Chagas Disease in Rural Areas of Chaco Province, Argentina: Epidemiologic Survey in Humans, Reservoirs, and Vectors

Abstract

We studied the seroprevalence of antibodies against Trypanosoma cruzi in the human population along with domiciliary infestation by triatomine bugs in an area endemic for Chagas disease in the Chaco Province of Argentina. In addition, we carried out parasitologic surveys in patients, dogs, wild mammals, and vectors. The mean seroprevalence in humans was 27.81% (109 of 392) and 24.14% (63 of 261) in 1-15-year-old children. The minimum domiciliary infestation rate was 13.33%, with certain areas reaching 53.85%. The prevalence was 15.09% (16 of 106) in dogs and 35.71% (10 of 28) in opossums. Infection with T. cruzi was detected in 30.10% (59 of 196) of the Triatoma infestans tested. Compared with nationwide studies, our data suggest that 1) there are zones requiring immediate sanitary action, and 2) nationwide estimates are based on very heterogeneous epidemiologic situations. This heterogeneity emphasizes the importance of in-depth studies of restricted areas to provide additional information for a better understanding of the present status of Chagas disease in Argentina.

Autonomic Dysfunction and Risk Factors Associated with Trypanosoma cruzi Infection among Children in Arequipa, Peru

“…This finding may reflect lower intensity of parasite exposure, lower parasite burdens, and/or strain differences in Arequipa compared with other study sites. The lower infection prevalence in Arequipa suggests a lower force of infection compared with study sites in Brazil, Argentina, or Bolivia, [33][34][35][36] whereas the relatively flat age prevalence curve supports the hypothesis that the parasite was only introduced into the periurban communities of Arequipa in the early 1990s. 26 Investigators have shown that repeated infection increases cardiac pathology in animal models 37,38 and have suggested that vector control, by decreasing reinfection rates, may be responsible for the milder disease now seen in formerly endemic communities.…”

New Sylvatic Hosts of Trypanosoma cruzi and Their Reservoir Competence in the Humid Chaco of Argentina: A Longitudinal Study

“…9 The prevalence of T. cruzi infection in Di. albiventris opossums (38%) was as high as in the past 37 or elsewhere in Chaco (36%) 18 and Santiago del Estero Provinces (32-36%). 16,17 However, in Santiago del Estero Province, infection prevalence decreased to 9% more recently.…”

“…Few areas have been investigated in recent decades, usually through cross-sectional or convenience surveys; sampling efforts have focused on a limited number of species and environments, and identification of parasite DTUs from wild hosts has been sparse. 7,9,[16][17][18][19][20]24 Identification of the triatomine species acting as sylvatic vectors is lagging. 7,8,20,25 Assessing the impacts of ongoing environmental changes requires more information on the structure of transmission cycles over time.…”

“…12 In this region, the most frequently identified sylvatic hosts of T. cruzi are didelphid marsupials and various species of armadillos, followed by carnivores (including skunks, ferrets, foxes, and coatis) and a few species of small rodents. 7,9,[13][14][15][16][17][18][19][20] In general, host and parasite distributions may be modified by the combined effects of alterations in climate, landscape and biodiversity, which may create new habitats suitable for the development of parasites and vectors and increase the risk of transmission of pathogens. 21 The sylvatic distribution of triatomine bugs and transmission of T. cruzi appear to be closely associated with vegetation cover and landscape use.…”

Seroprevalence of Chagas disease in schoolchildren from two municipalities of Jequitinhonha Valley, Minas Gerais, Brazil; six years following the onset of epidemiological surveillance

“…America have demonstrated the importance of seroprevalence of Chagas disease in children as a reliable indicator of transmissibility of the disease 4,16 .…”