Kerala reports seventh Nipah outbreak since 2018

New Nipah virus case confirmed in Kerala, with samples testing positive for the virus in a 42-year-old woman.

On May 8, a new case of Nipah virus was confirmed in Kerala in a 42-year-old woman from Valanchery in Malappuram district. On May 6, testing for the Nipah virus was first undertaken at the Calicut Medical College. When the tested samples were positive for Nipah, a sample was sent to the National Institute of Virology (NIV), Pune on May 7 afternoon for Nipah confirmation. The NIV confirmed Nipah on May 8 afternoon.

According to Dr. T.S. Anish, Nodal Officer, Kerala One Health, Centre for Nipah Research and Resilience, and Professor of Community Medicine at Government Medical College, Kozhikode, samples tested using Truenat came positive for the Nipah virus. To confirm the result, samples were tested in the microbiology lab using RT-PCR. Only the urine sample tested positive for the Nipah virus, says Dr. Anish.

According to him, blood and throat swab samples did not test positive for the Nipah virus. “This may be because of the late stage of viraemic infection. Viruses do not persist in the body for long and hence the blood and throat swab samples did not test positive for the virus, while the urine sample alone tested positive,” he says.

Samples collected from the infected person’s contacts were tested at the Manjeri Government Medical College in Malappuram district. All seven high-risk individuals closely connected to the woman tested negative for Nipah on May 8.

The patient had minor symptoms on April 25, and presented with worsened clinical symptoms on May 1 and was admitted to the EMS Hospital at Perinthalmanna. Her condition worsened by noon the following day and was shifted to the critical care intensive care unit, intubated and ventilated. She exhibited acute encephalitis syndrome and had classic symptoms of dengue. She tested positive for dengue and hence Nipah was not suspected. It was only when her condition did not improve that samples were sent for Nipah testing two days later.

The Nipah outbreak now reported is the seventh instance in Kerala. The first outbreak was reported in 2018, followed by outbreaks in 2019, 2021, 2023 and 2024. Last year, Kerala reported two Nipah outbreaks — July 21 in a 14-year-old boy and the second one on September 15 in a 24-year-old adult. Both outbreaks in 2024 were in Malappuram district.

With the May 8 outbreak, there have been three Nipah outbreaks in Malappuram district in all.