Demographic and Dispersal Constraints for Domestic Infestation by Non-Domicilated Chagas Disease Vectors in the Yucatan Peninsula, Mexico

Chagas disease is one of the most important diseases in Latin America. Insecticides have been sprayed to control domiciliated vectors. However, some triatomine species are not strictly domiciliated, and the transmission risk posed by immigrants is identified as a major challenge. The design of new control strategies requires disentangling the importance of demography and immigration in vector occurrence inside houses. Using a population dynamics model, we confirmed that dispersal can explain satisfactorily the domestic abundance of Triatoma dimidiata in Yucatan, Mexico. A surprisingly low fecundity was also required (no more than one to two female offspring per female per trimester). A wide range of survival probabilities was possible, although the best fit was obtained for a very low immature survival (< or = 0.01/trimester). Our model predicted that domestic populations are not sustainable, and up to 90% of the individuals found in houses are immigrants. We discuss the potential of different strategies to control the transmission of Chagas disease by non-domiciliated vectors.