EVALUATION OF RISK-FACTORS FOR HOUSE INFESTATION BY TRIATOMA-INFESTANS IN BRAZIL

An active entomologic survey was conducted by a team of trained health workers in a rural area endemic for Chagas' disease in central Brazil . They used pyrethrum as a flushing agent and 4,232 houses were inspec ted for triatomine bugs both inside and in the immediate environs. Hou ses with Triatoma infestans or evidence of an established colony were identified and defined as infested houses (cases). The building and en vironmental characteristics of 161 randomly selected infested houses w ere compared with 161 matched, noninfested houses (controls) that were the shortest distance from the infested house. Domestic and peridomes tic potential risk factors associated with house infestation by Triato ma infestans were assessed by logistic regression analysis. Incomplete house construction (odds ratio [OR] = 2.5, 95% confidence interval [C I] = 1.5-4.1) was confirmed as a risk factor related to the presence o r evidence of Triatoma infestans in the dwellings. The study also disc losed a statistically significant association between the presence of rats (OR = 1.6, 95% CI = 1.1-2.6) and indoor crop storage (OR = 2.3, 9 5% CI = 1.1-5.2) and house infestation. Further experimental field stu dies using tagged rodents should be conducted to assess their epidemio logic role in the domestic chain of Trypanosoma cruzi transmission.