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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Tritrichomonas foetus
Other Scientific Names
- Trichomonas foetus
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Protista
- Phylum: Protozoa
- Subphylum: Sarcomastigophora
- Order: Trichomonadida
- Family: Trichomonadidae
- Genus: Tritrichomonas
- Species: Tritrichomonas foetus
Distribution TableTop of page
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.Last updated: 06 Jan 2022
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Cabo Verde||Absent, No presence record(s)||Jul-Dec-2019|
|Central African Republic||Absent||Jul-Dec-2019|
|Congo, Democratic Republic of the||Absent||Jul-Dec-2019|
|Côte d'Ivoire||Absent, No presence record(s)|
|Guinea||Absent, No presence record(s)||Jan-Jun-2019|
|Madagascar||Absent, No presence record(s)|
|Mayotte||Absent, No presence record(s)||Jul-Dec-2019|
|Saint Helena||Absent, No presence record(s)||Jan-Jun-2019|
|São Tomé and Príncipe||Absent, No presence record(s)||Jan-Jun-2019|
|Seychelles||Absent, No presence record(s)||Jul-Dec-2018|
|Togo||Absent, No presence record(s)|
|Tunisia||Absent, No presence record(s)||Jul-Dec-2019|
|Bahrain||Absent, No presence record(s)||Jul-Dec-2020|
|Brunei||Absent, No presence record(s)||Jul-Dec-2019|
|Iraq||Absent, No presence record(s)||Jul-Dec-2019|
|Kyrgyzstan||Absent, No presence record(s)||Jan-Jun-2019|
|-Peninsular Malaysia||Absent, No presence record(s)|
|-Sabah||Absent, No presence record(s)|
|Maldives||Absent, No presence record(s)||Jan-Jun-2019|
|North Korea||Absent, No presence record(s)|
|Philippines||Absent, No presence record(s)|
|Singapore||Absent, No presence record(s)||Jul-Dec-2019|
|Sri Lanka||Absent, No presence record(s)||Jul-Dec-2018|
|United Arab Emirates||Absent||Jul-Dec-2020|
|Bosnia and Herzegovina||Absent||Jul-Dec-2019|
|Faroe Islands||Absent, No presence record(s)||Jul-Dec-2018|
|Iceland||Absent, No presence record(s)||Jul-Dec-2019|
|Ireland||Absent, No presence record(s)|
|Isle of Man||Absent, No presence record(s)|
|Jersey||Absent, No presence record(s)|
|Latvia||Absent, No presence record(s)||Jul-Dec-2020|
|Malta||Absent, No presence record(s)||Jan-Jun-2019|
|Netherlands||Present||Jul-Dec-2019; in wild animals only; suspected in domestic animals|
|San Marino||Absent, No presence record(s)||Jan-Jun-2019|
|Serbia and Montenegro||Absent, No presence record(s)|
|Slovenia||Absent, No presence record(s)||Jul-Dec-2018|
|Sweden||Absent, No presence record(s)||Jul-Dec-2020|
|Ukraine||Absent, No presence record(s)||Jul-Dec-2020|
|United Kingdom||Present||Jul-Dec-2019; in wild animals only|
|Bahamas||Absent, No presence record(s)||Jul-Dec-2018|
|Barbados||Absent, No presence record(s)||Jul-Dec-2020|
|Bermuda||Absent, No presence record(s)|
|British Virgin Islands||Absent, No presence record(s)|
|Curaçao||Absent, No presence record(s)||Jan-Jun-2019|
|Dominica||Absent, No presence record(s)|
|Greenland||Absent, No presence record(s)||Jul-Dec-2018|
|Haiti||Absent, No presence record(s)|
|Jamaica||Absent, No presence record(s)||Jul-Dec-2018|
|Saint Kitts and Nevis||Absent, No presence record(s)|
|Saint Lucia||Absent, No presence record(s)||Jul-Dec-2018|
|Saint Vincent and the Grenadines||Absent, No presence record(s)||Jan-Jun-2019|
|Trinidad and Tobago||Absent, No presence record(s)||Jan-Jun-2018|
|Cook Islands||Absent, No presence record(s)||Jan-Jun-2019|
|Federated States of Micronesia||Absent, No presence record(s)||Jan-Jun-2019|
|Fiji||Absent, No presence record(s)||Jan-Jun-2019|
|Kiribati||Absent, No presence record(s)||Jan-Jun-2018|
|Marshall Islands||Absent, No presence record(s)||Jan-Jun-2019|
|Palau||Absent, No presence record(s)||Jul-Dec-2020|
|Samoa||Absent, No presence record(s)||Jan-Jun-2019|
|Vanuatu||Absent, No presence record(s)||Jan-Jun-2019|
|Colombia||Present||Jul-Dec-2019; in wild animals only|
|Falkland Islands||Absent, No presence record(s)||Jul-Dec-2019|
|Guyana||Absent, No presence record(s)|
|Suriname||Absent, No presence record(s)||Jan-Jun-2019|
Pathogen CharacteristicsTop of page
Tritrichomonas foetus is typically 9-18 µm long x 5-10 µm wide, and somewhat spindle-shaped, although it can be quite pleomorphic. For comparison, the head of a Bos taurus sperm is approximately 9 x 5 µm. Organisms tend to become spheroid after lengthy in vitro culture. Three flagellae, about equal in length to the body of the organism, project from a periflagellar canal at the so-called anterior end of the protozoan. A recurrent flagellum reflects backward and is attached along one side as the ‘undulating membrane’ before continuing separately as the posterior flagellum. This wavy membrane is attached for nearly the entire length of the body of the parasite. An axostyle runs antero-posteriorly through the core of the organism, and its rapidly tapering form can be seen projecting posteriorly from the midline for a distance of about a fifth of a body length (Honigberg, 1978). The live organism exhibits an unusual motility, characterized as ‘aimless rolling’ or ‘jerky’ by various authors (See website listing for video of motility, morphology.)
