Officials in India fear the latest bird flu outbreak in the eastern state of West Bengal could spiral out of control. The disease has already spread to nine out of 19 districts in the state.

Laboratory tests have confirmed the H5N1 strain in two districts. It is likely that this strain will also be confirmed in the other districts.

Experts believe the H5N1 strain could easily mutate into a form, which would be easily transmitted from one human to another. So far there have been no cases of the H5N1 strain infecting humans in India.

Suspected human cases

But this week there have already been some scares said Gregory Hartl, the spokesperson for avian Influenza and other epidemic diseases at the World Health Organisation (WHO) in Geneva.

"What we know about the human cases is that there were five suspected cases. Three of which have definitely tested negative. The samples for the other two were apparently inconclusive but the people concerned were only showing extremely minor or weak symptoms."

The virus can be passed on through close contact with infected birds and their faeces.

"There is always the risk that it [the H5N1 strain] will jump to humans," explained Hartl. "The more widespread it is in animal populations the more chance there is of the virus mutating or reassorting. This is why it's so important to control the virus in animal populations."

Mass culling

The West Bengal government has deployed thousands of party members to help veterinary staff cull birds to control the virus. Until now, the culling of two million birds had been slow because of a shortage of staff.

Villagers, reportedly, were also reluctant to part with their birds, especially as compensation was slow being paid.

Other villagers criticised their government for not disseminating more information about the dangers of bird flu.

From Bangladesh

The central government has also criticised the West Bengal authorities for not informing it earlier about the outbreak of bird flu in the state, which it says came from Bangladesh originally.

"In Bangladesh for the moment it's just bird cases," assured Hartl. "We've not had any notification or even any rumoured cases [of human infection] in Bangladesh."

Bangladesh reported its first case of bird flu last February. It has spread to over a third of the country's districts since then and thousands of birds have been culled. However, experts say the government has played down the seriousness of the outbreak and are increasingly worried about human infection.

As bird flu spreads across Bangladesh and India, the popularity of chicken is subsiding rapidly. Sales have dropped dramatically and lamb and vegetables have reportedly taken over as the favourite dish at weddings.