Introduction

In many regions of South Africa sheep, goats or cattle graze the same pastures as various antelope species. Many of the helminths recovered from the antelopes are those usually encountered in domestic ruminants, especially sheep and cattle, while other helminths of cattle, sheep and antelopes are more host-specific and are rarely encountered in other species. Horak (1979) was able to artificially infect sheep with Haemonchus contortus, Trichostrongylus axei, Trichostrongylus falculatus and Impalaia nudicollis cultured from the faeces of blesbok, Damaliscus pygarthus dorcas, naturally infected with these worms. Haemonchus placei, Longistrongylus sabie, Trichostrongylus colubriformis, Trichostrongylus falculatus, Impalaia tuberculata and Cooperia hungi likewise became established in sheep, goats and cattle infected with larvae cultured from the faeces of impala, Aepyceros melampus. However, H. contortus, T. axei, T. colubriformis and T. falculatus are known from sheep, and H. placei and T. axei from cattle and it is not possible to determine what role cross-infection plays in maintaining the helminth populations in all four the host species.