Essentially all of these descriptors apply to T. suis as well. Infectivity experiments in the 1950s showed that the swine organism could establish infection in the bovine uterus and reproduce lesions consistent with bovine trichomonosis following inoculation at either estrus or diestrus (Fitzgerald et al., 1958; Kerr, 1958). Reciprocal infections (reproductive tract infection of swine by instillation of T. foetus from cattle) were less able to establish infection. Moreover, in recent experiments, intravaginal deposition in cattle of T. suis isolates have generally not reproduced trichomonosis (Cobo et al., 2001). However, the failure to establish infection may have occurred because the experimental inocula were from culture-adapted organisms, and not field strains.
Tissue location and life cycle
The organism is not notably invasive, dwelling for the most part in the lumen of the female tract, from the oviducts to the vagina, or in the crypts on the surface epithelium of the penis and prepuce. Rarely, organisms are found in sub-surface areas of the fetal membranes, or beneath the basement membrane of the gut or lung of an aborted fetus (Rhyan et al., 1988; Rhyan et al., 1995). It is likely that these organisms arrived in such locations in the superficial mucosal of the gut or lung as a result of fetal swallowing or inhalation of amniotic fluid, rather than by direct invasion of multiple fetal tissue layers.
As far as is known, Tritrichomonas foetus has a single life cycle stage, reproducing by simple mitosis of the trophozoite. A ‘pseudo cyst’ has been described, but whether it represents a dormant organism capable of prolonged survival in a hostile environment is not known (Mariante et al., 2004). The epidemiological relevance of a cyst stage, if present, is not known, but it may represent the means by which the rare, chronic ‘carrier cow’ remains infected throughout pregnancy.
Surface molecules and serotypes
The surface of T. foetus is widely coated with a lipophosphoglycan (LPG) moiety (Shaia et al., 1998). Part or all of the components of this surface molecule are shed into the environment as soluble antigen (SGA) (Singh et al., 2001). The purpose of this shedding is not known, but, using immunohistochemical methods, the antigen can be observed on the surface of and within host uterine cells or penile epithelial cells following infection (Corbeil et al., 2003). Other surface antigens are immunodominant, giving rise to at least three recognized serotypes, namely brisbane, belfast, and manley. The significance of differentiating these serotypes is unknown, as all of them have a spectrum of pathogenicity amongst their many strains (Rocha-Azevedo and Melo-Braga, 2005), and immunization against one serotype cross-protects against another (Florent, 1957). Furthermore, an isolate has been shown to change serotypes during the course of infection (Wosu, 1977).
As a primitive eukaryote, T. foetus does not have mitochondria. Instead, its energy-generating system is contained in numerous membrane-bound, electron-dense packets known as hydrogenosomes, which are round to ovoid organelles that contain ferredoxin as a major iron-binding molecule. Hydrogenosomes function much like mitochondria, providing energy in the form of ATP from oxidation of carbohydrate substrates via a complex electron transport system (Müller, 1980; Müller, 1988; Dinbergs and Lindmark, 1989; Lindmark et al., 1989; Lindmark and Meuller, 1973; Lloyd et al., 1979). Whether hydrogenosomes, like mitochondria, contain their own circular DNA is a subject of some controversy (Cerkasovova et al., 1976; Turner and Muller, 1983).
