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Swimming and recreating in lakes, oceans, and rivers is common, yet the literature suggests children may be at greater risk of illness following such exposures. These effects might be due to differences in immunity or differing behavioral factors such as poorer hygiene, longer exposures to, and greater ingestion of potentially contaminated water and sand. We pooled data from 12 prospective cohorts (n=68,685) to examine exposures to potentially contaminated media such as beach water and sand among children compared with adults, and conducted a simulation using self-reported time spent in the water and volume of water swallowed per minute by age to estimate the total volume of water swallowed per swimming event by age category. Children aged 4-7 and 8-12 years had the highest exposures to water, sand, and algae compared with other age groups. Based on our simulation, we found that children (6-12 years) swallow a median of 36 ml (90th percentile=150 ml), whereas adults aged ≥35 years swallow 9 ml (90th percentile=64 ml) per swimming event, with male children swallowing a greater amount of water compared with females. These estimates may help to reduce uncertainty surrounding routes and durations of recreational exposures and can support the development of chemical and microbial risk assessments.

Background Current guidelines recommend community-wide mass azithromycin for trachoma, but a targeted treatment strategy could reduce the volume of antibiotics required. Methods In total, 48 Ethiopian communities were randomized to mass, targeted, or delayed azithromycin distributions. In the targeted arm, only children aged 6 months to 5 years with evidence of ocular chlamydia received azithromycin, distributed thrice over the following year. The primary outcome was ocular chlamydia at months 12 and 24, comparing the targeted and delayed arms (0–5 year-olds, superiority analysis) and the targeted and mass azithromycin arms (8–12 year-olds, noninferiority analysis, 10% noninferiority margin). Results At baseline, the mean prevalence of ocular chlamydia in the 3 arms ranged from 7% to 9% among 0–5 year-olds and from 3% to 9% among 8–12 year-olds. Averaged across months 12–24, the mean prevalence of ocular chlamydia among 0–5 year-olds was 16.7% (95% confidence interval [CI]: 9.0%–24.4%) in the targeted arm and 22.3% (95% CI: 11.1%–33.6%) in the delayed arm (P  = .61). The final mean prevalence of ocular chlamydia among 8–12 year-olds was 13.5% (95% CI: 7.9%–19.1%) in the targeted arm and 5.5% (95% CI: 0.3%–10.7%) in the mass treatment arm (adjusted risk difference 8.5 percentage points [pp] higher in the targeted arm, 95% CI: 0.9 pp–16.1 pp higher). Conclusions Antibiotic treatments targeted to infected preschool children did not result in significantly less ocular chlamydia infections compared with untreated communities and did not meet noninferiority criteria relative to mass azithromycin distributions. Targeted approaches may require treatment of a broader segment of the population in areas with hyperendemic trachoma. [ABSTRACT FROM AUTHOR]

Objectives. To provide summary estimates of gastroenteritis risks and illness burden associated with recreational water exposure and determine whether children have higher risks and burden. Methods. We combined individual participant data from 13 prospective cohorts at marine and freshwater beaches throughout the United States (n = 84 411). We measured incident outcomes within 10 days of exposure: diarrhea, gastrointestinal illness, missed daily activity (work, school, vacation), and medical visits. We estimated the relationship between outcomes and 2 exposures: body immersion swimming and Enterococcus spp. fecal indicator bacteria levels in the water. We also estimated the population-attributable risk associated with these exposures. Results. Water exposure accounted for 21% of diarrhea episodes and 9% of missed daily activities but was unassociated with gastroenteritis leading to medical consultation. Children aged 0 to 4 and 5 to 10 years had the most water exposure, exhibited stronger associations between levels of water quality and illness, and accounted for the largest attributable illness burden. Conclusions. The higher gastroenteritis risk and associated burden in young children presents important new information to inform future recreational water quality guidelines designed to protect public health. [ABSTRACT FROM AUTHOR]