First report of eprinomectin-resistant isolates of Haemonchus contortus in 5 dairy sheep farms from the Pyrénées Atlantiques département in France

Infection of sheep by gastrointestinal nematodes (GIN) in pastoral systems such as those found in the South Western area of France, the Pyrénées Atlantiques, is one of the main reasons for economic loss and degradation of their welfare. In the present study, the efficacy of eprinomectin (EPN) was monitored on farms from this area following suspicion of lack of anthelmintic efficacy. Suspicions were raised by veterinarians, based on clinical signs ranging from milk and body condition loss, to anaemia, and mortality. Resistance was evaluated according to the World Association for the Advancement for Veterinary Parasitology (WAAVP) guidelines using fecal egg count reduction tests reinforced by individual analysis of drug concentration in the serum of all treated ewes by high-performance liquid chromatography (HPLC). EPN was administered by subcutaneous (SC) and topical (T) route according to manufacturer's requirements, as well as by the oral route (O) with the topical solution according to off-labelled practices in the field. For the first time in France, the presence of resistant isolates of Haemonchus contortus to EPN was observed in 5 dairy sheep farms. The HPLC dosages showed exposure of worms to concentrations compatible with anthelmintic activity for animals treated by the SC and O routes. By contrast, they showed under exposure to the drug of most individuals treated by the T route. EPN is the only null milk withdrawal anthelmintic molecule currently available. The presence of resistant isolates of the pathogenic H. contortus to EPN in this important dairy region requires an urgent change in grazing, and sometimes production, systems

Evidence of fine-scale genetic structure for the endangered Pyrenean desman (Galemys pyrenaicus) in the French Pyrenees

The Pyrenean desman (Galemys pyrenaicus) is a small, semiaquatic mammal endemic to the Pyrenean Mountains and the northern half of the Iberian Peninsula where it lives in cold and well-oxygenated flowing mountain streams. This species is currently classified as vulnerable on the IUCN Red List and has been undergoing habitat loss and fragmentation for decades, inevitably impacting its distribution. A recent genetic study, based on mitochondrial and intronic sequences, showed that the genetic variability of the Pyrenean desman is very low in the Pyrenees. In this study, we investigated the potential existence of genetic structure and gene flow at a smaller scale using 24 polymorphic microsatellite loci. As the Pyrenean desman is a very elusive species, we supplemented our tissue sample collection with samples of feces collected in the French range of this species. We successfully identified 70 individuals based on 355 fecal samples. Bayesian analyses revealed 3 genetic and geographic clusters (1 eastern, 1 central, and 1 western, including 3 genetic subclusters), with origins tracing back only 200 years. These clusters were characterized by low levels of genetic diversity and high inbreeding coefficients. Although gene flow among clusters appeared to be limited, populations seem to have exchanged alleles recently. Therefore, connectivity between watersheds should be enhanced to maintain genetic diversity and potentially improve the long-term survival of the Pyrenean desman in France.Peer Reviewe