The object of this study was to evaluate Japanese encephalitis virus (JEV) antibody titer changes in broodmares and foals. Antibodies of 112 sera were detected by applying hemagglutination inhibition test. To the best of our knowledge, this is the first report that compares antibody titers of foals to that of their dams in order for evaluate optimal time of JEV vaccination. Most mares` antibody titers were variable. However, the highest titers in foals presented in their first month, and antibodies titers in all foals decreased gradually over time. This study provides important benchmarks that can be used to select optimum time JEV of vaccination.

Japanese encephalitis virus (JEV), a mosquito-borne pathogen, is the most important cause of viral encephalitis worldwide. The major vector mosquito of this virus, known as Culex tritaeniorynchus, is mainly live in paddy rice field in Korea. So Japanese encephalitis (JE) is a disease of rural areas. During urbanization, rice cultivated land has decreased also resulting the number of JE patients has decreased. However, recent outbreak of JE in Korea 2010, the patients distribution was not related with that of the mosquito. Therefore, this study was conducted to evaluate involving other mosquito species in the transmission of JEV. Five localities, JE reported in 5 years, have been selected to collect mosquitoes according their habitats (mountain, swap, cow shed, and downtown area) in 2012. Total 22,774 collected mosquitoes were pooled by species, date and site of collection. Of the 1,282 pools, eight (five were from Culex orientalis, one from Culex pipiens complex, and two from Aedes vexans) were found positive for flavivirus RNA in SYBR Green I-based real-time RT-PCR assay. The results of sequences blasting on NCBI showed that the flaviviruses from Cx. orientalis and Cx. pipiens complex were identified as JEV genotype V.

Seropositivity against Japanese encephalitis virus (JEV) was measured by hemagglutination inhibition test (HI) on sera from 323 horses raised in Jeju. Enzyme-linked immunosorbent assay (ELISA) method was applied for the confirmation of its availability as a tool of detecting anti-JEV antibodies in horses. The positive rate scored 50.4%. The positive rates were increased according to ages. The highest peak was shown at October. And Jeju Ponies showed higher positivity compared to thoses of Thoroughbred horses. When compared the results obtained by HI and ELISA, there was slight correlations between the two methods (r=0.7100). Besides, ELISA could discriminate between true and false positive sera by neutralizing serum specimen with JEV antigen.