No abstract

Resistance to eprinomectin was suspected in a dairy sheep farm in southwestern France. The efficacy of topical and injection formulations of eprinomectin against gastrointestinal nematodes (GINs) was compared using a faecal egg count reduction test. GIN species were identified by real-time PCR, and eprinomectin concentrations were measured in serum by High-Performance Liquid Chromatography 2 and 5 days after treatment. Efficacies were 99.6% and 86.1% for injection and topical formulations, respectively. Before treatment, the three species Haemonchus contortus, Teladorsagia circumcincta and Trichostrongylus colubriformis were identified in both groups. After treatment, H. contortus and T. colubriformis were identified in the topical group only. Two days after treatment, eprinomectin concentrations were above 2 ng/ml in the injection group and under this value in the topical group, suggesting underexposure of GIN to eprinomectin in this latter group. High levels of exposure to eprinomectin are important to avoid loss of efficacy in the field.

Protozoan parasites of the Cryptosporidium genus cause severe cryptosporidiosis in newborn lambs. However, asymptomatic infections also occur frequently in lambs and ewes. In sheep, the most commonly detected Cryptosporidium species are C. ubiquitum, C. xiaoi and C. parvum. Due to a lack of relevant information about such infections in France, we investigated the situation on five dairy sheep farms in the Pyrénées-Atlantiques Department in south-western France in December 2017. Individual fecal samples were collected from 79 female lambs (5–17 days old) and their mothers (72 ewes). Oocysts were screened using Heine staining before and after Bailenger concentrations. Cryptosporidium species identification and genotyping were performed using real-time PCR and gp60 gene sequencing. No cases of clinical cryptosporidiosis were observed in the 79 lambs. Microscopically, Cryptosporidium spp. oocysts were observed in only one lamb on one farm (prevalence 1.3%) and one ewe on another farm (prevalence 1.4%). By contrast, Cryptosporidium spp. DNA was detected in 17 ewes (prevalence ranging from 10.5% to 50% depending on the farm) and in 36 lambs (prevalence ranging from 0% to 77.8% depending on the farm). Only zoonotic Cryptosporidium parvum IId and IIa genotypes were identified when genotyping was possible. Cryptosporidium ubiquitum and C. xiaoi were detected on one and three farms, respectively. We conclude that healthy young lambs and their mothers during the peripartum period could be a source of environmental contamination with oocysts.