Kyasanur Forest disease, Monkey Fever, Kyasanur Forest Disease Virus, Siddapura, Karnataka, India

Monkey Fever (Kyasanur Forest Disease)

Kyasanur forest disease or KFD is a tick-borne disease, which mostly affects the south India or Western Ghats’ region. This is a type of viral disease and caused by the Kyasanur Forest disease virus (KFDV), which belongs to the Flaviviridae family and genus flavivirus. The viruses of this family also cause fatal diseases like dengue fever and yellow fever. The first case came into existence in a small village named Kyasanur of Karnataka, India in 1957. From the village, it’s got the name of Kyasanur Forest Disease.  

Recent Outbreak

The very recent outbreak, which has claimed two deaths in Siddapura, Karnataka, India. The peak season for this disease in Malnad is “March to May” but has arrived early this year in January. There are 55 positive cases reported from Shivamogga, Karnataka, but the situation is under control as described by professionals [7].

Kyasanur Forest Disease Virus

The genome of this virus is positive single-stranded RNA and the length is 11 kb, which encodes for 3416 amino acid polyproteins. These give rises to envelope E, capsid C, and pre membrane M and also encode for nonstructural proteins named as NS1, NS2a, NS2b, NS3, NS4a, NS4b, and NS5. NS5 is most conserved in these viruses and used as a diagnostic tool to detect the virus.


The causative agent is the Haemaphysalis spinigera tick which belongs to the Haemaphysalis group. These ticks infect animals like monkeys, porcupine, squirrel, rats and normally live in the forest so when people visit the forests for collection of wood or any other work, they might get bitten by a nymph of the tick. Through the bite, the virus can enter the bloodstream of the human body and cause viral hemorrhagic fever.
monkey fever transmission, Monkey fever, Kyasanur Forest Disease, Karnataka, South India
Transmission of Monkey Fever Disease virus

Signs and Symptoms

  • The incubation period is usually 3–8 days.
  • High fever (40°C/104 °F)
  • Frontal headaches
  • Vomiting, Nausea, and photophobia
  • Diarrhea
  • Bleeding can start from gums, nose, intestines and sometimes bleeding can be caused in lungs and blood can be seen in sputum
  • In severe cases, encephalitis could be result and also cause a mental disturbance, vision impairment, tremors, etc.
  • The mortality rate of the disease is 2–10% and the disease affects the elder people and patients with morbidities.


  • PCR studies could be done to detect the virus, primers are used to detect the presence of NS-5 gene (Non-structural gene 5), which is highly conserved in KFDV.
  • Enzyme-linked ImmunoSorbent Assay (ELISA) can be performed to check immunoglobin M antibodies.

Prevention and Epidemiology

The formalin-inactivated tissue cultured vaccine has been used since 1990 in Karnataka’s five endemic districts which are Chikmagalur, Udupi, Shimoga, Uttar Kannada, and Dakshina Kannada and other affected states such as Karnataka including Maharashtra, Kerala, Gujarat, Goa, and Tamil Nadu. Dyeing of monkeys and other animals can be monitored in forest areas and sanctuaries, wildlife parks and national parks. Workers and people who work in these areas are at high risk of getting infected so they should use precautionary measures.


There is not well-proven therapy is available, timely hospitalization is necessary and treatment is based on supportive medicine. Continuous monitoring of patients is required and checking the BP, cells counts and taking care of hydration is important. For severe cases antimicrobial drugs can be administered, blood transfusion could be performed; pain killers and antipyretics could be given. Corticosteroids and anticonvulsants are given for the nervous related problem. There is no approved vaccination for the KFDV; vaccination is only available for the ticks.


  1. Yadav PD, Patil S, Jadhav SM, et al. Phylogeography of Kyasanur Forest Disease virus in India (1957-2017) reveals evolution and spread in the Western Ghats region. Sci Rep. 2020;10(1):1966. Published 2020 Feb 6. doi:10.1038/s41598-020-58242-w
  2. Shah SZ, Jabbar B, Ahmed N, et al. Epidemiology, Pathogenesis, and Control of a Tick-Borne Disease- Kyasanur Forest Disease: Current Status and Future Directions. Front Cell Infect Microbiol. 2018;8:149. Published 2018 May 9. doi:10.3389/fcimb.2018.00149

Pic Source: Pixabay

Keywords: Monkey Fever, Monkey disease, Kyasanur Forest disease, Karnataka Fever, Monkey Fever 2020, Monkey fever outbreak

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