As her stool samples could not be retaken to confirm the virus strain, the health officials in Bihar took samples from healthy children who came in close contact with her during her stay in Bihar.

When the sample of one of these otherwise healthy children tested positive for the wild poliovirus, it confirmed that Shobha was also infected with the same virus and was a possible transmitter.

Back from Rohtas, her native village in Bihar, Shobha’s mother did not want to speak about her daughter as it reminds her of the suffering her only child went through before her death. Ab kyon aate hain sab log. Jab zinda thi tabhi toh kuch nahin kiya, ab kya faida. Kuch karna hi hai toh jo bache zinda hain unke liye karo,” she says as she is consoled by neighbours.

According to Lilavati, Shobha was suffering from high fever for a month before paralysis set in on one leg. “I took her to several doctors here, even the civil hospital. But they couldn't do anything,” she said.

“Finally, we went to Bihar because we know people there,” she said, adding that all polio doses and routine immunisation had been administered to Shobha.

Lilavati is not ignorant about polio or the measures being taken by the government to curb its spread among children. Her elder brother-in-law is a health worker in Bihar who goes from door to door in their village to administer the oral polio vaccine, she said.

“The vaccine needs to be kept in an ice-box. It loses its effect if kept outside. No one sees that over here while administering the vaccine,” she said.

Locals echo her complaint about the way the polio immunisation campaign is run in their locality. “They (health workers) come and sit in the booth on polio day. During their rounds, they just mark houses blindly. They even mark the houses that are rented to people with no children,” said Urmila Yadav, Lilavati’s neighbour.

“We have a system in place which does the surveillance. First, it's the health worker then the supervisor who takes the round and finally a WHO officer looks into the coverage. Sometimes workers make errors but those are detected and necessary action is taken,” said Dr Prakash Doke, Director of Health Services, Maharashtra.

Maharashtra health officials have now taken samples from Janakipada to confirm “for academic interest” whether the virus was transmitted in Vasai as they debate its origins.

“We are eagerly awaiting the results of the samples taken from Vasai. It will tell us the origin of the virus. The results will be out in a few weeks,” Doke said.

In the meantime, two months after the second polio case from Maharashtra came to their notice this year, the health officials do not have any independent information on the presence of the virus in the environment. Till a major fire shut down the Indian Council for Medical Research-run laboratory at the Haffkine Institute in 2005, regular samples from major sewerage sites were tested there for the presence of the wild poliovirus. The laboratory is yet to resume operations.

“We do not have any independent information from sewerage sites as the laboratory is still shut,” said Doke.