Kerala: Alert issued against Nipah virus from April to September

Health officials in Kerala have issued an alert against Nipah infections in the State from April to September.

With cases being reported frequently here since 2018, the focus is on Kozhikode, Malappuram, Palakkad, and Thrissur districts. Awareness campaigns for children are also planned as some of the victims in recent years have been from that age group.

Kerala has had Nipah outbreaks in 2018 and 2023, both in Kozhikode, one spillover case each in 2019 and 2021, two spillover cases in 2024, and four such cases in 2025, most of which were in Kozhikode, Malappuram, and Palakkad. Spillovers are single instances of the infection while outbreaks include human-to-human transmissions.

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Outbreak patterns

According to T.S. Anish, nodal officer, Kozhikode-based Kerala One Health Centre for Nipah Research and Resilience, the Nipah virus is found to have been active in Kerala in the the six-month period starting in April. “The first outbreak in the State was in early May 2018. That patient could have got infected by the end of the previous month. At the same time, the highest number of cases so far have been in September. In the 2023 outbreak, the first patient died on August 30. But, subsequent cases – the others who got infected from him – were reported in the next month. We have had cases in September 2025 as well,” he says. Dr. Anish points out that no cases have been recorded in the six months after September till now.

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When asked about the reason for this phenomenon, he says that the infection has been found to transmit through fruits in Kerala since fruit bats are the “natural reservoirs” of the virus. The fruiting season in the State is around April. The breeding season of bats is in April-May and then in September, when they become more aggressive, Dr. Anish says. Virus shedding could increase during the period.

“Also, most of the cases have been in the six districts south of Kannur. Another pattern is the infection going southwards. From Kozhikode to Malappuram, then to Palakkad and to Thrissur, possibly because of the shifting of the bat roosts from one place to another. We are planning to focus also on Thrissur,” he says. Perinthalmanna in Malappuram and Kozhikode city have become the two most important places because of the presence of corporate hospitals and tertiary care government hospitals where Nipah patients are getting admitted.

Awareness sessions

The health officials are also planning awareness sessions focussing on children. “Two of those who succumbed to the infection so far were children from Kozhikode and Malappuram districts. There is a possibility of children picking fruits and spending time in the vicinity of the bat roosts,” Dr. Anish says.

Avoiding fruits lying on the ground or those bitten by bats, washing and peeling of fruits before consumption, and keeping away from bat roosts are some of the steps suggested to avoid the infection. The symptoms include fever, headache, muscle pain, and respiratory problems. Ensuring hand hygiene and wearing of face masks in public are among the preventive steps.