A SURVEY 0F CHAGAS CYCLES IN URUGUAY BY USE OF GENETIC MARKERS, WITH SPECIAL EMPHASIS 0N REINFESTATION HAZARDS OF DOMESTIC STRUCTURES BY SYLVATIC CYCLES.
In the 3 million people of Uruguay, serological surveys suggest the existence of 50.000 infected persons with about 1 million living in the endemic areas and at risk to infection. The parasite is found in the domestic cycle, transmitted bY T.infestans and also in sylvatic conditions, transmitted by T.rubrovaria. Indirect arguments exist indicating the possible infection of humans by sylvatic strains of T. cruzi.In spite of an efficient national control programme, treated areas are regularly reinfested, mainly by T.infestans but also by T.rubrovaria. Innorthern Uruguay areas where the domiciliary vector population was reduced by control measures, the traditionally sylvatic T.rubrovaria is substituting T.infestans in the domestic habitat. In other areas of Uruguay, T. rubrovaria is living in the peridomestic structures nearby the intradomiciliary T.infestans. To check hazards of reinfestations of domestic habitats by Chagas sylvatic cycles, three main activities will be developed requiring cooperation between different Faculties and Departments of the University of Uruguay, and the technical expertise of different European laboratories.
1. Using different genetic markers, reinfestation problems will be approached by the measure of the dispersal capacity of each vector (gene flow between local populations).
2.The vectorial importance of T. rubrovaria to man is not known, but it is generally found infected by T. cruzi at a higher rate than T. infestans. Using xenodiagnosis, the vector/parasite adaptation will be compared between T.infestans and T.rubrovaria.
3. Lack of identification data about different strains of the parasite make it impossible to know the actual amount of overlapping between the sylvatic and the domestic cycles. Using isoenzymes and the recently developed KDNA probes, we will identify local strains of Trypanosoma cruzi from Sylvatic and domestic vectors.
Funding SchemeCSC - Cost-sharing contracts