Search

Chagas disease is one of the most important vector-borne diseases in Latin America, including Mexico. Triatoma pallidipennis (Stål) (Hemiptera: Reduviidae) is a Mexican triatomine vector commonly associated with different hosts. The influence of six blood meals (rabbits, rats, mice, dogs, cats and chickens) on six biological parameters of the biology of T. pallidipennis was evaluated. A significant difference was found in the period of egg-to-adult development between the five mammalian feeds (mean 195 days) and the chicken feed (221 days). The probability of survival was significantly lower in the chicken cohort (0.285). The total number of blood meals to moult from the first instar to the adult stage was the highest in the chicken cohort (10-15). This cohort had the significantly highest rate of females at the end cycle. The mean number of eggs laid per female and the egg eclosion rate were similar among the six food sources. Most results seemed to be influenced by the higher nutritional quality of the mammalian blood compared to the bird's blood and the increased energy expenditure required for the digestion of bird blood. These results clearly show that T. pallidipennis, unlike other triatomine species, has a high reproductive capacity when feeding on different hosts., (© 2022 Royal Entomological Society.)

Chagas disease is one of the most important vector-borne diseases in Latin America. Studying the biological parameters of each vector species or subspecies contributes to our understanding of their epidemiologic importance. The aim of our study was to compare the biological parameters and start to estimate the vectorial capacity of Triatoma protracta protracta Ryckman, T. p. nahuatlae Ryckman, and their laboratory hybrids. Specifically, we estimated nine biological parameters to increase knowledge about the potential role of triatomine hybrids in the transmission of T. cruzi to reservoir hosts. Nine biological parameters related to the lifecycle, feeding and defecation patterns, number of females, fecundity, and egg eclosion rates in cohorts of T. p. protracta , T. p. nahuatlae, and their hybrids were evaluated and compared. Eight parameters (exception: number of laid eggs) indicated that T. p. nahuatlae was a potentially effective vector of T. cruzi. Our results showed that the hybrid cohorts had better fitness and could potentially have higher vectorial capacity than the parental cohorts. The outstanding characteristics of the hybrids found in our study could lead to an increase in the epidemiologic risks caused by transmission of T. cruzi to humans.

Background & Objectives: Meccus pallidipennis is one of the most epidemiologically important vectors of Trypanosoma cruzi to reservoir hosts in nine states of Mexico. Triatomines occurring in distinct locations normally adapt to local conditions. The aim of this study was to examine the biological attributes of three populations of M. pallidipennis from areas with different environmental characteristics as a factor influencing the triatomine capacity for T. cruzi transmission., Methods: The values of biological parameters related to the life cycle, the number of blood meals to molt to next instar, fecundity and percentage of females after a biological cycle of three populations of M. pallidipennis were evaluated. A cohort of each of the three studied populations from different geographical areas of Mexico was maintained under similar laboratory conditions and then compared with each other., Results: The life cycle was less than six months in all the studied cohorts, with differences among them. The number of blood meals to molt was lower for the cohort from Izϊcar de Matamoros. Laid eggs per day per female was lower for the cohort from Luvianos. In contrast, no important differences were recorded on the percentage of mortality, egg eclosion rate or percentages of obtained females., Interpretation & Conclusion: It was found that an important level of heterogeneity exist between the three studied populations of M. pallidipennis, apparently influenced by the remarkable differences on environmental conditions on the localities where the founders were initially collected, that emphasizes the necessity of studies on local populations of triatomines.

An entomological study of triatomine species was carried out to assess their prevalence in 10 localities of the state of Michoacán, Mexico. Entomological indices were calculated to estimate the risk for vector-borne transmission of Trypanosoma cruzi to the human population in this area. Four triatomine species (Triatoma barberi, Triatoma dimidiata, Meccus pallidipennis and Meccus longipennis) were collected from the study area. This is the first report of M. longipennis and T. dimidiata in Michoacán. M. pallidipennis was significantly (p < 0.05) more abundant than any of the other species collected in the study area. Infection indices were greater than 50% for each of the four collected triatomine species. Significantly more triatomines were collected from intradomiciliary areas than from peridomiciliary or sylvatic areas. Infestation, crowding and density indices were low, whereas colonisation indices were high in five localities. The current vectorial conditions in the study area require continuous entomological and serological surveillance to diminish the risk of T. cruzi transmission to human populations.