Association between Household Triatomine Density and Incidence of Trypanosoma Cruzi Infection during a Nine-Year Study in Castro Alves, Bahia, Brazil

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  • * Department of Tropical Public Health, Harvard School of Public Health, Boston, Massachusetts 02115
  • | ** Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
  • | Department of Preventive Medicine, Medical School, Federal University of Bahia, Salvador, Bahia, Brazil

We studied the association between human incidence of Trypanosoma cruzi infection and household infestation density of Panstrongylus megistus in Castro Alves, Bahia, Brazil. During a 9-year period, 19 persons seroconverted; 17 were children, 17 lived in nonplastered houses, and 13 lived in houses infested with triatomines. Although 6 seroconverting persons lived in houses where triatomines could not be found, the risk of seroconversion was significantly greater in infested houses and 16 times greater in densely infested houses (> 15 bugs/person-hour of search). The highest rate of seroconversion (6/100 person-years exposure) occurred in houses containing the greatest number of bugs infected with T. cruzi (>6 infected bugs/person-hour). These observations suggest that vector control measures could have a dramatic impact on transmission of T. cruzi by P. megistus.