Modeling household transmission of American trypanosomiasis

American trypanosomiasis, or Chagas disease, caused by the protozoan parasi te Trypanosoma cruzi and transmitted by blood-feeding triatomine bugs, is a chronic, frequently fatal infection that is common in Latin America. Neith er adequate drugs nor a vaccine is available. A mathematical model calibrat ed to detailed household data from three villages in northwest Argentina sh ows that householders could greatly reduce the risk of human infection by e xcluding domestic animals, especially infected dogs, from bedrooms; removin g potential refuges for bugs from waits and ceilings; and using domesticall y applied insecticides. Low-cost, locally practicable environmental managem ent combined with intermittent use of insecticides can sustainably control transmission of T. cruzi to humans in rural Argentina and probably elsewher e.