Mortality and blood intake in Triatoma infestans fed on goats treated with pour-on formulation of cypermethrin.

AMELOTTI I; CATALÁ SS; GORLA DE

MEMóRIAS DO INSTITUTO OSWALDO CRUZ.

FUNDACO OSWALDO CRUZ

Lugar: Rio de Janeiro; Año: 2012

0074-0276

<!-- @page { margin: 2cm } P { margin-bottom: 0.21cm; direction: ltr; color: #000000; widows: 2; orphans: 2 } P.western { font-family: "Times New Roman", serif; font-size: 12pt; so-language: es-ES } P.cjk { font-family: "Times New Roman", serif; font-size: 12pt; so-language: zh-CN } P.ctl { font-family: "Times New Roman", serif; font-size: 12pt; so-language: ar-SA } A:link { color: #0000ff } A.western:link { so-language: zxx } A.ctl:link { so-language: zxx } --> Triatoma infestans is the main vector of Trypanosoma cruzi, the etiological agent of Chagas disease in the Gran Chaco region of South America. Domestic goats play a key role in the eco-epidemiology of Chagas disease, as a frequent source of blood meal for triatomine bugs. The aim of this study was to evaluate the mortality and blood intake of T. infestans fed on goat calves treated with different pour-on insecticide doses. Third instar nymphs were fed on goats treated with 0, 5, 10 and 15 cc of a cypermethrin pour-on formulation. T. infestans exposure to treated animals at different post-application intervals revealed residual activity of the insecticide. The mortality rate in treated groups was higher than in control groups until 30 days post-insecticide application (p=0.03), except in the group treated with 5 cc where no mortality was detected after 7 days of the insecticide application. Rainfall affected the triatomicide effect, reducing the residual activity time. Cypermethrin pour-on treatment decreased T. infestans blood intake. Thirty days after the cypermethrin application, nymph mortality was 16% (±13) with both doses (10 and 15 cc). Dose of 15 cc did not show higher insecticidal effect or increased persistence than the dose of 10 cc.