New codon 198 β-tubulin polymorphisms in highly benzimidazole resistant Haemonchus contortus from goats in three different states in Sudan

To our knowledge, this is the first report of E198L in BZ resistant H. contortus and the second where this is the predominant genotype associated with resistance in any strongyle species. Since this variant cannot be quantified using pyrosequencing, the results highlight important limitations in the general applicability of pyrosequencing to quantify BZ resistance genotypes.