Impact of drainage and sewerage on diarrhoea in poor urban areas in Salvador, Brazil

Abstract

A longitudinal prospective study of the effect of drainage and sewerage systems on diarrhoea in children aged < 5 years was conducted in 9 poor urban areas of the city of Salvador (population 2.44 million) in north-east Brazil in 1989-90. Due to complex political and administrative reasons, 3 areas had benefited from drainage improvements, 3 from both drainage and sewerage improvements, and 3 from neither. An extensive questionnaire was applied to collect information on each child and on the conditions of the household, and mothers recorded diarrhoea episodes in their children aged < 5 years daily for 1 year, using calendars. Fortnightly home visits were made to collect the data. The incidence of diarrhoea in children in neighbourhoods with drainage was less than two-thirds, and in neighbourhoods with drainage and sewerage less than one-third, of the incidence in neighbourhoods with neither. After controlling for potential confounders, the proportion of children with 'frequent diarrhoea' showed the same significant trend across the study groups. Though the groups were not exactly comparable, more than one child was monitored per household, and it was not possible to rotate fieldworkers between study groups, the study provides evidence that community sanitation can have an impact on diarrhoeal disease, even without measures to promote hygiene behaviour.

Incidence of diarrhea: poor parental recall ability

“…In this study, diarrhea was defined by the passing of three or more loose stools in a 24-hour period as detected by the mother or the responsible caregiver, similar to what has been suggested by the WHO [12] and adopted in many studies [13][14][15][16][17][18][19][20], but contrasting to others who have defined diarrhea as at least four dejections per day [21][22][23] or according to parental definition [10,[24][25][26]. Most recent studies consider that the passing of three or more unformed stools or any number with the presence of blood over a 24-hour period define diarrhea satisfactorily on adults and children older than two years, while to define an episode of diarrhea, the illness has to be preceded and followed by at least three days free of diarrhea [6,13,14,[27][28][29].…”

“…The study was conducted in Nova Divinéia and Vila Balbino, two urban slums in Salvador, Brazil, whose demographic, social and sanitary conditions are described elsewhere. [10] Eighty-four children younger than 40 months (42 from each slum) were enrolled in the study after being selected at random. Informed consent was obtained from the parents or legal guardians and the whole research was conducted under the guidance of the guidelines for research involving humans of the Ethics Committee of the Professor Edgard Santos University Hospital, Federal University of Bahia, Brazil.…”

Risk factors for infection with Giardia duodenalis in pre-school children in the city of Salvador, Brazil

“…The presence of an open sewer near the house has been found to be associated with infection of Brazilian children with other faecal pathogens [25,26]. Exposure to open sewers can be seen as analogous to exposure to untreated wastewater used for irrigation [27] although, in the latter, the associated risk seems to stem from the consumption of the irrigated vegetables rather than from wastewater contact [28].…”

Acondicionamento e coleta de resíduos sólidos domiciliares e impactos na saúde de crianças residentes em assentamentos periurbanos de Salvador, Bahia, Brasil

“…As crianças menores de cinco anos de idade foram acompanhadas durante um ano num estudo longitudinal para estimar a incidência de diarréia, e em estudos seccionais espaçados de dois em dois meses para medição de peso e de altura. As de idade entre 5 e 14 anos foram observadas em três estudos seccionais, sendo dois deles para avaliar a reinfecção por nematóides intestinais 14 .…”