Kyasanur Forest disease virus (KFDV) is enzootic to In-dia and maintained in ticks, mammals, and birds. It causes severe febrile illness in humans and was first recognized in 1957 associated with a high number of deaths among monkeys in Kyasanur Forest. Genetic analysis of 48 virus-es isolated in India during 1957–2006 showed low diversity (1.2%). Bayesian coalescence analysis of these sequences and those of KFDVs from Saudi Arabia and the People's Republic of China estimated that KFDVs have evolved at a mean rate of ≈6.4 × 10–4substitutions/site/year, which is similar to rates estimated for mosquito-borne flaviviruses. KFDVs were estimated to have shared a common ancestor in ≈1942, fifteen years before identification of the disease in India. These data are consistent with the view that KFD rep-resented a newly emerged disease when first recognized. Recent common ancestry of KFDVs from India and Saudi Arabia, despite their large geographic separation, indicates long-range movement of virus, possibly by birds
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