what is flystrike in sheep

Flystrike in sheep is a myiasis condition, in which domestic sheep are infected by one of several species of flies which are external parasites of sheep. Flystrike is a significant health and welfare risk to Australian sheep and costs $280 million annually. There are five types of flystrike, but both body and breech strike are seen as the most prevalent and important ahead of poll and pizzle strike. Risk of these types of flystrike will depend on environmental conditions as well as how susceptible sheep may be. Flystrike occurs when larvae (maggots) of blow flies hatch on the skin and feed on tissues of live animals. Adult flies lay eggs in wool moistened from a range of causes such as urine or faecal staining, skin wounds, weeping from eyes, or the lesions of footrot, fleece rot or lumpy wool. Affected animals may lose condition and be predisposed to secondary bacterial infections and septicaemia or toxaemia. Flystrike is usually visible as a discolored, moist area of wool which, on closer examination, reveals maggots and is foul-smelling. The struck area is usually soiled or damaged in some way to attract flies. It is a legal requirement to inspect all sheep daily during the highest risk periods for signs of blowfly strike.