Genetic structure of Triatoma infestans populations from northern Argentina and other South America countries based on mithocondrial DNA analysis

MARCET PAULA L, JONES LEEANN, PICCINALI ROMINA, GÜRTLER RICARDO E, KITRON URIEL, DOTSON ELLEN M

Washington, DC

Congreso; American Society of Tropical Medicine and Hygiene 54th Annual Meeting; 2005

American Society of Tropical Medicine and Hygiene

Triatoma infestans is the main South American vector of Trypanosoma cruzi, the causative agent of Chagas disease. This species is widely distributed in the Southern Cone countries, including Argentina, Bolivia, Chile, Paraguay, Uruguay, southern Brazil and southern Peru. An understanding of the genetic structure, dispersion dynamics and phylogeographical relationships among populations will contribute to improve and target control strategies.In the present study the genetic variability of a 470 bp region of the Cytochrome B mitochondrial gene was analyzed. Sequences of 304 T. infestans from 43 villages of different regions in South America were obtained, and their phylogenetic relationships were studied by parsimony, genetic distance and minimum evolution criteria and compared with the pattern of geographical distribution. The 22 different haplotypes were consistently grouped in 3 main clades by the three methods. The single haplotype found in Bolivia and Peru (Andean populations) was highly different from haplotypes from the other regions sampled. In contrast, populations of northern Argentina expressed high variability (including 2-3 haplotypes within the same house), suggesting the occurrence of several colonization sources. Two haplotypes (differing in only one synonymous substitution) were distributed widely throughout northern Argentina and were also previously reported in Brazil. The genetic variability data presented in this work provides a valuable tool for the study of T. infestans evolutionary dynamics.