Influence of specific treatment on the morbidity of schistosomiasis mansoni in an endemic area of Minas Gerais, Brazil

Abstract

Key words: schistosomiasis mansoni -clinical evolution -morbidity -treatment -Minas Gerais -BrazilThe elevated prevalence and severity of Schistosoma mansoni infection in the area of Itanhomi, Minas Gerais, was first observed in 1972 in the Santa Luzia do Carneiro village, in a pilot sectional survey ). In 1973 a hyper endemic area was detected in Capitão Andrade, Vale do Rio Doce, Minas Gerais (Figure), with the splenomegaly index of 5.6%. The severity of the clinical forms in the present municipality of Capitão Andrade (Conceição 1976) motivated a longitudinal study that was conducted despite the limitations of case follow-up due to the marked migratory flow of inhabitants into and out of the area.A survey, starting in 1973, was conducted on a group of 1,234 subjects with further re-examinations of 324 inhabitants in 1984 and of 224 in 1994. The study area is located in the municipality of Capitão Andrade. Three stools tests were performed in the patients to verify positivity for S. mansoni eggs according to Kato method modified by Katz et al. (1972). All the subjects were inhabitants of Capitão Andrade. The same two physicians, responsible for the study, examined the individual subjects in all phases of the study without any random selection. The same group of subjects who had been examinated in 1973 and who had not left the study area were re-examined in the subsequent phases of the study. To evaluate the size of liver and the spleen the subjects were examined under the position of Schuster, as well as in the dorsal position (during deep expiration). It was not possible to conduct abdominal ultrasound examinations of subjects in the initial phase of the study (1973), because this technique was not in use on the occasion. Another reason was the absence of electricity in the study area. The patients were included in three groups and it was continued in the subsequent phases of the study: type I -schistosomiasisinfection, with or without intestinal symptoms, which, if present, were moderate and not necessarily attributed to the disease; type II -hepatointestinal form, frequent intestinal symptoms, dysenteric diarrhea and hepatomegaly; and type III -hepatosplenic form, very frequent intestinal symptoms, dysentery and hepatosplenomegaly with or without hematemesis or melena. During the clinical examination information was obtained from the subjects about episodes of fever, epistaxis, digestive bleeding, icterus and alcoholism. The specific therapy was performed in 1984 with oxamniquine, single oral dosis, 15 mg/kg for adults and 20 mg/kg for children. After 60 and 90 days of therapy the fecal examinations were performed for the control of cure. Analysis of variance with emphasis on the analysis of regression were employed to evaluate the progress or regression of hepato and or splenomegaly during the various phases of the study considering age, height and weight of the subjects. The p-value was significant at the 0.05 level.In 1973, the positivity for S. mansoni eggs among the 1,234 inhabitants was 60.8%. Coura e...

Evaluation of a 25-Year-Program for the Control of Schistosomiasis Mansoni in an Endemic Area in Brazil

“…In the last two decades, studies performed in Brazil [5] , [6] , [9] , [10] , [12] , [13] , [17] – [19] , [32] , and in other countries [20] – [27] , have described the distribution of infection, reasons and frequency of contact with natural waters, as well as other parameters related to schistosomiasis mansoni.…”

Specific schistosomiasis treatment as a strategy for disease control

“…Unfortunately, the results from these campaigns could not be properly investigated, although such evaluations would have been extremely important for disease control efforts. In experimental field studies conducted on a smaller scale, Prata (1970, 1974) in Bahia, Katz et al (1977Katz et al ( , 1980 in Minas Gerais (MG) and Coura et al ( , 1984Coura et al ( , 1992, Conceição and Borges-Pereira (2002) and Conceição et al (2007) in other areas of MG have demonstrated the possibility of reducing the rates and intensities of infection among treated individuals who remained in the endemic area. Furthermore, they have shown a reduction in the progression of the disease to severe forms.…”

“…Personal experience with specific treatment for schistosomiasis as a strategy for control -It has already been proven that large-scale specific treatment for schistosomiasis in endemic areas (excluding the cases with contraindications) can reduce the prevalence of infection over the short term, as well as the morbidity due to the disease over the medium and long term (Jansen 1946, Sette 1953, Rodrigues da Silva 1958, Kloetzel 1963, 1972, Bina & Prata 1974, Prata 1976, Katz et al 1977, 1992, Machado 1982, Conceição et al 2002, 2007. This advance can then be consolidated through repeated treatments (Coura 1995, Coura & Amaral 2004.…”

A comparative cross-sectional study on the prevalence and morbidity of schistosomiasis in a community in northeastern Brazil (1979-2010)

“…Following the master’s degree dissertations and PhD thesis of Conceição (1976, 1985) in Capitão Andrade, MG, and of Mendonça (1982) in Alhan- dra, PB, several studies were conducted by Conceição and Borges-Pereira (2002), Conceição et al (2007) and Conceição and Coura (2012) on the prevalence of morbidity, evolution and the response to specific treatment of schistosomiasis in rural areas in MG. In PB, in addition to the study conducted by Mendonça (1982) in Alhandra, Coura et al (1987) conducted an evaluation of the Schistosomiasis Control Program in all areas covered by the program in that state, including Alhandra.…”