The government said on Wednesday that Britain will slaughter 35,000 birds after bird flu was found in one of the biggest poultry farm areas. The tests conducted on the domestic birds on farms near Dereham, in Norfolk showed the presence of the H7 strain, a less risky virus for people than H5N1, but government officials do not know yet where this strain came from. In March, the only confirmed case of infection with H5N1 was at a swan discovered in Cellardyke, Fife. In 2003, the H7N7 forced the Dutch government to kill over 30 million birds in order to stop the spread. The outbreak in Netherlands infected over 80 people. A vet working on an infected Dutch farm caught the disease and later died of pneumonia. British chief vet Debby Reynolds is expected to reveal more information on this case within 24 hours. "Those results will allow us to decide whether it's the highly pathogenic dangerous form to birds, which kills a lot of birds, or the low pathogenic which is a much less serious infection.""Further tests are being carried out to determine the strain of the virus and more will be known tomorrow," the government said in a statement. "As a precautionary measure, birds on the premises will be slaughtered." The H7N7 is less dangerous for humans, as for H5N1, as long as it does not mutate into a form easily transmitted from person to person, it will not cause massive human damage. Bird flu can infect people, but rarely does so. Only those who have extremely close contact with infected birds or their feces can catch the disease.