Internal Parasites in Algerian Arab Sheep in a Semiarid Area of Algeria

A study of internal parasites was performed on an Algerian Arab sheep breed (Ouled Djellal) naturally infected in a semiarid area of Algeria (Tiaret). Fecal examinations carried out on 423 sheep during the year 2004 revealed a global infection rate of 78.9% and the presence of cestodes (Moniezia spp., Avitellina sp.), coccidia (Eimeria spp.), and nematodes including lungworms (Dictyocaulus sp., Muellerius sp., Protostrongylus sp.). The parasitism pattern was seasonal for all parasites. Coccidia were more present in lambs (n = 164), with a prevalence of 44.5%. The strongyle infection was highest (70.4%) in ewes (n = 240), with a peak in March and November. The following strongyles were identified: Trichuris ovis (5.8%), Marshallagia marshalli (28.3%) and Nematodirus spp. (27%). The other strongyles, of which some genera/species were identified by fecal culture, had a prevalence of 56.6%. M. marshalli and Nematodirus spp. had a remarkably similar evolution, but at a lower level than that of other strongyles. The fecal egg count (EPG, i.e. eggs/gram of feces) showed two peaks; the highest (average of 1081 EPGs) occurred in November (lambing period) and was probably linked to the periparturient rise. Generally, the strongyle infection was moderate even though it was predominant. The prevalence of individual and under 500 EPGs was 74.1%, that more than or equal to 1000 EPGs was 14%, and the EPG monthly average exceeded this threshold in November only. Besides climatic conditions, the implication of some factors, such as the grazed vegetation type in the area and sheep breed, deserves investigation. For disease control, two anthelmintic treatments (in spring and fall) may be sufficient