title: Relationships between altitude, triatomine (Triatoma dimidiata) immune response and virulence of Trypanosoma cruzi, the causal agent of Chagas' disease.
abstract: Little is known about how the virulence of a human pathogen varies in the environment it shares with its vector. This study focused on whether the virulence of Trypanosoma cruzi (Trypanosomatida: Trypanosomatidae), the causal agent of Chagas' disease, is related to altitude. Accordingly, Triatoma dimidiata (Hemiptera: Reduviidae) specimens were collected at three different altitudes (300, 700 and 1400 m a.s.l.) in Chiapas, Mexico. The parasite was then isolated to infect uninfected T. dimidiata from the same altitudes, as well as female CD-1 mice. The response variables were phenoloxidase (PO) activity, a key insect immune response, parasitaemia in mice, and amastigote numbers in the heart, oesophagus, gastrocnemius and brain of the rodents. The highest levels of PO activity, parasitaemia and amastigotes were found for Tryp. cruzi isolates sourced from 700 m a.s.l., particularly in the mouse brain. A polymerase chain reaction-based analysis indicated that all Tryp. cruzi isolates belonged to a Tryp. cruzi I lineage. Thus, Tryp. cruzi from 700 m a.s.l. may be more dangerous than sources at other altitudes. At this altitude, T. dimidiata is more common, apparently because the conditions are more beneficial to its development. Control strategies should focus activity at altitudes around 700 m a.s.l., at least in relation to the region of the present study sites.
authors.affiliation: Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: J A
authors.initials: JA
authors.lastname: DE Fuentes-Vicente
authors.affiliation: Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: M
authors.initials: M
authors.lastname: Cabrera-Bravo
authors.affiliation: Departamento de Ecología Evolutiva, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: J N
authors.initials: JN
authors.lastname: Enríquez-Vara
authors.affiliation: Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: M I
authors.initials: MI
authors.lastname: Bucio-Torres
authors.affiliation: CONACYT-Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico.
authors.forename: A E
authors.initials: AE
authors.lastname: Gutiérrez-Cabrera
authors.affiliation: Laboratorio Experimental y Bioterio, Instituto de Ciencias Biológicas, Universidad de Ciencias y Artes de Chiapas, Mapastepec, Mexico.
authors.forename: D G
authors.initials: DG
authors.lastname: Vidal-López
authors.affiliation: Departamento de Desarrollo Regional, Centro Universitario del Sur, Universidad de Guadalajara, Guadalajara, Mexico.
authors.forename: J A
authors.initials: JA
authors.lastname: Martínez-Ibarra
authors.affiliation: Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: P M
authors.initials: PM
authors.lastname: Salazar-Schettino
authors.affiliation: Departamento de Ecología Evolutiva, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: A
authors.identifier: 0000-0002-5978-1660
authors.initials: A
authors.lastname: Córdoba-Aguilar
mesh_terms: D000531:Altitude; D000818:Animals; D014355:Chagas Disease / Q000276:immunology / Q000469:parasitology; D005260:Female; D007113:Immunity, Innate; D007303:Insect Vectors / Q000276:immunology / Q000469:parasitology; D008800:Mexico; D051379:Mice; D014224:Triatoma / Q000276:immunology* / Q000469:parasitology*; D014349:Trypanosoma cruzi / Q000469:parasitology* / Q000472:pathogenicity / Q000502:physiology; D014774:Virulence
keywords: Chagas' disease; Triatoma dimidiata; Trypanosoma cruzi; altitude; amastigotes; parasitaemia; phenoloxidase