Molecular epidemiology of Japanese encephalitis in East Asia.
Japanese encephalitis virus is genetically divided into five genotypes. Until the early 1990s, only genotype-3 JE virus was identified in Japan, then, the genotype shifted to type-1 countrywide. Based on our molecular epidemiological study of JEV in Vietnam, China, and Japan, 8 subgroups of genotype 1 JEVs are circulating in East Asia and, at least, 4 of these subgroups are chronologically related and frequently introduced to Japan through China. Possibly, this subgroup distribution is due to bird migration and/or infected mosquitoes which carry viruses for long distances. While in Japan, a small population of genotype 1 is circulating locally.
Department of Virology, Institute of Tropical Medicine, Nagasaki University, GCOE Program, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan. moritak@nagasaki-u.ac.jp
Kouichi
K
Morita
D000818:Animals; D004664:Encephalitis Virus, Japanese / Q000235:genetics*; D004672:Encephalitis, Japanese / Q000453:epidemiology* / Q000821:virology; D005202:Asia, Eastern / Q000453:epidemiology; D005838:Genotype; D006801:Humans; D017720:Molecular Epidemiology