The impact of shared sanitation facilities on diarrheal diseases with and without an environmental reservoir: a modeling study

<p>Epidemiological studies have identified an increased risk of diarrheal diseases associated with using shared sanitation facilities. We hypothesized that this might be related to differences in transmission routes of pathogens. We proposed a mathematical model of two fictitious pathogens, one transmitted with an environmental reservoir and one without. We assumed that individuals susceptible to one pathogen are not susceptible to the other, and therefore, decoupled the two models. We initialized the model with 99% individuals being susceptible. We sampled the parameter space using Latin Hypercube Sampling. We simulated 10,000 parameter sets. We varied the effective shared sanitation coverage (the product of latrine coverage and users’ compliance). Our results show that, in our hypothetical scenario, across all levels of effective coverage of shared sanitation, the median final cumulative incidence of diarrheal disease was higher than that of zero coverage. Our simulation findings suggest that increasing effective coverage of shared sanitation may have limited benefits against diarrhea-causing pathogens with an environmental reservoir and may lack benefit against diarrhea-causing pathogens without an environmental reservoir given increased human contacts if latrines are poorly maintained.</p

Pregnant women’s selected socio-demographic, anthropometrics, and clinical characteristics stratified by adverse pregnancy outcome (<i>n</i> = 667).

<p>Data are given as <i>n</i> (percent).</p><p>*Principal component analysis with varimax rotation was used for computing the wealth index. Based on the distribution of the wealth index, the households were then divided into four groups (quartiles).</p><p>Pregnant women’s selected socio-demographic, anthropometrics, and clinical characteristics stratified by adverse pregnancy outcome (<i>n</i> = 667).</p

Study design and sampling scheme.

<p>Study design and sampling scheme.</p

Assessment of interaction between life stage group and water, sanitation, and hygiene exposures on symptoms of RTIs.

<p>Assessment of interaction between life stage group and water, sanitation, and hygiene exposures on symptoms of RTIs.</p

Definition of confounder and exposure variable levels.

<p>Definition of confounder and exposure variable levels.</p

Associations between water, sanitation, and hygiene variables, social life stage status, and reported symptoms of abnormal vaginal discharge, itching, and irritation in 3,952 girls and women in Odisha, India.

<p>Associations between water, sanitation, and hygiene variables, social life stage status, and reported symptoms of abnormal vaginal discharge, itching, and irritation in 3,952 girls and women in Odisha, India.</p

Chi squared P value for trend in differences in frequencies of water, sanitation, and hygiene practices by life stage group.

<p>Chi squared P value for trend in differences in frequencies of water, sanitation, and hygiene practices by life stage group.</p

Site-stratified frequencies for socioeconomic confounders by life stage group.

<p>Site-stratified frequencies for socioeconomic confounders by life stage group.</p

Univariate analysis among women who use reusable cloth pads (N = 249) comparing the odds of different MHM practices for washing, drying and storing cloth pads among BV or UTI laboratory confirmed cases and BV or UTI laboratory negative controls (excluding symptomatic controls) (Group 4).

<p>*OR, odds ratio; CI, confidence interval, no = number.</p><p>Denominators vary as not all respondents answered all questions.</p><p>Univariate analysis among women who use reusable cloth pads (N = 249) comparing the odds of different MHM practices for washing, drying and storing cloth pads among BV or UTI laboratory confirmed cases and BV or UTI laboratory negative controls (excluding symptomatic controls) (Group 4).</p

Univariate analysis assessing association between different menstrual hygiene management practices and aspects of the household enabling environment for women according to symptomatic status.

<p>*OR, odds ratio; CI, confidence interval, no = number. Denominators vary as not all respondents answered all questions</p><p>Univariate analysis assessing association between different menstrual hygiene management practices and aspects of the household enabling environment for women according to symptomatic status.</p