Socioeconomic determinants of schistosomiasis in an urban area in the Northeast of Brazil

OBJECTIVE: To identify and quantify the socioeconomic determinants of schistosomiasis in the urban section of Säo Lourenço da Mata, a town in the Northeast of Brazil. METHODS: A cross-sectional study was carried out in 1988 to measure the prevalence of schistosomiasis in Säo Lourenço da Mata among individuals aged 10-25 years and to estimate the socioeconomic characteristics of the households of those individuals. Household aggregation was tested. The data were analyzed on two levels, the family level and the individual level. On the family level we estimated the odds ratios for the association of schistosomiasis and socioeconomic variables related either to the head of the family or to the household. On the individual level we investigated if for the infected individuals there were differences in the intensity of infection (mean egg count) for the different levels of the socioeconomic variables. RESULTS: We found a significant degree of household aggregation of schistosomiasis (allowing for sex and area of residence (neighborhoods with similar socioeconomic conditions, according to census data)). In the analysis on the family level, better socioeconomic indicators for the place in the productive process (occupation, economic sector, and position in production of the head of the family, plus family income) and better socioeconomic indicators for patterns of consumption (level of education of the head of the family, type of housing, household possessions, water supply for the home, sanitation (that is, excreta collection), and family access to medical care) were all associated with a lower risk of schistosomiasis. The estimation of the probability of schistosomiasis for different levels of the socioeconomic variables showed a lower risk (0.072) for individuals whose households were at the top (best) levels of the indicators relative to the risk (0.715) for individuals whose households were at the baseline (lowest) levels of the indicators. Infected individuals whose families had better socioeconomic conditions had lower mean egg count values. CONCLUSIONS: Control measures that may have a long-term effect, such as improvements in the water supply and sanitation, should be strongly encouraged. The theoretical reduction that we found in the probability of being infected if water supply and sanitation were improved highlights the importance of these measures. Implementing them would have a more permanent effect on the control of schistosomiasis and would...

Socioeconomic determinants of schistosomiasis in an urban area in the Northeast of Brazil.

OBJECTIVE: To identify and quantify the socioeconomic determinants of schistosomiasis in the urban section of São Lourenço da Mata, a town in the Northeast of Brazil. METHODS: A cross-sectional study was carried out in 1988 to measure the prevalence of schistosomiasis in São Lourenço da Mata among individuals aged 10-25 years and to estimate the socioeconomic characteristics of the households of those individuals. Household aggregation was tested. The data were analyzed on two levels, the family level and the individual level. On the family level we estimated the odds ratios for the association of schistosomiasis and socioeconomic variables related either to the head of the family or to the household. On the individual level we investigated if for the infected individuals there were differences in the intensity of infection (mean egg count) for the different levels of the socioeconomic variables. RESULTS: We found a significant degree of household aggregation of schistosomiasis (allowing for sex and area of residence (neighborhoods with similar socioeconomic conditions, according to census data)). In the analysis on the family level, better socioeconomic indicators for the place in the productive process (occupation, economic sector, and position in production of the head of the family, plus family income) and better socioeconomic indicators for patterns of consumption (level of education of the head of the family, type of housing, household possessions, water supply for the home, sanitation (that is, excreta collection), and family access to medical care) were all associated with a lower risk of schistosomiasis. The estimation of the probability of schistosomiasis for different levels of the socioeconomic variables showed a lower risk (0.072) for individuals whose households were at the top (best) levels of the indicators relative to the risk (0.715) for individuals whose households were at the baseline (lowest) levels of the indicators. Infected individuals whose families had better socioeconomic conditions had lower mean egg count values. CONCLUSIONS: Control measures that may have a long-term effect, such as improvements in the water supply and sanitation, should be strongly encouraged. The theoretical reduction that we found in the probability of being infected if water supply and sanitation were improved highlights the importance of these measures. Implementing them would have a more permanent effect on the control of schistosomiasis and would also result in other benefits to the population.

