J, 1997. Treatment of subclinical mastitis during lactation. Tijdschrift voor Diergeneeskunde, 122(19):544-546

Ichikawa M, Ichikawa T, Mizomoto T, 1996. Productivity of enterotoxins and toxic shock syndrome toxin-1, and coagulase type of Staphylococcus aureus strains isolated from bovines and humans in the same district. Animal Science and Technology, 67(9):780-786; 11 ref

Ismail TM, Hatem ME, 1998. Prevalence of subclinical mastitis in a dairy cattle herd in the Eastern region of Saudi Arabia. Eighth Scientific Congress, Faculty of Veterinary Medicine, Assiut University, 15-17 November, 1998., 646-653; 19 ref

Jensen HE, Jensen B, Arnbjerg J, Aalbaek B, 1999. Chronic purulent osteomyelitis complicated by chondritis at the costochondral junction of slaughter pigs. European Journal of Veterinary Pathology, 5(1):3-7; 8 ref

Jones TO, 1998. Toxin production by Staphylococcus aureus from cases of bovine mastitis. British Mastitis Conference 1998., 94

Kang ByongKyu, Son ChangHo, Song EunAh, 1996. Toxin and/or enzyme production and pathogenicity of coagulase-negative staphylococci isolated from bovine milk. Korean Journal of Veterinary Clinical Medicine, 13(1):20-25; 36 ref

Katic V, Bojanic M, Stojanovic L, 1996. Effects of some factors influencing the adherence of mastitis pathogens to epithelial cells of the bovine mammary gland. Acta Veterinaria (Beograd), 46(5-6):327-334; 10 ref

Khan MA, Kim CH, Kakoma I, Morin E, Hansen RD, Hurley WL, Tripathy DN, Baek BK, 1998. Detection of Staphylococcus aureus in milk by use of polymerase chain reaction analysis. American Journal of Veterinary Research, 59(7):807-813; 37 ref

Khan-Nazer AH, Niyakan S, 1995. A comprehensive study on bacterial flora isolated from yolk sac infection in chicks and their antibacterial sensitivity testing in poultry farms around Shiraz city. Journal of the Faculty of Veterinary Medicine, University of Tehran, 49:23-34

Kim D, Kwon T, Ahn S, Kim D, Kwon ST, Ahn SJ, 1999. Genomic fingerprinting of S. aureus isolated from bovine mastitic milk by PCR. Korean Journal of Veterinary clinical medicine, 16(1):19-25

Kleczkowski M, Jakubczak A, Biskupski J, Klucinski W, Sitarska E, Sikora J, Lechowski R, 1999. The evaluation of bacterial agents of pig diseases and their sensibility to chemotherapeutics in the North-Eastern Poland. Praxis Veterinaria (Zagreb), 47(1/2):37-38; 6 ref

Klinger I, Rosenthal I, 1997. Public health and the safety of milk and milk products from sheep and goats. Revue Scientifique et Technique - Office International des épizooties, 16(2):482-488; 26 ref

Kosev K, Tzolov S, Denev S, Vitkov M, Koleva M, 1996. Influence of the different forms of udder inflammations and the species of microbial agents on the somatic cell count in goat milk. Somatic cells and milk of small ruminants. Proceedings. Bella, Italy, 25-27 September 1993., 107-109; [EAAP Publication No. 77]; 8 ref

Kumajock VL, Bagadi HO, Shears P, Mukhtar MM, 1999. Prevalence of multiple antibiotic resistances among bovine mastitis pathogens in Khartoum state, Sudan. Sudan Journal of Veterinary Science and Animal Husbandry, 38(1-2):64-70

Kumar AVR, Hamza PA, Choudhuri PC, 1996. Economic implications of treating subclinical mastitis. Indian Journal of Dairy Science, 49(7):459-641; 8 ref

Lafi S, Al-Rawashdeh O, Na'Was T, Hailat N, 1994. National cross-sectional study of mastitis in dairy cattle in Jordan. Tropical Animal Health and Production, 26(3):168-174; 14 ref

Lam TJGM, Dejong MCM, Schukken YH, Brand A, 1996. Mathematical modeling to estimate efficacy of postmilking teat disinfection in split-udder trials of dairy cows. Journal of Dairy Science, 79(1):62-70; 27 ref

Lammers, A., Kruijt, E., Kuijt, C. van de, Nuijten, P. J. M., Smith, H. E., 2000. Identification of Staphylococcus aureus genes expressed during growth in milk: a useful model for selection of genes important in bovine mastitis?. Microbiology (Reading), 146(4), 981-987.

