Picobirnaviruses (PBV) are small, bisegmented double-stranded RNA viruses. The name "Picobirnavirus" derives from the prefix "pico" (latin for small) in reference to the small virion size. Discovery of PBV dates back to 1988 from Brazil, when human fecal samples collected during the acute gastroenteritis outbreaks. Farm mammals such as pigs, calves, foals, lambs, avians such as chickens, free-living mammals, companion and zoo animals, a variety of wild birds, and even snakes have been found to shed PBV with or without diarrhea. PBVs have also been associated with acute watery diarrhea and gastroenteritis in humans. PBVs are genetically distinct, rapidly evolving and spreading worldwide and have the capability to move and spread rapidly between animal to animal as well as interspecies transmission from pigs to horses, especially foals.
Signs if infection include depression, loss of appetite, rectal temperature >38.6 °C and nasal or ocular discharge.