Socioeconomic determinants of schistosomiasis in a poor rural area in Brazil

Abstract

The objective of this paper is to identify and quantify socioeconomic determinants of S. mansoni infection in the rural area of Virgem das Graças in Minas Gerais State of Brazil. A cross-sectional study was carried out to examine the prevalence and intensity of schistosomiasis in relation to socioeconomic characteristics of the households. Log-binomial regression analysis was used to examine the data on both the household and individual levels, analyzing the prevalence ratios for the association of schistosomiasis and socioeconomic variables related to the head of the household. Multiple comparisons through mixed effect modeling were used to examine the relationship between intensity of infection (geometric mean egg counts) and different levels of socioeconomic variables, respectively. In the univariate analysis, place of residence, number of persons per room, and lack of motorized transport were associated with schistosomiasis at the household level and age and unsafe water contact at the individual level. Age, unsafe water contact, number of persons per room, household possessions and lack of education of head of household remained significant predictors of schistosomiasis in the multivariable analysis. Only age was significantly associated with intensity of infection of individuals. It is concluded that widespread poverty, the rural environment, and weak socioeconomic differentiation that result in intense contact with infective water appear to minimize the protective effect of piped water supply and other socioeconomic parameters on schistosomiasis found in other studies. The potential role of socioeconomic development in conjunction with schistosomiasis control is described and areas for further studies are identified.

Factors related to transmission of and infection with Schistosoma mansoni in a village in the South-eastern Region of Brazil

“…Although vulnerability for infection depends on environmental, demographic and socio-economic factors specific for each endemic area, our data follow, in some aspects a pattern that was found in other study areas. In particular, the age group of 10-30 years represents such a subset of the population, which seems to be common (Lima e Costa 1983, Gazzinelli et al 2006). This information may be useful for the planning of more differentiated control programs that consider an approach involving target groups in areas of low or medium prevalence.…”

“…Demographic, socio-economic, water contact variables and data collection -Different sets of variables, which have shown association with transmission and infection in other study areas, were chosen to evaluate their relation to the disease in our setting (Bethony et al 2004, Massara et al 2004, Gazzinelli et al 2006. In order to investigate these different sets of variables, a questionnaire based on a model developed by Firmo (1994) during research activities in the region of Gorduras, Belo Horizonte, MG and adapted to the local conditions of this study area was used.…”

“…105(4): 570-577, July 2010 There is much scientific evidence that socio-demographic variables and contact with unsafe water are associated with infection with schistosomiasis. Studies in different settings have been carried out describing vulnerable parts of the population, such as school children, types of behaviour related to a higher risk of acquiring the infection, as is the case with household, occupational and leisure activities, or involving socio-economical status and its correlation to the disease (Lima e Costa 1983, Guimarães et al 1985, Cairncross et al 1996, da Silva et al 1997, Moza et al 1998, Watts et al 1998, Bethony et al 2001, Massara et al 2004, Gazzinelli et al 2006. Studies carried out in Africa investigating infections with Schistosoma haematobium present similar associations, demonstrating the importance of studies involving snail hosts, water contacts and micro-spatial distribution for an integrated epidemiological approach (Stothard et al 2002).…”

Use of a saline gradient for the diagnosis of schistosomiasis

“…The selected group lives in the endemic area of Virgem das Graças, state of Minas Gerais (MG), Brazil. After several stool examinations by the Kato-Katz method and negative findings over years of studies, these patients had been referred to as "normal endemic" (Corrêa-Oliveira et al 1998, Gazzinelli et al 2006. The saline gradient method identified a positive infection rate for S. mansoni of 25% based on analysis of two faecal samples of 500 mg. On the other hand, two sets of 12 Kato-Katz slides per each individual revealed a prevalence of 20% of infection.…”

Schistosomiasis transmission; socio-demographic, knowledge and practices as transmission risk factors in pregnant women

“…These groups in turn could serve as source of disease transmission to the treated population in resource poor communities thus rendering the area-wide infection prevalence and intensity to pre-control levels. Unlike other studies in Nigeria (Oladejo and Ofoezie 2006;Ugbomoiko et al 2010) and other parts of the world (Gazzinelli et al 2006) which considered association between socio-demographic/cultural characteristics and transmission dynamics of schistosomiasis in school children population and the general populace of the endemic communities, the current study focuses on pregnant women population. This becomes necessary as the Ministry of Health of many endemic countries is yet to adopt praziquantel administration in this group.…”