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

GURTLER RE; CEBALLOS LA,; STARIOLO R; KITRON U; REITHINGER R

TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE

ELSEVIER SCIENCE INC

Lugar: London; Año: 2009 vol. 103 p. 298 - 304

0035-9203

We assessed the insecticidal effects of fipronil spot-on applied to experimentaldogs on the blood-feeding success and other vital parameters of the Trypanosoma cruzi vectorTriatoma 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.