More UK Poultry Workers with H7N3 Bird Flu Symptoms
Recombinomics Commentary
April 30, 2006
"H7 avian flu remains largely a disease of birds," said Dr Jonathan Van Tam, a flu expert at the Health Protection Agency.
"The virus does not transmit easily to humans, as evidenced by the small number of confirmed infections worldwide to date."
The three workers who were suspected of having conjunctivitis work at a slaughterhouse owned by Banham Poultry, which runs Witford Lodge Farm.
They underwent tests and specimens were sent to the regional HPA laboratory but the results came back negative and their symptoms are not linked to bird flu, an HPA spokeswoman said.
The above comments on negative test results on poultry workers with conjunctivitis symptoms remains highly suspect. H7 is easily transmitted from birds to humans as well as human-to-human. The best evidence for the transmission was generated with serum samples linked to the 2003 H7N7 outbreak in the Netherlands. Like the current outbreak in the UK, poultry workers developed conjunctivitis symptoms and over 80 had H7 antibodies. However, a follow-up study using a sensitive assay for H7 antibodies indicated over 2000 contacts were also infected.
In the current outbreak, at least one poultry worker has tested positive for H7N3. However, bird flu antibodies typically peak 3-4 weeks after exposure. Thus, the "negative" workers should be retested for H7 antibodies using the sensitive assay. Poultry workers and contacts with conjunctivitis symptoms are likely to be H7 antibody positive. H7 typically produces mild symptoms or is asymptomatic.
However, the early detection of H7N3 in one poultry worker suggests H7N3 infections in the UK may be significant.
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