Status of Dorper sheep as hosts of ectoparasites.

Seventeen ixodid tick species or subspecies have been collected from Dorper sheep in South Africa. The diseases transmitted or the conditions caused by these ticks in sheep are discussed. Although Dorper sheep may be infested with the scab mite, Psoroptes ovis, this does not seem to cause production losses. These sheep may, however, serve as a source of mite infestation for woolled sheep. The majority of Dorper sheep are infested with the larvae of the nasal bot fly, Oestrus ovis, they may also be subject to myiasis caused by the larvae of two calliphorid flies. In certain regions of the country Dorper sheep are prone to serious fly worry by female Simulium chutteri. Although Dorper sheep may be infested by various louse species these do not seem to reach large numbers or cause production losses.