October 19, 2021

I, Science

The science magazine of Imperial College

A fish’s eye-view of a poultry pen at Mudchute Farm, London shows these free-range chickens happily frolicking in their surroundings. They can count themselves lucky to be living the high life on a visitor-orientated city farm whilst thousands of chickens are being culled in India this month.

This past week has seen the Indian Government order the cull of approximately 4,000 farmed chickens and ducks in the north-eastern state of Tripura. This comes after scientists at the Department of Animal Husbandry confirmed the nation’s third outbreak of the H5N1 strain of avian bird influenza in four years, despite declaring the country free from avian flu as recently as June 2010.

The H5N1 strain of avian influenza is capable of mutating upon infection in humans, who do not have any immunity against the virus. Around 400 people have been diagnosed with avian influenza since 1997, and around 60% of cases have resulted in fatality.

At the first sign of an outbreak, livestock culls are immediate and severe, as shown in India this month. Rapid action is required because infected but surviving birds can still transmit the virus in their feces and saliva for up to 10 days after recovery.

The last qualified case of H5N1 in the UK was in January 2008 when three mute swans were found to have died from the virus in Dorset.