The sylvatic transmission cycle of Trypanosoma cruzi in a rural area in the humid Chaco of Argentina

• Published in: Acta tropica Vol. 124; no. 1; pp. 79 - 86
• Main Authors: Alvarado-Otegui, J.A., Ceballos, L.A., Orozco, M.M., Enriquez, G.F., Cardinal, M.V., Cura, C., Schijman, A.G., Kitron, U., Gürtler, R.E.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01.10.2012; Elsevier
• Subjects: Animals; Animals, Wild; Argentina; Biological and medical sciences; burrows; Chagas Disease - parasitology; Chagas Disease - transmission; Chagas Disease - veterinary; Dasypus; Dasypus novemcinctus; Didelphis albiventris; Discrete typing unit; Disease Reservoirs; Disease Vectors; DNA, Kinetoplast - chemistry; DNA, Kinetoplast - genetics; DNA, Protozoan - chemistry; DNA, Protozoan - genetics; Felidae; General aspects; habitats; hares; hosts; Humans; Humidity; kinetoplast DNA; Life Cycle Stages; Medical sciences; Molecular epidemiology; Molecular Sequence Data; opossums; Panstrongylus; Panstrongylus geniculatus; parasites; Polymerase Chain Reaction; Procyon lotor; rabbits; Reservoir; rodents; rural areas; Rural Population; Sequence Analysis, DNA; surveys; Triatoma sordida; Trypanosoma cruzi; Trypanosoma cruzi - isolation & purification; Trypanosoma cruzi - pathogenicity; Vector; xenodiagnosis; Argentina; South America; America; Argentina, Chaco; Argentina, Pampa; Discrete typing unit; Molecular epidemiology; Reservoir; Dasypus novemcinctus; Vector; Didelphis albiventris; Trypanosoma cruzi; Kinetoplastida; Protozoa; Rural environment; Typing; Transmission; Microbiological investigation; Tropical medicine
• ISSN: 0001-706X; 1873-6254
• DOI: 10.1016/j.actatropica.2012.06.010

We conducted surveys to identify the main sylvatic hosts of Trypanosoma cruzi, parasite discrete typing units and vector species involved in a rural area in the humid Argentine Chaco. [Display omitted] ► We identified the main sylvatic hosts of Trypanosoma cruzi in northeastern Argentina. ► Didelphis albiventris opossums and Dasypus novemcinctus armadillos were infected. ► Opossums were infected with T. cruzi I and armadillos with T. cruzi III. ► Panstrongylus geniculatus and Triatoma sordida were found in sylvatic habitats. ► Two independent sylvatic transmission cycles of T. cruzi occur in the humid Chaco. 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.