Prevalence and Morbidity Data on Schistosoma mansoni Infection in Two Rural Areas of Jequitinhonha and Rio Doce Valleys in Minas Gerais, Brazil

Objective. This study aimed to compare the prevalence and morbidity data on Schistosoma mansoni infection in two rural areas: the Jequitinhonha valley (area 1) and the Rio Doce valley (area 2) in the state of Minas Gerais, Brazil, covering the period from 2007 to 2010. Material and Methods. The parasitological stool tests were based on the quantitative method of Kato modified by Katz et al. Three clinical forms were considered: type I—schistosomiasis infection, type II—hepatointestinal form, and type III—hepatosplenic form. Results. The prevalence of infection among inhabitants of area 1 was 22.9%, with 2.1% presenting the hepatosplenic form and two cases of schistosomal myeloradiculopathy. The infection prevalence rate in area 2 was 20.2%, with 3.3% presenting the hepatosplenic form. Conclusion and Recommendation. There was no difference in the prevalence and in the morbidity of Schistosoma mansoni infection between the two areas, but it was predominant in young men with a low intensity of infection. The cases of schistosomal myeloradiculopathy in area 1 can be highlighted: these emphasize that schistosomiasis should not be neglected in Brazil. The lack of infection control in both areas may be related to the poor sanitation system, the absence of previous treatment, and the reinfection process. 1. Background Surveys on infection by Schistosoma mansoni that have been conducted in Minas Gerais since the 1970 decade have aimed to follow up the natural history of schistosomiasis with emphasis on (1) the pathogenicity of the etiological agent and its experimental behavior [1], (2) the host’s characteristics and the influence of race, occupation, education level, age group, sex, specific treatment and frequency of contact with water streams for the activities of washing clothes, leisure, and fishing [2, 3], and (3) environmental conditions, distribution of streams and their distance to homes, presence of Biomphalaria, and its infection rates and infectivity, with comparison of exposure to different isolates of the parasite [4, 5]. The morbidity of infection has been evaluated through clinical and epidemiological studies in two field areas, in the Rio Doce and Jequitinhonha valleys of the state of Minas Gerais, Brazil. Patients with hepatosplenic forms have been evaluated at the University Hospital of the Federal University of Rio de Janeiro, Brazil. The aim of the present work was to compare the prevalence of infection by S. mansoni in these two areas, the morbidity due to schistosomiasis according to classification of clinical forms of the disease. 2.