Kyasanur Forest disease is a viral hemorrhagic fever caused by Kyasanur Forest disease virus, a member of the Flaviviridae family. The disease is endemic to southwestern India and is associated with infected forest ticks. [1]
Disease overview
Kyasanur Forest disease
基亚萨努尔森林病
Evidence-backed informationEN 6/7 applicable sections · ZH 6/7 applicable sectionsUpdated Sep 3, 2026
Kyasanur Forest disease is a tick-borne viral hemorrhagic fever endemic to southwestern India. It is caused by Kyasanur Forest disease virus, a flavivirus transmitted through bites of infected hard ticks. [1]
Read the full clinical and epidemiological profile7
Reported manifestations include high fever, frontal headache, chills, severe muscle pain, vomiting, and other gastrointestinal symptoms. Bleeding may develop several days after symptom onset, alongside low blood pressure and reduced platelet, red blood cell, and white blood cell counts. A subset of patients has a second phase beginning around the third week, with fever and neurologic manifestations such as severe headache, mental disturbances, tremor, and visual deficits. [1]
Kyasanur Forest disease is endemic to southwestern India. Risk is described in settings where people interact with wildlife, particularly villages adjoining forest areas and interstate borders. [1]
Humans acquire infection through bites of infected nymphal hard ticks, particularly Haemaphysalis spinigera. Monkeys serve as major amplifying hosts, while several small mammals are considered potential reservoir hosts; humans are terminal hosts, and person-to-person transmission is not described. [1]
People who frequently enter forest areas of the Western Ghats may have increased risk. Risk is also described for people living in villages adjacent to forests or in border areas where human interaction with wildlife occurs, particularly among those who decline KFD vaccination. [1]
Avoiding exposure to infected ticks is relevant to prevention because transmission occurs through tick bites. Vaccination status is identified as a factor associated with risk among people who frequently visit forest areas of the Western Ghats. [1]
- 1Wikipedia contributors. Kyasanur Forest disease - Wikipedia [Internet]. Wikipedia. cited 11 Aug 2026.Available from: https://en.wikipedia.org/wiki/Kyasanur_Forest_disease
- 2Lasala PR et al. Tick-borne flaviviruses. Clin Lab Med. 2010 Mar. PMID: 20513549. doi: 10.1016/j.cll.2010.01.002.PubMed: https://pubmed.ncbi.nlm.nih.gov/20513549/
- A98.2
- 1D47.Y
Coverage
Reporting countries and regions
Trends by reporting country
Monthly patterns over time
Research Radar
Recent related research
Coverage and Effectiveness of Kyasanur Forest Disease (KFD) Vaccine in Karnataka, South India, 2005–10
PLoS Neglected Tropical Diseases
Literature links are provided for discovery and do not alter or validate the surveillance series above.
Data access
Page dataset index with source links and update metadata.
Official sourcesAuthority, cadence, notes1
JP NIID Weekly
Japan
Japan weekly infectious disease surveillance via NIID/JIHS.