T. foetus is probably dependent on host lipids, since it neither synthesizes cholesterol from a variety of potential precursors nor ß-oxidizes fatty acids (Beach et al., 1991).
T. foetus is a facultative anaerobe, able to fermentatively degrade a variety of carbohydrate sources, including endogenous glycogen, or exogenous glucose, pyruvate and malate. End products include acetate, succinate, glycerol, carbon dioxide and, under anaerobic conditions, molecular hydrogen. The parasite has rather limited biosynthetic capability, and must acquire many macromolecules from the host environment. For example, it must salvage purines and pyrimidines, because of an inability to synthesize them de novo (Jarroll et al., 1983). Novel, perhaps unique enzymatic pathways are critical elements of purine and pyrimidine salvage. T. foetus has robust endonucleases that presumably help it in this salvage function. Similarly, the parasite produces a battery of powerful proteases, including low molecular-weight cysteine proteinases. Some of these are released into the parasite’s immediate environment, presumably to hydrolyze large proteins into peptides for its use (Mallinson et al., 1995; North, 1994; Thomford et al., 1996). Some of the proteinases have a cosmopolitan substrate preference, including host immunoglobulin, which T. foetus can bind non-specifically and degrade (Granger and Warwood, 1996; Talbot et al., 1991). Likewise, the serum complement component, C3, can be degraded by T. foetus extracellular proteinases (Kania et al., 2001). In vitro studies have suggested that at least some of the cytotoxic properties of T. foetus are a result of the action of proteinases on target cells; thus, they can be considered virulence factors. Among important protein substrates in bovine female reproductive tract secretions, fibrinogen, fibronectin, and albumin are rapidly degraded by the extracellular proteinases of T. foetus, while lactoferrin, IgG1, and IgG2 were more slowly digested. Transferrin, IgM and IgA were most resistant. Additionally, the parasite releases significant amounts of hydrolases into the environment, including beta-N-acetylglucosaminidase, alpha-mannosidase, beta-glucosidase, and acid phosphatase (Lockwood et al., 1988).
In vitro culture
T. foetus is readily cultivated axenically in partially defined media, including cysteine-peptone-liver infusion-maltose (CPLM) medium, Clausen’s medium, Diamond’s TYM medium, and modified Plastridge medium (Diamond, 1983). Additionally, a commercial culture kit is available which contains growth/transport medium in a transparent pouch (InPouch TF, Biomed Diagnostics, White City, Oregon, USA). In addition, long-term maintenance of T. foetus and some non-pathogenic trichomonads can be achieved in Schneider’s egg shell medium (Schneider, 1942).
Non-T. foetus trichomonads of faecal origin may occasionally appear in samples of preputial secretions (smegma) submitted for diagnostic culture. These include various tetratrichomonad species (4 anterior flagellae) and Pentatrichomonashominis (5 anterior flagellae). While differentiation of these genera may be relatively straightforward with sophisticated microscopy, it can be challenging for clinicians who examine live specimens at the bright-field microscope level, often without benefit of phase contrast optics.
Disease(s) associated with this pathogen is/are on the list of diseases notifiable to the World Organisation for Animal Health (OIE). The distribution section contains data from OIE's Handistatus database on disease occurrence. Please see the AHPC library for further information from OIE, including the International Animal Health Code and the Manual of Standards for Diagnostic Tests and Vaccines. Also see the website: www.oie.int.
Host AnimalsTop of page
ReferencesTop of page
Cerkasovova A; Cerkasov J; Kulda J; Reischig J, 1976. Circular DNA and cardiolipin in hydrogenosomes, microbody-like organelles of trichomonads. Folia Parasitol (Praha), 23(1):33-37.
Corbeil LB; Campero CM; Rhyan JC; BonDurant RH, 2003. Vaccines against sexually transmitted diseases. Reprod Biol Endocrinol, 1(1):118.
Dinbergs ID; Lindmark DG, 1989. Hydrogenosomal ATP:AMP phosphotransferase (adenylate kinase) of Tritrichomonas fetus. Biochemistry and molecular biology of 'anaerobic' protozoa., 172-185; [Proceedings of the Symposium on 'Anaerobic Protozoa' held at Cardiff, UK, July 23-24, 1988.]; 17 ref.
Fitzgerald PR; Johnson AE; Thorne JL; Hammond DM, 1958. Experimental infections of the bovine genital system with trichomonads from the digestive tracts of swine. Am J Vet Res, 19(73):775-779.
Florent A, 1957. Immunologic dans la trichomonase bovine. Les infestation a Trichomonas; Paris: Masson. Int. Symp. Europ, Reims, May, 1957; p. 313.
