Odor masking to decrease the attraction of Triatoma infestans (Hemiptera: Reduviidae, Triatominae), a Chagas disease vector, towards a host.

Chagas disease, vectored by kissing bugs, poses a public health problem across the Americas. The best way for reducing disease transmission is through vector control, which is currently based on the use of insecticides. However, insecticide resistance, and environmental and health issues, stress the need for new, environmentally-friendly methods for reducing vector-host contacts. Kissing bugs use the odor blend emitted by hosts to locate them. The proportions of the constituents of that blend are important to determine the attraction evoked by it. We aimed at assessing whether artificial alterations of those proportions could render an attractive host, unattractive for the kissing bug Triatoma infestans. Thus, the behavior of the bugs after adding a source of nonanal, a component of vertebrate odor detected by the bugs, to an attractive mouse was studied. For this, nymphs were tested using a dual-choice trap-olfactometer and different doses of nonanal. Addition of nonanal resulted in a dose- dependent reduction in the attraction of the bugs towards the mouse although it did not prevent the bugs from leaving their release zone nor it affected their (reduced) host preference near the host. Nonanal per se did not evoke any behavior at the doses tested. We suggest that the increase in the proportion of nonanal resulted in masking of the mouse odor. This approach could help reach a "push" effect within an effective push- pull strategy for kissing bugs. That strategy would help diminish the vector-host contacts and, therefore, Chagas disease incidence, in an environmentally-friendly manner. It remains to be established whether this strategy proves effective in the field when adequate odor dispensers and socially acceptable odors are used.