Social environment, behavior, and schistosomiasis in an urban population in the northeast of Brazil / Medio social, conducta y esquistosomiasis en una población urbana del nordeste de Brasil

The objective of our study was to gain greater insight into the pattern of water contact in relation to schistosomiasis among residents of São Lourenço da Mata, a town in Pernambuco, a state in the Northeast of Brazil. We had two primary objectives: 1) to identify water contact activities that were more likely to produce infection and 2) to examine the socioeconomic factors behind water contact activities. Using a sample of persons 10­25 years old, we carried out a population-based case-control study to investigate the first objective, and a cross-sectional study for the second objective. We found that leisure water contact with flowing water (stream or river) was significantly associated with schistosomiasis.Variables showing a statistically significant association with leisure water contact were economic sector, income, and level of education of the head of the household; type of housing; possessions inside the house; type of domestic water supply; and method of excreta collection. We introduced these variables into a multivariate model to select the ones that were most closely associated with leisure water contact. We used a stepdown procedure, and two variables were retained in the final model: type of domestic water supply and type of housing. We concluded that a decrease in leisure water contact was associated with better socioeconomic conditions. Our results suggest that with the subjects we studied in São Lourenço da Mata there was a socioeconomic determination for leisure water contact. Our data highlight the importance of a broad and integrated approach in studying water contact activities and in implementing behavioral interventions for schistosomiasis prevention and control

El objetivo de este estudio consistió en contribuir a una mejor comprensión de la relación entre el tipo de contacto con el agua y la esquistosomiasis en los residentes de São Lourenço da Mata, una ciudad del estado de Pernambuco, en el Nordeste de Brasil. Los dos objetivos principales fueron: 1) identificar los tipos de contacto con el agua con mayores probabilidades de producir infección, y 2) investigar los factores socioeconómicos subyacentes a esas actividades. Utilizando una muestra de personas de 10 a 25 años de edad, se realizó un estudio de casos y controles basado en la población para alcanzar el primer objetivo, y un estudio transversal para el segundo objetivo. Se comprobó que las actividades recreativas que implicaban contacto con cursos de agua (arroyos o ríos) estaban significativamente asociadas a la esquistosomiasis; las variables asociadas de forma significativa con dichas actividades fueron el sector económico, los ingresos y el nivel de educación del cabeza de familia; el tipo de domicilio y los enseres que contenía; el tipo de suministro de agua al domicilio, y el sistema de eliminación de los excrementos. Estas variables fueron introducidas de forma escalonada en un modelo multivariado para seleccionar las más estrechamente asociadas al contacto recreativo con el agua. En el modelo final quedaron dos variables: el tipo de suministro de agua al domicilio y el tipo de domicilio. Se concluyó que el menor contacto recreativo con el agua estaba asociado a mejores condiciones socioeconómicas. Los resultados obtenidos indican que, en los sujetos estudiados de São Lourenço da Mata, el contacto recreativo con el agua era determinado por factores socioeconómicos y destacan la importancia de un abordaje amplio e integrado a la hora de estudiar las actividades que implican contacto con el agua y de poner en práctica intervenciones conductuales de prevención y control de la esquistosomiasis

Migration and urban schistosomiasis: the case of São Lourenço da Mata, Northeast of Brazil

A population-based case-control design was used to investigate the association between migration, urbanisation and schistosomiasis in the Metropolitan Region of Recife, Northeast of Brazil. 1022 cases and 994 controls, aged 10 to 25, were selected. The natives and the migrants who come from endemic areas have a similar risk of infection. On the other hand, the risk of infection of migrants from nonendemic areas seems to be related with the time elapsed since their arrival in São Lourenço da Mata; those who have been living in that urban area for 5 or more years have a risk of infection similar to that of the natives. Those arriving in the metropolitan region of Recife mostly emigrate from "zona da mata" and "zona do agreste" in the state of Pernambuco. Due to the changes in the sugar agro-industry and to the increase in the area used for cattle grazing these workers were driven to villages and cities. The pattern of urbanisation created the conditions for the establishment of foci of transmission in São Lourenço da Mata.

Epidemiology of Schistosoma haematobioum in Ruruma Location, Kilifi, District, Kenya.

A study of the distribution of S. haematobium in Ruruma Location of Kilifi District, Kenya, was undertaken between December 1988 and June 1990. Schistosomiasis haematobia was found to be highly endemic with prevalence rates of upto 85%. The distribution of prevalences of infection in this location is very varied ranging from 1.6% in the East to 85% in the Southwest. Prevalences of infection were also noted to be lower in those areas closer to the main roads than farther away, a pattern that coincided also with the distribution of piped water in the area. Gross haematuria, observed by naked eye, did not give a similar picture as that of infection prevalences. Certain areas with high infection rates had relatively low levels of haematuria and vice versa. Thus, gross haematuria alone cannot be used (even in a broad sense) to categorize to compare levels of endemicity of S.heaematobium in this area.