A Triatoma maculata (Hemiptera, Reduviidae, Triatominae) population from Roraima, Amazon region, Brazil, has some bionomic characteristics of a potential Chagas disease vector

Abstract

Even though Chagas disease is rare in the Brazilian Amazon, the conditions for the establishment of domiciliated cycles prevail in many areas where triatomines are of frequent occurrence. In Roraima, a previous serological and entomological survey in three agricultural settlements showed the existence of all transmission cycle elements, i.e., individuals infected by Trypanosoma cruzi, triatomine species previously found harboring T. cruzi in the broader Amazon region of neighboring countries and, domicile/ peridomicile conditions favorable to triatomine colonization. Triatoma maculata was the most frequent species, found in chicken houses in the peridomicile and sporadically within residences. Aiming to investigate the possibility of T. maculata to possess the potentiality to transmit T. cruzi in the area, bionomic characteristics were studied under laboratory conditions. These were feeding frequency, time for defecation after a blood meal, time elapsed in voluntary fasting pre- and pos-ecdysis, moulting time periods, pre-oviposition and oviposition periods and index of oviposition, incubation period, egg viability, longevity and mortality rate. Results show that the Passarão population of T. maculata should be considered a potential vector of T. cruzi since it shows a capacity to infest artificial ecotopes in the peridomicile, to carry out large number of meals during the nymphal cycle, to have a relatively short developmental cycle capable of producing 2.9 generations/year, to blood source eclecticism, to defecate immediately after the blood meal while still on the host and to the fact that has been previously found naturally infected by T. cruzi.

The association of Triatoma maculata (Ericsson 1848) with the gecko Thecadactylus rapicauda (Houttuyn 1782) (Reptilia: Squamata: Gekkonidae): a strategy of domiciliation of the Chagas disease peridomestic vector in Venezuela?

“…Furthermore, the distribution of these individuals collected in different development stages is in agreement with the population levels described for this species found in henhouses in Brazil and with a population equivalent to that reported for a typical domiciliary species such as Rhodnius prolixus [8,9] . In Roraima (Brazil), T. maculata was the most numerous species found in henhouses, with a peridomiciliary infestation index of 16.7% (number of triatomines captured/number of captured 暳 100) and a crowding index of 12 500 % (number of triatomines captured/ number of houses 暳 100) [17] .…”

“…In T. maculata can be found in Aruba, Bonaire, Brazil, Colombia, Curazao, Guyana, Suriname and Venezuela [7] , it is an ornitophilic specie, considered opportunistic because on occasion it has been found to colonize near henhouses in Brazil and Venezuela [8,9] . At the same time, T. maculata is considered to be responsible for the Chagas diseases peridomestic cycle in some of the countries mentioned above [10,14] .…”

Biological aspects of crosses between Triatoma maculata (Erichson, 1848) and Triatoma pseudomaculata Corrêa & Espínola, 1964 (Hemiptera: Reduviidae)

“…Silva et al (1995), by studying the influence of temperature on the development of T. maculata blood fed on chicken, verified a difference in the egg incubation period: 29 and 16 days at 25 and 30°C, respectively. Luitgards-Moura et al (2005) have also shown that higher temperatures diminish the incubation period; with temperatures ranging from 21.5 to 32°C (average 27.6°C) and weekly blood feeding on mice, these authors reported a variation in the period of egg incubation between 14 and 42 days, with a significant negative correlation between temperature and incubation time (-0.98).…”

Estudio de componentes hemolinfáticos de Rhodnius prolixus y Triatoma maculata alimentados con diferentes fuentes sanguíneas

“…En Venezuela T. maculata ha sido considerado tradicionalmente como un vector secundario del agente etiológico de la enfermedad de Chagas, ya que aunque se le ha encontrado infectado naturalmente por T. cruzi, se considera que está adaptado a hábitats peridomiciliarios y silvestres, siendo una especie principalmente ornitófaga, asociada con gallinas y palomas que raramente se alimenta del hombre 2,8 . Sin embargo recientemente ha estado emergiendo un nuevo escenario epidemiológico de esta especie en Venezuela 9-14 y países vecinos como Brasil 15,16 y Colombia 17,18 ya que ha sido encontrada domiciliada y en medios urbanos, lo cual impone la necesidad de revisar el carácter secundario en su capacidad de transmitir al agente etiológico de la enfermedad de Chagas. Pese a que todas las especies de triatominos son potencialmente vectores de T. cruzi 5 , la capacidad vectorial está sujeta a múltiples factores entre los que se encuentran por ejemplo la composición faunística local disponible al insecto, la competencia de transmisión del parásito a mamíferos domésticos, sinantrópicos y silvestres, la tasa de contacto hospedador-vector o la adaptación a diferentes fuentes sanguíneas.…”