An Abattoir Survey of Gastro-Intestinal Nematodes in Sheep in the Burdur Region, Turkey

The gastro-intestinal (GI) organs of 50 sheep randomly selected from local abattoirs in the Burdur region were investigated between September 2000 and August 2001 for the prevalence of GI nematodes and their larval forms and the seasonal fluctuations of these parasites. All the animals examined were infected (100%) with GI nematodes. Twenty-two nematode species were identified and 38,639 nematodes were collected from the infected sheep. The number of parasites per sheep ranged from 11 to 5052 (mean 772.78), while the number of nematode species per animal ranged from 1 to 12 (mean 5.98). The most frequently detected nematodes in the sheep were Ostertagia circumcincta (80%), Trichuris skrjabini (74%), T. ovis (72%), Marshallagia marshalli (64%), Nematodirus spathiger (44%), Trichostrongylus vitrinus (42%), N. abnormalis (40%) and Trichuris discolor (40%). The parasite counts in the sheep increased slightly in spring and summer, and then reached maximum levels in autumn. Species of Ostertagia, Marshallagia, Trichostrongylus, Nematodirus and Trichuris were observed in all seasons of the year, with minimum levels in winter. The numbers of Ostertagia spp. and Trichostrongylus spp. peaked in spring, and M. marshalli and Nematodirus spp. counts moved in parallel, increasing in October and July. The infection level of the Trichuris spp. was not uniform throughout the season, but increased slightly in May, July, September and January and remained at minimum levels in the other months of the year.