Field safety and efficacy of an orally administered combination of sarolaner, moxidectin and pyrantel (Simparica Trio) for the prevention of angiostrongylosis in dogs presented as veterinary patients.

Background: Infection with the cardiopulmonary nematode Angiostrongylus vasorum may cause severe disease in dogs, therefore prophylactic treatments are necessary to prevent infection in dogs at risk. A clinical field study was conducted to demonstrate the efficacy and safety of an oral combination of sarolaner, moxidectin and pyrantel (Simparica Trio) for the prevention of A. vasorum infection in dogs (prevention study). A survey study was conducted concurrently to determine the infection pressure in the same areas.

Methods: Prevention and survey studies were both conducted at the same veterinary clinics in endemic hot spots for A. vasorum in Denmark and Italy. The prevention study was a randomized, placebo controlled, double masked study where 622 client-owned dogs were treated and tested at 30 days intervals for 10 months. In the survey study 1628 dogs that were at risk of infection and/or were suspected to be infected were tested by fecal and/or serological methods, and the percent of dogs positive for A. vasorum was calculated.

Results: In the prevention study, there were no adverse events related to treatment with Simparica Trio. Two placebo-treated animals became infected with A. vasorum during the 10-month study period, while none of the dogs in the combination product-treated group became infected. In the survey study, 12.2% of the study dogs were found positive to A. vasorum, indicating high exposure to the parasite during the period of the prevention study.

Conclusions: Monthly oral treatment with the combination of sarolaner, moxidectin and pyrantel (Simparica Trio) was 100% effective in the prevention of natural infection with A. vasorum in dogs in highly endemic areas. In endemic areas, A. vasorum occurrence in dogs at risk is considerable.