Anthelmintic resistance (AR) of trichostrongyloids is widespread in Europe, but there is no up-to-date information on the spread of AR in caprine parasites in Austria. Eprinomectin (EPR) is currently the only anthelmintic drug of the macrocyclic lactones registered for goats in Europe. The aim of the present study was to gather information regarding the efficacy of anthelmintics against trichostrongyloids on a dairy goat farm in Austria with reported treatment failure of macrocyclic lactones and to determine the presence of different trichostrongyloid genera. Faecal egg count reduction tests (FECRT) using Mini-FLOTAC were performed with eprinomectin (EPR) and moxidectin (MOX). Egg count reduction, calculated with the R package egg-Counts, was 44% for EPR and 86% for MOX, confirming AR of trichostrongyloids for both compounds. The most frequently detected genus in larval cultures was Haemonchus, followed by Trichostrongylus. This is the first report of MOX resistance in caprine trichostrongyloids in Europe. Failure of EPR and MOX to control trichostrongyloid infections is a severe threat to dairy goat farming, since other compounds must not be applied in goats used for milk production. Haemonchus contortus is one of the most pathogenic parasites of small ruminants and can quickly develop AR. Thus, immediate action should be taken to slow the further spread of AR in this and other roundworm species of ruminants in Austria.
Haemonchus contortus is the most pathogenic nematode in small ruminants and anthelmintic resistance (AR) hampers its efficient control. Early detection of AR status is required to reduce selection for AR and cannot be achieved using phenotypic tests. For benzimidazoles (BZs), the detection of AR-associated alleles characterised by single nucleotide polymorphisms (SNPs) in the isotype 1 β-tubulin gene allows early AR detection in strongyles. The F200Y, F167Y, E198A and E198L polymorphisms have been described in BZ-resistant populations with a clear variation in frequencies between regions. A novel digital PCR (dPCR) enables the detection of all of the above-described polymorphisms in H. contortus. Assays were validated using synthetic DNA fragments containing these SNPs. Then, larvae obtained and pooled at farm level from 26 Austrian and 10 Italian sheep farms were analysed. For all assays a detection limit of 15 copies/μl of resistance alleles and a high level of accuracy were demonstrated, allowing to detect allele frequencies of 1% in most samples. In Austrian samples, elevated frequencies of F200Y resistance alleles were detected on all farms. Polymorphisms in codon 167 and codon 198 were identified in H. contortus from Austria for the first time. In Italian samples, the frequency of resistance alleles was still comparatively low, but F200Y resistance alleles were traceable. In conclusion we developed for the first time dPCR assays that target all SNPs of relevance associated with BZ-resistance in H. contortus. Future research on AR development could benefit from an early onset of SNP-based surveillance that would include the developed assays for all SNPs of relevance. Improved surveillance in the long term will include other important, though less pathogenic, nematode genera in the analyses.
18 September 2023 in Research in Veterinary Science
Due to their close associations with humans, dogs and cats can be important reservoirs for zoonotic pathogens. In the current study 200 fecal samples of dogs (n = 70 samples) and cats (n = 130 samples) from animal shelters in Carinthia, southern Austria, were examined for the presence of parasites (fecal flotation and larval migration assay) and selected bacteria. Overall, 17.1% of the canine and 38.5% of the feline samples were positive for parasites (p < 0.001), most commonly Giardia duodenalis (dogs and cats), including potentially zoonotic genotypes revealed by multilocus genotyping, and Toxocara cati (cats). Cryptosporidium (C. felis), Cystoisospora spp. (dogs and cats), hookworms (dog), Trichuris (dog) Capillaria hepatica (cats), taeniids (cat), and Aelurostrongylus abstrusus (cat) were also found. Zoonotic bacteria were detected in 10.5% of the samples, Salmonella enterica (dogs), Campylobacter jejuni (dogs and cats) and Yersinia enterocolitica (cat) and were significantly associated with parasite infections in cats but not in dogs. Samples that were positive for several pathogens were common; especially G. duodenalis and T. cati were frequently found in association with each other, other parasites or bacteria. The spectrum of detected pathogens is comparable to that of other dog and cat populations in central Europe. However, since animals from shelters are frequently rehomed, diagnostic measures, appropriate hygiene and therapy as well as training of shelter staff are recommended to prevent zoonotic transmission of enteropathogens to staff or new owners. The presence of heteroxenic parasites, i.e. Aelurostrongylus abstrusus and Taenia taeniaeformis, and spurious excretion of Ca. hepatica in cats, indicates that these animals preyed on intermediate hosts, and that biosafety measures in pet shelters need to be evaluated for their efficacy in the prevention of pathogen transmission.