The Japanese encephalitis virus (JEV) is a zoonotic pathogen that affects the nervous systems of humans, pigs, and horses. It has been classified into five genotypes (G1-G5) based on molecular analysis of the pre-membrane or envelope gene. In the Republic of Korea, the predominant JEV genotype has recently shifted from G3 to G1 and G5, highlighting the need for a rapid and accurate diagnostic method. In this study, we designed specific common and differential primer sets for JEV G1, G3, and G5 to detect the JEV gene. Four specific primer sets for JEV G1, G3, and G5 were used to selectively amplify the target gene. The detection limits of the common primer set for JEV G1, G3, and G5 were 100, 0.1, and 10 TCID50/reaction, respectively. The detection limits of the three differential primer sets were 1, 0.1, and 1 TCID50/reaction, respectively. No cross-reactivity was observed with non-JEV reference viruses. We successfully developed a multiplex reverse transcription polymerase chain reaction (RT-PCR) assay to distinguish the three JEV genotypes. Our multiplex RT-PCR assay is highly sensitive and specific, providing a reliable tool for confirming JEV infection in suspected samples. Additionally, our assay can be applied to suspected mosquito samples and commercial veterinary biological products.

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.

Population density of Culex tritaeniorhynchus was annually monitored to predict the possibility of a Japanese encephalitis (JE) outbreak at 10 collection sites throughout Republic of Korea (ROK) during mosquito season from 2011 to 2015. Prevalence of Cx. tritaeniorhynchus in ROK was spatially and timely very variable and was significantly highest at Busan city during August. Monthly average population density of Cx. tritaeniorhychus showed high correlation to the monthly average daily average temperature and monthly average precipitation. Two models for the estimation of occurrence of Cx. tritaeniorhynchus based on annual monthly daily average temperature and monthly precipitation are shown with linear regression equations of exp(0.413×temperature-0.949) and exp(0.01258×precipitation+3.777). JE vector surveillance and vector control is warranted as part of an effective JE management program at ROK.

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.

Toxoplasmosis is a rare but fatal opportunistic infection in immunocompromised patients such as acquired immunodeficien-cy syndrome. We report a case of toxoplasmic encephalitis in a patient with acquired immunodeficiency syndrome (AIDS). A 44-year-old Thai male presented with loss of consciousness from a day ago and fever from 14 days ago. A magnetic reso-nance imaging scan of the brain revealed multiple, variable sized ring-enhancing lesions in the cerebral hemispheres. Toxo-plasma gondii immunoglobulin G antibody was tested positive by a serologic test. We diagnosed the patient as toxoplasmic encephalitis and he received pyrimethamine and sulfadiazine. We report here a rare case of patient with toxoplasmic enceph-alitis.