“So far there is no evidence to link the migratory birds with present outbreak of bird-flu in Dhule-Nandurbar, as far we know,” said Dr Taej Mundkur, an ornithologist and a member of scientific task force on ‘Wild Birds and Avian Influenza’, set up by United Nations.

Moreover, he told PTI, “Migratory birds land in India much early, ie in September-October. So if they at all had carried the virus, it would have been noticed much earlier.” He added though, that “theoretically” all species of birds” can carry the virus responsible for bird flu.

He said that there are various ways in which the virus can spread, but most commonly it spreads through poultry-droppings.

Until now, he said, that movement of poultry and poultry products has been found to be most common cause of spread of virus across the world. “Illegal trafficking of pet or exotic birds is also one of the ways the virus can travel across,” he said.

Another reason, he said, could be illegally made substandard vaccines, which, instead of immunising, may infect the birds.

Migratory birds not likely to spread virus, says UN expert