Japanese encephalitis

Identity

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Preferred Scientific Name

Japanese encephalitis

Other Scientific Names

Japanese B encephalitis

International Common Names

English: hydranencephaly with or without cerebellar lesions in ruminants; japanese b encephalitis in pigs- exotic

English acronym

JE

Pathogen/s

Top of page Japanese encephalitis virus

Overview

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Japanese encephalitis (JE) is a mosquito-borne viral disease in animals and humans. Many domestic and wild animals are susceptible to the JE virus. The virus causes various forms of reproductive failures in pregnant sows, and lesions in the central nervous system (CNS) in horses. In other animals, infection is usually subclinical. Japanese encephalitis is one of the most common mosquito-borne diseases of the human central nervous system, epidemics having been recorded in Japan, Korea, and India. Pigs are considered the most important natural amplifying animal for the virus. Episodes of human infection occur annually during the mosquito season. Disease in most people is subclinical or mild, but fatal encephalitis develops in some children.

This disease is on the list of diseases notifiable to the World Organisation for Animal Health (OIE). The distribution section contains data from OIE's WAHID database on disease occurrence. For further information on this disease from OIE, see the website: www.oie.int.

Host Animals

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Animal name	Context	Life stage
Bos indicus (zebu)
Bos taurus (cattle)
Capra hircus (goats)
Ovis aries (sheep)
Sus scrofa (pigs)	Domesticated host	Pigs: All Stages

Hosts/Species Affected

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The population densities of susceptible hosts are the most important predisposing factor for JEV transmission. In the countries within the temperate zone, the mosquito season starts in late spring, and the pig-mosquito cycle becomes evident shortly afterward. During this time, the pig population contains a high proportion of susceptible breeding stock in which the passive immunity has waned during the winter. In such conditions, a high concentration of the virus can be built up and maintained in the pig population. This build up is not as prevalent in the tropical countries of South-East Asia, where the mosquito-pig cycle may continue throughout the year.

Birds, in particular herons and egrets are maintainence hosts of JEV, while pigs are amplifier hosts.

Systems Affected

Top of page nervous system diseases of pigs
reproductive diseases of pigs

Distribution

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Geographic distribution of the disease is restricted to South-East Asia: infection has been recognized in Japan, far eastern Soviet Union, Korea, China, Taiwan, the Philippines, Indonesia, Singapore, Malaysia, Hong Kong, Vietnam, Laos, Bangladesh, Nepal, Thailand, Burma, Sri Lanka, India, and the Pacific islands.

For current information on disease incidence, see OIE's WAHID Interface.

Distribution Table

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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: 10 Jan 2020

