Monkey Fever or Kyasanur Forest Disease is a tick-borne viral disease. It is caused by Kyasanur forest disease virus (KFDV), a member of the virus family Flaviridae, which also causes dengue and yellow fever.
The virus has been detected in monkeys in parts of Bandipur National Park (Chamarajnagar) and parts of the Nilgiris. It is endemic to South Asia and was first detected in 1957 in Kyasanur Forest of Karnataka. The disease first manifested as an epizootic outbreak among monkeys killing several of them in the year 1957. Hence the disease is also locally known as Monkey Disease or Monkey Fever. The vector responsible for its transmission is ticks (Hemaphysalis spinigera).