Seasonal forcing represents a pervasive source of environmental variability in natural systems. Whilst it is reasonably well understood in interacting populations and host-microparasite systems, it has not been studied in detail for host-macroparasite systems. In this paper we analyse the effect of seasonal forcing in a general host-macroparasite system with explicit inclusion of the parasite l...

VILJOEN, J . H . Further studies on the epizootiology of nematode parasites of sheep in the Karoo. Onderstepoort J. vet. Res., 36 (2) , 233-264, (1969). The dominant parasites in the Karoo are Nematodirus spathiger (Railliet , 1896) and Trichostrongylus falculatus Ransom , 1911 . In the moister eastern regions Haemonchus contortus (Rudolphi, 1803) and Oesophagostomum columbianum (Curtice, 1890)...

Seasonal density of trichostrongylid nematode larvae was investigated on a pasture used for communal grazing of livestock, using standard procedure of pasture larval count. For this purpose, herbage samples were collected from a posture near Faisalabad at fortnightly intervals over a 12 month period from July 2000 to June 2001. The larvae of Haemonchus (H) contortus, Trichostrongylus species, O...

The prevalence of concurrent nematode-trypanosome infections in traditionally reared West African Dwarf sheep and goats in eastern Nigeria was monitored over a 12-month period during 1987-1988. The most prevalent nematodes were Haemonchus contortus and Trichostrongylus colubriformis, which usually occurred together in all nematode infected animals. Their combined prevalence rates ranged from 90...

Given their global distribution and abilities to persist in the host, helminths can play a crucial role in affecting risk of infections by increasing individual variation in infection. Helminth co-infections are of particular interest because by altering host immune responses, they can modify host susceptibility and thus intensity and transmission of other parasites/pathogens. The dynamics of c...

The abundance and distribution of parasitic helminths in populations of African buffaloes, Syncerus caffer, have not been well documented. A total of 28 buffaloes of different ages and sexeswere sampled in the Kruger National Park, South Africa, for nematodes of the small intestine. Three nematode species were identified, namely Cooperia fuelleborni, Cooperia hungi and Trichostrongylus deflexus...