Lange C, Cardoso M, Pianta C, 1997. Epidemiological characterization of Staphylococcus aureus isolated from bovine mastitis in Porto Alegre (Rio Grande do Sul, Brazil). Revista de Microbiologia, 28(3):215-219; 13 ref

Larsen, H. D., Sloth, K. H., Elsberg, C., Enevoldsen, C., Pedersen, L. H., Eriksen, N. H. R., Aarestrup, F. M., Jensen, N. E., 2000. The dynamics of Staphylococcus aureus intramammary infection in nine Danish dairy herds. Veterinary Microbiology, 71(1/2), 89-101. doi: 10.1016/S0378-1135(99)00161-3

Leitner, G., Shoshani, E., Krifucks, O., Chaffer, M., Saran, A., 2000. Milk leucocyte population patterns in bovine udder infection of different aetiology. Journal of Veterinary Medicine. Series B, 47(8), 581-589. doi: 10.1046/j.1439-0450.2000.00388.x

Longan KE et al, 1998. Immunological responses of Holstein Friesian cattle to S. aureus. In: British mastitis conference No. 93, 991-993

Mackie DP, Logan EF, Pollock DA, Rodgers SP, 1988. Antibiotic sensitivity of bovine staphylococcal and coliform mastitis isolates over four years. Veterinary Record, 123(20):515-517; 20 ref

Mahanta PN, Thungchamo K, Dutta GN, Devriese LA, 1997. Identification and characterization of staphylococci isolated from cutaneous lesions of goats. Journal of Veterinary Medicine. Series B, 44(5):309-311; 5 ref

Mahapatra S, Kar BC, Misra PR, 1996. Occurrence of mycotic mastitis in buffaloes of Orissa. Indian Veterinary Journal, 73(10):1021-1023; 8 ref

Majic B, Ljubic Z, Jovanovic-Bunta V, 1994. Prevalence, aetiology and diagnosis of subclinical mastitis in goats. Praxis Veterinaria (Zagreb), 42(3):225-233; 10 ref

Makaya PV, 1998. Use of biotyping, phage typing and ribotyping to study the epidemiology of Staphylococcus aureus mastitis in the Zimbabwean dairy farming sectors. Zimbabwe Veterinary Journal, 29(2):37-46; 24 ref

McCullagh JJ, McNamee PT, Smyth JA, Ball HJ, 1998. The use of pulsed field gel electrophoresis to investigate the epidemiology of Staphylococcus aureus infection in commercial broiler flocks. Veterinary Microbiology, 63(2/4):275-281; 12 ref

Mecha I, 1975. Traditional goat husbandry in Southern Nigeria. Nigerian Journal of Animal Production, 2:67-70

Merchant IA, Parker RA, 1967. The genus staphylococci. In: The Text book of Veterinary Bacteriology and Virology, edition 7, Iowa, USA: Iowa State University Press, 237-245

Mercier P, 1999. Mastitis: antibiotic treatment at drying off is effective. Chèvre, No. 234:26,28,30

Miltenburg JD, Lange Dde, Crauwels APP, Bongers JH, Tielen MJM, Schukken YH, Elbers ARW, 1996. Incidence of clinical mastitis in a random sample of dairy herds in the Southern Netherlands. Veterinary Record, 139(9):204-207; 35 ref

Mirt D, 1998. An investigation into the aetiology and morphogenesis of so called flank biting in pigs in an intensive type of breeding. Zbornik Veterinarske Fakultete Univerza Ljubljana, 35(1/2):71-78; 34 ref

Mishra PR, Sidhartha-Hazari, Pal-A, Hazaris, 1996. Sub-clinical mastitis in goats with special reference to fungus. Indian Journal of Dairy Science, 49(3):209-210

Moclerson SC, Owens WE, de Rouen SM, 2000. Mastitis prevalence in calf beef heifers and effect on calf weaning weight. Large Animal Practice, 21(3):20-23

Moller K, Agerholm JS, Ahrens P et al. , 2000. Abscess disease, caseous lymphadenitis, and pulmonary adenomatosis in imported sheep. Journal of Veterinary Medicine, Series B, 47(1):55-62

