Resumen de Precisión del test de eclosión de huevos para el diagnóstico de la resistencia antihelmíntica en condiciones de campo.

C. Calvete, Rebeca Calavia, Joaquín Uriarte Abad

• Benzimidazole resistance was monthly estimated in two natural sheep parasite populations during one year. Egg hatch assay (EHA) was used to estimate proportion (Pdd) of hatched eggs at a discriminant dose of 0.1 μg/ml of thiabendazol after controlling by natural mortality. Every month, each population was sampled during three consecutive days, and EHA was replicated three times every day. Variance component analysis was performed to estimate precision of EHA (measured as length of the 95% confidence semi-interval, CSI-95%). Results showed that EHA was notably imprecise, since performing EHA with a single sampling with two replicates, such as it is advised by World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) yielded a CSI 95%=0.2, whereas four samplings with two replicates each or three samplings with five replicates each, were needed to reach a CSI-95% = 0.1. Monthly mean Pdd was modulated by variation in relative abundances of parasite genera but, also, by other confounding factors not controlled in the survey.