Alarming levels of anthelmintic resistance against gastrointestinal nematodes in sheep in the Netherlands.

Autor: Ploeger HW; Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands. Electronic address: h.w.ploeger@uu.nl., Everts RR; Dutch Sheep and Goat Breeders Association (NSFO), P.O.Box 160, 5300 AD Zaltbommel, the Netherlands; Veterinary Practice (Diergeneeskundig Centrum), Zuid-Oost Drenthe, Looweg 84, 7741 EE, Coevorden, the Netherlands.
Jazyk: angličtina
Zdroj: Veterinary parasitology [Vet Parasitol] 2018 Oct 15; Vol. 262, pp. 11-15. Date of Electronic Publication: 2018 Sep 17.
DOI: 10.1016/j.vetpar.2018.09.007
Abstrakt: In a survey involving 34 sheep flocks spread over the Netherlands anthelmintic resistance (AR), based on a fecal egg count reduction (FECR) test, was determined for six different products. The study was conducted in ewes shortly after lambing during spring 2015. A FECR of less than 90%, indicating presence of AR against one or more nematode genera producing strongylid eggs, was found in 22 of 30 (73.3%) flocks against oxfendazole, 18 of 23 (78.3%) flocks against ivermectin, 15 of 32 (46.9%) flocks against moxidectin, and 2 of 26 (7.7%) flocks against monepantel. No AR was observed against levamisole. If oxfendazole resistance was observed, Haemonchus contortus was involved in 90.5% of the cases. If resistance against ivermectin, moxidectin or monepantel was observed, it invariably involved H. contortus. In the majority of cases resistance was also observed for Teladorsagia circumcincta and/or Trichostrongylus spp, between which no distinction was made in this study. Based on FECR 9 of 15 (60.0%) flocks showed resistance against closantel, which was mainly due to closantel not being effective against most other nematode species than H. contortus. However, in 44.4% of flocks showing reduced FECR it did involve H. contortus as well. Multi-drug resistance (excluding closantel) was found in 16 flocks, of which 8 showed resistance against 2 products, 7 against 3 products and 1 flock showed resistance against 4 products. If resistance against 3 or 4 products was present, there invariably was resistance against both ivermectin and moxidectin. Overall, of the 22 flocks in which both macrocyclic lactones (ML) were tested, 4 (18.2%) showed no resistance against both products, 9 (40.9%) showed resistance against ivermectin only, and 9 (40.9%) showed resistance against both MLs. It is concluded that AR is widespread in sheep in the Netherlands and involves products from all major anthelmintic classes, with possibly the exception of levamisole. It appears that the macrocyclic lactones have lost much of their efficacy against sheep nematodes over the last decade.
(Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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