Mondadori AJ, Riet-Correa F, Carter GR, Mendez MC, 1994. Actinobacillosis in cattle in the state of Rio Grande do Sul, Brazil. Ciência Rural, 24(3):571-577; 19 ref

Morin DE, Constable PD, 1998. Characteristics of dairy cows during episodes of bacteriologically negative clinical mastitis or mastitis caused by Corynebacterium spp. Journal of the American Veterinary Medical Association, 213(6):855-861; 40 ref

Mousing J, Kyrval J, Jensen TK, Aalbæk B, ButtenschOn J, Svensmark B, Willeberg P, 1997. Meat safety consequences of implementing visual postmortem meat inspection procedures in Danish slaughter pigs. Veterinary Record, 140(18):472-477; 49 ref

Muhammad G, Lodhi LA, Athar M, Fazal-ur-Rehman, 1997. Evaluation of cephalexin in the treatment of clinical mastitis in buffalo. Indian Journal of Dairy Science, 50(3):205-208; 11 ref

Mulei M, 1991. Teat lesions and their relationship to intrammary infections on small scale dairy farms in Kiambu district in Kenya. Journal of South African Veterinary Medical Association, 70(4):156-157

Murray PR, Drew LW, Mosayashi G, Thompson JH, 1990. Staphylococcus. In: Medical Microbiology. Baltimore, USA: CV Mosby Company

Nakaya I, Hakogi E, Maruo Y, Ogura Y, Noma S, Nukina M, 1995. Identification of Staphylococcus aureus and group B streptococci from bovine mastitis cases by latex agglutination. Journal of the Japan Veterinary Medical Association, 48(1):13-17; 15 ref

Nickerson SC, Boddie RL, 1995. Efficacy of barrier-type postmilking teat germicides against intramammary infection. Journal of Dairy Science, 78(11):2496-2501; 13 ref

Nickerson SC, Owens WE, De-Rouen SM, 2000. Mastitis prevalence in first beef heifers and effect on calf weaning weight. Large Animal Medicine, 21(3):20-23

Nissen JR, 1999. Homeopathic treatment of production animals. Two cases from practice. Dansk Veterinærtidsskrift, 82(17):759, 762

Nordhaug ML, Nesse LL, Norcross NL, Gudding R, 1994. A field trial with an experimental vaccine against Staphylococcus aureus mastitis in cattle. 1. Clinical parameters. Journal of Dairy Science, 77(5):1267-1275; 35 ref

Nordhaug ML, Nesse LL, Norcross NL, Gudding R, 1994. A field trial with an experimental vaccine against Staphylococcus aureus mastitis in cattle. 2. Antibody response. Journal of Dairy Science, 77(5):1276-1284; 30 ref

Oboegbulem SI, Fidelis AP, 1996. Detection of antimicrobial residues in poultry meat and slaughter cattle in Nigeria. Meat Science, 43(1):71-74; 7 ref

Oliveira SSde, Póvoa DC, Nascimento JSdos, Pereira MSVdo, Siqueira JPJrde, Bastos MCFde, 1998. Antimicrobial substances produced by Staphylococcus aureus strains isolated from cattle in Brazil. Letters in Applied Microbiology, 27(4):229-234; 12 ref

Oliver SP, Lewis MJ, Gillespie BE, Ivey SJ, Coleman LH, Almeida RA, Fang W, Lamar K, 1999. Evaluation of a postmilking teat disinfectant containing a phenolic combination for the prevention of mastitis in lactating dairy cows. Journal of Food Protection, 62(11):1354-1357; 11 ref

Omore AO, McDermott JJ, Arimi SM, Kyule MN, Ouma D, 1996. A longitudinal study of milk somatic cell counts and bacterial culture from cows on smallholder dairy farms in Kiambu District, Kenya. Preventive Veterinary Medicine, 29(1):77-89; 43 ref

OsterÅs O, ROnningen O, Sandvik L, Waage S, 1995. Field studies show associations between pulsator characteristics and udder health. Journal of Dairy Research, 62(1):1-13; 24 ref

Owens WE, Ray CH, Watts JL, Yancey RJ, 1997. Comparison of success of antibiotic therapy during lactation and results of antimicrobial susceptibility tests for bovine mastitis. Journal of Dairy Science, 80(2):313-317; 12 ref

Pankey JW, Pankey PB, 1994. Mastitis in New Zealand heifers. Proceedings 46th Ruakura Farmers' Conference, incorporating Ruakura Dairy Conference & Whatawhata Sheep & Beef Day, held at Ruakura & Whatawhata, New Zealand, 15 June 1994., 49-53; 13 ref

