Triatomicidal effect of new spot-on formulations applied to poultry in semi-field conditions.

Chagas disease is an endemic disease affecting ten million people in the American continent. Produced by a parasite transmitted by triatomine insects, the main actions for reducing the incidence of this disease are focused on the control of insect vectors. This type of control has produced highly effective results within rural homes, but not in peridomestic areas (kitchens, warehouses, hen houses and other buildings not attached to the houses). The object of the present study was to assess the triatomicidal effect of new spot-on formulations developed by our laboratory in a semi-rural environment. The active ingredients of the formulations were β-cypermethrin, pyriproxyfen, or β-cypermethrin + pyriproxyfen. All formulations were applied to hens and tested in miniature replicas of rural households where experimental populations of Triatoma infestans, the main vector of Chagas disease in Argentina, had been previously released. The experimental populations exposed to formulations containing β-cypermethrin or β-cypermethrin + pyriproxyfen were noticeably reduced compared to non-treated control groups. However, no differences were observed between the effects produced by β-cypermethrin alone and β-cypermethrin + pyriproxyfen. Pyriproxyfen alone produced no significant reduction in the experimental populations of T. infestans. These results suggest that spot-on application of β-cypermethrin could be a useful complementary tool for controlling triatomine insects in the peridomestic areas of rural homes.