Banna Virus, China, 1987–2007

Banna viruses (BAVs) have been isolated from pigs, cattle, ticks, mosquitoes, and human encephalitis patients. We isolated and analyzed 20 BAVs newly isolated in China; this finding extends the distribution of BAVs from tropical zone to north temperate climates and demonstrate regional variations in BAV phylogeny and mosquito species possibly involved in BAV transmission.