ABSTRACT INTRODUCTION The province of La Rioja is endemic for Chagas disease, which is primarily transmitted by its vector, the hematophagous insect Triatoma infestans (vinchuca). The objective of this work was to develop a comprehensive approach in order to know the importance given by the community to Chagas disease and its vectors, and to survey information related to the prevention of transmission METHODS A cross-sectional study was carried out with a non-probabilistic mixed approach through a semi-structured questionnaire. The perception of 96 residents from 41 localities of Los Llanos community, La Rioja, was explored RESULTS T. infestans took the sixth place among the animals residents are most worried about. While 83% of the people interviewed were capable of correctly identifying T infestans adults when compared to other triatomine bugs, 79% expressed confusion regarding the vector transmission process of Chagas disease. Henhouses were recognized as the most common place to find vinchucas, followed by corrals. Besides, 92% reported they had never collected insects found in their housing to have them analyzed in health facilities DISCUSSION This descriptive research provided useful information to guide the work with local communities and to identify aspects to be addressed to avoid the vector transmission of Chagas in the area of study.

RESUMEN INTRODUCCIÓN La provincia de La Rioja es endémica para la enfermedad de Chagas, que es transmitida principalmente en forma vectorial por el insecto hematófago Triatoma infestans (vinchuca). El objetivo de este trabajo fue generar un abordaje integrador para conocer la importancia asignada por la comunidad a la enfermedad de Chagas y sus vectores, y relevar información relacionada con la prevención de la transmisión MÉTODOS Se realizó un estudio de corte transversal con un abordaje mixto no probabilístico mediante una encuesta semiestructurada, con la cual se indagaron las percepciones de 96 pobladores pertenecientes a 41 localidades de Los Llanos riojanos RESULTADOS T. infestans apareció en sexto lugar entre los animales que más preocupan a la población. El 83% de los encuestados fue capaz de identificar correctamente a los adultos de T. infestans respecto de otros triatominos. Sin embargo, el 79% expresó confusión con relación al proceso de transmisión vectorial de la enfermedad de Chagas. El gallinero fue reconocido como el sitio más frecuente donde se encontraban vinchucas, seguido por los corrales. El 92% informó que nunca había colectado insectos que encontraba en su vivienda para llevarlos a analizar a un centro de salud DISCUSIÓN Esta investigación descriptiva permitió generar información útil para guiar el trabajo en conjunto con las comunidades locales e identificar aspectos a ser abordados para evitar la transmisión vectorial de Chagas en el área de estudio. ^s+

Triatoma infestans is the main vector of the parasite that causes the Chagas disease in South America. It is known that T. infestans has different reproductive and development patterns depending on whether they feed on birds or mammals. Using the head of adult insects as an estimator of the specimen development, we attempt to determine if there are any differences in the sexual size dimorphism associated with the availability of the food resource in T. infestansof natural habitats in the Llanos Riojanos region (Argentina). The nutritional status resulted higher in chicken coops and, in both habitats, it was higher for females in relation to males. The centroid size was larger in females than in males from chicken coops, but not in the specimens from goat corrals. Centroid sizes revealed smaller medians in goat insects in comparison to those coming from chicken coops. Sexual size dimorphism occurs associated with differences in the nutritional status only for triatomines from chicken coops in natural habitats. The heads shape was not infuenced by the nutritional status. The sexual morphophysiological differences found in T. infestanshelp us understand aspects of the behavior of the species in diverse environments and its implications in the vectorial transmission o f Trypanosoma cruzi.

Triatoma infestanses el principal vector del parásito que causa la enfermedad de Chagas en Sudamérica. Se sabe que T. infestanstiene diferentes patrones reproductivos y de desarrollo dependiendo de si se alimentan de aves o mamíferos. Utilizando la cabeza de insectos adultos como estimador del desarrollo, se intenta determinar si existen diferencias en el dimorfsmo de tamaño sexual asociado con la disponibilidad del recurso alimenticio e n T. infestans de hábitats naturales en la región de Llanos Riojanos (Argentina). El estado nutricional fue mayor en gallineros y, en ambos hábitats, fue mayor para las hembras en relación con los machos. El tamaño centroide fue mayor en las hembras que en los machos de gallineros, pero no en los especímenes de corrales de cabras. Los tamaños centroide revelaron medianas más pequeñas en insectos de cabra en comparación con los procedentes de gallineros. El dimorfsmo sexual del tamaño se asocia con diferencias en el estado nutricional solo para triatominos de gallineros de habitats naturales. La conformación de las cabezas no se vio infuenciada por el estado nutricional. Las diferencias morfofsiológicas encontradas en T. infestans ayudan a comprender aspectos del comportamiento de la especie en diversos ambientes y sus implicaciones en la transmisión vectorial d eTrypanosoma cruzi.

Triatoma infestans is the most important vector of Chagas disease in Argentina. We report for the first time the presence of T. infestans (Klug) (Hemiptera: Reduviidae) associated with burrowing parrot nests Cyanoliseus patagonus (Psittasiformes: Psittacidae) built on abandoned adobe houses. The possible implications of this finding are discussed, for entomological surveillance of the vector.

Triatoma infestans es el vector más importante de la enfermedad de Chagas de la Argentina. Se cita por primera vez la presencia de T. infestans (Klug) (Hemiptera: Reduviidae) asociado a nidos de loro barranquero Cyanoliseus patagonus (Psittasiformes: Psittacidae) construidos en viviendas de adobe abandonadas. Se discuten las posibles implicancias de este hallazgo para la vigilancia entomológica del vector.

Triatoma infestans is the main vector of Trypanosoma cruzi, the aetiological agent of Chagas disease in the Gran Chaco region of South America. As a frequent blood meal source for triatomine bugs, domestic goats play a key role in the eco-epidemiology of Chagas disease. The aim of this study was to evaluate the mortality and blood intake of T. infestans fed on goats that had been treated with different doses of pour-on insecticide. Third-instar nymphs were fed on goats that had been treated with 0 cc, 5 cc, 10 cc or 15 cc of a pour-on formulation of cypermethrin. The exposure of T. infestans to animals treated at different post-application intervals revealed a residual activity of the insecticide. The mortality rate in the treated groups was higher than in the control groups until 30 days post-insecticide application (p = 0.03), except in the group treated with 5 cc, in which no mortality was detected after seven days of insecticide application. Rainfall affected the triatomicide effect, reducing the time of residual activity. The cypermethrin pour-on treatment decreased the blood intake of T. infestans. Thirty days after the cypermethrin application, nymph mortality was 16% (± 13) with both doses (10 cc and 15 cc). The 15 cc dose did not result in higher insect mortality or increased persistence compared to the 10 cc dose.

This article reports the effects of a pour-on formulation of cypermethrin (6% active ingredient) applied to chickens exposed to Triatoma infestans, the main vector of Chagas disease in rural houses of the Gran Chaco Region of South America. This study was designed as a completely random experiment with three experimental groups and five replicates. Third instar nymphs were fed on chickens treated with 0, 1 and 2 cc of the formulation. Nymphs were allowed to feed on the chickens at different time intervals after the insecticide application. Third-instar nymphs fed on treated chickens showed a higher mortality, took less blood during feeding and had a lower moulting rate. The mortality rate was highest seven days after the insecticide solution application and blood intake was affected until 30 days after the application of the solution.