Continent/Country/Region	Distribution	Last Reported	Reference	Notes
Africa
Algeria	Absent, No presence record(s)		OIE (2009)
Botswana	Absent, No presence record(s)		OIE (2009)
Burundi	Absent, No presence record(s)		OIE Handistatus (2005)
Cabo Verde	Absent, No presence record(s)		OIE Handistatus (2005)
Cameroon	Absent, No presence record(s)		OIE Handistatus (2005)
Central African Republic	Absent, No presence record(s)		OIE Handistatus (2005)
Congo, Democratic Republic of the	Absent, No presence record(s)		OIE Handistatus (2005)
Kenya	Absent, No presence record(s)		OIE (2009)
Lesotho	Absent, No presence record(s)		OIE (2009)
Libya	Absent, No presence record(s)		OIE Handistatus (2005)
Madagascar	Absent, No presence record(s)		OIE (2009)
Malawi	Absent, No presence record(s)		OIE (2009)
Mauritius	Absent, No presence record(s)		OIE (2009)
Morocco	Absent, No presence record(s)		OIE (2009)
Namibia	Absent, No presence record(s)		OIE (2009)
Nigeria	Absent, No presence record(s)		OIE (2009)
Réunion	Absent, No presence record(s)		OIE Handistatus (2005)
Rwanda	Absent, No presence record(s)		OIE (2009)
São Tomé and Príncipe	Absent, No presence record(s)		OIE Handistatus (2005)
Seychelles	Absent, No presence record(s)		OIE Handistatus (2005)
South Africa	Absent, No presence record(s)		OIE (2009)
Sudan	Absent, No presence record(s)		OIE (2009)
Tanzania	Absent, No presence record(s)		OIE (2009)
Tunisia	Absent, No presence record(s)		OIE (2009)
Zambia	Absent, No presence record(s)		OIE (2009)
Zimbabwe	Absent, No presence record(s)		OIE (2009)
Asia
Armenia	Absent, No presence record(s)		OIE (2009)
Azerbaijan	Absent, No presence record(s)		OIE (2009)
Bahrain	Absent, No presence record(s)		OIE (2009)
Bangladesh	Absent, No presence record(s)		OIE (2009)
Brunei	Absent, No presence record(s)		OIE Handistatus (2005)
China	Present, Localized		OIE (2009); Wang et al. (1966); CABI (Undated)
Georgia	Absent, No presence record(s)		OIE Handistatus (2005)
Hong Kong	Absent, No presence record(s)	2000	OIE (2009); Higgins (1970)
India	Absent, No presence record(s)		OIE (2009); Daniels et al. (2002)
Indonesia	Absent, No presence record(s)		OIE (2009); Daniels et al. (2002)
Iran	Absent, No presence record(s)		OIE (2009)
Iraq	Absent, No presence record(s)		OIE (2009)
Israel	Absent, No presence record(s)		OIE (2009)
Japan	Present		OIE (2009); KONO and KIM (1969)
-Hokkaido	Present		Takashima et al. (1988)
Kazakhstan	Absent, No presence record(s)		OIE (2009)
Kuwait	Absent, No presence record(s)		OIE (2009)
Lebanon	Absent, No presence record(s)		OIE (2009)
Malaysia	Absent, No presence record(s)	2004	OIE (2009); BENDELL (1970); CABI (Undated)
-Peninsular Malaysia	Absent, No presence record(s)		OIE Handistatus (2005)
-Sarawak	Present		HILL (1970); OIE Handistatus (2005)
North Korea	Absent, No presence record(s)		OIE Handistatus (2005)
Oman	Absent, No presence record(s)		OIE (2009)
Pakistan	Absent, No presence record(s)		OIE (2009); Daniels et al. (2002)
Saudi Arabia	Absent, No presence record(s)		OIE (2009)
Singapore	Absent, No presence record(s)		OIE (2009); CHAN and LOH (1966)
South Korea	Absent, No presence record(s)	2007	OIE (2009); KONO and KIM (1969)
Sri Lanka	Absent, No presence record(s)	2004	OIE (2009); Vesenjak Hirjan et al. (1969); Daniels et al. (2002)
Syria	Absent, No presence record(s)		OIE (2009)
Taiwan	Absent, No presence record(s)		Okuno et al. (1975); OIE Handistatus (2005)
Tajikistan	Absent, No presence record(s)		OIE (2009)
Turkmenistan	Absent, No presence record(s)		OIE Handistatus (2005)
United Arab Emirates	Absent, No presence record(s)		OIE (2009)
Uzbekistan	Absent, No presence record(s)		OIE Handistatus (2005)
Europe
Albania	Absent, No presence record(s)		OIE (2009)
Andorra	Absent, No presence record(s)		OIE Handistatus (2005)
Austria	Absent, No presence record(s)		OIE (2009)
Belgium	Absent, No presence record(s)		OIE (2009)
Bosnia and Herzegovina	Absent, No presence record(s)		OIE Handistatus (2005)
Bulgaria	Absent, No presence record(s)		OIE (2009)
Croatia	Absent, No presence record(s)		OIE (2009)
Cyprus	Absent, No presence record(s)		OIE (2009)
Czechia	Absent, No presence record(s)		OIE (2009)
Denmark	Absent, No presence record(s)		OIE (2009)
Finland	Absent, No presence record(s)		OIE (2009)
France	Absent, No presence record(s)		OIE (2009)
