Prevalence of gastrointestinal helminthes in sheep from some localities of the Sudan

Abstract

This study was carried out from November 1997 to October 1998 to determine species and prevalence of gastrointestinal helminthes infecting sheep from two major sheep production areas in the Sudan at Oumdurman Central Abattoir and from sheep designated for export. A total of 1005 faecal samples and 75 gastrointestinal tracts were randomly collected and were processed using microscopic coprological examination, faecal culture and post-mortem examination. Faecal examination revealed that strongyle/ trichostrongyle eggs were the commonest from both areas. Other eggs encountered were Strongyloides papillosus, Trichuris spp., Moniezia expansa, Moniezia benedeni and Paramphistomum spp. The third stage infective larvae obtained from faecal culture were identified as Haemonchus contortus, Trichostrongylus spp., Coopeia spp., Oesophagostomum spp. and Strongyloides papillosus. Mixed helminth infection was found common with 92% of the gastrointestinal tracts harbouring concurrent infections. Nematode infection was the commonest reaching 86.7% in the animals with H. contortus and Trichostrongylus colubriformis having the highest prevalence (72% and 70.7%, respectively). Other nematode species identified were Cooperia pectinata, Oesophagostomum columbianum, S. papillosus, Trichuris globulosa and Skrjabinema ovis with frequencies of 37.3, 44.6, 24 and 6.7%, respectively. Cestodes were identified in 66.7% of gastrointestinal tracts. The species identified were Moniezia expansa, Moniezia benedeni, Avitellina centripunctata and Stilesia globipunctata. The most prevalent species were A. centripunctata and S. globipunctata with frequencies of 46.7% and 49.3%, respectively. These results from post-mortem examination substantiate those reported from faecal examination. The study indicated that there was a seasonal effect on nematode infection in sheep from both areas of study as judged by egg output and worm burden. Both parameters showed their highest levels in the rainy season. It is concluded that nematodes may be involved in causing significant losses in sheep production in this country. This is evidenced by the involvement of some of the potentially pathogenic forms such as H. contortus and T. colubriformis and the high prevalence of these specific parasites. The fact that worm burdens were mostly moderate suggests presence of chronic infections, which may precipitate continuous loss in productivity. It is imperative, therefore, that effective programs be constructed to control this group of parasites. Four species of helminthes were reported for the first time in sheep in the Sudan. These were Trichuris globulosa, skrjabinema ovis, Avitellina centripunctata and Stilesia globipunctata.