Spatio-temporal genetic structure in populations of the Chagas’ disease vector Triatoma infestans from Argentina

Triatoma infestans (Hemiptera, Reduvidae) is the main vector of Chagas disease in South America between the latitudes 10° and 46° S. The analysis of the spatial genetic structure of populations at fine scale can provide insight into the dynamic population and evolutionary process of T. infestans and a complementary approach to help improve vector control strategies. Spatio-temporal analysis of the genetic structure of T. infestans populations was performed using inter-simple sequence repeats markers. A total of 242 polymorphic bands were detected from 234 individuals captured in different houses from the locality of San Martín and in one surrounding area (Capayan department, Catamarca province, Argentina) in October 2007 and May 2010. Significant levels of genetic differentiation were detected among the collection sites in both temporal samples, including the different sampled sites within the same house. These results confirm a high degree of subdivision in T. infestans populations. Comparative analysis between the first and the second sample indicated that they form two different groups. The genetic differentiation level was higher among samples from the second capture compared to the first. It is probable that in subdivided populations, when restricted gene flow is sustained over time, the genetic drift leads to accentuate the differentiation among subpopulations. The spatial autocorrelation analysis indicated that the dispersion range could occur around 500–550 m. Therefore, the probability of reinfestation by active dispersal of the insect could be reduced by implementing control and surveillance within an approximate radius of 500–550 m around the infested area.