Novel small strongyle (Cyathostominae) beta-tubulin sequences.

Several coding sequences of the benzimidazole (BZ) target beta-tubulin have been described for different parasitic nematodes. However, until recently no tubulin sequences from Cyathostome species were available, despite the importance of BZ resistance in horses in the field. Here, we describe several full-length beta-tubulin coding sequences of two major small strongyle species, namely Cylicocyclus nassatus and Cyathostomum coronatum. In the latter sequence, the putative BZ resistant mutation in codon 200 leading to a Phe to Tyr exchange is present. High nucleotide sequence similarities (>95%) were found among the tubulin sequences of the two different genera. This will be of advantage for the development of an allele-specific BZ resistance polymerase chain reaction (PCR) for multiple small strongyle species.