Epidemiological study on gastrointestinal tract helminthosis of small ruminants in Dawuro Zone

Abstract

An epidemiological study on GIT helminthosis of small ruminants in three different agro ecological zones (AEZ) of Dawuro Zone was carried out from March to August 2012 on 21 gastrointestinal tracts and 486 faecal samples collected from sheep and goats to identify helminth species, determine the occurrence and factors related to the helminth infection. The cross sectional study was carried out through postmortem examination (PME) and coprological examinations using sedimentation, floatation and McMaster egg counting methods. PME revealed the existence of nematode, cestode and trematode species in 95.2%, 33.3% and 4.8% of animals, respectively. The postmortem examination also indicated the existence of ten (10) nematode species with different percent prevalence (Haemonchus contortus, 85. 7; Trichostrongylus colubriformis, 76.2; Oesophagostomum columbianum, 52.4; Trichuris ovis, 42.9; Trichostrongylus axei, 19.0; Bunostomum trigonocephalum, 14.3; Teladorsagia spp., 14.3; Trichostrongylus falculatus, 9.5; Trichostrongylus longyspicularis, 4.8 and Cooperia curticei, 4.8). The variation in the prevalence of individual nematode species on agro-ecological basis was significant (P<0.05) except for Bunostomum trigonocephalum (p>0.05). Except for T. axei, the seasonal prevalence of all nematodes was significantly varied (p<0.05) between seasons of the year. Mean nematode burden have shown significant differences for seasonal variation (p<0.05). The variation was also observed between body condition differences (p<0.05), and age differences especially for H. contortus (p<0.05). Out of 95.2% of nematode infected animals in the study area, 70% harbored moderate level infestation and, 30% were lightly infected by GIT nematode species. Faecal examination results from population of sheep and goats during two sampling periods indicated significant seasonal variation (p<0.05) in prevalence and mean fecal egg counts for all study sites. Majority (54%) of infected animals had a faecal egg count in the range of 50-800 and only few proportions (10.4%) of animals had faecal egg count over 1200 during wet season of the year. The widespread existence of various helminthes in the form of polyparasitism in sheep and goats in all agroecology of the study area, both at postmortem and coproscopic examination suggest the institution of various control measures including strategic anthelmintic treatment for efficient utilization of the small ruminant resources at hand.