RESUMEN
The virulence of genotype I (GI) Japanese encephalitis virus (JEV) is under debate. We investigated differences in the virulence of GI and GIII JEV by calculating asymptomatic ratios based on serologic studies during GI- and GIII-JEV endemic periods. The results suggested equal virulence of GI and GIII JEV among humans.
Asunto(s)
Virus de la Encefalitis Japonesa (Especie)/patogenicidad , Encefalitis Japonesa/virología , Adulto , Virus de la Encefalitis Japonesa (Especie)/genética , Virus de la Encefalitis Japonesa (Especie)/aislamiento & purificación , Encefalitis Japonesa/epidemiología , Femenino , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Taiwán/epidemiología , VirulenciaRESUMEN
Genotype I of Japanese encephalitis virus first appeared in Taiwan in 2008. Phylogenetic analysis of 37 viruses from pig farms in 2009-2010 classified these viruses into 2 unique subclusters of genotype I viruses and suggested multiple introductions and swift replacement of genotype III by genotype I virus in Taiwan.
Asunto(s)
Virus de la Encefalitis Japonesa (Especie)/clasificación , Virus de la Encefalitis Japonesa (Especie)/genética , Encefalitis Japonesa/veterinaria , Enfermedades de los Porcinos/virología , Animales , Secuencia de Bases , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/veterinaria , Enfermedades Transmisibles Emergentes/virología , Culex/virología , ADN Viral/genética , Virus de la Encefalitis Japonesa (Especie)/aislamiento & purificación , Encefalitis Japonesa/epidemiología , Encefalitis Japonesa/virología , Genotipo , Insectos Vectores/virología , Epidemiología Molecular , Filogenia , Sus scrofa/virología , Porcinos , Enfermedades de los Porcinos/epidemiología , Taiwán/epidemiologíaAsunto(s)
Distonía/epidemiología , Distonía/genética , Proteínas de la Membrana/genética , Proteínas del Tejido Nervioso/genética , Adolescente , Adulto , Edad de Inicio , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Mutación/genética , Fenotipo , Taiwán/epidemiología , Adulto JovenRESUMEN
BACKGROUND: Genotype I (GI) Japanese encephalitis virus (JEV) that replaced GIII virus has become the dominant circulating virus in Asia. Currently, all registered live and inactivated JEV vaccines are derived from genotype III viruses. In Taiwan, the compulsory JEV vaccination policy recommends that children receives four doses of formalin-inactivated Nakayama (GIII) JEV vaccine. METHODOLOGY/PRINCIPAL FINDINGS: To evaluate the influence of genotype replacement on the post-vaccination viral neutralizing ability by GIII and GI viruses, the small panel of vaccinated-children serum specimens was assembled, and the reciprocal 50% plaque-reduction neutralizing antibody titers (PRNT(50)) were measured against Nakayama vaccine strain, CJN GIII human brain isolate and TC2009-1 GI mosquito isolate. The seropositivity rate (PRNT(50) ≥ 1:10) and geometric mean titers (GMT) against the TC2009-1 virus were the lowest among the three viruses. The protective threshold against the CJN and TC2009-1 viruses could only be achieved when the GMT against Nakayama virus was ≥ 1:20 or ≥ 1:80, respectively. Using undiluted vaccinees' sera, the enhancement of JEV infection in K562 cells was observed in some low or non-neutralizing serum specimens. CONCLUSIONS/SIGNIFICANCE: Our preliminary study has shown that neutralizing antibodies, elicited by the mouse brain-derived and formalin-inactivated JEV Nakayama vaccine among a limited number of vaccinees, have reduced neutralizing capacity against circulating GI virus, but more detailed studies are needed to address the potential impact on the future vaccine policy.