Esquistossomose mansoni na Baixada Ocidental Maranhense, Estado do Maranhão, Brasil: estudos transversais realizados em 1987 e 1993 Realizou-se, em 1993, estudo transversal acerca da ocorrência de esquistossomose mansoni em três localidades da Baixada Ocidental Maranhense: Alegre (município de São Bento), Aliança (município de Cururupu) e Coroatá II (município de São João Batista). Os resultados foram cotejados aos de outro estudo, efetuado nas mesmas localidades e em condições semelhantes, em 1987. Em ambos os estudos, salvo poucas exceções, toda a população das três localidades foi submetida a exame parasitológico de fezes, pelo método de Kato-Katz e a intradermorreação para esquistossomose. Os indivíduos que apresentaram resultado positivo em algum desses exames foram avaliados clinicamente, por meio de exame físico. Em 1993, ao todo, 827 pessoas foram submetidas a exame de fezes e 826 a intradermorreação. Nas fezes de 154 (18,6%) encontraram-se ovos de Schistosoma mansoni e 478 (57,9%) apresentaram reação intradérmica positiva. Em Alegre o exame parasitológico de fezes foi realizado em 367 indivíduos, com índice de positividade de 14,9% e a intradermorreação, efetuada em 366 indivíduos, foi positiva em 47,5% dos casos. Em Aliança, 277 indivíduos foram examinados por exame de fezes e intradermorreação apresentando taxas de positividade de, respectivamente, 34,4% e 70,7%. Finalmente, em Coroatá II 183 moradores submetidos a exame de fezes e intradermorreação revelaram índices de positividade de 2,2% e 59,0%, respectivamente. Quando estes dados foram cotejados aos obtidos em inquérito efetuado em 1987 observou-se queda significativa da prevalência de infecção por S. mansoni nas localidades de Alegre e Coroatá II e aumento da prevalência em Aliança.

A cross-sectional study on the prevalence of schistosomiasis mansoni in three sites of the "Baixada Ocidental Maranhense" was carried out in 1993 in: Alegre (in the municipality of São Bento), Aliança (in Cururupu) and Coroatá II (in the municipality of São João Batista). Results were compared to those of another study performed at the same sites and in similar conditions, in 1987. The entire population of the three sites, with few exceptions, was submitted to fecal tests using the Kato-Katz method and immediate intradermal tests for schistosomiasis in both studies. Subjects with positive results in one of these tests were clinically evaluated by a physical examination. In 1993, the total of 827 subjects were submitted to fecal examination and 826 to intradermal test. Schistosoma mansoni eggs were found in the feces of 154 (18.6%) subjects, while 478 (57.9%) subjects presented a positive intradermal test. Stool examination was carried out in 367 subjects in Alegre with a positivity rate of 14.9%; the intradermal test, performed in 366 subjects, was positive in 47.5% of the cases. In Aliança, 277 subjects had their feces examined and were submitted to an intradermal test, with a positivity rate of 34.4% and 70.7%, respectively. Finally in Coroatá II, 183 inhabitants submitted to fecal and intradermal tests had positivity rates of 2.2% and 59.0%, respectively. When the present data were compared to those obtained in the survey performed in 1987, a significant decrease in the prevalence of infection by S. mansoni was observed in Alegre and Coroatá II, and a prevalence increase in Aliança.

Padrões de contato com água e fatores de risco para a infecção por Schistosoma mansoni em localidade rural do nordeste brasileiro. A esquistossomose mansônica na localidade de Serrano, município de Cururupu, Estado do Maranhão, Brasil, é uma endemia de difícil controle. Desde 1979, o PECE tem logrado reduzir a prevalência de infecção pelo S. mansoni e das formas graves da doença. Na tentativa de identificar os fatores de risco responsáveis pela persistência da infecção, realizou-se, em novembro de 1995, um censo na localidade e, através de amostragem sistemática, aplicou-se questionário domiciliar a 294 pessoas de todas as idades. Neste inquérito domiciliar do tipo seccional, estudou-se dados socioeconômicos, demográficos, variáveis ambientais e de saneamento e indagou-se sobre os padrões de contato com a água. Realizou-se exame de fezes pelo método de Kato-Katz. A prevalência da infecção foi de 24,1%, maior no sexo masculino (35,5%) e na 2ª década de vida (36,6%). A prevalência da infecção esteve associada com extração de juçara e/ou buriti (Razão de Prevalências - RP = 2,92), deslocamento (RP = 2, 55), banho (RP = 2, 35), pesca (RP = 2,19), caça (RP = 2,17), criação de animais (RP = 2,04), atividade de colocar mandioca n’água (RP = 1,90) e lazer (RP = 1,56). Após o ajuste para fatores de confusão através da regressão de Cox modificada por Breslow, sexo masculino, contato com água de rio ou igapó, realizar atividades de extração de juçara e banho de rio foram os fatores que restaram associados com a infecção, sendo prioritários no estabelecimento das medidas de controle

