- 1 Introduction: Kyasanur forest disease?
- 2 History of the Kyasanur forest disease
- 3 Who are the Kyasanur forest disease hosts?
- 4 Where does Kyasanur forest disease occur?
- 5 Kyasanur forest disease: Distribution in India
- 6 How is Kyasanur forest disease spread to humans?
- 7 What are the symptoms of Kyasanur forest disease?
- 8 Who is at risk from the Kyasanur forest disease?
- 9 How is Kyasanur forest disease diagnosed?
- 10 Is Kyasanur forest disease fatal?
- 11 How can Kyasanur forest disease be prevented?
- 12 How Kyasanur forest disease is treated?
Introduction: Kyasanur forest disease?
- Kyasanur forest disease (KFD) is caused by Kyasanur forest disease virus (KFDV).
- Kyasanur forest disease virus (KFDV) is of zoonotic origin (originating from animals).
- KFD virus belongs to Russian Spring Summer Encephalitis group, a member of family Flaviviridae.
- KFDV was identified in 1957 when it was isolated from a sick monkey from the Kyasanur forest in the Karnataka (formerly Mysore) State, India.
- It is also locally known as Monkey Disease or Monkey Fever.
- Kyasanur Forest Disease (KFD), is an infectious bleeding disease in monkey and human caused by a highly pathogenic virus called KFD virus (KFDV).
- Kyasanur forest disease virus (KFDV) is ranked as one of the highest risk category pathogenic virus belonging to Bio-safety Level-4, showing this virus needs to be handled extremely carefully.
History of the Kyasanur forest disease
- The first epidemic season of KFD in human was observed in Jan – May, 1956 when four villages were affected. In 1957, KFD spread to more than 20 villages and by 2003 it had affected more than 70 villages in four districts adjacent to Shimoga in western Karnataka.
- In 1957 KFDV was isolated from this tick, the primary vector, and later in sixteen other tick species as well.
Who are the Kyasanur forest disease hosts?
- It is transmitted primarily by infective tick, Haemaphysalis Spinigera, which is Kyasanur forest disease’s major vector.
- Monkeys which come in contact with the infected ticks in the forest get the virus and act as the amplifying host.
- Some small mammals such as rats and shrews are known to act as hosts for the virus.
- Till now there is no evidence of man-to-man transmission of the virus.
Where does Kyasanur forest disease occur?
- KFD is limited to Karnataka State, India.
- Though a variant of the virus has been identified in Saudi Arabia in recent years, the disease has not been reported elsewhere in the world.
Kyasanur forest disease: Distribution in India
How is Kyasanur forest disease spread to humans?
- The main hosts of KFDV are small rodents, but shrews, bats, and monkeys may also carry the virus. KFD is transmitted from the bite of an infected tick (Haemaphysalis spinigera is the major vector). Humans can get these diseases from a tick bite or by contact with an infected animal, such as sick or recently dead monkey.
- Larger animals such as goats, cows, and sheep may become infected with KFD, but they do not have a role in the transmission of the disease. Furthermore, there is no evidence of the disease being transmitted via the unpasteurized milk of any of these animals.
What are the symptoms of Kyasanur forest disease?
- KFD symptoms at onset in human are sudden chills, high fever, frontal headache, heightened sensitivity to light, followed by continuous fever for 12 days or longer often associated with diarrhea, vomiting, cough, severe pain in the neck, low back and extremities, accompanied by severe prostration & bleeding problems.
- Patients may experience abnormally low blood pressure, and low platelet, red blood cell, and white blood cell counts.
- After 1-2 weeks of symptoms, some patients recover without complication.
- However, in most patients, the illness is biphasic and the patient begins experiencing a second wave of symptoms at the beginning of the third week. These symptoms include fever and signs of encephalitis (inflammation of the brain).
Who is at risk from the Kyasanur forest disease?
- People with exposure to rural or outdoor settings (e.g., hunters, campers, forest workers, farmers) are potentially at risk for infection by contact with infected ticks.
How is Kyasanur forest disease diagnosed?
- The diagnosis is made by virus isolation from blood or by serologic testing using enzyme-linked immunosorbent serologic assay (ELISA).
Is Kyasanur forest disease fatal?
- There are approximately 400-500 cases of KFD per year.
- The infection, which starts with high fever and body ache, produces a haemorrhagic reaction in the body, similar to that produced by dengue fever, and has a mortality rate of 5 to 10 per cent.
How can Kyasanur forest disease be prevented?
- There is no specific treatment for KFD, but supportive therapy is important. Supportive therapy includes the maintenance of hydration and the usual precautions for patients with bleeding disorders.
- Utilizing insect repellents and wearing protective clothing in areas where ticks are endemic is recommended.
How Kyasanur forest disease is treated?
- Spearheaded by National Institute of Virology at Pune in India, a vaccine has been made available since 1966.
- Formalin inactivated KFDV vaccine is prepared by growing the virus in chick embryo fibroblast cells by employing modern cell culture techniques. This vaccine is currently used in the endemic areas of KFD.
- Over 50 thousand doses of KFDV vaccine are administered annually. Despite this prophylactic effort, reports of large numbers of KFD cases from Karnataka highlights a need for a fresh look into vaccine preparation as well as post-production vaccine handling and overall disease management protocols.
- Though KFD is still an epidemic that threatens periodically, identification of KFDV and development of a largely effective vaccine, is in itself considered to be a success story in Indian science scenario.
- Once infected, timely management is the only treatment, as in the case of dengue fever.