Germany	Absent, No presence record(s)		OIE (2009)
Greece	Absent, No presence record(s)		OIE (2009)
Hungary	Absent, No presence record(s)		OIE (2009)
Iceland	Absent, No presence record(s)		OIE (2009)
Ireland	Absent, No presence record(s)		OIE (2009)
Isle of Man	Absent, No presence record(s)		OIE Handistatus (2005)
Jersey	Absent, No presence record(s)		OIE Handistatus (2005)
Latvia	Absent, No presence record(s)		OIE (2009)
Liechtenstein	Absent, No presence record(s)		OIE (2009)
Lithuania	Absent, No presence record(s)		OIE (2009)
Luxembourg	Absent, No presence record(s)		OIE (2009)
Malta	Absent, No presence record(s)		OIE (2009)
Moldova	Absent, No presence record(s)		OIE Handistatus (2005)
Montenegro	Absent, No presence record(s)		OIE (2009)
Netherlands	Absent, No presence record(s)		OIE (2009)
North Macedonia	Absent, No presence record(s)		OIE (2009)
Norway	Absent, No presence record(s)		OIE (2009)
Portugal	Absent, No presence record(s)		OIE (2009)
Romania	Absent, No presence record(s)		OIE (2009)
Russia	Absent, No presence record(s)		OIE (2009)
Serbia and Montenegro	Absent, No presence record(s)		OIE Handistatus (2005)
Slovakia	Absent, No presence record(s)		OIE (2009)
Slovenia	Absent, No presence record(s)		OIE (2009)
Spain	Absent, No presence record(s)		OIE (2009)
Sweden	Absent, No presence record(s)		OIE (2009)
Switzerland	Absent, No presence record(s)		OIE (2009)
Ukraine	Absent, No presence record(s)		OIE (2009)
Union of Soviet Socialist Republics	Present		GRASCENKOV (1964); Dandurov (1967)
United Kingdom	Absent, No presence record(s)		OIE (2009)
-Northern Ireland	Absent, No presence record(s)		OIE Handistatus (2005)
North America
Barbados	Absent, No presence record(s)		OIE Handistatus (2005)
Belize	Absent, No presence record(s)		OIE (2009)
Bermuda	Absent, No presence record(s)		OIE Handistatus (2005)
British Virgin Islands	Absent, No presence record(s)		OIE Handistatus (2005)
Canada	Absent, No presence record(s)		OIE (2009)
Cayman Islands	Absent, No presence record(s)		OIE Handistatus (2005)
Costa Rica	Absent, No presence record(s)		OIE (2009)
Cuba	Absent, No presence record(s)		OIE (2009)
Curaçao	Absent, No presence record(s)		OIE Handistatus (2005)
Dominica	Absent, No presence record(s)		OIE Handistatus (2005)
Dominican Republic	Absent, No presence record(s)		OIE (2009)
El Salvador	Absent, No presence record(s)		OIE (2009)
Greenland	Absent, No presence record(s)		OIE (2009)
Guatemala	Absent, No presence record(s)		OIE (2009)
Haiti	Absent, No presence record(s)		OIE (2009)
Honduras	Absent, No presence record(s)		OIE (2009)
Martinique	Absent, No presence record(s)		OIE (2009)
Mexico	Absent, No presence record(s)		OIE (2009)
Nicaragua	Absent, No presence record(s)		OIE (2009)
Panama	Absent, No presence record(s)		OIE (2009)
Saint Kitts and Nevis	Absent, No presence record(s)		OIE Handistatus (2005)
Saint Vincent and the Grenadines	Absent, No presence record(s)		OIE Handistatus (2005)
Trinidad and Tobago	Absent, No presence record(s)		OIE Handistatus (2005)
United States	Absent, No presence record(s)		OIE (2009)
Oceania
Australia	Absent, No presence record(s)	2004	OIE (2009); Chong Sue Kheng et al. (1968); Daniels et al. (2002)
Fiji	Absent, No presence record(s)		MILES et al. (1964)
French Polynesia	Absent, No presence record(s)		OIE (2009)
New Caledonia	Absent, No presence record(s)		OIE (2009)
New Zealand	Absent, No presence record(s)		OIE (2009)
Papua New Guinea	Present		Daniels et al. (2002)	CAB Abstracts Data Mining
Samoa	Absent, No presence record(s)		OIE Handistatus (2005)
Vanuatu	Absent, No presence record(s)		OIE Handistatus (2005)
South America
Argentina	Absent, No presence record(s)		OIE (2009)
Bolivia	Absent, No presence record(s)		OIE (2009)
Brazil	Absent, No presence record(s)		OIE (2009)
Chile	Absent, No presence record(s)		OIE (2009)
Colombia	Absent, No presence record(s)		OIE (2009)
Ecuador	Absent, No presence record(s)		OIE (2009)
Falkland Islands	Absent, No presence record(s)		OIE Handistatus (2005)
Guyana	Absent, No presence record(s)		OIE Handistatus (2005)
Paraguay	Absent, No presence record(s)		OIE Handistatus (2005)
Peru	Absent, No presence record(s)		OIE (2009)
Uruguay	Absent, No presence record(s)		OIE (2009)
Venezuela	Absent, No presence record(s)		OIE (2009)

