Molecular epidemiology of domestic and sylvatic Trypanosoma cruzi infection in the Gran Chaco region

CARDINAL MV

Congreso; XIII International Congress of Protistology, XXV Meeting of the Brazilian Society of Protistology, XXXVI Anual Meeting on Basic Research in Chagas Disease; 2009

The structure of Trypanosoma cruzi transmission cycles includes a wide diversity of mammal hosts, triatomine bug species and parasite lineages. Domestic and sylvatic transmission cycles show different degrees of overlapping. Few such studies have been conducted in the Gran Chaco, a hyperendemic region for Chagas disease where Triatoma infestans is the main vector. Could the introduction of sylvatic T. cruzi parasites pose a threat to domestic transmission control efforts? As part of a regional study aimed at modeling the transmission dynamics and control of T. cruzi in the Gran Chaco, we assessed the distribution of T. cruzi lineages (identified by PCR strategies) in Triatoma infestans, domestic dogs, cats, humans and sylvatic mammals in the Argentinean Chaco. T. cruzi lineage II predominated among the 99 isolates characterized and lineage I among the six isolates obtained from sylvatic mammals. T. cruzi lineage IIe predominated in domestic habitats. Domestic and sylvatic cycles overlapped in our study area in Santiago del Estero in the late 1980s, when intense domestic transmission occurred, and still overlap at present though marginally. The household distribution of T. cruzi lineages showed that bugs, dogs and cats from a given house compound shared the same parasite lineage in most cases. This result lends further support to the importance of dogs and cats as domestic reservoir hosts of T. cruzi. The introduction of T. cruzi from sylvatic into domestic habitats would occur very rarely in the current epidemiological context of rural communities under sustained vector surveillance in the Argentine Chaco. Supported by NIH, IRDC, TDR, UBA.