Last week veterinary authorities in the UK reported that there had been some cases of A/H7 avian influenza (AI) in birds in a commercial chicken farm in Eastern England.
Avian influenzas of the A/H7 type can be either highly pathogenic (Highly Pathogenic Avian Influenza – HPAIs) or of low pathogenicity for birds (so called LPAIs). Low pathogenicity viruses are less dangerous than HPAIs to birds and some birds infected with LPAIs do not even become ill. There is now a preliminary report from the European Union Veterinary Influenza Reference Laboratory that the virus in the chickens is of type A/H7N3, and that it is of low pathogenicity.
Both low pathogenicity and high pathogenicity H7N3 avian influenza viruses acquired from birds have occasionally infected humans in the past in Europe, and elsewhere in the world. This sometimes has resulted in mild illness (usually eye infections sometime with flu like symptoms) or simply asymptomatic infection in people handling infected birds.1,2 On Friday (April 28th) the UK authorities (the Health Protection Agency) reported that a man working with the chickens in the affected farm has developed conjunctivitis (an eye-infection), that this had been confirmed to be H7N3 and is being treated with anti-virals. The UK authorities also reported that they had intensive surveillance in place and were offering antivirals to all exposed persons.