CDC: About Horse Flu
At a glance Background The influenza viruses that cause “horse flu” are “equine influenza viruses” or “EIVs.” EIVs originally spread from birds to horses. Historically, EIVs have been type A influenza viruses belonging to two subtypes: H7N7 and H3N8. Evolving viruses The EIV H7N7 subtype was first reported in the 1950s and last reported in the 1970s. It […]