2006-04-12-Bird flu tests in Britain flawedUnderstanding Avian Influenza
2006-04-12-Bird flu tests in Britain flawed
Tests for bird flu in Britain may fail to detect cases because of the way samples are collected. Scientists abroad are puzzled that so few of the tests carried out by the Department for Environment, Food and Rural Affairs (Defra) prove positive for the forms of flu commonly carried by birds.
International experience indicates that 6 to 7 per cent of birds should test positive for mild forms of flu distinct from the H5N1 strain found in the dead swan in Scotland. Defra's tests, New Scientist reports, found only two cases of low-pathogenicity bird flu in 3,343 samples collected in December ? 0.06 per cent. "There's something wrong with these numbers," Bjorn Olsen, of the University of Kalmar, in Sweden, told New Scientist.
The collection method may be the key. A sterile swab is used to take a faecal sample and stored in a refrigerator. Scientists say that the swabs should be immersed in a saline solution and then frozen. "If you left a swab in the refrigerator like that it would dry out and you?셝 lose all your virus," Dr Olsen said.