Evaluation of the effectiveness of fluralaner against adult stages of Rhodnius prolixus in dogs.

Triatomines are vectors of American Trypanosomiasis also known as Chagas´ disease where several reservoirs including dogs are involved in the transmission cycle of the causal agent (Trypanosoma cruzi). Considering that the prevalence of American trypanosomiasis in dogs is higher than in humans and that dogs in addition are susceptible of this disease, and are involved in peridomestic transmission to humans, the search for new alternatives for vector control of the triatomines responsible for transmission in dogs is required. Over the 20 weeks the study lasted, 600 individual female, adult of Rhodnius prolixus were offered to the 15 dogs treated with a single oral dose of Fluralaner (Bravecto®, MSD). Feeding pattern of triatomines was not affected by the treatment during the whole study. The fluralaner-induced mortality of R. prolixus had a significant effect until week 12 at which time 100% mortality was observed. Mortality decreased to 67.5% at week 16 to practically nil 0.8% on week 20. Fluralaner achieved 100% mortality of triatomines between 12- and 48-h post-feeding. It was demonstrated that a single oral dose of fluralaner in dogs is highly effective in producing mortality in adult R. prolixus for the time guaranteed by the manufacturer for other blood-sucking insects, with a considerable effective residual effect for up to 16 weeks. Due to this high efficacy, fluralaner could be considered in strategies to control the transmission vectors of Chagas disease in dogs and in turn decrease the peri-domestic transmission cycle, particularly in hyperendemic areas.