A survey of anthelmintic resistance in Slovakia.

A survey of prevalence of anthelmintic resistant nematode strains was carried out in 77 sheep farms in the Slovak Republic. An egg hatch assay was used for the detection of resistance to the benzimidazole group of anthelmintics. Results could not be obtained from five farms because of low egg counts in faecal samples. On 64 farms, the effective dose (ED50) values were under 0.1 microgram ml-1 while on six farms, trichostrongylid populations with resistance to benzimidazoles were found. Their ED50 values ranged from 0.10 to 0.12 microgram ml-1.