Pathology

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Major pathologic lesions have not been found in pigs infected with JEV. However, various abnormalities have been observed in litters from dams infected with the virus during pregnancy. Gross pathologic lesions noted in stillborn or weak neonatal piglets include hydrocephalus, subcutaneous oedema, hydrothorax, ascites, petechial haemorrhages on serous membranes, congestion of lymph nodes, necrotic foci in liver and spleen, and congested meninges or spinal cord (Burns, 1950). Cerebellar hypoplasia and spinal hypomyelinogenesis have also been described (Morimoto, 1969).

Histopathologically, significant lesions in affected piglets or stillborn pigs are restricted to the central nervous system (CNS). Most CNS lesions, mainly involving the cortex, basal ganglion, brain stem, and spinal cord, occur in pigs up to 6 months of age. Perivascular cuffing and scattered neuronal degeneration and necrosis are found in the cerebrum and cerebellum in pigs. Neuronal degeneration is prominent in the grey matter and Purkinje layers.

Pathologic changes in the testes in association with JEV infection are described (Hashimura et al., 1976; Ogasa et al., 1977). In naturally affected pigs, a large amount of mucous fluid is observed in the cavity tunica vaginalis, as well as fibrous thickening along the edge of the epididymis and the visceral layer of the tunica vaginalis. Microscopically, such testicles show oedema and inflammatory changes, with cellular infiltrations in the interstitial tissue of the epididymis and tunica vaginalis. Cell infiltration and haemorrhage are also evident in the interstitial tissue of the testes.

Diagnosis

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Diagnosis of JEV infection is based upon isolation of the virus from foetuses and infected pigs. A differential diagnosis must be made to distinguish it from other infections, especially Nipah. Lack of clinical signs in sows and piglets with JEV infection is useful in excluding many diseases. Seasonal distribution also indicates JEV infection.

Isolation of the virus can be performed by intracerebral inoculation of brain extracts into suckling mice between 1 and 5 days of age. Signs of central nervous system disturbance or death follow between 4 and 14 days post-inoculation, and virus in mouse brain tissue can readily be identified by in vivo neutralization tests in suckling mice or in cell culture. The commonly used cell cultures are derived from hamster, pig kidney, and mosquito, in all of which the virus causes a cytopathic effect. It should be recognized that tissue suspected of being infected with JEV must be handled with care, because the virus is not only heat labile but also pathogenic to humans.

Several serologic tests are available that detect antibody titres of JEV infection in pig serum, such as the haemagglutination inhibition test, ELISA (Konishi and Yamaoka, 1982), antigen biotin-labelled ELISA, single radial haemolysin, plaque reduction test, and serum neutralization (SN) technique. Detection of cerebral spinal fluid-IgM, using ELISA diagnostic kits is used in humans. However, in an area where vaccination is routine, paired serum samples should be considered in the serology. The presence of the antibody in foetuses is also of diagnostic value. There are often cross reactions to antibodies to other flaviviruses.

Detection of viral antigens in infected tissues such as brains, placenta and mummified fetuses is also diagnostically important. Methods such as avidin-biotin staining and fluorescent antibody staining have been used to detect JE viral antigen in formatin-fixed tissues following treatment of such tissues with trypsin or other proteolytic enzyme (Iwasaki et al., 1986).

