Indian authorities inspected poultry markets on Thursday in an attempt to prevent the country's worst outbreak of bird flu from spreading to crowded Calcutta, as Thailand announced a new outbreak, prompting the United Nations to warn of the global threat posed by the virus.
The danger of the virulent H5N1 strain of the disease was illustrated in Indonesia, where a man from the outskirts of Jakarta died of bird flu on Thursday, bringing the country's death toll to 98. On Wednesday, Vietnam announced its first death this year, taking its toll to 48 since the virus began devastating Asian poultry stocks in late 2003.
Bird flu has killed at least 219 people worldwide, according to the World Health Organisation. Although it remains hard for humans to catch, experts fear it will mutate into a new form that spreads easily among people, potentially sparking a pandemic.
Calcutta health officials searched poultry markets on Thursday, looking for signs of infected birds after the virus was discovered just 30 kilometers (18 miles) from the city of 14 million people.
"We are keeping a strict vigil," said DD Chattopadhyay, the city's chief medical officer. No human cases have been reported in India so far.
About 700,000 birds have been slaughtered since the disease was discovered last week in eastern India's West Bengal state and health workers plan to kill another 1.4 million, said state Animal Husbandry Minister Anisur Rahman.
"We are doing our best to stop the virus from spreading to Calcutta and other districts," Rahman said, adding that some 750 teams were involved in the slaughter.
But concerns have been heightened by Indian authorities' failure so far to halt the spread of the disease, amid accusations of bureaucratic bungling and problems securing cooperation from villagers, who have hidden chickens or smuggled them to other areas, fearing financial loss.
"Culling is slow and ham-handed," said West Bengal Poultry Welfare Association President Sheikh Nazrul Islam, who said losses to the poultry industry totaled $25 million (Dh91.25 million) in the last week.
While India has successfully contained two previous outbreaks, they were both in large poultry farms. This outbreak has largely struck chickens kept by peasants in their small yards, and many villagers were unaware of the danger.
India's neighbours, Nepal, Sri Lanka, Bhutan and Bangladesh, all announced they were halting imports of poultry products from India.
Also Thursday, the UN Food and Agriculture Organization issued a statement in Rome warning that despite international efforts bird flu remains a global threat.
"The H5N1 avian influenza crisis is far from over and remains particularly worrying in Indonesia, Bangladesh and Egypt, where the virus has become deeply entrenched despite major control efforts," FAO Chief Veterinary Officer Joseph Domenech said in the statement.
"The virus has not become more contagious to humans but has managed to persist in parts of Asia, Africa and probably Europe. It could still trigger a human influenza pandemic," he said.
Officials in Indonesia, the country hardest hit by the disease, have not determined how the 30-year-old man who died on Thursday became infected with the H5N1 virus, said Sunan Raja, an official at the Health Ministry's Bird Flu Center.
Officials in a number of Asian countries have urged increased monitoring of the disease, which tends to flare during the colder months. Vietnam and China have stressed the need for heightened vigilance before the upcoming Lunar New Year holiday, when large numbers of people and poultry are on the move.
Thailand on Thursday announced its first bird flu outbreak in 10 months, at a farm in the country's north. Livestock officials in Turkey also have been battling the disease this week. (AP)
India under bird flu threat as virus flares in Asia