INVESTIGADORES
ALVAREZ Luis Ignacio
artículos
Título:
Relationship between increased albendazole systemic exposure and changes in single nucleotide polymorphisms on the beta-tubulin isotype 1 encoding gene in Haemonchus contortus
Autor/es:
BARRÈRE, V.; ALVAREZ, L.; SUAREZ, G.; CEBALLOS, L.; MORENO, L.; LANUSSE, C.; PRICHARD, R.
Revista:
VETERINARY PARASITOLOGY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 186 p. 344 - 349
ISSN:
0304-4017
Resumen:
Resistance to benzimidazole anthelmintics in the nematode Haemonchus contortus has been
correlated with single nucleotide polymorphisms (SNPs) on the -tubulin isotype 1 gene.
Three mutations can be used as markers for the detection of resistance, namely SNPs at
position 200 and 167 (both TTC to TAC) or at position 198 (GAA to GCA). Harbouring a resistance
genotype at any one of these codons can lead to a resistant phenotype. Our objective
in this study was to analyse the frequencies of the three mutations when the albendazole
dose rate and selection pressure were increased. We used adult H. contortus (males and
females) collected directly from the abomasum of untreated lambs, or lambs treated with
the manufacturers recommended dose rate (5 mg/kg), three times the recommended dose
rate (15 mg/kg), or nine times the recommended dose rate (45 mg/kg). Anthelmintic efficacy
was determined by worm and egg count reductions. For the surviving worms of the
four treatment groups, the frequencies of each resistance SNP at codons 167, 200 and 198
were measured using pyrosequencing. Our results showed a strong relationship between
an increasing dose rate and an increase in the frequency of the (TAC)200 SNP and a decrease
in the (TAC)167 SNP. All worms genotyped were GAA at codon 198