First reported low pathogenicity avian influenza virus subtype H9 infection of domestic fowl in England

摘要

Avian influenza viruses of haemagglutinin subtypes H5, H7 and H9 are a constant and major concern to the poultry industry. H5 and H7 avian influenza viruses are classified as notifiable diseases because these subtypes can mutate from a low pathogenicity avian influenza (LPAI) virus to a fully virulent phenotype and genotype, defined as highly pathogenic avian influenza (HPAI) virus. HPAI is typified by high morbidity and mortality with rapid spread in susceptible birds. Poultry disease outbreaks, caused by viruses of H9N2 subtype have been reported in many parts of Asia and the Middle East. Since the 1990s, these infections have been characterised clinically by respiratory disease and a reduction in egg production. Transmission to human beings has also been reported. Historically, a H9N7 LPAI was isolated from infected turkeys in Scotland in 1970. This paper presents a detailed epidemiological investigation of a H9N1 poultry outbreak in the UK and Europe.