Atividade inseticida do fluralaner (Exzolt®) administrado em Gallus gallus domesticus contra Triatoma vitticeps (Hemiptera: Reduviidae: Triatominae)

Abstract

Triatoma vitticeps is a vector of Trypanosoma cruzi, the etiological agent of Chagas disease. Vector control efforts for Chagas disease rely primarily on the spraying of residual pyrethroid insecticides in domestic and peridomestic environments. However, the residual effect in the peridomestic area may be short-lived due to environmental conditions, and the emergence of resistance to pyrethroids has been increasingly reported among triatomine populations. Although chickens are not considered reservoirs of T. cruzi, they represent an important and frequent blood source for triatomines in many endemic areas. This study aimed to evaluate the insecticidal activity of fluralaner (Exzolt®) administered orally to chickens against T. vitticeps. Sixteen chickens (Gallus gallus domesticus) were randomized by weight into four groups: Group 1: untreated control (n=4); Group 2: treated with 2 doses of 0.5 mg/kg of fluralaner/Exzolt® (n=4); Group 3: treated with 2 doses of 2.5 mg/kg of fluralaner/Exzolt® (n=4); Group 4: treated with 2 doses of 5 mg/kg of fluralaner/Exzolt® (n=4). To evaluate the efficacy of fluralaner (Exzolt®) in inducing triatomine mortality, the chickens were subjected to blood feeding by the insects on days 0, 1, 7, 14, 21, 28, 35, 56 and 77 after treatment. Cumulative insect mortality was determined up to 7 days after each blood-feeding event. Treatment of chickens with fluralaner (Exzolt®) did not affect the feeding success of triatomines. Treatment with 0.5 mg/kg, 2.5 mg/kg, and 5.0 mg/kg of Exzolt® resulted in 100% insecticidal activity against triatomines for up to 14, 28, and 28 days, respectively. The doses of 2.5 mg/kg and 5.0 mg/kg showed comparable insecticidal activity, both superior to the 0.5 mg/kg dose. The results demonstrate that treating chickens with 2.5mg/kg and 5.0 mg/kg of fluralaner induces insecticidal activity against triatomines for up to 35 days after treatment. The results indicate that oral administration of fluralaner to chickens results in sustained insecticidal activity against T. vitticeps, suggesting its potential use as a complementary control strategy in endemic areas of Chagas disease.