Water-contact patterns and risk factors for Schistosoma mansoni infection in a rural village of Northeast Brazil

Abstract

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).

Socioeconomic determinants of schistosomiasis in a poor rural area in Brazil

“…The association of these household-based variables with S. mansoni infection corroborates the findings by Bethony et al (2001Bethony et al ( , 2004, who pointed out the importance of the household in water contact behavior and transmission. 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).…”

“…Other reasons for the continued use of unsafe water supplies include availability of larger water quantities in the streams, recreational and social needs, and periodic blockage of pipes or breakdown of the rudimentary distribution systems. In other Brazilian rural areas as well, the provision of piped water supply tended to reduce but not eliminate exposure risk during domestic activities Silva et al, 1997). Similarly, the relatively weak sanitation effect in Virgem das Graças is also due to conditions of rural living which impede the use of latrines and absence of a sewage system.…”

“…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.…”

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

“…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).…”

Factors associated with schistosomiasis mansoni in a population from the municipality of Jaboticatubas, State of Minas Gerais, Brazil

“…Several studies have been carried out in order to evaluate such association in endemic areas (Lima e Costa 1983, Silva et al 1997, Moza et al 1998, Bethony et al 2001. In Brazil, Lima e Costa (1983) have reported that the water used for agricultural purposes showed to be a factor closely associated with S. mansoni infection in schoolchildren, while Guimarães et al (1985) have shown that water contact in household activities were associated with the infection in people aged less than 15 years old.…”