A multivariate analysis of socio-demographic factors, water contact patterns and Schistosoma mansoni infection in an endemic area in Brazil

Abstract

Associations between socio-demographic factors, water contact patterns and Schistosoma mansoni infection were investigated in 506 individuals (87% of inhabitants over 1 year of age) in an endemic area in Brazil (Divino), aiming at determining priorities for public health measures to prevent the infection. Those who eliminated S. mansoni eggs (n = 198) were compared to those without eggs in the stools (n = 308). The following explanatory variables were considered: age, sex, color, previous treatment with schistosomicide, place of birth, quality of the houses, water supply for the household, distance from houses to stream, and frequency and reasons for water contact. Factors found to be independently associated with the infection were age (10-19 and > 20 yrs old), and water contact for agricultural activities, fishing, and swimming or bathing (Adjusted relative odds = 5.0, 2.4, 3.2, 2.1 and 2.0, respectively). This suggests the need for public health measures to prevent the infection, emphasizing water contact for leisure and agricultural activities in this endemic area.

Microgeographical patterns of schistosomiasis and water contact behavior; examples from Africa and Brazil

“…Results show that the water contact patterns in Nova União are more complex than indicated by earlier studies using the interview method exclusively (Lima e Costa et al 1991, Coura-Filho et al 1994) for five reasons: (1) most households lacking a water supply obtained most or all their water from neighbors or relatives free of charge; they used the streams mainly for washing clothes and utensils; (2) eleven households with their own supply used the streams for domestic activities, mainly for washing clothes and utensils, and eight households used the wells, springs and piped outlets of other households, mainly because they preferred their water for cooking, drinking or other purposes or because their own supplies were inadequate; (3) all the households lacking their own supply or those with a supply and borrowing from other households were located on the slope away from the stream, where wells yielded less water and its quality was inferior (salty) to that of sources along the stream, indicating the importance of the hydrological environment in water use (Fig. 11); (4) the number of water contacts, particularly contacts for washing clothes and utensils at the distant stream sites decreased by more than 30% during the rainy season (February-March), when the streams carried large amounts of soil; and (5) the eight households which either constructed new wells, laundry sites, latrines and showers or installed an electric pump in their well during the 1-year study period increased their use of well water and de- creased the use of the streams showing a dynamic water use pattern.…”

Socioeconomic determinants of schistosomiasis in a poor rural area in Brazil

“…Absence of a significant association between the widely used socioeconomic indicators household income, occupation (especially agriculture), and water supply and sanitation is in contrast with the findings of other investigators in Brazil Coutinho et al, 1997;CouraFilho et al, 1994;Silva et al, 1997). The individual-level variables age and unsafe water contact, the strongest predictors of S. mansoni infection, were also identified by other studies in Brazil (Barreto, 1991;Lima e Costa et al, 1991;Barbosa et al, 1998).…”

“…Schistosomiasis previously has been linked to environmental factors, such as water supply, that tend to be common to all members of a household (Bethony et al, , 2004CouraFilho et al, 1996, Ximenes et al, 2003Lima e Costa et al, 1991). Because multiple members of households were sampled, schistosomiasis infection among members of the same household may not have been independent events.…”

“…This relationship was first described in detail by Farooq et al, (1966) in Egypt and since then by studies in different endemic areas (Rosenfield, 1990;Yi-Xin and Manderson, 2005). In Brazil, the role of socioeconomic factors in Schistosoma mansoni transmission has been examined by studies in rural areas (Coura-Filho et al 1994;Lima e Costa, 1991;Silva et al, 1997) and urban (Barreto,1991 ;Kloetzel, 1989;Lima e Costa et al, 1987;Ximenes et al, 2003). However, only Ximenes et al (2003) studied the relationship between socioeconomic determinants and schistosomiasis distribution in depth, using noncausal determinism, which posits that socioeconomic conditions determine and operate through various conditioning factors, or intermediate mechanisms, not necessarily in a causal manner.…”

Epidemiological Characteristics of Schistosoma mansoni Infection in Rural and Urban Endemic Areas of Minas Gerais, Brazil

“…In rural areas, due to the absence of appropriate infrastructure, people using water from streams to perform domestic or professional activities are the target population for infection (Dalton 1976, Lima e Costa et al 1987.…”