Nipah Virus ‘Reservoir’ Detected in Cooch Behar in West Bengal and Dhubri in Assam
Fruit bats caused the Nipah virus outbreak. (Photo Credits: Flickr, shellac)

After the death of 17 people in Kozhikode and Malappuram districts of Kerala, the Nipah virus has been successfully routed out of the state. Kerala Health Minister KK Shylaja spoke to PTI on Sunday, stating that both districts have been declared Nipah free. But two findings, one by the Indian Council of Medical Research (ICMR) and National Institute of Virology (NIV) have made some groundbreaking revelations.

The findings of ICMR have confirmed that fruit bats, which were earlier exonerated, has been found to be the source of the virus. Pune’s National Institute of Virology (NIV) confirmed that out of 51 fruit bats from Kozhikode sampled by the virology team at the institute, 11 was tested to have genetic material from the Nipah virus.

The genetic material from the virus was detected with a test called Reverse Transcriptase Polymerase Chain Reaction and it was a 99 percent match with the virus found in the patients. NIV director Devendra T Mourya told The Hindu that this conclusively points to the role played by bats as the carriers of the disease in the Kerala outbreak.

While the finding is important, it still doesn’t explain how the virus found its way into the human body. Epidemiologist Jonathan Epstein told The Hindu that the information is crucial to prevent future outbreaks. The Bangladesh outbreak of Nipah was the result of patients drinking raw date-palm sap infected by the fruit bats. But in Kerala, no such instance has been reported since date-palm sap is not consumed in the state.

A recent study by NIV shows that the virus could be present in previously unexplored regions of the country. The findings of their latest study in the Indian Journal of Medical Research, where fruit bats in West Bengal and Assam were tested positive for the Nipah virus. A 107 bats collected from Cooch Behar, Jaipaiguri in West Bengal and Dhubri in Assam were tested. These regions have a close proximity to Bangaldesh, which raises the possibility that the virus is circulating in the same region. Nine samples of bats from the region tested positive for the Nipah virus. This means that several states in India harbours bats with the virus, which calls for better surveillance of the animals.

The researchers noted that during the study, large colonies of bats were in close proximity to human settlements in Dhubri, Assam and Cooch Behar districts. This shows how the virus spilled over to the humans. The presence of the virus in the bats in a previously unexplored region shows that necessary steps should be taken to detect other reservoirs of bats in the northeast India.