Dr Basavaprabhu
Mangaluru, Dec 15: KFD is an abbreviation for Kyasanur Forest Disease, also known as monkey fever. It is a type of viral haemorrhagic fever caused by the Kyasanur Forest Disease virus, which is part of the family Flaviviridae. It mainly occurs in some districts of Karnataka, namely Shivamogga, Dakshina Kannada, Udupi, Uttara Kannada and Chikkamagaluru. The disease was first identified in 1957 in the forests of Kyasanur in Shivamogga district, from which it derives its name.
The disease spreads to humans through tick bites. Monkeys are the main reservoirs of this virus, and there is no human-to-human transmission. Infection mainly occurs through handling dead monkeys or through bites from ticks that carry the virus. The primary hosts are monkeys, especially macaques, found in the Western Ghats region.
The common symptoms are similar to other viral fevers and usually occur in two phases — the initial febrile phase and a later encephalitic or complication phase. The initial phase is characterised by high-grade fever and headaches, especially frontal headache. It may sometimes be associated with bleeding manifestations, joint pains, myalgia, eye pain, and rarely diarrhoea and vomiting. These symptoms can mimic dengue fever. The disease is commonly seen during the months from December to May, when tick activity is at its peak.
The disease is often identified by the presence of dead monkeys in forest-dwelling areas. People such as hunters and those who work or live in forest areas are more prone to acquiring this infection. During the later phase, which can occur after a transient recovery period of one to two weeks, patients may present with confusion and seizures. Encephalitis may occur in about 10 to 20 per cent of patients and can sometimes lead to death.
People living in forested areas, farmers, cattle grazers, hunters and those who work in forests are at high risk. Veterinarians working in these regions and handling animals are also at risk. Precautions for people working in these areas include the use of tick-repellent creams, wearing full-sleeved clothing, avoiding venturing into forests during the peak tick season from December to May, regularly inspecting the body for tick bites, and wearing boots to prevent bites. People should also avoid touching or handling monkey carcasses and should inform the health department and forest officials if dead monkeys are found.
The disease can also be prevented by vaccination for people at risk of exposure. A live attenuated vaccine is available and is given in two doses one month apart, followed by a booster after nine months. Thereafter, booster doses can be taken once every five years. The disease has no specific cure, but most cases are self-limiting and do not cause complications. The case fatality rate varies from 3 to 10 per cent. Haemorrhage, encephalitis and shock are the usual causes of death.
Patients who appear very ill, have bleeding manifestations, significant prostration, feeble pulse, confusion, seizures or altered sensorium should be immediately shifted to a hospital. Supportive and symptomatic management, including fluids, inotropic support, platelet transfusions if required, and appropriate management of encephalitis, should be undertaken.
(Dr Basavaprabhu, Consultant Internal Medicine, KMC Hospital, Mangaluru)