Natural infection and distribution of triatomines (Hemiptera: Reduviidae) in the state of Querétaro, Mexico

Abstract

Chagas disease is present in Mexico but data on the presence of its vectors are not known for all the states. We conducted an epidemiological study to ascertain the presence of bedbugs in 23 communities of seven municipalities in the state of Querétaro, Mexico. Sampling was performed within and outside dwellings, using the technique of one person searching per hour per house. Four triatomine species were found: Triatoma mexicana (94%), Tri. dimidiata (3%), Tri. gerstaeckeri (2%) and Tri. pallidipennis (1%). Triatoma mexicana was found in six of the seven municipalities but has previously been found only in the state of Hidalgo, where it is considered the most important vector species of Trypanosoma cruzi. This is the first time that the presence of Tri. gerstaeckeri or Tri. dimidiata has been reported in the state of Querétaro. Tolimán municipality had the highest entomological indices: infestation index 73%; infection index 34.5%; crowding index 9.2%; density index 6.7%; and colonization index 20.6%. Although the prevalence and colonization indices were low, the infestation and infection indices indicate that different Triatoma species are becoming established in Querétaro. This work represents the first entomological study in this Mexican state and suggests that some triatomine vectors are extraordinarily mobile.

Influence of temperature and humidity on the biology of Triatoma mexicana (Hemiptera: Reduviidae: Triatominae) under laboratory conditions

“…These results could be due to an adaptive response to different climatic conditions, such as those recorded in the natural distribution area of T. mexicana in Mexico (López-Cárdenas et al 2005, Becerril-Flores et al 2007, Salazar-Schettino et al 2007, Villagrán et al 2008). According to most of the studied parameters in this study, T. mexicana cannot be considered to be an effective transmitter of T. cruzi to humans, which is different from other similar species, such as six species in the Phyllosoma complex (Martínez-Ibarra et al 2003a, Martínez-Ibarra & Novelo-López 2004.…”

“…This species usually occurs inside human houses (especially on walls and bedrooms) and in the peridomicile and is mostly collected from yards and in sylvatic foci at the center of Mexico (López-Cárdenas et al 2005, Becerril-Flores et al 2007, Salazar-Schettino et al 2007, Villagrán et al 2008. The climate in this area is mild and dry with 400-1000 mm annual rainfall and temperatures ranging from 0-40 o C (SEGOB 2005).…”

“…In spite of the important role of T. mexicana in the transmission of T. cruzi to human populations in an epidemiologically important areas of Mexico, such as the states of Guanajuato, Hidalgo, Querétaro and San Luis Potosí (Becerril-Flores et al 2007, Salazar-Schettino et al 2007, Villagrán et al 2008, the biology and behavior of this species has not been documented.…”

Entomological Indices, Feeding Sources, and Molecular Identification of Triatoma phyllosoma (Hemiptera: Reduviidae) One of the Main Vectors of Chagas Disease in the Istmo de Tehuantepec, Oaxaca, Mexico

“…For the infestation and colonization indices the vectors of the peridomestic area, such as the surrounding areas of houses, where the inhabitants stay for a long period of time during the day and frequently sleep during the night, were also considered as has been reported in other regions of Mexico. 14,26 For the infection index, feces were obtained from each insect by abdominal pressure and diluted in phosphate buffered saline. The presence of T. cruzi was determined by direct microscopic observation at 400× magnification.…”

Triatoma mexicana Herrich-Schaeffer (Hemiptera: Reduviidae: Triatominae) Descripción de la Genitalia Externa del Macho y Morfología Externa de la Hembra.

“…Actualmente T. mexicana se encuentra distribuida en cuatro estados: Guanajuato, Hidalgo, Querétaro y San Luis Potosí (lent & WiGodzinSky 1979;zárate & zárate 1985;vidal et al 2000;villaGrán et al 2008). El hallazgo de los transmisores se ha realizado tanto en el intradomicilio como en el peridomicilio, la infección natural con T. cruzi se reportó por primera vez en los estados de Guanajuato e Hidalgo (vidal et al 2000).…”