A Maharashtra Poultry Welfare Association member eats chicken in Pimpri to convince people to buy poultry again. (PTI)

New Delhi, Feb. 25: Medical tests have shown that none of the 95 people in Navapur who had handled the diseased poultry were infected with even type A influenza ? the family of flu viruses of which H5N1 is a member, scientists claimed today.

The deadly avian influenza virus is just one among many possible sub-types of influenza viruses such as H3N2 or H1N1 or H1N3, most of them less dangerous, and some of them known to cause sickness in humans.

A rapid test kit that was part of the standard guidelines for suspected influenza diagnosis had indicated that none of the 95 patients had even type A influenza, Nirmal Kumar Ganguly, the director-general of the Indian Council of Medical Research, said. “But these rapid test kits have very low sensitivity and need a significant load of viruses in the samples for detection.”

So, despite the negative result for influenza A, the investigating laboratories used another set of tools called polymerase chain reaction tests to specifically look for the genetic signatures of H5N1 in the samples, Ganguly told The Telegraph.

The genetic tests did reveal some non-classical signals that were difficult to interpret, but there was no conclusive evidence of H5N1, Ganguly said. “We also tried to grow the virus by trying to multiply it in cells, but we’ve not got any virus so far.”

However, the National Institute of Virology in Pune will seek to validate these findings through influenza detection kits from Hong Kong and the US Centers for Disease Control that are expected to arrive on Monday, Ganguly said.

Virologists had been puzzled by assertions by investigating scientists earlier this week that there was no sign of H5N1 in the samples. “What they didn’t tell us was whether they found type A influenza or not, which is important,” a virologist said.

The absence of type A influenza would imply that the 12 people who had been under observation in hospital with upper respiratory infections were infected by one of the myriad other organisms that cause sore throat, cold and mild fever.

All 12 patients are recovering from what appear to be upper respiratory infections. “I’ve seen patients with influenza. By no stretch of imagination did any of these patients have clinical symptoms that came even close to influenza,” Ganguly said.

Animal husbandry officials said culling operations are on in a district in Gujarat neighbouring Navapur where poultry had tested positive for H5N1. “It appears to be part of the same outbreak,” an official said.