Honigberg BM, 1978. Trichomonads of veterinary importance. In: Kreier J, ed. San Diego, USA: Academic Press, Inc., 207-273.
Kania SA; Reed SL; Thomford JW; BonDurant RH; Hirata K; Corbeil RR; North MJ; Corbeil LB, 2001. Degradation of bovine complement C3 by trichomonad extracellular proteinase. Veterinary Immunology and Immunopathology, 78(1):83-96; 53 ref.
Kerr WR, 1958. Experiments in cattle with Trichomonas suis. Vet Rec 70:613-5.
Lindmark DG; Eckenrode BL; Halberg LA; Dinbergs ID, 1989. Carbohydrate, energy and hydrogenosomal metabolism of Tritrichomonas foetus and Trichomonas vaginalis.. Journal of Protozoology, 36(2):214-216; 27 ref.
Lindmark DG; Meuller M, 1973. Hydrogenosome, a cytoplasmic organelle of the anaerobic flagellate Tritrichomonas foetus, and its role in pyruvate metabolism. Journal of Biological Chemistry, 248(22):7724-8.
Lloyd D; Lindmark DG; Meuller M, 1979. Adenosine triphosphatase activity of Tritrichomonas foetus. Journal of General Microbiology, 115(2):301-307.
Mallinson DJ; Livingstone J; Appleton KM; Lees SJ; Coombs GH; North MJ, 1995. Multiple cysteine proteinases of the pathogenic protozoon Tritrichomonas foetus: identification of 7 diverse and differentially expressed genes. Microbiology (Reading), 141(12):3077-3085; 39 ref.
Mariante RM; Lopes LC; Benchimol M, 2004. Tritrichomonas foetus pseudocysts adhere to vaginal epithelial cells in a contact-dependent manner. Parasitol Res, 92(4):303-312.
Müller M, 1980. The hydrogenosome. In: The Eukaryotic Microbial Cell. Cambridge: Cambridge View Press, 127-143.
North MJ, 1994. Cysteine endopeptidases of parasitic protozoa. Methods in Enzymology, 244:523-39.
OIE Handistatus, 2002. World Animal Health Publication and Handistatus II (dataset for 2001). Paris, France: Office International des Epizooties.
OIE Handistatus, 2003. World Animal Health Publication and Handistatus II (dataset for 2002). Paris, France: Office International des Epizooties.
OIE Handistatus, 2004. World Animal Health Publication and Handistatus II (data set for 2003). Paris, France: Office International des Epizooties.
OIE Handistatus, 2005. World Animal Health Publication and Handistatus II (data set for 2004). Paris, France: Office International des Epizooties.
Rhyan JC; Blanchard PC; Kvasnicka WG; Hall MR; Hanks D, 1995. Tissue-invasive Tritrichomonas foetus in four aborted bovine fetuses. Journal of Veterinary Diagnostic Investigation, 7(3):409-412; 15 ref.
Rocha-Azevedo B; Melo-Braga MB; FC ES-F, 2005. Intra-strain clonal phenotypic variation of Tritrichomonas foetus is related to the cytotoxicity exerted by the parasite to cultured cells. Parasitol Res, 95(2):106-12.
Schneider MD, 1942. A new thermostable medium for the prolonged bacteria-free cultivation of Trichomonad foetus. J Parasitol, (28):428-9.
Shaia CS; Voyich J; Gillis SJ; Singh BN; Burgess DE, 1998. Purification and expression of the Tf190 adhesion in strains of Tritrichomonas foetus. Infect Immun, 66:1100-1105.
Singh A; Singh J; Grewal AS; Brar RS, 2001. Studies on some blood parameters of crossbred calves with experimental Theileria annulata infections. Veterinary Research Communications, 25(4):289-300; 44 ref.
Singh BN; BonDurant RH; Campero CM; Corbeil LB, 2001. Immunological and biochemical analysis of glycosylated surface antigens and lipophosphoglycan of Tritrichomonas foetus. Journal of Parasitology, 87(4):770-777; 41 ref.
Turner G; Müller M, 1983. Failure to detect extranuclear DNA in Trichomonas vaginalis and Tritrichomonas foetus. J Parasitol, 69(1):234-6.
Wosu LO, 1977. Trichomonas infection in a bull--an apparent change in serotype of the infecting organism. Australian Veterinary Journal, 53(7):340-1.
CABI Data Mining, 2001. CAB Abstracts Data Mining.,
OIE Handistatus, 2005. World Animal Health Publication and Handistatus II (dataset for 2004)., Paris, France: Office International des Epizooties.
Distribution MapsTop of page
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CABI Summary Records
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