The trichostrongyloid parasites of sheep in South Australia and their regional distribution

Abstract

Summary. The species of trichostrongyloid nematodes present in 376 sheep from different agricultural regions of the state of South Australia were determined. Parasites encountered in the abomasum were Teladorsagia circumcincta, T. trifurcata, T. davtiani, Camelostrongylus mentulatus, Haemonchus contortus and Trichostrongylus axel. T. circumcincta was the species most commonly encountered, but C. mentulatus was widespread in arid areas. H. contortus was present in a small number of sheep only, mainly in southern areas. In the small intestine, Trichostrongylus vitrinus predominated in the wetter, southern districts, and T. rugatus in dry, northern areas. T. colubriformis was common, but was rarely dominant. T. probolurus was found in one sheep. Nematodirus filicollis was restricted to wetter, southern areas, while N. spathiger and N. abnormalis were widespread and predominated in dry areas. N. helvetianus was found once. Cooperia species were uncommon; species encountered were C. oncophora, C. surnabada and C. pectinata. Thanks are due to P. M. Bonnin, E. Moore, S. M. Fitzsimons, F. M. and R. R. Martin and M. G. O'Callaghan for excellent technical assistance, and to members of the South Australian Department of Agriculture, particularly the staff of the Northern Region, for collecting material or helping with the collection.