Chagas' disease, a leading cause of heart disease in Latin America, is caused by the parasite Trypanosoma cruzi. Approximately 90 million people are at risk for infection and more than 13 million are currently infected with this parasite. It is carried by Triatomine bugs (the vectors) which transmit the parasite to  humans through their feces which are deposited at the time that they take a blood meal from their human host.  In Guatemala, the most important insect vectors are Triatoma dimidiata and Rhodnius prolixus.

Although most T. dimidiata look similar, we suspect that there are, in fact,  different strains (varieties) of these insects. Indeed, several apparently occupy different ecological niches and show different behaviors. Effective disease control depends on proper identification of these varieties or strains. For example, certain strains of the bugs may be more or less susceptible to particular insecticides, may show differences in how well they transmit the parasite, or may be localized to particular environments, for example houses or the forest. In addition, if differences are found between groups, we can ask questions such as:  What is the capability of  Triatomines to spread from one area to another?  If they are eradicated from one area can they move in from another ?  To be able to ask these questions we must first understand the genetic structure of T. dimidiata. For example, are different strains found within one house, between nearby houses or only in geographically distant areas? Which are the genetic markers to use to best identify the different strains? To answer these and related questions, we are investigating the genetic structure of  T. dimidiata in order to better understand the role of the insect vector in the spread of Chagas disease.