Sheep gastro-intestinal parasites and risk of parasite infection from pasture during the rainy season in the central area of Burkina Faso.

A study carried on from two villages in the central area of Burkina Faso al lowed to identify sheep gastro-intestinal parasites, to estimate their prev alences and numbers, and to evaluate the risk of nematode infection from pa sture during the rainy season. Tracer (n = 24) along with farm (n = 100) an imals were grazed on the same pastures. Coproscopies, coprocultures, as wel l as necropsies were performed. It turned out that all sheep examined were infected with at least one type of parasite. Combining the results of sever al laboratory techniques, it was possible to evaluate for the rainy season the following parasite prevalences : Haemonchus contortus (95 %), fourth st age larvae or L4 (89 %), Cooperia sp. (74 %), Trichoslrongylus sp. (63 %), Moniezia sp. (47 %), coccidia (36,9 %), Bunostomum trigonoce-phalum (26 %), Oesophagostomum sp. (16 %), Strongyloides sp. (14,1 %), trichures (1,1 %) and paramphistome (0,7 %). Mean parasite burdens on individual sheep of the area ranged from 1400 to 15180. While parasites prevalences were more impo rtant in august, burdens peaked in September and October. Over 1677 nematod e infesting larvae per kg of grass dry matter were numerated for the area, confirming a high risk of sheep contamination during the rainy season.