List of Symptoms/Signs

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Sign	Life Stages	Type
Digestive Signs / Anorexia, loss or decreased appetite, not nursing, off feed		Sign
Digestive Signs / Anorexia, loss or decreased appetite, not nursing, off feed		Sign
General Signs / Ataxia, incoordination, staggering, falling		Sign
General Signs / Dysmetria, hypermetria, hypometria		Sign
General Signs / Fever, pyrexia, hyperthermia	Pigs:All Stages	Sign
General Signs / Generalized weakness, paresis, paralysis		Sign
General Signs / Inability to stand, downer, prostration		Sign
General Signs / Lack of growth or weight gain, retarded, stunted growth		Sign
General Signs / Opisthotonus		Sign
General Signs / Trembling, shivering, fasciculations, chilling	Pigs:All Stages	Sign
General Signs / Underweight, poor condition, thin, emaciated, unthriftiness, ill thrift		Sign
General Signs / Weight loss		Sign
Nervous Signs / Abnormal behavior, aggression, changing habits		Sign
Nervous Signs / Dullness, depression, lethargy, depressed, lethargic, listless		Sign
Nervous Signs / Dullness, depression, lethargy, depressed, lethargic, listless		Sign
Nervous Signs / Tremor	Pigs:Piglet	Sign
Ophthalmology Signs / Blindness		Sign
Ophthalmology Signs / Nystagmus		Sign
Reproductive Signs / Abortion or weak newborns, stillbirth	Pigs:Gilt,Pigs:Sow	Sign
Reproductive Signs / Female infertility, repeat breeder	Pigs:Gilt,Pigs:Sow	Sign
Reproductive Signs / Heat on palpation scrotum, testes	Pigs:Boar	Sign
Reproductive Signs / Lack of libido or erection	Pigs:Boar	Sign
Reproductive Signs / Male infertility	Pigs:Boar	Sign
Reproductive Signs / Mummy, mummified fetus	Pigs:Gilt,Pigs:Sow	Sign
Reproductive Signs / Small litter size	Pigs:Gilt,Pigs:Sow	Sign

Disease Course

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Pigs become infected with JEV via the bites of mosquitoes carrying the virus. Infected pigs develop viremia, which persists for approximately 12 hours to a few days. After the initial viremia, the virus disseminates to vascular tissues such as the liver, spleen, and muscle, where further replication augments the viremia. The virus enters the central nervous system via: cerebral spinal fluid; endothelial cell-, macrophage-, or lymphocyte infection; or a haematogenous route. In humans and mice, JEV infects and destroys neurons selectively, mostly in the areas of brain stem, thalamus, basal ganglion, and lower layer of cortex. In mosquitoes, JEV infection is noncytopathic.

Transplacental infection of JEV has been reported in pigs (Shimizu et al., 1954). In pregnant pigs, foetuses may become infected during the viremic period. Experimentally, after intravenous infection of pregnant pigs with JEV, virus is recoverable from foetuses as early as 7 days post-infection. In some animals, the virus fails to cross the placenta. Successful transplacental infection may depend on the time of gestation at which the dam was infected or on the strain of virus. When infection of pregnant dams takes place in the mid-third of gestation, transplacental infection and pathogenic effects are more obvious. Field observations show that fetal death and mummification are associated with JEV infection of dams between 40 and 60 days of gestation; fetuses from the gilts infected after 85 days gestation were little affected.

Epidemiology

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In nature, infection with JEV is maintained cyclically, involving vector mosquitoes (Culex tritaeniorhynchus), birds, and mammals. A correlation between infection in pigs and infection in humans is apparent, with evidence indicating that swine play an important role in the build-up of the virus within a population. In enzootic zones, pigs are favoured feeding sources for mosquitoes. Consistent development of viremia in susceptible pigs ensures a continued supply of infected mosquitoes. Epidemiologic patterns may differ among areas of South-East Asia, as the activity of the vector mosquito is modified by differing climatic conditions.

Other animals and many different mosquito species (mainly Culex spp.) could alter infection cycles and are factors involved in the transmission of JEV (Chang and Kim, 1966; Sazawa, 1968; Hasegawa et al., 1975). The disease is a growing threat in India where the pig populations are much lower compared with other endemic areas. Chickens and wild birds, especially herons and egrets, are able to maintain the virus.

Impact: Economic

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The economic significance of Japanese encephalitis in domestic animals is not known. The significance in swine is only evident with various forms of reproductive failure in low parity sows.

Zoonoses and Food Safety

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No report is available on JEV infection in humans from pork. Virus survival in the environment is not expected, because the virus is highly temperature sensitive. Infection in humans can, however, occur during the mosquito season.

Disease Treatment

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The treatment of JE in humans with human recombinant interferon-α gives clinically satisfactory results. This treatment of JE in swine is not available.

Prevention and Control

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Breaking the infectious cycle in this arthropod-borne disease is usually a good step toward management. However, it is not practical to control the insect. Therefore, immunizing the breeders with JEV vaccine is widely used as an applicable control and preventive measure.

