Prevalence and risk factors of Japanese encephalitis virus (JEV) in livestock and companion animal in high-risk areas in Malaysia

Japanese encephalitis (JE) is vector-borne zoonotic disease which causes encephalitis in humans and horses. Clinical signs for Japanese encephalitis virus (JEV) infection are not clearly evident in the majority of affected animals. In Malaysia, information on the prevalence of JEV infection has not been established. Thus, a cross-sectional study was conducted during two periods, December 2015 to January 2016 and March to August in 2016, to determine the prevalence and risk factors in JEV infections among animals and birds in Peninsular Malaysia. Serum samples were harvested from the 416 samples which were collected from the dogs, cats, water birds, village chicken, jungle fowls, long-tailed macaques, domestic pigs, and cattle in the states of Selangor, Perak, Perlis, Kelantan, and Pahang. The serum samples were screened for JEV antibodies by commercial IgG ELISA kits. A questionnaire was also distributed to obtain information on the animals, birds, and the environmental factors of sampling areas. The results showed that dogs had the highest seropositive rate of 80% (95% CI: ± 11.69) followed by pigs at 44.4% (95% CI: ± 1.715), cattle at 32.2% (95% CI: ± 1.058), birds at 28.9% (95% CI: ± 5.757), cats at 15.6% (95% CI: ± 7.38), and monkeys at 14.3% (95% CI: ± 1.882). The study also showed that JEV seropositivity was high in young animals and in areas where mosquito vectors and migrating birds were prevalent

Prevalence and risk factors of Japanese encephalitis virus (JEV) in livestock and companion animal in high-risk areas in Malaysia

Japanese encephalitis (JE) is vector-borne zoonotic disease which causes encephalitis in humans and horses. Clinical signs for Japanese encephalitis virus (JEV) infection are not clearly evident in the majority of affected animals. In Malaysia, information on the prevalence of JEV infection has not been established. Thus, a cross-sectional study was conducted during two periods, December 2015 to January 2016 and March to August in 2016, to determine the prevalence and risk factors in JEV infections among animals and birds in Peninsular Malaysia. Serum samples were harvested from the 416 samples which were collected from the dogs, cats, water birds, village chicken, jungle fowls, long-tailed macaques, domestic pigs, and cattle in the states of Selangor, Perak, Perlis, Kelantan, and Pahang. The serum samples were screened for JEV antibodies by commercial IgG ELISA kits. A questionnaire was also distributed to obtain information on the animals, birds, and the environmental factors of sampling areas. The results showed that dogs had the highest seropositive rate of 80% (95% CI: ± 11.69) followed by pigs at 44.4% (95% CI: ± 1.715), cattle at 32.2% (95% CI: ± 1.058), birds at 28.9% (95% CI: ± 5.757), cats at 15.6% (95% CI: ± 7.38), and monkeys at 14.3% (95% CI: ± 1.882). The study also showed that JEV seropositivity was high in young animals and in areas where mosquito vectors and migrating birds were prevalent

Seroprevalence of Japanese Encephalitis Virus (JEV) in birds in Malaysia

Japanese Encephalitis is one of the most important zoonotic diseases caused by Japanese Encephalitis virus from family Flaviviridae and genus Flavivirus. The virus is transmitted through Culex mosquito primarily by Culex tritaeniorhynchus with ardeid birds as reservoir. Pigs and birds play an important role as the main vertebrate amplifier with human and horse as the dead-end host. Forty-five birds consisted of village chicken, jungle fowl cross and waterbirds were sampled in Tanjung Piandang, Perak, Jenderam Hulu, Sepang, Selangor and Putrajaya Wetland, respectively. Blood samples were processed and the serum were subjected to double-antigen sandwich ELISA for detection of antibody against Japanese Encephalitis virus (MyBiosource®). Out of forty-five sample, 28.89% (13/45) were positive for JEV antibodies. Based on location, Jenderam Hulu has the highest seroconversion (50%) followed by Tanjung Piandang (21.74%) and Putrajaya Wetland (20%). Based on age, young birds showed higher seroconversion (35.71%) than adult (25.81%). According to species, both jungle fowl cross and American flamingo has 50% seroconversion followed by village chicken with 21.74%. Male showed highest seroconversion (50%) followed by female (28.13%). Chi square test analysis revealed that there were no association between the risk factors and seroprevalence of JEV. In conclusion, there was presence of seroconversion against JEV in birds in Malaysia and all birds have similar risk to JEV infection in terms of age, sex, species and location. Further work should examine the genotype of the virus circulating in the birds’ population by molecular studies