Biological and ecological factors in the epidemiology of Chagas' disease in Chile
Schenone, H.; Villarroel, F.; Rojas, A.; Alfaro, E.
Boletin Chileno de Parasitologia 35(3-4): 42-54
1980
ISSN/ISBN: 0365-9402 PMID: 6797447 Document Number: 167951
Chagas' disease exists in Chile in rural and suburban areas of the zone between 18.degree.30' and 34.degree.36'S. It comprises 7 regions (1st-6th plus Metropolitan Region) in which Trypanosoma cruzi infected vectors and humans were found. Infection of domestic mammals, mainly the dog (11.7%) and cat (15.1%) were demonstrated in the 1st 5 regions and Metropolitan Region; infection in wild mammals (1 sp. of rodents and 2 of canids) was observed only in 2 of the regions. There exist only 2 spp. of vectors, a domestic one, Triatoma infestans, which is the most important vector, and a wild one, T. spinolai, in which epidemiological importance, although not well-defined, should have a role of some significance in the wild enzootic infection. Within variable ranges global infection rates are 33.2% for T. infestans and 6.9% for T. spinolai. In Chagas' endemic areas human and animal infection may exist in dwellings where it has not been possible to detect the presence of triatomids. The risk of infection is 6 times higher in houses harboring infected triatomids. In Chile human infection reaches an average of 16.7% in endemic areas, having a total population of 2 million people, with an estimate of 300,000 being infected. From these infected persons, 25% would have presented some pathology attributable to T. cruzi; the remaining 75% corresponds to asymptomatic infections.