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More bird flu cases rock UK
30/04/2006 10:01 - (SA)
London - More poultry flocks will be slaughtered after chickens tested positive for the H7 strain of bird flu in two more farms in eastern England, the British environment ministry said on Saturday.
Preliminary results indicate the H7N3 strain, but further tests are being carried out, according to the Department for Environment, Food and Rural Affairs (Defra).
The H7 strain is much less of a threat to humans than the H5N1 form of the virus, which was confirmed in a dead swan in Scotland in early April, the only case so far in Britain.
The two free-range flocks will be slaughtered on suspicion of having bird flu, Defra said. The farms are in the vicinity of one affected already near Dereham, close to the eastern English city of Norwich.
A cull of 35 000 chickens was due to be completed in Dereham Saturday.
The health authorities were taking measures to prevent the spread of the disease in the two new farms, including imposing a restricted zone extending one kilometre from each of the infected premises.
"We still can not say whether either of these two further farms are the index case; further premises may be involved," said Debby Reynolds, the chief veterinary officer.
"We are investigating whether there any links or movements" between the two newly-affected farms and the other infected premises, she said. "The working hypothesis remains that the most likely source of the virus is from another premises or from wild birds."
Meanwhile officials continued to reassure the public of the "extremely low" risk to human health after a poultry worker at the first farm affected contracted the virus in the form of conjunctivitis, an eye infection.
The Health Protection Agency (Hapa) said H7N3 does not pass easily from human to human, adding that the risk to the general public was "extremely limited".
Defra said the avian flu that had been discovered at the farm near Dereham was of the H7N3 strain and that tests indicated that it had low pathogenicity.
However, the results are subject to further investigations by the Veterinary Laboratories Agency before high pathogenicity can be completely ruled out. Results were due to be released next week.
H7N3 bears no relation to the deadly H5N1 strain of bird flu which has killed more than 100 people, mainly in Asia.
H7 symptoms in humans generally include flu-like illness and conjunctivitis.
Workers at the farm, including the person suffering conjunctivitis, were given the anti-viral drug oseltamivir on Thursday. The HPA was closely monitoring the workers' health.
Reynolds said the H7N3 strain of bird flu last occurred in Britain in 1979. The last recorded case of an H7 virus infecting a human in Britain was in 1996 when a woman contracted it after cleaning out a duck shed.
Professor Ian Jones, director of research at Reading University, said the first and only human fatality linked to the H7 influenza was in the Netherlands in 2003.
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