Yet another Kyasanur Forest Disease outbreak in Karnataka: All about KFD

Dr KK Aggarwal, Padma Shri Awardee

New Delhi, January 10, 2019: Yet, another outbreak of Kyasanur Forest Disease (KFD), a viral haemorrhagic fever has been reported in some villages of Shivamogga district in Karnataka. Six deaths have been reported due to the disease.

Here are some salient facts about KFD, also known as monkey fever.

• KFD is a reemerging zoonotic disease caused by the KFD virus.
• The disease is derived from Kyasanur forest area in Shimoga district of Karnataka in 1957. It is now endemic in India, along the Western Ghats. Cases have been reported in China.
• The KFD virus is an arbovirus, genus flavivirus and family Flaviviridae.
• Humans acquire the infection by bite of infective ticks.
• The main reservoirs of the virus are small mammals, especially rats and squirrels. Monkeys are amplifying hosts for the virus. Man is an incidental dead end host. Human to human transmission has not been reported.
• The epidemic period usually begins in October or November and peaks from January to April, then declines by May and June.
• Incubation period is 3-8 days after an infective tick bite.
• Clinical presentation: Sudden onset of high grade fever with chills, intense frontal headache and severe myalgia, prostration. In severe cases, GI disturbances and hemorrhagic symptoms (bleeding from nose, gums, stomach and intestine) may occur.
• In some cases, a second phase of illness occurs after an afebrile period of 7-21 days. Clinically, it manifests as return of fever, severe headache, neck stiffness and coarse tremors and presents as meningoencephalitis.
• Diagnosis is established via PCR, virus isolation from blood or enzyme-linked immunosorbent serologic assay (ELISA).
• Case fatality rate is 2-10%. Fatality is higher in the elderly and in the presence of comorbidities such as liver disease.
• Prevention is by control of ticks in forests by insecticide spraying of the endemic zones and “hot spots” in the forests i.e. within 50 m of the area where monkey deaths have occurred; wearing adequate clothing and using insect repellents (DEET).
• At risk population should be vaccinated with killed KFD vaccine.
• There is no specific treatment for KFD; treatment is supportive with maintenance of hydration and circulation.

(Source: Park’s Textbook of Preventive and Social Medicine, Integrated Disease Surveillance Programme (IDSP)-National Center for Disease Control)