A variety of mostly live-attenuated vaccines has been developed for the prevention of JE in pigs and is being used successfully in the field (Hsu et al., 1972; Fujisaki et al. 1975; Kwon et al. 1976). Inactivated vaccines have proved to be less efficient. It is recommended that attenuated vaccines be given to young gilts or boars twice at an interval of 2-3 weeks before the start of the mosquito season. The live virus vaccines are not recommended for use in pregnant pigs.

References

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Bendell PJE, 1970. Japanese encephalitis in Sarawak: Studies on mosquito behavior in a Land Dyak village. Trans Royal Trop Med & Hyg, 64:497-502.

Burns KF, 1950. Congenital Japanese B encephalitis infection of swine. Proceedings Society Experimental Biology Medicine, 75:621-625.

Carey DE; Reuben R; Myers RM; George S, 1968. Japanese encephalitis studies in Vellore, South India. IV Search for virological and serological evidence of infection in animals other than man. Indian Journal of Medical Research, 56:1340-1352.

Chan YC; Loh TF, 1966. Isolation of Japanese encephalitis virus from the blood of a child in Singapore. American Journal of Tropical Medicine and Hygiene, 15:567-572.

Chang IC; Kim IH, 1966. Serologic survey of Japanese encephalitis virus infection in wild birds in Korea. Korean J Int Med, 9:173-188.

Chen WR; Rico-Hesse R; Tesh RB, 1992. A new genotype of Japanese encephalitis virus from Indonesia. American Journal of Tropical Medicine and Hygiene, 47(1):61-69; 19 ref.

Chen WR; Tesh RB; Rico-Hesse R, 1990. Genetic variation of Japanese encephalitis virus in nature. Journal of General Virology, 71(12):2915-2922; 22 ref.

Chong SK; Teoh KC; Marchette NJ; Garcia R; Rudnick A; Coughlan RF, 1968. Japanese B encephalitis in a horse. Australian Veterinary Journal, 44:23-25.

Dandurov IV, 1967. Japanese encephalitis in the Primorsk region in 1965. Vopr Virusol, 12:739-742.

Daniels PW; Williams DT; Mackenzie JS, 2002. Japanese Encephalitis Virus. In: Trends in Emerging Viral Infections of Swine (eds, Morilla A, Yoon KJ, Zimmerman JJ). Iowa State Press, USA.

Fujisaki Y; Sugimori T; Morimoto T; Miura Y; Kawakami Y; Nakano K, 1975. Immunization of pigs with the attenuated S strain of Japanese encephalitis virus. National Institute of Animal Health Quarterly (Tokyo), 15:55-60.

Gould DJ; Edelman R; Crossman RA; Nisalak A; Sullivan MF, 1974. Study of Japanese encephalitis virus in Chiangmai valley, Thailand. IV. Vector studies. Am J Epidemiol, 100:49-56.

Grascenkov NI, 1964. Japanese encephalitis in the USSR. Bull WHO, 30:161-172.

Hasegawa T; Takehara Y; Takahashi K, 1975. Natural and experimental infections of Japanese tree sparrows with Japanese encephalitis virus. Archives of Virology, 49:373-376.

Hashimura K; Uemiyada S; Komemura S; Fukumoto S; Okuda G; Miura K; Hayashi S, 1976. Isolation of Japanese encephalitis virus from orchitis in pigs. Summary 81st Meeting Japanese Society of Veterinary Science.

Higgins DA, 1970. A serological survey of pigs in Hong Kong for antibodies to Japanese encephalitis virus. Tropical Animal Health & Production, 2:23-27.

Hill MN, 1970. Japanese encephalitis in Sarawak: Studies on adult mosquito populations. Transactions of the Royal Society of Tropical Medicine and Hygine, 64:489-496.

Hori H; Morita K; Igarashi A, 1986. Oligonucleotide fingerprint analysis on Japanese encephalitis virus strains isolated in Japan and Thailand. Acta Virologica, 30(5):353-359; 21 ref.

Hsu ST; Chang LC; Lin SY; Chuang TY; Ma CH; Inoue YK; Okuno T, 1972. The effect of vaccination with a live attenuated strain of Japanese encephalitis virus on stillbirths in swine in Taiwan. Bulletin of WHO, 46:465-471.

