About the disease
Kyasanur Forest Disease (KFD), locally called "monkey fever", is a tick-borne haemorrhagic fever endemic to the Western Ghats and adjacent forest belts in India. It primarily affects people who spend time in the forest — tribal communities, agricultural workers, hunters, forest staff and pilgrims.
The disease follows a biphasic pattern: sudden high fever, severe headache and muscle pain (phase 1) in around 3–8 days after tick exposure, and in about 15 % of patients a second neurological phase begins after a brief remission.
- Sudden high fever (> 39 °C), chills
- Severe muscle pain, headache, photophobia
- Bleeding from nose, gums or GI tract
- Second-phase neurological signs (confusion, tremors) in ~15 % of cases
Causative agent & transmission
Pathogen
Kyasanur Forest Disease Virus (KFDV) — a member of the tick-borne encephalitis complex of the family Flaviviridae, genus Flavivirus. Single-stranded RNA virus, enveloped, ~50 nm in diameter.
Vector
Hard tick Haemaphysalis spinigera is the principal vector. Nymphs are the main biting stage transmitting the virus to humans. Peak tick activity: Nov–May.
Reservoir hosts
Small forest rodents and shrews maintain the virus in nature. Primates — langurs & bonnet macaques — act as amplifying hosts and typically die from the infection, which is why monkey die-offs are a sentinel warning.
Route of exposure
Humans get infected via tick bite, usually in forests and forest-fringe farmland. No person-to-person spread. Humans are dead-end hosts.
What is happening right now
A rapid response team from the Directorate of Public Health, Tamil Nadu, is coordinating with the Forest Department, IDSP surveillance and the NCDC Centre for One Health. Case confirmation is being done at ICMR-NIV, Pune. Ring vaccination has been initiated in Kotagiri and Gudalur blocks; tick control (acaricide application) is under way at monkey carcass sites.
Red zones — where extra caution is needed
Active human transmission. Monkey mortality reported. Forest visits discouraged except for essential work with full PPE.
Increased tick activity, no confirmed human cases yet. Vaccination camps & carcass surveillance active.
Two langur carcasses tested positive by NIV Pune. Ring vaccination initiated. Villages within 3 km on watch.
No cases; historical risk profile. Enhanced surveillance and community awareness.
Step-by-step precautions
Drawn from US CDC's Kyasanur Forest Disease prevention guidance, the NCDC Technical Guidance on Zoonotic Disease and ICMR-NIV Pune KFD vaccine protocols. Every step below cites the source it is drawn from.
Use insect repellent containing DEET
US CDCUS CDC's direct KFD guidance: "Use insect repellent containing DEET to prevent tick bites." Apply 20–30 % DEET on exposed skin, and permethrin on clothing (do NOT apply permethrin directly to skin). Reapply every 4–6 hours in the forest.
Consider getting the KFD vaccine if you live in an endemic area
US CDC ICMR-NIVUS CDC: "Consider getting the KFD vaccine if you live in or are traveling to an area where KFD is found." ICMR-NIV Pune's protocol: two doses of the KFD-Shimoga formalin-inactivated tissue-culture vaccine 4 weeks apart, followed by an annual booster. Free camps at PHCs in Kotagiri, Gudalur and Coonoor.
Avoid contact with dead or sick animals, particularly monkeys
US CDCUS CDC's third core recommendation: "Avoid contact with dead or sick animals, particularly monkeys." Monkey die-offs are a sentinel warning. Infected ticks leave a dead monkey and can bite anyone nearby — do NOT touch, move or bury a carcass. Mark the spot, stay at least 20 m away, and call the Forest Range Officer (1926) or the District Health Officer.
Cover skin with light-coloured clothing before forest entry
NCDCNCDC Technical Guidance on Zoonotic Disease recommends full-sleeve shirts, full pants tucked into socks, and closed footwear (boots) for anyone entering a KFD endemic forest. Light colours make it easier to spot ticks. Avoid shorts and open sandals in the forest.
Do a full body tick-check after every forest visit
US CDC · Tick preventionStandard CDC tick-borne disease guidance (which US CDC's KFD page cross-references): check armpits, groin, behind ears, waistband and hairline. Ticks are the size of a poppy seed. Remove with tweezers grasping close to the skin — pull straight out, do not twist.
Fever within 14 days of forest exposure? Go to PHC the same day
NCDCUnder NCDC's zoonotic-disease surveillance protocol, any sudden fever within 14 days of forest exposure warrants a same-day visit to the nearest Primary Health Centre. Mention the forest visit and possible tick bite so early management can be initiated — this reduces the risk of the biphasic neurological phase.