Papadopoulou C, Dimitriou D, Levidiotou S, Gessouli H, Panagiou A, Golegou S, Antoniades G, 1997. Bacterial strains isolated from eggs and their resistance to currently used antibiotics: is there a health hazard for consumers?. Comparative Immunology, Microbiology and Infectious Diseases, 20(1):35-40; 21 ref

Park HeeMyung, Oh TaeHo, Han HongRyul, 1999. Production and partial purification of Staphylococcus aureus alpha toxin. Korean Journal of Veterinary Research, 39(5):1028-1032; 14 ref

Pengov A, 1997. Differences in the inflammatory response of the mammary gland of cows and ewes infected with coagulase-negative staphylococci. Zbornik Veterinarske Fakultete Univerza Ljubljana, 34(2):157-162; 20 ref

Pereira MSV, Siquiera-Júnior JP, 1995. Antimicrobial drug resistance in Staphylococcus aureus isolated from cattle in Brazil. Letters in Applied Microbiology, 20(6):391-395; 39 ref

Petrovic M, Milunov B, Ignjatovic R, Georgijevski G, 1997. Incidence of mammary gland infections and subclinical mastitis of cows in southern Serbia. Veterinarski Glasnik, 51(9/10):503-508; 10 ref

Poornima M, Upadhye AS, 1995. Bacterial flora of respiratory tract of poultry in health and disease. Mysore Journal of Agricultural Sciences, 29(1):68-72; 1 ref

Pozza MCD, Ricci A, Vicenzoni G, 1999. Protein A gene polymorphism analysis in Staphylococcus aureus strains isolated from bovine subclinical mastitis. Journal of Dairy Research, 66(3):449-453; 14 ref

Prem Singh, Jit Singh, Sukhbir Singh, Kharole, M. U., 1998. Evaluation of povidone-iodine and Lugol's iodine for treatment of bacterial osteomyelitis in cattle. Indian Journal of Veterinary Surgery, 19(1), 25-26.

Pyrah ITG, Scott PR, Penny CD, 1994. Possible involvement of Staphylococcus aureus as a primary pathogen in lamb septicaemia. Veterinary Record, 134(26):679-680; 7 ref

Pyörälä S, Pyörälä E, 1994. Efficacy of systemic therapy in bovine clinical mastitis during lactation. Proceedings 18th World Buiatrics Congress: 26th Congress of the Italian Association of Buiatrics, Bologna, Italy, August 29-September 2, 1994. Volume 1., 571-574; 5 ref

Pyörälä S, Pyörälä E, 1997. Accuracy of methods using somatic cell count and N-acetyl--D-glucosaminidase activity in milk to assess the bacteriological cure of bovine clinical mastitis. Journal of Dairy Science, 80(11):2820-2825; 21 ref

Quinones J, Demo M, 1997. Coagulase-negative Staphylococcus isolated from bovine mammary glands: cytolysin production, synergistic haemolysin and slime production. Veterinaria Argentina, 14(132):95-100; 12 ref

Raimundo O, Deighton M, Capstick J, Gerraty N, 1999. Molecular typing of Staphylococcus aureus of bovine origin by polymorphisms of the coagulase gene. Veterinary Microbiology, 66(4):275-284; 19 ref

Ramaswamy V, Saravanabava K, Latha N, Nachimuthu K, Manickam M, 1997. Staphylococcus and Klebsiella infection in layer chickens. Indian Journal of Poultry Science, 32(3):308-310; 6 ref

Ramtamaki LK, Muller H, 1995. The purification of goat immunoglobulin IgG1 and IgG2 antibodies by use of Streptococcus dysagalactiae cells with FC receptors. Veterinary Immunology and Immuno-Pathology, 45(1-2):115-126

Rao MS, Kumar AA, Sreemannarayana O, 1996. Sub-clinical mastitis in sheep. Indian Veterinary Journal, 73(11):1189-1190; 6 ref

Rapoport E, Kanterowitz B, Sheinmann R, 1994. Lethal effect of TSST-1 producing Staphylococcus aureus in young lambs. Israel Journal of Veterinary Medicine, 49(3):127-128; 8 ref

