Overview of anthelmintic resistance of gastrointestinal nematodes of small ruminants in Brazil

Jordana Andrioli Salgado,Clóvis De Paula Santos

doi:10.1590/s1984-29612016008

Abstract

Frequent and inappropriate use of all classes of antiparasitic drugs in small ruminants has led to failures in their effectiveness, culminating in a global problem of anthelmintic resistance. Brazil stands out as one of the world's leaders in publications about anthelmintic resistance, and for having the most numerous reports of this resistance in small ruminants in the Americas. These studies have involved mainly the fecal egg count reduction test (FECRT) and its correlation with field management practices. In vivoeffectiveness testing is conducted in areas where livestock is of greater economic significance, e.g., in the South (sheep) and Northeast (goats), or is important for research and economic centers, such as the Southeast (sheep). The most widely studied species is sheep, for which the widest range of drugs is also evaluated. Despite significant advances achieved in molecular research, laboratory analyses should include knowledge about the reality in the field so that they can become feasible for the producer. Moreover, molecular studies can be underpinned by the analysis of field studies, such as the maintenance of antiparasitic effectiveness over time and the mechanisms involved in this process.

Highlights

The worldwide production of small ruminants is strongly impacted by gastrointestinal parasites that cause high mortality rates (HOSTE & TORRES-ACOSTA, 2011; STEAR et al, 2011; KNOX et al, 2012; FALZON et al, 2014), as well as losses resulting from subclinical infections that are reflected in low productivity (CHARLIER et al, 2014)
The large number of studies on anthelmintic resistance (AHR) in Brazil reflects the concern of the country, which has production potential and seeks to organize the sheep and goat production chain
The vast worldwide literature on AHR in small ruminants contributes to guidelines for controlling the situation

Summary

Introduction

The worldwide production of small ruminants is strongly impacted by gastrointestinal parasites that cause high mortality rates (HOSTE & TORRES-ACOSTA, 2011; STEAR et al, 2011; KNOX et al, 2012; FALZON et al, 2014), as well as losses resulting from subclinical infections that are reflected in low productivity (CHARLIER et al, 2014).

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Conclusion