Triatoma dimidiata with different epidemiological importance as Chagas disease vectors
Chromosomal variation and genome size support existence of cryptic species of
The wide geographical distribution of Triatoma dimidiata, one of the three major vectors of Chagas disease, ranges from Mexico to northern Peru. Since this species occupies a great diversity of artificial and natural ecotopes, its eradication is extremely difficult. In order to assist control efforts, we used chromosome analyses and DNA amount as taxonomic markers to study genetic variability in populations of T. dimidiata from Mexico, Guatemala, El Salvador and Colombia. We differentiated three groups or cytotypes defined by characteristic chromosome C-banding patterns and genome size measured by flow cytometry. The three cytotypes are restricted to different geographic locations. Cytotype 1 occurs in Mexico (excluding Yucatán), Guatemala (excluding Petén), El Salvador and Colombia. Cytotype 2 occurs in Yucatán and cytotype 3 occurs in Petén. Cytotype 1, commonly associated with domestic and peridomestic environments but also inhabiting sylvatic ecotopes, is the most widespread and with major epidemiological significance. In contrast, the Yucatán cytotype inhabits wild ecotopes but increasingly enters houses, while the Petén cytotype appears exclusively sylvatic. We suggest that these cytotypes represent cryptic species of T. dimidiata with different epidemiological relevance as Chagas disease vectors. Poor ability to colonize human dwellings, together with their restricted geographic distribution, indicate that the Yucatán and Petén putative species probably have much less epidemiological significance than cytotype 1. Thus, the genetic markers we describe are powerful tools to differentiate cryptic species in T. dimidiata with different epidemiological significance, contributing to planning the most effective control measures.
Document Type: Research Article
CISEI, Instituto Nacional de Salud Pública. Cuernavaca, Morelos, Mexico
Facultad de Medicina, Universidad Nacional Autónoma de México, México DF, Mexico
Escuela de Biología, Universidad de San Carlos, Ciudad de Guatemala, Guatemala
Facultad de Farmacia, Universidad de Valencia, Valencia, Spain
Laboratorio de Citómica, Centro de Investigación Príncipe Felipe, Valencia, Spain
Centro de Investigaciones en Enfermedades Tropicales, Universidad Industrial de Santander, Piedecuesta, Colombia
Grupo Chagas. Instituto de Biología, Universidad de Antioquia, Medellín, Colombia
Center for Health Studies, Universidad del Valle de Guatemala. Guatemala
Centro de Investigación y Desarrollo en Salud, Universidad de El Salvador, San Salvador
Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
Publication date: July 1, 2006
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Salazar-Schettino, P. M.
Monroy, M. C.
Bargues, M. D.
O'Connor, J. E.
Angulo, V. M.