Schistosomiasis mansoni in the Serrano village, municipality of Cururupu, state of Maranhão, Brazil, is a widely spread disease. The PECE (Program for the Control of Schistosomiasis), undertaken since 1979 has reduced the prevalence of S. mansoni infection and the hepatosplenic form of the disease. Nevertheless piped water is available in 84% of the households, prevalence remains above 20%. In order to identify other risk factors responsible for the persistence of high prevalence levels, a cross-sectional survey was carried out in a systematic sample of 294 people of varying ages. Socioeconomic, environmental and demographic variables, and water contact patterns were investigated. Fecal samples were collected and analyzed by the Kato-Katz technique. Prevalence of S. mansoni infection was 24.1%, higher among males (35.5%) and between 10-19 years of age (36.6%). The risk factors identified in the univariable analysis were water contacts for vegetable extraction (Risk Ratio - RR = 2.92), crossing streams (RR = 2.55), bathing (RR = 2.35), fishing (RR = 2.19), hunting (RR = 2.17), cattle breeding (RR = 2.04), manioc culture (RR = 1.90) and leisure (RR = 1.56). After controlling for confounding variables by proportional hazards model the risks remained higher for males, vegetable extraction, bathing in rivers and water contact in rivers or in periodically inundated parts of riverine woodland (swamplands)

A cross-sectional study for schistosomiasis was carried out in the localities of Aliança, Alegre and Coroatá (districts of Cururupu, São Bento and São João Batista, respectively) in the lowland of the state of Maranhão, after respectively 13, 11 and 4 mass treatments with oxamniquine in the period of ten years (1977-1987). The study included clinical and quantitative fecal examination, skin test for Shistosoma mansoni infection, evaluation of man-water contact of the total population (829 persons) in the three localities and other epidemiological investigations such as infection rate and dynamics of the snail population. After 13 mass treatments in Aliança, the prevalence of S. mansoni infection was reduced from 57.9% to 7.4%. In Coroatá with 11 mass treatments the prevalence fell from 69.2% to 12.8% and in Alegre, with only 4 mass treatments there was pratically no reduction in prevalence: 22.9% to 21%. After mass treatments the type II hepatointestinal clinical form was 10.8% in Aliança, 17.9% in Alegre and 18% in Coroatá. The hepatosplenic (type III) form was not seen in Aliança and Coroatá but unexplanably it was 7.6% in Alegre. There was no correlation between the egg load elimination and the clinical forms.

Cross-sectional and evolutive studies on schistosomiasis mansoni were carried out before and after mass treatment in the endemic areas of Capitao Andrade and Padre Paraíso, state of Minas Gerais, Riachuelo, state of Sergipe, Alhandra, state of Paraíba, and Aliança, Alegre and Coroatá, lowland of the state of Maranhao, Brazil, in the last eighteen years. The studies included clinical and fecal examination by the Kato-Katz quantitative technique, skin testfor Schistosoma mansoni infection, evaluation of man-water contact and other epidemiological investigations such as infection rate and dynamic of the snail population. Results showed: (1) Higher prevalence of S. mansoni infection, greater egg load elimination and higher and earlier morbidity of the chronic froms of the disease in the southeast areas of Capitao Andrade and Padre Paraíso; (2) The incidence of hepatosplenic form is higher in some family clusters, in whites and mullattos in all the endemic areas but develop earlier in the southeast; (3) The prevalence and morbidity of schistosomiasis are decreasing both in the mass treated northeast and in the untreated southeast areas; (4) The mass treatment reduces rapidily the prevalence of the infection and the morbidity of the disease but can not control it because of the frequent reinfections due to the intensity of man-water contact.