Refsdal AO, 1996. What is mastitis?. Buskap og AvdrÅtt, 48(2):6-7

Repetti E, Santos RVdos, Guárdia N, Polegato EPdos S, Pacchini CE, Oliveira AAde, 1998. Antibiogram and aetiological agents isolated from milk samples from cattle with mastitis. UNIMAR Ciências, 7(1):121-130; 9 ref

Ridgway TD, Wettemann RP, Lents CA, Spicer LJ, Paape MJ, 1999. Influence of mastitis, weaning and intramammary antibiotic treatment on somatic cells and tumor necrosis factor- in milk of beef cows. Animal Science Research Report - Agricultural Experiment Station, Oklahoma State University, No. P-973:296-300; 2 ref

Riolett C Rainard P, Poultrel B, 2000. Differential induction of complement fragment C5a and inflammatory cytokines during inflammatory infections with Escherichia coli and S. aureus. Clinical and Diagnostic Laboratory Imminology, 7(2):161-167

Rivas, A. L., Quimby, F. W., Coksaygan, O., Olmstead, L., Lein, D. H., 2000. Longitudinal evaluation of CD4+ and CD8+ peripheral blood and mammary gland lymphocytes in cows experimentally inoculated with Staphylococcus aureus. Canadian Journal of Veterinary Research, 64(4), 232-237.

Roberson JR, 1995. Epidemiology of Staphylococcus aureus intramammary infections in prepartum dairy heifers [in the USA]. Proceedings of the Third IDF International Mastitis Seminar Tel-Aviv, Israel, 28 May - 1 June 1995. Book 2., s-6,13-17; 10 ref

Rojano Flores U, Hernández Andrade L, Pérez Domínguez M, 1994. One year survey of pathogens isolated from the milk of cows with high somatic cell counts and their sensitivity to antibiotics. Técnica Pecuaria en México, 32(1):47-54; 28 ref

Sá, M. E. P. de, Mota, R. A., Souza, M. I. de, Oliveira, A. A. da F., 2000. Etiological mastitis subclinical in dairy cattle on meridional agreste of Pernambuco State - Brazil. (Etiologia da mastite subclínica em bovinos leiteiros do agreste meridional do Estado de Pernambuco). Revista Brasileira de Ciência Veterinária, 7(2), 100-103.

Sabreen MS, Abdel-Haleen AA, 2000. Microbiological evaluation of sheep and goats milk in Assuit Governorate. Assuit Veterinary Medical Journal, 42(84):36-46

Saini SS, Sharma JK, Kwatra MS, 1994. Prevalence and etiology of subclinical mastitis among crossbred cows and buffaloes in Punjab. Indian Journal of Dairy Science, 47(2):103-106; 14 ref

Salmon SA, Watts JL, Aarestrup FM, Pankey JW, Yancey RJJr, 1998. Minimum inhibitory concentrations for selected antimicrobial agents against organisms isolated from the mammary glands of dairy heifers in New Zealand and Denmark. Journal of Dairy Science, 81(2):570-578; 25 ref

Sanchez MS, Ford CW, Yancey RJJr, 1994. Effect of tumor necrosis factor-, interleukin-1, and antibiotics on the killing of intracellular Staphylococcus aureus. Journal of Dairy Science, 77(5):1251-1258; [28 ref]

Sandgren CH, Ekman T, 1996. Policy on antibiotics in the treatment of mastitis in cows. 4. Measures against subclinical mastitis. Svensk Veterinärtidning, 48(2):53-58; 14 ref

Saratsis P, Leontides L, Tzora A, Alexopoulos C, Fthenakis GC, 1998. Incidence risk and aetiology of mammary abnormalities in dry ewes in 10 flocks in Southern Greece. Preventive Veterinary Medicine, 37(1/4):173-183; 33 ref

Sargeant, J. M., Scott, H. M., Leslie, K. E., Ireland, M. J., Bashiri, A., 1998. Clinical mastitis in dairy cattle in Ontario: frequency of occurrence and bacteriological isolates. Canadian Veterinary Journal, 39(1), 33-38.

