Effects of topical application of fipronil spot-on on dogs against the Chagas disease vector Triatoma infestans

Abstract

Summary We assessed the insecticidal effects of fipronil spot-on applied to experimental dogs on the blood-feeding success and other vital parameters of the Trypanosoma cruzi vector Triatoma infestans. In the first trial, the cumulative mortality of 30 third or fourth instar nymphs exposed to eight fipronil-treated dogs differed significantly from those exposed to untreated dogs at 1 week post-treatment, but not at baseline or at 2–6 weeks post-treatment. In the second trial, the effects of multiple exposures to fipronil-treated dogs on bug population dynamics were assessed. A population of 80–84 bugs of various life stages were allowed to colonize eight closed experimental huts, and then exposed twice weekly to control or treated dogs over a period of 110 days and censused at monthly intervals. Throughout the trial, multiple exposure to fipronil did not significantly affect bug population size, fecundity, hatching, molting, survival, blood-feeding success and degree of engorgement. Only when engorgement was taken to include only fully fed bugs, did fipronil significantly reduce their degree of engorgement relative to bugs exposed to control dogs. We conclude that at tested dosages fipronil spot-on would have little effect in controlling (peri)domestic Tri. infestans or protecting dogs from contact with the bugs.

Vector Blood Meals Are an Early Indicator of the Effectiveness of the Ecohealth Approach in Halting Chagas Transmission in Guatemala

“…Other authors have suggested that dogs could be used as sentinels or as "bug lethal traps" by "applying lotions or insecticide impregnated collars." 40 Another important result is the increase in the proportion of bugs where no blood sources were detected after the interventions (among the ones tested). This may suggest that the population is experiencing a worsening nutritional status and this could negatively affect the fecundity of females.…”

Insecticide resistance in vector Chagas disease: Evolution, mechanisms and management

“…Some results are contradictory even with the same insecticide (e.g. fipronil) (Gentile et al, 2004;Gürtler et al, 2009), however, in general the studies showed some degree of effectiveness, although with remarkable variation in residual effect, showing its potential as complementary tool to the traditional spray mainly in highly infested peridomestic environments. The insecticidal paints are other promising alternative tools for the control of triatominae including the resistant foci.…”

“…pour-on, spot-on, collars) under different experimental conditions (e.g. laboratory, semi-field, field) (Gentile et al, 2004;Reithinger et al, 2005Reithinger et al, , 2006Gürtler et al, 2009;Amelotti et al, 2009aAmelotti et al, , 2012Juan et al, 2013;Dadé et al, 2014;Carvajal et al, 2014). Some results are contradictory even with the same insecticide (e.g.…”

Response of Triatoma infestans to pour-on cypermethrin applied to chickens under laboratory conditions

“…(Hewitt & Rowland 1999), lice (Pediculus sp.) (Levot 2000) and T. infestans (Gürtler et al 2009). Reithinger et al (2005Reithinger et al ( , 2006 reported that the use of rubber collars with 40 mg/g deltamethrin on dogs reduced the feeding success and the survival, fecundity and moulting rates of T. infestans, resulting in vector population extinction after 196 days.…”