Entomological aspects of Chagas' disease transmission in the domestic habitat, Argentina

Abstract

ObjectiveTo study the risk of Trypanosoma cruzi domestic transmission using an entomological index and to explore its relationship with household's characteristics and cultural aspects. Methods There were studied 158 households in an endemic area in Argentina. Each household was classified according to an entomological risk indicator (number of risky bites/ human). A questionnaire was administered to evaluate risk factors among householders. ResultsInfested households showed a wide range of risk values (0 to 5 risky bites/human) with skewed distribution, a high frequency of lower values and few very high risk households. Of all collected Triatoma infestans, 44% had had human blood meals whereas 27% had had dogs or chickens blood meals. Having dogs and birds sharing room with humans increased the risk values. Tidy clean households had contributed significantly to lower risk values as a result of low vector density. The infested households showed a 24.3% correlation between time after insecticide application and the number of vectors. But there was no correlation between the time after insecticide application and T. infestans' infectivity. The statistical analysis showed a high correlation between current values of the entomological risk indicator and Trypanosoma cruzi seroprevalence in children. ConclusionsThe risk of T. cruzi domestic transmission assessed using an entomological index show a correlation with children seroprevalence for Chagas' disease and householders' habits. Resumen Objetivo

Factors Associated With PeridomesticTriatoma sanguisuga(Hemiptera: Reduviidae) Presence in Southeastern Louisiana

“…Interestingly, the current study did not Þnd a relationship between ownership of other pets and T. sanguisuga presence. These results appear to contrast with previous research that found peridomiciliary infestation signiÞcantly associated with numbers of dogs (Enger et al 2004) and dogs entering the house (Ramsey et al 2005), and that dogs inside the house were responsible for a high infection rate among triatomine vectors and bites to humans (Gü rtler et al 1998, Catalá et al 2004. Previous studies in Central and South America have identiÞed dogs as important reservoirs of T. cruzi, with signiÞcant associations between the presence of infected dogs and both the presence of infected vectors and human seropositivity (Mott et al 1978, Gü rtler et al 1991, Gü rtler et al 1996, Jimé nez-Coello et al 2010.…”

Dispersal of Triatoma infestans and other Triatominae species in the arid Chaco of Argentina: Flying, walking or passive carriage? The importance of walking females

“…Nymphs, eggs and adults may be transported in or on human clothes, mammalian hair or bird feathers (Forattini et al 1971, Lent & Wygodzinsky 1979. Chickens often enter houses and sleep in the bedrooms, allowing for the growth of large populations of T. infestans (Gürtler et al 1996, Catalá et al 2004; chickens have also been suspected of being passive carriers of bugs. In our study however, no T. infestans nymphs or adults or other triatomines were found in the feathers of chickens.…”

Reinfections and Trypanosoma cruzi strains can determine the prognosis of the chronic chagasic cardiopathy in mice

“…Several points about this different evolution are still poorly understood (Higuchi et al 2003). People living in endemic areas are exposed to suffer reinfections, a relevant factor even in congenital disease (Rabinovich et al 1990;Catalá et al 2004;Torrico et al 2006). We have previously demonstrated that reinfections with different T. cruzi strains have a potent role in developing early cardiac damage in the acute and indeterminate phase of experimental Chagas' disease (Bustamante et al 2002(Bustamante et al , 2003.…”