Departamento de Parasitologia, Instituto de Biociências, Estadual University of Julio Mesquita Filho, UNESP, Botucatu, São Paulo, Brazil.
PLoS Negl Trop Dis. 2010 Feb 2;4(2):e588. doi: 10.1371/journal.pntd.0000588.
In the city of Salvador, a large urban centre in Northeast Brazil, a city-wide sanitation intervention started in 1997, aimed at improving the sewerage coverage of households from 26% to 80%. Our aim was to study the impact of the intervention on the prevalence and incidence of geohelminths in the school-aged population.
THE STUDY COMPRISED TWO COMPARABLE COHORTS: the first assembled in 1997, before the intervention, and the second assembled in 2003, after the intervention. Both were sampled from 24 sentinel areas chosen to represent the different environmental conditions throughout the city. Copro-parasitological examinations were carried out on every individual from both cohorts, at baseline and nine months later. Demographic, socio-economic, and environmental data were collected using semi-structured questionnaires and environmental surveys. A hierarchical modelling approach fitting a sequence of Poisson multivariate linear models was undertaken to test the effect of the intervention variables on the prevalence and incidence rate ratios.
729 and 890 children aged 7-14 years (mean = 10.4 y, SD = 0.05 y) were analysed over the first and the second cohorts, respectively. The adjusted reductions of the prevalence and incidence rates at the second in relation to the first cohort were 27% and 34%, 25% and 32%, 33% and 26%, and 82% and 42% for geohelminths overall, Ascaris lumbricoides, Trichuris trichiura, and hookworm, respectively. Hierarchical modelling showed that a major part of each of these reductions was explained by the intervention.
Our results show that a city-wide sanitation program may reduce significantly the prevalence and incidence of geohelminths.
在巴西东北部的一个大型城市中心萨尔瓦多市，1997 年开始了一项全市范围的环境卫生干预措施，旨在将家庭的污水覆盖范围从 26%提高到 80%。我们的目的是研究该干预措施对学龄人口中土壤传播性蠕虫病的流行率和发病率的影响。
该研究包括两个可比的队列：第一个队列于 1997 年在干预前组建，第二个队列于 2003 年在干预后组建。这两个队列都是从全市 24 个选定的有代表性的监测区中抽取的。对两个队列中的每个个体在基线和九个月后进行了粪便寄生虫检查。使用半结构式问卷和环境调查收集了人口统计学、社会经济和环境数据。采用分层建模方法，拟合一系列泊松多元线性模型，以检验干预变量对流行率和发病率比值的影响。
分别对第一和第二队列中的 729 名和 890 名 7-14 岁儿童（平均年龄为 10.4 岁，标准差为 0.05 岁）进行了分析。调整后的第二队列相对于第一队列的流行率和发病率降低率分别为 27%和 34%、25%和 32%、33%和 26%以及总体土壤传播性蠕虫病、蛔虫、鞭虫和钩虫分别为 82%和 42%。分层模型显示，这些降低率中的大部分可以归因于干预措施。
我们的研究结果表明，全市范围的环境卫生干预措施可显著降低土壤传播性蠕虫病的流行率和发病率。