Sayed AM, 1997. Some bacteriological and mycological studies on sheep pneumonia at Assiut Governorate. Assiut Veterinary Medical Journal, 36(71):68-73; 12 ref

Schlegelová J, Sedivá I, 1999. Resistance to antimicrobial drugs of Staphylococcus aureus strains isolated from milk. Veterinárství, 49(11):470-472; 22 ref

Schofield LN, DiNinno VL, Bhatti AR, 1997. A Staphylococcus aureus enterotoxin-B induced type 1 immediate hypersensitivity reaction in a goat. Microbios, 89(358):29-30; 4 ref

Scott PR, Murphy S, 1997. Outbreak of staphylococcal dermatitis in housed lactating Suffolk ewes. Veterinary Record, 140(24):631-632; 1 ref

Sears PM, 1999. Management alternatives in mastitis control and eradication programs. Proceedings of the Thirty-Second Annual Conference American Association of Bovine Practitioners, Nashville, Tennessee, USA, 23-26 September, 1999., 29-32; 12 ref

Sharma LK, 1994. Abscess disease in goats. Indian Veterinary Journal, 71(5):520; 3 ref

Shekimweri MT, Kurwijila LR, Mgongo FOK, 1998. Incidence, causative agents and strategy of control of mastitis among smallholder dairy herds in Morogoro, Tanzania. Tanzania Journal of Agricultural Sciences, 1(1):28-36; 26 ref

Shibahara T, Nakamura K, 1999. Pathology of acute necrotizing mastitis caused by Staphylococcus aureus in a dairy cow. JARQ, Japan Agricultural Research Quarterly, 33(2):139-142; 8 ref

Shoshani E, Leitner G, Saran A, Spiegel NY, Trainin Z, Berman A, 1995. Changes in mammary function induced by Staph. aureus from inoculation to chronic infection state. Proceedings of the Third IDF International Mastitis Seminar Tel-Aviv, Israel, 28 May - 1 June 1995. Book 1., s-1,65-66

Shoukry S, Shabana MS, 1997. Prevalence of bovine subclinical mastitis in dairy cows and buffaloes in some villages in Ismailia Governorate. Egyptian Journal of Agricultural Research, 75(3):799-809; 26 ref

Shwimmer A, Shpigel NY, Yeruham I, Saran A, 1995. Epidemiological and bacteriological aspects of mastitis associated with yellow jacket wasp teat lesions in Israeli dairy cows. Proceedings of the Third IDF International Mastitis Seminar Tel-Aviv, Israel, 28 May - 1 June 1995. Book 2., s-6,100-102; 5 ref

Simko S, Bartko P, 1996. Antibiotic resistance in Staphylococcus aureus from cases of ovine mastitis, ewe milk and ewe milk products. Veterinární Medicína, 41(8):241-244; 22 ref

Simpson RB, Wesen DP, Anderson KL, Armstrong JD, Harvey RW, 1995. Subclinical mastitis and milk production in primiparous Simmental cows. Journal of Animal Science, 73(6):1552-1558; 28 ref

Smith M, Roquinsky MC, 1977. Mastitis and other diseases of goats udder. Journal of American Veterinary Medical Association, 17:1241-1248

Smith TH, Fox LK, Middleton JR, 1998. Outbreak of mastitis caused by one strain of Staphylococcus aureus in a closed dairy herd. Journal of the American Veterinary Medical Association, 212(4):553-556; 15 ref

Sordelli, D. O., Buzzola, F. R., Gómez, M. I., Steele-Moore, L., Berg, D., Gentilini, E., Catalano, M., Reitz, A. J., Tollersrud, T., Denamiel, G., Jeric, P., Lee, J. C., 2000. Capsule expression by bovine isolates of Staphylococcus aureus from Argentina: genetic and epidemiologic analyses. Journal of Clinical Microbiology, 38(2), 846-850.

Su C, Herbelin C, Frieze N, Skardova O, Sordillo LM, 1999. Coagulase gene polymorphism of Staphylococcus aureus isolates from dairy cattle in different geographical areas. Epidemiology and Infection, 122(2):329-336; 32 ref

Sutra L, Poutrel B, 1994. Virulence factors involved in the pathogenesis of bovine intramammary infections due to Staphylococcus aureus. Journal of Medical Microbiology, 40(2):79-89; 142 ref

Swamy MCM, Krishnamurthy GV, 1998. Prevalence of Staphylococcus species in California mastitis test positive cows. Indian Veterinary Journal, 75(2):101-103; 12 ref

Swiderek WP, 1996. A trial at evaluating biological and environmental factors on the health state of the udders in sheep. Annals of Warsaw Agricultural University, Animal Science, No. 32:55-64; 31 ref

Takele G, Zerihun A, 2000. Epidemiology of infectious keratoconjunctivities in cattle in South east Ethiopia. Journal of Veterinary Medicine Series A, 47(3):169-173

