Concerned by the recent Nipah outbreak in West Bengal, the state government has decided to launch a survey of bats in a bid to identify the source of the infection.

According to an official with the forest department, the survey will start from Nadia district, as primary investigation indicates that the infection may have originated in the region. A senior official with the health department said, “Nipah virus generally spreads from bats, which is why a survey of bats will be conducted.”

Around 100 people in West Bengal have been advised to stay in home quarantine after two nurses at a private hospital in Barasat, North 24 Parganas district, tested positive for Nipah virus on Monday.

A senior Forest Department official said, “We have just given the permission to conduct the bat survey. A special committee will conduct the entire study as we don’t have the necessary expertise. They will collect blood and urine samples of bats from vulnerable areas and the samples will be sent for culture.”

“Once the culture report is available, the source can be identified. The expert committee will decide whether to conduct the survey in other districts,” he added.

Around 30 of those in quarantine are being closely monitored even as the condition of the nurses – a man from Purba Medinipur district and a woman from Mongolkot in Purba Bardhaman district – remain critical, sources indicated.

Contact tracing indicated that the female nurse attended a family wedding in Nadia on December 15 and 17. From there, she visited several places, including Shantiniketan. After falling ill, she was admitted to a medical college in South Bengal on January 2. She is currently on ventilator support. Health authorities suspect she may have contracted the virus after consuming raw date palm sap during her visit to Nadia.

According to her neighbors, since she developed the initial symptoms, very few people, apart from her immediate family, came in contact with her. All of them have been quarantined.

The male nurse was on night duty at the hospital with the female nurse on December 20 and 21.

A senior health official said, “We suspect the infection or contamination started in Nadia where the female nurse went for a family ceremony. We will start collecting blood and samples from bats in Nadia first. We will then continue the survey in other districts.”

“The case of the male nurse seems to be due to human-to-human transmission. The National Institute of Virology (NIV), Pune have also confirmed Nipah virus,” an official said.

While the woman remains critical, the male nurse is out of ventilator support.