5 research outputs found
Heterogeneities in the Ecoepidemiology of Trypanosoma cruzi Infection in Rural Communities of the Argentinean Chaco
We conducted a cross-sectional survey of Trypanosoma cruzi infection of Triatoma infestans as well as dogs and cats in 327 households from a well-defined rural area in northeastern Argentina to test whether the household distribution of infection differed between local ethnic groups (Tobas and Creoles) and identify risk factors for host infection. Overall prevalence of infection of bugs (27.2%; 95% confidence interval = 25.3–29.3%), dogs (26.0%; 95% confidence interval = 23.3–30.1%), and cats examined (28.7%; 95% confidence interval = 20.2–39.0%) was similar. A multimodel inference approach showed that infection in dogs was associated strongly with the intensity and duration of local exposure to infected bugs and moderately with household ethnic background. Overall, Toba households were at a substantially greater risk of infection than Creole households. The strong heterogeneities in the distribution of bug, dog, and cat infections at household, village, and ethnic group levels may be used for targeted vector and disease control.Fil: Cardinal, Marta Victoria. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Orozco, Maria Marcela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Enriquez, Gustavo Fabián. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Ceballos, Leonardo A.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; ArgentinaFil: Gaspe, Maria Sol. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Alvarado Otegui, Julián Antonio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; ArgentinaFil: Gurevitz, Juan Manuel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Kitron, Uriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; ArgentinaFil: Gurtler, Ricardo Esteban. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin
Factors Affecting Infestation by Triatoma infestans in a Rural Area of the Humid Chaco in Argentina: A Multi-Model Inference Approach
Vector-borne transmission of Chagas disease remains a major public health problem in parts of Latin America. Triatoma infestans is the main vector in the countries located in the South American Cone, particularly in the Gran Chaco ecoregion where residual insecticide control has achieved only a moderate, irregular impact. To contribute to improved control strategies, we analyzed the factors associated with the presence and abundance of T. infestans in 327 inhabited houses in a well-defined rural area with no recent vector control interventions in the humid Argentine Chaco. Bugs were found mainly in domiciles, kitchens, storerooms, and chicken coops and nests, particularly where adequate refuge and animal hosts (humans, dogs, cats or poultry) were available. Domiciles constructed from mud were the most often infested, but brick-and-cement domiciles, even in good conditions, were also found infested. Availability of refuge and hosts for T. infestans are key targets for vector control. Ten-fold variations in domestic infestation observed across neighboring villages, and differences in the relevant factors for T. infestans presence with respect to other areas of the Gran Chaco region suggest that host management, building techniques and insecticide use need to be tailored to the local environment, socio-economic characteristics, and climatic conditions
New sylvatic hosts of Trypanosoma cruzi and reservoir competence in the humid Argentinean Chaco: A longitudinal study
A four-year longitudinal study was conducted to investigate the structure of sylvatic transmission cycles of Trypanosoma cruzi, assess reservoir host competence and identify parasite discrete typing units (DTUs) in a disturbed rural area of the humid Argentinean Chaco. Among 190 mammals examined by xenodiagnosis and polymerase chain reaction amplification, the composite prevalence of infection was substantially higher in Dasypus novemcinctus armadillos (57.7%) and Didelphis albiventris opossums (38.1%) than in Euphractus sexcinctus (20.0%), Tolypeutes matacus (12.5%) and Chaetophractus vellerosus (6.3%) armadillos. T. cruzi was detected for the first time in Thylamys pusilla opossums and in two unidentified small rodents. Infection was spatially aggregated only in armadillos. All Didelphis were infected with T. cruzi I and all armadillo species with T. cruzi III, implying two distinct sylvatic cycles with no inputs from the domestic cycle. Dasypus armadillos and Didelphis opossums were much more infectious to vectors than other armadillos, opossums or rodents.Fil: Orozco, Maria Marcela. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de EcologÃa, Genética y Evolución de Buenos Aires; ArgentinaFil: Enriquez, Gustavo Fabián. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de EcologÃa, Genética y Evolución de Buenos Aires; ArgentinaFil: Alvarado Otegui, Julián A.. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecologia, Genetica y Evolucion. Laboratorio de Eco - EpidemiologÃa; ArgentinaFil: Cardinal, Marta Victoria. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de EcologÃa, Genética y Evolución de Buenos Aires; ArgentinaFil: Schijman, Alejandro Gabriel. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Investigaciones en IngenierÃa Genética y BiologÃa Molecular; ArgentinaFil: Kitron, Uriel. University Of Emory; Estados UnidosFil: Gurtler, Ricardo Esteban. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de EcologÃa, Genética y Evolución de Buenos Aires; Argentin
The sylvatic transmission cycle of Trypanosoma cruzi in a rural area in the humid Chaco of Argentina
Little is known about the sylvatic transmission cycle of Trypanosoma cruzi in the Gran Chaco ecoregion. We conducted surveys to identify the main sylvatic hosts of T. cruzi, parasite discrete typing units and vector species involved in Pampa del Indio, a rural area in the humid Argentinean Chaco. A total of 44 mammals from 14 species were captured and examined for infection by xenodiagnosis and polymerase chain reaction amplification of the hyper-variable region of kinetoplast DNA minicircles of T. cruzi (kDNA-PCR). Ten (22.7%) mammals were positive by xenodiagnosis or kDNA-PCR. Four of 11 (36%) Didelphis albiventris (white-eared opossums) and six of nine (67%) Dasypus novemcinctus (nine-banded armadillos) were positive by xenodiagnosis and or kDNA-PCR. Rodents, other armadillo species, felids, crab-eating raccoons, hares and rabbits were not infected. Positive animals were highly infectious to the bugs that fed upon them as determined by xenodiagnosis. All positive opossums were infected with T. cruzi I and all positive nine-banded armadillos with T. cruzi III. Extensive searches in sylvatic habitats using 718 Noireau trap-nights only yielded Triatoma sordida whereas no bug was collected in 26 light-trap nights. Four armadillos or opossums fitted with a spool-and-line device were successfully tracked to their refuges; only one Panstrongylus geniculatus was found in an armadillo burrow. No sylvatic triatomine was infected with T. cruzi by microscopical examination or kDNA-PCR. Our results indicate that two independent sylvatic transmission cycles of T. cruzi occur in the humid Chaco. The putative vectors of both cycles need to be identified conclusively.Fil: Alvarado Otegui, Julián Antonio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; ArgentinaFil: Ceballos, Leonardo A.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; ArgentinaFil: Orozco, Maria Marcela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Enriquez, Gustavo Fabián. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Cardinal, Marta Victoria. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Cura, Carolina Inés. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Investigaciones en IngenierÃa Genética y BiologÃa Molecular "Dr. Héctor N. Torres"; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Schijman, Alejandro Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Kitron, U.. University of Emory; Estados UnidosFil: Gurtler, Ricardo Esteban. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de EcologÃa, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin