Novel insights in the faecal egg count reduction test for monitoring drug efficacy against gastrointestinal nematodes of veterinary importance

Abstract

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

“…The FECRT can be performed by means of an overall count of strongyle eggs (Strongylida) or individual counts of parasitic genera through fecal culture (MCKENNA, 1997). Albeit very common, there are several limitations inherent to the interactions between host, parasite and the environment (LEVECKE et al, 2012), and there are variations in the calculation formula , in the need for control groups (MCKENNA, 2013(MCKENNA, , 2014, and in use of arithmetic (COLES et al, , 2006 or geometric means (SMOTHERS et al, 1999;DOBSON et al, 2009) in the calculation. According to Falzon et al (2014), the various methods to calculate FECRT are influenced by the level of AHR and if a bias correction is used in the formula, so it is important to analyze each case.…”

Erratum to: Comparison of calculation methods used for the determination of anthelmintic resistance in sheep in a temperate continental climate

“…By contrast, the levamisole FECR percentages obtained with the different calculation methods showed greater heterogeneity, compared with the other two anthelmintic treatment groups. The reason for this heterogeneity in FECR percentages could partly be explained by the overall low levels of levamisole resistance present in the studied sheep flocks, which led to a clustering of results and consequent right skewness of the posttreatment data, as suggested by Levecke et al (2012a). Greater heterogeneity of FECR results for levamisole was observed for farms 25 and 26 specifically, where ewe lambs in their first grazing season were used for the FECRT; young lambs could not be used as they were kept indoors during their first summer because of predator concerns.…”

“…However, the results from a FECRT may be influenced by several factors, including the study design, the host-parasiteenvironment interaction (Levecke et al 2012a), and the mathematical formula used to calculate drug efficacy (Miller et al 2006). The literature describes several methods to calculate the fecal egg count reduction (FECR); these methods differ based on whether the arithmetic or geometric mean is used, whether control animals are tested, and whether pre-and posttreatment fecal egg counts (FECs) are used in the calculation (Cabaret and Berrag 2004).…”

“…Host-parasite-environment interactions can also influence FECRT results, as shown by simulation studies based on data from Belgium (Levecke et al 2012a). In addition, Torgerson et al (2005) examined AR to mebendazole, ivermectin, and moxidectin in a goat herd in Switzerland using both FEC and slaughter examination of worm burdens posttreatment, and found that commonly used mathematical techniques failed to detect low anthelmintic efficacy.…”

Current state of anthelmintic resistance in horses with a special focus on the situation in Germany

“…variiert hinsichtlich seiner Aussagekraft u.a. je nach vorliegender Eiausscheidungsintensität und angewendetem koproskopischem Verfahren (Levecke et al 2012 (Hodgkinson et al 2008). …”