Takeuchi S, Ishiguro K, Ikegami M, Kaidoh T, Hayakawa Y, 1996. Detection of toxic shock syndrome toxin-1 gene in Staphylococcus aureus bovine isolates and bulk milk by the polymerase chain reaction. Journal of Veterinary Medical Science, 58(11):1133-1135; 16 ref

Takeuchi, S., Ishiguro, K., Ikegami, M., Kaidoh, T., Hayakawa, Y., 1998. Production of toxic shock syndrome toxin by Staphylococcus aureus isolated from mastitic cow's milk and farm bulk milk. Veterinary Microbiology, 59(4), 251-258. doi: 10.1016/S0378-1135(96)01253-9

Tanabe T, Sato H, Ueda K, Chihara H, Watanabe T, Nakano K, Saito H, Maehara N, 1995. Possible receptor for exfoliative toxins produced by Staphylococcus hyicus and Staphylococcus aureus. Infection and Immunity, 63(4):1591-1594; 11 ref

Taponen S, Laitala T, 1996. The effect of washing methods on the hygiene of towels used in premilking udder preparation. Suomen Eläinlääkärilehti, 102(1):17-20; 9 ref

Teper G, Ziv G, Skutelsky E, 1995. Cytochemical ultrastructural visualization of capsular constituents of Staphylococcus aureus isolated from bovine mastitis. Proceedings of the Third IDF International Mastitis Seminar Tel-Aviv, Israel, 28 May - 1 June 1995. Book 1., as-2,11-15; 10 ref

Tichácek A, 1999. Discrepancies between the legislation and veterinary executive concerning milk production at farm level. Vyzkum v Chovu Skotu, 41(1):11-17

Tisala TA, Forsman P, Alatossava T, 2000. Bovine mastitis diagnosis from milk by a polymerase chain reaction based method. Milchewissensch aft, 55(9):488-492

Tollersrud T, Kenny K, Reitz AJ, Lee JC, 2000. Genetic and serologic evaluation of capsule production by bovine mammary isolate of S. aureus and other staphylococci species from Europe and United States. Journal of Clinical Microbiology, 38:2998-3003

Tomita GM, Todhunter DA, Hogan JS, Smith KL, 1995. Antigenic crossreactivity and lipopolysaccharide neutralization properties of bovine immunoglobulin G. Journal of Dairy Science, 78(12):2745-2752; 25 ref

Topolko S, Benic M, 1997. Problems and epidemiology of subclinical mastitis in small-farm milk production. Praxis Veterinaria (Zagreb), 45(1/2):69-76; 9 ref

Trolldenier H, 1996. Development of resistance to bacterial pathogens among farm animals in Germany (1990-1994) - an overview. Deutsche Tierärztliche Wochenschrift, 103(7):256-260; 9 ref

Twardon, J., Mordak, R., Dejneka, G., Dobrzynska, Z., Dzieciol, M., 1999. Efficacy of Cloxa-coli (Virbac) formulation in the treatment of subclinical and chronic mastitis in lactating dairy cows. (Skutecznóc preparatu Cloxa-coli (Virbac) w leczeniu podlinicznych i przewleklych zapalen wymienia krów w okresie laktacji). Zycie Weterynaryjne, 74(8), 402-403.

Tyagunenko, Y., Sotirova, P., Rachkova, K., Urumova, V., Dukova, I., Lazarova, G., Rukanova, D., Djeneva, H., 1999. Study on the drug resistance of Staphylococcus aureus, isolated from humans and animals. I. Comparative analysis of the antibiotic resistance of Staphylococcus aureus isolates from hospital patients and animals. Bulgarian Journal of Veterinary Medicine, 2(4), 143-151.

Umakanthan T, 1997. Treatment of peracute mastitis in cows. Indian Veterinary Journal, 74(8):698-699; 1 ref

Unger A, Babella G, 1997. Examination of Staphylococcus aureus counts and the significance of microbial flora in raw milk in Hungary from a technological point of view. Tejgazdaság, No. Special:109-114

Vasil' M, 1994. Occurrence of antibiotic resistance in bacteria causing bovine mastitis. Veterinární Medicína, 39(9):503-509; 27 ref

Vicenzoni, G., Piccinini, R., Madinelli, R., Bertocchi, L., Zecconi, A., Ruffo, G., 1994. Epidemiological aspects of Staphylococcus aureus mastitis in dairy herds in Padana valley, Italy. (Aspetti epidemiologici delle mastiti da Staphylococcus aureus in alcuni allevamenti della Pianura Padana). In: Proceedings 18th World Buiatrics Congress: 26th Congress of the Italian Association of Buiatrics, Bologna, Italy, August 29-September 2, 1994. Volume 2 [Proceedings 18th World Buiatrics Congress: 26th Congress of the Italian Association of Buiatrics, Bologna, Italy, August 29-September 2, 1994. Volume 2], [ed. by Trenti, F.]. Bologna, Italy: Società Italiana di Buiatria. 1487-1490.

