Infection being reported in the State for the first time
A case of the Kyasanur forest disease, a viral disease transmitted to human beings through a species of ticks usually found on monkeys, has been reported from the Noolpuzha-Aalathoor colony in Wayanad district. The 18-year-old patient now at the Government Medical College Hospital, Kozhikode, is reportedly out of the critical state.
This is the first time that the zoonotic disease is being reported in Kerala, health officials told The Hindu. The disease has been found in Shimoga, the district where it was first detected in 1957, Dakshina Kannada, Chikmagalur and in Karnataka.
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, according to literature.
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 five per cent to 10 per cent.
While surveillance activities have been stepped up in the forest areas on the Wayanad-Karnataka border, no other case has been detected, Wayanad District Surveillance Officer Srikumar Mukundan said.
“We detected the case through active fever surveillance and it was first taken for dengue fever. When the blood test was negative for dengue and there was no response to antibiotics, the samples were sent to Manipal Hospital and the National Institute of Virology, Pune. Both institutes have confirmed it to be a case of the Kyasanur forest disease,” Dr. Mukundan said.
He said the possibility of this viral infection spilling across the Karnataka-Kerala border had been discussed at an inter-State border meeting of health officials of Kerala, Karnataka and Tamil Nadu about three months ago. An alert was issued to medical officers then.
“We were told that the presence of the virus should be suspected if there is a mass death of monkeys anywhere in the forest area. The case now reported seems to be an isolated one, but we have alerted the Forest Department’s range wardens in the district. We are proposing to conduct an awareness class for them,” Dr. Mukundan said.
Information provided by the Indian Council for Medical Research says the virus is a highly pathogenic member in the family Flaviviridae, which causes dengue and yellow fever. The pathogen was named after the forest area where it was first detected in 1957.
Though the virus has been isolated from 16 species of ticks, the species Haemaphysalis spinigera is the 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. Campers or others passing through the forest get the disease from the bites of infected nymphs of the tick or through contact with the infected monkey or even a monkey which died recently from the infection.
Health officials said that they did not expect more cases because the infected nymphs of the ticks were active through January to May. Once the rains start, the ticks remain dormant in the forest litter. They come alive post-monsoon when the temperature starts rising.
Till now there is no evidence of man-to-man transmission of the virus. The National Institute of Virology has developed a vaccine for the disease and this is available in Karnataka, where in recent years the number of human cases has been going up.
Once infected, timely supportive management is the only treatment modality, as in the case of dengue fever.