Doctors at the Beliaghata ID Hospital in Calcutta are keeping a close watch on a 26-year old man who has recently returned from Kerala and continues to show symptoms of the deadly Nipah virus. The good news, though, is that the state health department believes that the patient’s incubation period, typically the time elapsed between exposure to the virus and its multiplication threshold necessary to produce symptoms in the host, is already over and chances of the disease’s full-blown manifestation in the patient are slim.

The youth, a migrant worker from East Burdwan district, was admitted to the Calcutta National Medical College on September 11 with high fever, nausea, and a sore throat, all of which are Nipah symptoms alongside a multitude of other viral infections, after his return from Ernaklulam in Kerala, a state where the spread of the bat-borne virus has already created some amount of panic. He was transferred to the Beliaghata ID hospital on Tuesday evening on account of non-remission of fever and kept in isolation, it was learnt.

Dr Siddhartha Neogi, state director of health services, said: “The patient is past the incubation period. But since he returned from Kerala where several cases of Nipah virus infections have been reported, we are not taking any chances. Doctors are keeping a close watch on him."

No clarification was offered from the state health department on why the requisite tests to confirm or rule out the infection were not done on the patient despite him remaining in state-run hospitals for nine days, or whether there were plans to conduct those tests soon. Family members of the patient, however, said they had no knowledge of the hospital conducting any such tests on him yet.

Additional caution was being exercised by doctors on grounds that the patient was initially admitted to a hospital in Ernakulam after he complained of high fever. He returned to West Bengal after being discharged from the hospital but fell ill again within a couple of days. “We have learnt from the patient that two of his co-workers in Kerala were afflicted with the virus and perished,” an official said.