Things you really should know about: bird flu
Do you know your H5N1 from your H3N2? Laura Halpin, Farah Janmohamed and Sanjay Patwardhan consider some of the commonly asked questions about bird flu
Bird flu has recently received extensive media coverage, with escalating concerns surrounding a potential influenza pandemic. Despite the availability of many information sources, ranging from newspapers to guidance from the Department of Health and the chief medical officer, medical students and junior doctors may not have a satisfactory understanding of the key facts.
Bird flu is a highly infectious viral disease caused by influenza A viruses, which normally infect birds and, less commonly, pigs. All birds are thought to be susceptible, but some species are more resistant than others. There are 16 H-types of influenza A, two of which affect birds—the H5 and H7 subtypes. The H5N1 subtype is responsible for the current outbreak.
All subtypes of influenza A viruses, including those from different species, can undergo reassortment of genetic material and merge. Consequently, these viruses show high levels of genetic variation due to antigenic shift, enabling subtypes such as