Potential sources of Triatoma infestans reinfesting peridomiciles identified by morphological characterization in Los Llanos, La Rioja, Argentina

Abstract

The presence of Triatoma infestans in habitats treated with insecticides constitutes a frequent problem in endemic areas. Basing our study on the hypothesis that descendants of a residual population should be more similar to the pre-treatment population than to any other, we compared the indications of two quantitative morphological approaches. This study seeks to find the origin of 247 T. infestans from three populations found in two chicken coops and a goat corral after treatment with insecticides. The results obtained by quantitative morphology suggest that the T. infestans found between three-34 months after the application of insecticides formed mixed populations with insects derived from residual foci and neighbouring habitats. Our analyses also showed the presence of a phenotype which does not resemble neither the pre-treatment phenotype nor the one from neighbouring populations, suggesting the presence of a particular post-treatment phenotype. The heads size showed some variations in males from different populations and remained unchanged in females, which reinforces the hypothesis of an intraspecific competition for food with priority for females. This article presents, for the first time, the combined analysis of geometric morphometry of heads and antennal phenotypes to identify the composition of reinfesting populations.

A motorized vehicle-mounted sprayer as a new tool for Chagas disease vector control

“…The trial also provided updated information on the occurrence of house infestation with T. infestans and other triatomine species in northern Mendoza province, documenting high bug abundance in domestic and peridomestic sites. Peridomestic (re)infestation by T. infestans has been documented elsewhere in the Gran Chaco ecoregion 19,20,21,22,23,24 but not in Mendoza province.…”

Can body traits, other than wings, reflect the flight ability of Triatominae bugs?

“…Schofi eld et al (84) collected very few adult M. spinolai after six years of sampling. Moreover, in studies of reinfestant Triatominae, low number of insects collected after an insecticide spray can also raise doubts about the technique used (27) (85) . The results of these studies can provide evidence for further long-term studies, which might increase the number of insects collected and enhance the power of statistical tests.…”

Control of experimental Triatoma infestans populations: effect of pour‐on cypermethrin applied to chickens under natural conditions in the Argentinean Chaco region

“…Pyrethroid‐based suspension concentrate formulations applied using traditional spraying techniques have been reported as less efficacious in peridomestic habitats in which exposure to the environmental conditions of peridomestic structures decreases the residual lethality of the insecticide, favouring the survival of residual T. infestans populations after the application of insecticide (Gürtler et al ., ; Cecere et al ., ). Active or passive dispersal from these residual foci may represent the most probable mechanisms of the subsequent domiciliary re‐infestation of rural settlements that have been treated with pyrethroid insecticides (Schofield, ; Abrahan et al ., ; Hernández et al ., ).…”