Ecohealth Interventions Limit Triatomine Reinfestation following Insecticide Spraying in La Brea, Guatemala

Abstract

Abstract. In this study, we evaluate the effect of participatory Ecohealth interventions on domestic reinfestation of the Chagas disease vector Triatoma dimidiata after village-wide suppression of the vector population using a residual insecticide. The study was conducted in the rural community of La Brea, Guatemala between 2002 and 2009 where vector infestation was analyzed within a spatial data framework based on entomological and socio-economic surveys of homesteads within the village. Participatory interventions focused on community awareness and low-cost home improvements using local materials to limit areas of refuge and alternative blood meals for the vector within the home, and potential shelter for the vector outside the home. As a result, domestic infestation was maintained at 3% and peridomestic infestation at 2% for 5 years beyond the last insecticide spraying, in sharp contrast to the rapid reinfestation experienced in earlier insecticide only interventions.

Vector Blood Meals Are an Early Indicator of the Effectiveness of the Ecohealth Approach in Halting Chagas Transmission in Guatemala

“…Although these indices are an important piece of information, several studies have shown that they can be subject to substantial error 18,19 and do not always correlate with T. cruzi infection in humans. 20,21 It will be important in future triatomine control programs to include other measures of epidemiological risk, such as presence of human blood meals and the spatial analysis of reinfestaion patterns Lucero and others, 8 in addition to traditional entomological indices. The lack of early reduction in the entomological indices after phase 1 could perhaps be caused by surviving eggs hatching, because they are not susceptible to insecticides.…”

“…We compare this novel assessment method to the traditional method of monitoring entomological indices. This article is a companion paper to Lucero and others, 8 which addresses how the Ecohealth intervention limited triatomine reinfestation in another village within the same study area.…”

Information to Act: Household Characteristics are Predictors of Domestic Infestation with the Chagas Vector Triatoma dimidiata in Central America

“…24 After 5 years of interventions, the percentage of Triatoma dimidiata feeding on humans dropped from 38% to 7% and Trypanosoma cruzi infection in Triatoma dimidiata dropped from 49% to 16% in one intervention village, 26 whereas in the other intervention village, the number of Triatoma dimidiata dropped drastically and it was not possible to obtain an estimate of percent of insects feeding on humans. Infestation levels in that village have remained under the 5% threshold set by the Guatemalan Ministry of Health for insecticide application 27 and also under the suggested threshold of infestation (8%) at which Trypanosoma cruzi transmission becomes unlikely. 28 Central American ministries of health are interested in introducing low-cost longer-lasting plastering mix to repair cracked walls in areas with domestic infestation of Triatoma dimidiata to help with regional control goals.…”

Household Model of Chagas Disease Vectors (Hemiptera: Reduviidae) Considering Domestic, Peridomestic, and Sylvatic Vector Populations

“…Recently, Lucero et al (2013) reported that lowcost home improvements (i.e., construction of chicken coops away from houses and plastering of walls) that limit areas of vector refuge within the home are more effective at keeping infestation low and increase spraying efÞcacy because there are fewer places inside houses for vectors to hide. Our model supports these Þndings; Fig.…”

“…In some regions, sylvatic vector populations likely jeopardize control efforts (Noireau 2009). Research to date suggests low-cost economic and human behavior strategies, in combination with insecticide spraying and housing improvement, are the most effective way to reduce disease transmission (Bustamante et al 2009, Monroy et al 2011, Lucero et al 2013.…”