Virtala AM, Nevalainen M, 2000. Questionnaire survey concerning the experience of veterinarians about the efficacy and safety of the autogenous inactivated staphylococcal toxoid vaccine used against mastitis in cattle in Finland. Suomen Eläinlääkärilehti, 106(9):528-534; 18 ref

Vural R, Esendal O, Izgur H, Aslan S, Kilicoglu C, 1999. Sub-clinical mastitis in premiparous Holsterin cows part II: Intra mammary infections during first lactation veteriner-Fakultesi-Dergisi, Ankara Universitesi, 46(2/3):287-298

Waage, S., Mørk, T., Røros, A., Aasland, D., Hunshamar, A., Ødegaard, S. A., 1999. Bacteria associated with clinical mastitis in dairy heifers. Journal of Dairy Science, 82(4), 712-719. doi: 10.3168/jds.S0022-0302(99)75288-4

Waller KP, Colditz IG, 1999. The effect of experimental infectious mastitis on leukocyte subpopulations and cytokine production in non-lactating ewes. Journal of Veterinary Medicine. Series B, 46(5):289-299; 19 ref

Watts JL, Salmon SA, 1997. Activity of selected antimicrobial agents against strains of Staphylococcus aureus isolated from bovine intramammary infections that produce -lactamase. Journal of Dairy Science, 80(4):788-791; 12 ref

Webster KA, Mitchel GBB, 1986. Experimental tick Pyemia in lambs. Veterinary Record, 119:186

White EC, Hinckley LS, 1999. Prevalence of mastitis pathogens in goat milk. Small Ruminant Research, 33(2):117-121; 24 ref

Williamson G, Pyne WJA, 1978. An Introduction to Animal Husbandry in the Tropics, edition 3, ELBS London

Wilson DJ, González RN, Das HH, 1997. Bovine mastitis pathogens in New York and Pennsylvania: prevalence and effects on somatic cell count and milk production. Journal of Dairy Science, 80(10):2592-2598; 27 ref

Xun XinLian, Hu Wei, Zhang XinMei, 1995. Diagnosis and control of mastitis caused by Candida albicans. Chinese Journal of Veterinary Medicine, 21(10):13-14

Yanni AA, 1999. Aerobic and anaerobic bacterial causes of lung infections in buffalo calves. Veterinary Medical Journal Giza, 47(2):231-238; 28 ref

Yeruham I, Perl S, Elad D, Avidar Y, 1999. A generalized staphylococcal scalded skin-like disease in lambs. Journal of Veterinary Medicine. Series B, 46(9):635-640; 27 ref

Yoo JongHyun, Park HeeMyung, Oh TaeHo, Sohn DaeHo, Han HongRyul, 1999. Distribution and characteristics of Staphylococcus aureus subtypes isolated from dairy herds. Korean Journal of Veterinary Research, 39(5):995-1005; 42 ref

Yoshida M, Kashiwagi Y, Okuda M, Tsumagari S. Takeishi M, 1997. Drug sensitivity of S. aureus isolates from cases of bovine mastitis. Journal of Veterinary Medicine, 50:826-828

Zadoks, R., Leeuwen, W. van, Barkema, H., Sampimon, O., Verbrugh, H., Schukken, Y. H., Belkum, A. van, 2000. Application of pulsed-field gel electrophoresis and binary typing as tools in veterinary clinical microbiology and molecular epidemiologic analysis of bovine and human Staphylococcus aureus isolates. Journal of Clinical Microbiology, 38(5), 1931-1939.

Zecconi A, Piccinini R, 1999. Theory and practice of control of Staphylococcus aureus mastitis. Scienza e Tecnica Lattiero-Casearia, 50(6):445-454; 13 ref

Zurzul D, 1994. Results of the long-term control of mastitis in intensively kept cows. Veterinarski Glasnik, 48(3/4):267-270; 8 ref

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