India, Jan. 16 -- The source of the Nipah infection in West Bengal remains unconfirmed, with two possible routes under investigation

Officials are examining exposure to bat-contaminated date palm sap near the Bangladesh border and contact with a patient treated by the nurses

No additional cases have been detected so far

The source of the Nipah virus infection detected in West Bengal - the first such cases in the state in 19 years - remains unclear, with investigators examining two possible routes of transmission.

So far, two nurses have tested positive for the virus. Both are hospitalised and, according to state health department sources, are showing marginal improvement, though they remain at risk.

Initial investigations suggested t...