2007-05-27 00:24:43 -

LONDON (AP)- More people have shown symptoms similar to those caused by a strain of bird flu found at farm in north Wales, British health authorities said Saturday.

The cases come a day after four people tested positive for the H7N2 type virus_ a far milder form of the illness than the deadly H591

strain.

The illnesses were reported after poultry died at a small chicken farm earlier this week.

The Health Protection Agency, which is an independent body, was not immediately able to say how many more people were showing signs of illness.

Those affected either had direct contact with the affected poultry or with farm workers, said Chris Lines, a spokesman for the agency.

The H7 subtype of bird flu is believed to be less virulent than H5, but it has in the past caused human cases, and was responsible for a large outbreak which led to one death in the Netherlands in 2003.

The mortality rates of H7 viruses are far lower than H5N1_ which experts say causes death in around half of cases.

The farm came to the attention of British authorities after a number of chickens died.

Dr. Christianne Glossop, the chief veterinary officer for Wales, said in a statement Thursday that they had tested positive for H7N2.

A one-kilometer (1.6-mile) exclusion zone was put in place around the farm, and the remaining chickens have been slaughtered.

Welsh officials said Saturday that chicken from a second farm were being tested for the virus.