Iwasaki Y; Zhao JX; Yamamoto T; Konno H, 1986. Immunohistochemical demonstration of viral antigens in Japanese encephalitis. Acta Neuropathol, 70:79-81.

Ketel WB, 1971. Japanese B encephalitis in Vietnam. American Journal of Medical Science, 261:271-279.

Konishi E; Yamaoka M, 1982. Evaluation of ELISA for quantitation of antibodies to Japanese encephalitis virus in swine sera. J Virol Methods, 5:247-253.

Kono R; Kim KH, 1969. Comparative epidemiological features of Japanese encephalitis in the Republic of Korea, China (Taiwan) and Japan. Bulletin of WHO, 40:263-277.

Kwon HJ; Kang BJ; Lim YM; Lee CK; Kwon YB; Hur W; Jeon; YS, 1976. Studies on Japanese encephalitis live virus vaccine. III. Pathogenicity of tissue culture attenuated strain of virus (Anyang strain). Research Report Office of Rural Development (Korea), 18:21-28.

Miles JA, 1964. Evidence of arbovirus infection in Fiji. American Journal of Tropical Medicine and Hygiene, 13:327-330.

Morimoto T, 1969. Epizootic swine stillbirth caused by Japanese encephalitis virus. Proceedings of a symposium on factors producing embryonic and fetal abnormalities, death, and abortion in swine. US ARS, 91-73:137-153.

Ogasa A; Yokoki Y; Fujisaki Y; Habu A, 1977. Reproductive disorders in boars infected experimentally with Japanese encephalitis virus. Japanese Journal of Animal Reproduction, 23:171-175.

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OIE Handistatus, 2005. World Animal Health Publication and Handistatus II (data set for 2004). Paris, France: Office International des Epizooties.

OIE, 2009. World Animal Health Information Database - Version: 1.4. World Animal Health Information Database. Paris, France: World Organisation for Animal Health. http://www.oie.int

Okuno T; Tseng PT; Hsu ST; Huang CT; Kuo CC; Lin SY, 1975. Japanese encephalitis surveillance in China (Province of Taiwan) during 1968-1971. I. Geographical and seasonal features of case outbreaks. Japanese Journal of Medical Science and Biology, 28:235-253.

Rojanasuphot S; Shaffer N; Chotpitayasunondh T; Phumiamorn S; Mock P; Chearskul S; Waranawat N; Yuentrakul P; Mastro TD; Tsai TF, 1998. Response to JE vaccine among HIV-infected children, Bangkok, Thailand. Southeast Asian Journal of Tropical Medicine and Public Health, 29(3):443-450; 24 ref.

Salafranca ES; Espiritu L, 1949. Report on the presence of Japanese B encephalitis neutralizing antibody among Fillipinos and certain Philippine animals. American Journal of Tropical Medicine, 29:219-227.

Sazawa H, 1968. Japanese encephalitis in domestic animals. Bull Int Epizootics, 70:627-633.

Shimizu T; Kawakami Y; Fukuhaira S; Matsumoto M, 1954. Experimental stillbirth in pregnant swine infected with Japanese encephalitis virus. Japanese Journal of Experimental Medicine, 24:363-375.

Simpson DIH; Smith CEG; Marshall TFC, et al. , 1976. Arbovirus infections in Sarawak: the role of domestic pig. Trans Royal Trop Med & Hyg, 70:66-72.

Takashima I; Watanabe T; Ouchi N; Hashimoto N, 1988. Ecological studies of Japanese encephalitis virus in Hokkaido: interepidemic outbreaks of swine abortion and evidence for the virus to overwinter locally. American Journal of Tropical Medicine and Hygiene, 38(2):420-427; 16 ref.

Vesenjak Hirjan J; Hermon Y; Vitarana T, 1969. Arbovirus infections in Ceylon. Bulletin WHO, 41:243-249.

Wakai S, 1998. Scourge of Japanese encephalitis in southwestern Nepal. Lancet (British edition), 351(9104):759; 2 ref.

Wang YC; Chen HM; I HY, 1966. Isolation of Japanese B encephalitis virus from a horse in Peking. Acta Vet Zootech Sin, 9:155-156.

Work TH; Shah KV, 1956. Serological diagnosis of Japanese B type of encephalitis in North Arcot district of Madras state, India with epidemiological notes. Indian Journal of Medical Science, 10:582-592.

