The lack of proper surveillance and dependence of a sizeable chunk of the population on poultry farming seems to be standing in the way of preventing another recurrence of bird flu in areas in and around West Bengal which has seen a spate of outbreaks since January 2008.

“Chances of the human infections are indeed high. Human infections occur when the virus mutates, but we know very little about the mechanism,” says Shekhar Chakraborty, deputy director at Kolkata’s National Institute for Control of Endemic Diseases.

Experts fear the H5N1 virus might mutate or combine with the highly contagious seasonal influenza virus and spark a pandemic that could kill millions of people. “I have given a proposal to the Health Secretary that we want to do a survey of human influenza in Bengal villages,” adds Chakraborty.

In recent months, areas like Sikkim, Darjeeling, Assam and Nepal have been affected by the outbreak, while Bangladesh — from where the deadly H5N1 virus was suspected to have sneaked into Bengal — continues to report new cases almost every month. While more than 30,000 birds have been culled in West Bengal over the past year, as many as 30 dead birds from Ravang La in southern Sikkim tested positive for the virus at a central laboratory.

Similarly, thousands of birds had to be culled in Nepal and Assam over the past few months.

Experts say frequent and recurring outbreaks of bird flu increase the risk of human infection. In fact, it was in Bengal that backyard poultry was infected for the first time, suggested a higher risk of human infection in the state. The problem is compounded by the fact that there is no human surveillance mechanism in place. The Government has also failed to find the source of the H5N1 virus, despite the fact that the first outbreak was reported in 2006.

... contd.