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The relationship of infection with Trypanosoma cruzi to ECG abnormalities was studied in a defined population in rural Bahia, Brazil. Of 644 individuals 10 years of age or older who had complement fixation tests for antibodies to T. cruzi and ECGs, 53.7% were seropositive. ECG abnormalities were more common in seropositive individuals than in seronegative individuals, and more common in men than in women. The peak prevalence rate of abnormal ECGs occurred among seropositive individuals between 25 and 44 years of age; in this age group ECG abnormalities occurred 9.6 times more frequently among seropositive individuals than among seronegative individuals. The most common abnormalities were ventricular conduction defects, and right bundle branch block with or without fascicular block occurred in 10.7% of the infected population. PR intervals were longer in seropositive individuals than in seronegative individuals. Ventricular extrasystoles were slightly more common in seropositive individuals. A declining prevalence rate of abnormal ECGs among older seropositive individuals suggested selective mortality due to Chagas' heart disease.

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Oral oxamniquine was tested as a control strategy for endemic schistosomiasis in a rural area of Bahia, Brazil. Adults were treated with a single dose (12.5 to 15 mg per kg) and children (less than 12 years old) with a total of 20 mg per kg in two doses. The 191 (infected) persons treated represented 69% of the infected population in the study area. Follow-up stool examinations (Kato-Katz method) at one, 3, 6, 13, 25 and 33 months showed the cure rate declining from 80% at three months to 46% at 33 months. Over one half of those not cured showed a decrease in egg counts throughout the follow-up which, after 33 months, remained 66% below the pre-treatment levels. Stool examinations conducted on all study area residents during three years before chemotherapy showed the prevalence and intensity of Schistosoma mansoni infection to be high and stable. 33 months after the chemotherapy the prevalence was 41% and for infected individuals the geometric mean egg count was 121 epg, a decline of respectively 35% and 40% from pre-treatment levels for each index. Chemotherapy of infected persons with oxamniquine protected the community as a whole from high worm burdens for almost three years, although at this point the prevalence began to rise towards pretreatment levels.

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Por meio de experiências em laboratório e em condições naturais, fo i constatada a ação letal do m alathion U L V concentrado INTRODUÇÃOAo lado de alguns outros requisitos para um inseticida ser considerado ideal, uma ação letal sobre os ovos dos triatomíneos transmissores da doença de Chagas é uma das condições procura das pelos que tentam controlar a transmissão da doença.No nosso programa de experimentação de substâncias para combater o P. m egistus, princi pal vetor da doença de Chagas na Bahia, entre outros inseticidas estamos usando o Malathion, sobre o qual já existia informações a respeito de sua ação letal contra os ovos de triatomíneos2. Resolvemos investigar essa propriedade do Ma lathion.Apresêntamos os resultados que obtivemos nas observações que realizamos para verificar o efeito ovicida desse inseticida sobre os ovos de algumas espécies de triatomíneos vetores de T. cruzi, tanto em condições de laboratório como naturais.