Zhang HL; Mi ZQ; Gong ZD, et al. , 1998. Characteristics of mosquitoes distributed and isolation of Japanese encephalitis virus in Dehong Prefecture, Yunnan province. Endemic Disease Bulletin, 13:78-80.

Distribution References

BENDELL P J E, 1970. Studies on arbovirus epidemiology associated with established and developing rice culture. Japanese encephalitis in Sarawak : studies on mosquito behaviour in a Land Dayak village. Transactions of the Royal Society of Tropical Medicine and Hygiene. 64 (4), 481-522; 497-502 pp. DOI:10.1016/0035-9203(70)90069-6

CABI, Undated. Compendium record. Wallingford, UK: CABI

CABI, Undated a. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI

CHAN Y C, LOH T F, 1966. Isolation of Japanese Encephalitis Virus from the Blood of a Child in Singapore. American Journal of Tropical Medicine and Hygiene. 15 (4), 567-72.

Chong Sue Kheng, Teoh Kim Chee, March-Ette N J, Garcia R, Rudnick A, Coughlan R F, 1968. Japanese B encephalitis in a horse. Australian Veterinary Journal. 23-25. DOI:10.1111/j.1751-0813.1968.tb04908.x

Dandurov IV, 1967. Japanese encephalitis in the Primorsk region in 1965. In: Vopr Virusol, 12 739-742.

Daniels P W, Williams D T, Mackenzie J S, 2002. Japanese encephalitis virus. In: Trends in emerging viral infections of swine. [ed. by Morilla A, Yoon K J, Zimmerman J J]. Ames, USA: Iowa State Press. 249-263.

GRASCENKOV N I, 1964. Japanese Encephalitis in the USSR. Bulletin of the World Health Organization. 30 (2), 161-72.

Higgins D A, 1970. A serological survey of pigs in Hong Kong for antibodies to Japanese encephalitis viras. Tropical Animal Health and Production. 23-27. DOI:10.1007/BF02359325

HILL M N, 1970. Studies on arbovirus epidemiology associated with established and developing rice culture. Japanese encephalitis in Sarawak : studies on adult mosquito populations. Transactions of the Royal Society of Tropical Medicine and Hygiene. 64 (4), 481-522; 489-496 pp. DOI:10.1016/0035-9203(70)90068-4

KONO R, KIM K H, 1969. Comparative epidemiological features of Japanese encephalitis in the Republic of Korea, China (Taiwan) and Japan. Bulletin of the World Health Organization. 40 (2), 263-77.

MILES J A R , MAGUIRE T , AUSTIN F J , ROSS R W , ORDISH R, 1964. Evidence of arbovirus infection in Fiji. American Journal of Tropical Medicine and Hygiene. 13 (2), 327-330 pp.

OIE Handistatus, 2005. World Animal Health Publication and Handistatus II (dataset for 2004)., Paris, France: Office International des Epizooties.

OIE, 2009. World Animal Health Information Database - Version: 1.4., Paris, France: World Organisation for Animal Health. https://www.oie.int/

Okuno T, Tseng PT, Hsu ST, Huang CT, Kuo CC, Lin SY, 1975. Japanese encephalitis surveillance in China (Province of Taiwan) during 1968-1971. I. Geographical and seasonal features of case outbreaks. In: Japanese Journal of Medical Science and Biology, 28 235-253.

Takashima I, Watanabe T, Ouchi N, Hashimoto N, 1988. Ecological studies of Japanese encephalitis virus in Hokkaido: interepidemic outbreaks of swine abortion and evidence for the virus to overwinter locally. American Journal of Tropical Medicine and Hygiene. 38 (2), 420-427.

Vesenjak Hirjan J, Hermon Y, Vitarana T, 1969. Arbovirus infections in Ceylon. In: Bulletin WHO, 41 243-249.

Wang Yung-Chi, Ch'En Hsing-Min, I Hsiu-Ylin, 1966. Isolation of Japanese B encephalitis virus from a horse in Pekin. Acta Veterinaria et Zootechnica Sinica. 155-156.

Links to Websites

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Website	URL	Comment
Japanese encephalitis links	http://www.geocities.com/HotSprings/2188/je.html	Dr.M.Vadivale's Homepage: includes links to other JE sites, mainly from human health angle

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