Dealing with double trouble: Combination deworming against double-drug resistant cyathostomins

A national survey of anthelmintic resistance in ascarid and strongylid nematodes in Australian Thoroughbred horses

“…We did not observe resistance to the two combinations of the MLs with THPs (IVM + MOR, and IVM + PYR) which could be due to the additive effect of THPs. Previously, Scare et al (2020) reported 100% efficacy of a combination of anthelmintics (MOX and oxibendazole) against resistant cyathostomin populations in the USA. However, the study population was never exposed to MOX, which presumably has preserved its efficacy against cyathostomins.…”

“…However, the study population was never exposed to MOX, which presumably has preserved its efficacy against cyathostomins. A modelling study that simulated the development of AR showed that the use of combination products delayed its onset compared to using a single active when appropriate treatment strategies were applied ( Scare et al, 2020 ). Currently, no anthelmintic containing a single active from the THP class is available for use in Australian horses which significantly decreases the use of these compounds and may prevent or delay resistance to this compound when used in combinations.…”

Cyathostomin resistance to moxidectin and combinations of anthelmintics in Australian horses

“…Similarly, in another trial, an additive effect was observed for the efficacy of the OBZ + PYR combination against horse cyathostomins in the first of the four consecutive treatments, whereas the individual efficacies of both drugs were much lower [ 28 ]. In addition, a recent simulation-based study demonstrated that the use of a combination of anthelmintics could be helpful in delaying the development of AR in cyathostomins, despite one of the active ingredients exhibiting lower efficacy [ 29 ].…”

Behandlung gastrointestinaler Parasiten beim Pferd

“…In diesem besteht kein Selektionsdruck auf Resistenzen. Diese Refugien können entweder frei lebende Stadien auf der Weide, Stadien im Darm von unbehandelten Pferden oder auch enzystierte Stadien im Darm von behandelten Pferden bei der Wahl eines Wirkstoffs, der nur luminale Stadien erfasst, sein 8 . Man geht davon aus, dass Situationen, in denen sich ein Großteil der Wurmpopulation im Refugium befindet, die Entwicklung von Anthelminthikaresistenzen verlangsamt.…”

“…stoffs, der nur luminale Stadien erfasst, sein[8]. Man geht davon aus, dass Situationen, in denen sich ein Großteil der Wurmpopulation im Refugium befindet, die Entwicklung von Anthelminthikaresistenzen verlangsamt.…”