Papadopoulos E, Himonas C, Theodoridis Y.

The aim of this study was to investigate the presence of anthelmintic resistance of gastrointestinal nematode parasites in sheep and goats of Greece. The detection of resistance was carried out in 322 flocks of sheep and goats by using in vivo and in vitro methods. The in vivo method of the ''faecal egg count reduction test'' was applied in 21 flocks of sheep. The anthelmintics used belonged to the groups of pro- and benzimidazoles, imidazothiazoles and tetrahydropyrimidines. The anthelmintic efficacy was found to vary from 99.6 to 100% and consequently, there was no resistance detected in the tested flocks. The in vitro methods of the ''egg hatch test'' and the ''larval development test'' were applied in 301 flocks of sheep and goats. The prevalence of anthelmintic resistance was 7% (5.9% for sheep and 8.9% for goats). All the resistant strains were detected on the islands, except 3 cases on the mainland in animals imported from abroad and the islands. The confirmation of the first greek resistant strain was based on the ''controlled test'' in lambs. The strain was identified to be Teladorsagia (Ostertagia) circumcincta.

Key words: anthelmintic resistance, nematode parasites, sheep, goats