Seasonal incidence of helminths in sheep and goats in south Mozambique.

The seasonal fluctuations in faecal worm egg counts were studied at monthly intervals for over a year in 20 male sheep and goats on extensive grazing tracts at a farm near Maputo, Mozambique. Larval differentiation from faecal cultures showed that Haemonchus contortus and Oesophagostomum columbianum were the most prevalent worm species. Trichostrongylus colubriformis, Cooperia spp., Strongyloides papillosus, Moniezia spp., Paramphistomum spp. and Trichuris spp. also occurred. After the onset of heavy rains in October 1978, the mean total egg counts increased due to a higher egg-output of Haemonchus contortus, reaching peak values in January 1979 in sheep and in February 1979 in goats. A second smaller peak in the mean total egg counts occurred in both groups in May 1979. With the beginning of the drier season the mean total egg counts in the goats fell to a low level, those of the sheep had a third rise in July 1979 due in that case to Oesophagostomum columbianum. The mean total strongyloids egg counts were generally much higher in sheep than in goats. Only at the beginning of February 1979, did the goats have a mean total egg count nearly as high as that of the sheep. Paramphistomum spp. are reported for the first time from sheep and goats in Mozambique.