Invasion of rural houses by wild Triatominae in the arid Chaco.

Triatomines are the vectors of Trypanosoma cruzi, the etiologic agent of Chagas disease, the main endemic disease affecting five to seven million people in Latin America. Besides Triatoma infestans, the most important T. cruzi vector in the Gran Chaco region, other triatomine species associated with sylvatic birds and mammals are responsible for the maintenance of the wild cycle of T. cruzi. The present study aimed at evaluating the house invasion by sylvatic triatomine species in rural communities of the Los Llanos region (La Rioja, Argentina) and its association with environmental variables. House invasion by flying adult triatomines was recorded by trained collectors that surveyed over 377 houses distributed over 73 localities in a 56,600 km(2) study region, between October, 2014 and February, 2015. The result of the study showed the frequent house invasion by adult triatomines: 26.3% houses were infested in 53% of the localities. Seven sylvatic triatomine species were collected, with T. guasayana and T. garciabesi among the most abundant. House invasion by triatomine species showed no spatial aggregation and was not associated with temperature, precipitation, or vegetation cover at the spatial scale considered in the present study. House invasion by the epidemiologically important T. infestans is a concern of rural communities. Besides constituting a latent, although low, risk, the presence of these species negatively interferes with the vigilance activities of the provincial Chagas disease program.