Equine influenza

Equine influenza virus causes equine influenza (flu), a respiratory disease of horses and other Equidae, such as donkeys and zebras. The disease is highly contagious although rarely fatal. Vaccines to protect against equine flu have been available since the 1970s, but high variability of virus strains in circulation in different geographical regions is a hurdle to effective vaccination. The World Organisation for Animal Health monitors the current strains in circulation to make recommendations on which strains should be included in the current vaccine.