UK garden birds hit by avian pox virus | Environment | The Guardian

UK garden birds hit by avian pox virus

Conservationists call on public to help track the spread of the disease, which has taken hold among great tits and other birds

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• Alok Jha, science correspondent
• The Guardian, Wednesday 3 August 2011
• Article history

Great tits have been particularly badly afftected by the pox. Photograph: Christopher Furlong/Getty Images

Conservationists are calling on the public to help efforts to track the spread of a bird disease that has taken hold in garden birds in recent years, with great tits particularly badly hit by the lesions it causes.

In 2006, scientists confirmed the first case of avian pox in a British great tit – before then, the virus had been confined to birds in Scandanavia, Austria, Czech Republic and Slovakia. Last year, the pox virus reached Wytham Woods in Oxfordshire, which contains a population of great tits that have been monitored by scientists since 1947, the longest running study of its kind in the world.

"We were very concerned when we first detected this disease," said Ben Sheldon of the Edward Grey Institute at the University of Oxford. "We're using our detailed observations to try to understand how this new form of pox affects survival and reproductive success."

Avian pox leads to warty, tumour-like growths on birds, particularly around the eyes and beak. It is known to have mild effects on a wide range of British birds such as the dunnock, house sparrow, starling and the wood pigeon. But things are worse for great tits.

"When we see this infection in great tits, the lesions can be a lot more severe than in other species," said Becki Lawson, a wildlife vet at the Zoological Society of London. "[The lesions] can be very large, most common on the head, but they can occur on different areas of the body. It seems not uncommon for multiple birds to be affected in any one incident."

No one knows whether the infections are fatal but the lesions can interfere with the bird's ability to see or fly, which means they are more likely to fall prey to predators.

The virus can spread via insect bites or direct contact between birds. It can also be spread through indirect contact via places where birds congregate such as perches or bird feeders in gardens. According to Lawson, the virus is "is persistent in the environment for weeks or, even, months".

Lawson is working with the researchers at Oxford to isolate and sequence the genes of the avian pox virus, to work out whether or not it is the same strain that affects birds in central Europe.

In the meanwhile, she recommends that anyone with bird tables or feeders keep these areas disinfected. "We can't give medicine to free-ranging birds," she said. "We'd always recommend that people give particular attention to good hygiene at feeding stations to prevent the cycle of transmission of any particular disease agent that could occur there."

Sightings of birds displaying symptoms of avian pox should be reported to the RSPB Wildlife Enquiries Unit on 01767 693690 or reported online.

via guardian.co.uk