Fachbereich Veterinärmedizin



    Analysis of the beta-tubulin codon 200 genotype distribution in a benzimidazole-susceptible and -resistant cyathostome population (2003)

    Zeitschriftenartikel / wissenschaftlicher Beitrag
    Pape, M
    Posedi, J
    Failing, K
    Schnieder, T
    von Samson-Himmelstjerna, G (WE 13)
    Parasitology; 127(Pt 1) — S. 53–59
    ISSN: 0031-1820
    Pubmed: 12885188
    Institut für Parasitologie und Tropenveterinärmedizin

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    14163 Berlin
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    Abstract / Zusammenfassung

    To study the prevalence of the polymorphism in position 200 of the beta-tubulin gene in the mechanism of benzimidazole (BZ) resistance in cyathostomes of horses, an allele-specific PCR was used to detect the genotype of individuals of BZ-susceptible and BZ-resistant populations. The molecular analysis of 100 adults recovered from an anthelmintic-naïve horse revealed 80% homozygous TTC/TTC individuals, 17% heterozygous TTC/TAC and 3% homozygous TAC/TAC. A naturally infected horse was treated with increasing fenbendazole (FBZ) dosages to select a BZ-resistant population of cyathostomes. The PCR based analysis of 3rd-stage larvae (L3) during the experiment revealed a decrease of the homozygous TTC/TTC genotype and an increase in heterozygous TTC/TAC and homozygous TAC/TAC individuals. After treatment 42.3% of the adults (n=104) were homozygous TTC/TTC, 55.8% were heterozygous TTC/TAC and only 1.9% showed the homozygous genotype TAC/TAC. The results of the molecular analysis lead to the proposal that polymorphism within codon 200 is not the only reason for the development of BZ resistance in small strongyles.