The recurring instances of Nipah infection in Kerala, especially in Kozhikode district in north Kerala, has stressed the need for in-depth studies to identify any specific reasons.
While the large extent of forest lands that attract birds and huge floating population from other states are generally assumed as the reasons, experts said that it was high time to have detailed studies.
Kerala witnessed a major Nipah outbreak in 2018 leading to the death of nearly 20 persons in Kozhikode district. Presence of virus was found in fruit bats, even as the exact source of the infection could not be traced conclusively.
In 2019, one person in Kochi got infected by Nipah. Even as he got cured, the source of infection was not identified.
A 12-year-old boy died of Nipah in Kozhikode in 2021. Though the source of infection was not identified, later tests found presence of antibodies against Nipah in specimens collected from some fruit bats in the region where the boy resided.
Now two deaths have been reported and four are under treatment with symptoms in Kozhikode.
WHO former technical officer Dr S S Lal told DH that it was unfortunate that despite recurring instances of the rare infection in Kerala, the state government did not initiate any serious studies. A person who got the infection in 2019 in Kochi is still alive. "It enhances the scope for detailed studies," he said.
Senior public health expert Dr V Ramankutty also said that it was quite curious why Nipah infection was recurring in Kozhikode.
Meanwhile, the health authorities have traced around 200 persons who came into contact with the infected in Kozhikode, and all are being monitored. Majority of them were learnt to be health workers.
While a 49-year old man hailing from Maruthonkara in the suburbs of the district died on August 30, another 40-year-old man hailing from Ayanchery in Vadakara, about 20 kilometres from Maruthonkara, died on Monday.
Son and brother-in-law of the 49-year-old were the others found infected.
Samples of more persons are also being tested.
The 49-year old had other ailments and hence no detailed examinations on the cause of death were conducted.
After the death of the 41-year old man at a private hospital on Monday with symptoms of Nipah, further examinations were done. Subsequently it was found that both the deceased visited a private hospital in Kuttiyadi in the district on the same day in August.
The 49-year old man, who was suspected to have contracted the infection first, was said to have visited some farms in the district. There are chances of the presence of fruit bats at the farm. Fruit bats are generally considered to spread the zoonotic Nipah virus.
Headache, encephalitis and respiratory difficulties are the common symptoms of Nipah infection. The case fatality rate was estimated at 40 to 75 per cent.