Bill & Melinda Gates Foundation, International Initiative for Impact Evaluation (3ie), and Department for International Development-backed SHARE Research Consortium at the London School of Hygiene & Tropical Medicine.

Microbially induced concrete corrosion (MICC) in sewer systems has been a serious problem for a long time. A better understanding of the succession of microbial community members responsible for the production of sulfuric acid is essential for the efficient control of MICC. In this study, the succession of sulfur-oxidizing bacteria (SOB) in the bacterial community on corroding concrete in a sewer system in situ was investigated over 1 year by culture-independent 16S rRNA gene-based molecular techniques. Results revealed that at least six phylotypes of SOB species were involved in the MICC process, and the predominant SOB species shifted in the following order: Thiothrix sp., Thiobacillus plumbophilus, Thiomonas intermedia, Halothiobacillus neapolitanus, Acidiphilium acidophilum, and Acidithiobacillus thiooxidans. A. thiooxidans, a hyperacidophilic SOB, was the most dominant (accounting for 70% of EUB338-mixed probe-hybridized cells) in the heavily corroded concrete after 1 year. This succession of SOB species could be dependent on the pH of the concrete surface as well as on trophic properties (e.g., autotrophic or mixotrophic) and on the ability of the SOB to utilize different sulfur compounds (e.g., H 2 S, S 0 , and S 2 O 3 2؊). In addition, diverse heterotrophic bacterial species (e.g., halo-tolerant, neutrophilic, and acidophilic bacteria) were associated with these SOB. The microbial succession of these microorganisms was involved in the colonization of the concrete and the production of sulfuric acid. Furthermore, the vertical distribution of microbial community members revealed that A. thiooxidans was the most dominant throughout the heavily corroded concrete (gypsum) layer and that A. thiooxidans was most abundant at the highest surface (1.5-mm) layer and decreased logarithmically with depth because of oxygen and H 2 S transport limitations. This suggested that the production of sulfuric acid by A. thiooxidans occurred mainly on the concrete surface and the sulfuric acid produced penetrated through the corroded concrete layer and reacted with the sound concrete below.Concrete corrosion has an enormous economic impact worldwide, especially when the replacement or repair of municipal sewer systems is required. Concrete corrosion is the result of several causes such as carbonation, chloride erosion, and other chemical reactions. In sewer systems and wastewater treatment facilities where high concentrations of hydrogen sulfide, moisture, and oxygen are present in the atmosphere, the deterioration of concrete is caused mainly by biogenic acid (i.e., sulfuric acid) and is known as microbially induced concrete corrosion (MICC). The biogenic acid is generated by various microbial species and complex mechanisms. The general mechanism for the sulfuric acidcaused corrosion of sewer systems has been described in the literature (17, 36). In the first step, hydrogen sulfide (H 2 S) is produced by sulfate-reducing bacteria under anaerobic conditions in sewer pipes. This hydrogen sulfide enters the sewer atmosphere by v...

Efforts to eradicate open defecation and improve sanitation access are unlikely to achieve health benefits unless interventions reduce microbial exposures. This study assessed human fecal contamination and pathogen exposures in rural India, and the effect of increased sanitation coverage on contamination and exposure rates. In a cross-sectional study of 60 villages of a cluster-randomized controlled sanitation trial in Odisha, India, human and domestic animal fecal contamination was measured in community tubewells and ponds (n = 301) and via exposure pathways in homes (n = 354), using Bacteroidales microbial source tracking fecal markers validated in India. Community water sources were further tested for diarrheal pathogens (rotavirus, adenovirus and Vibrio cholerae by quantitative PCR; pathogenic Escherichia coli by multiplex PCR; Cryptosporidium and Giardia by immunomagnetic separation and direct fluorescent antibody microscopy). Exposure pathways in intervention and control villages were compared and relationships with child diarrhea examined. Human fecal markers were rarely detected in tubewells (2.4%, 95%CI: 0.3–4.5%) and ponds (5.6%, 95%CI: 0.8–10.3%), compared to homes (35.4%, 95%CI: 30.4–40.4%). In tubewells, V. cholerae was the most frequently detected pathogen (19.8%, 95%CI: 14.4–25.2%), followed by Giardia (14.8%, 95%CI: 10.0–19.7%). In ponds, Giardia was most often detected (74.5%, 95%CI: 65.7–83.3%), followed by pathogenic E. coli (48.1%, 95%CI: 34.8–61.5%) and rotavirus (44.4%, 95%CI: 34.2–54.7%). At village-level, prevalence of fecal pathogen detection in community drinking water sources was associated with elevated prevalence of child diarrhea within 6 weeks of testing (RR 2.13, 95%CI: 1.25–3.63) while within homes, higher levels of human and animal fecal marker detection were associated with increased risks of subsequent child diarrhea (P = 0.044 and 0.013, respectively). There was no evidence that the intervention, which increased functional latrine coverage and use by 27 percentage points, reduced human fecal contamination in any tested pathway, nor the prevalence of pathogens in water sources. In conclusion, the study demonstrates that (1) improved sanitation alone may be insufficient and further interventions needed in the domestic domain to reduce widespread human and animal fecal contamination observed in homes, (2) pathogens detected in tubewells indicate these sources are microbiologically unsafe for drinking and were associated with child diarrhea, (3) domestic use of ponds heavily contaminated with multiple pathogens presents an under-recognized health risk, and (4) a 27 percentage point increase in improved sanitation access at village-level did not reduce detectable human fecal and pathogen contamination in this setting.

Objective To assess the prevalence of menstrual hygiene management (MHM) knowledge and practices among adolescent schoolgirls in Indonesia, and assess factors associated with poor MHM and school absenteeism due to menstruation. Methods A cross‐sectional survey enrolled a representative sample of urban and rural school‐going girls aged 12–19 years in four provinces of Indonesia. A semi‐structured, self‐administered questionnaire obtained socio‐demographic characteristics, knowledge, practices and attitudes related to menstruation, MHM and school absenteeism. School water, sanitation and hygiene (WASH) facilities were also assessed. Univariate weighted population prevalence was estimated and multivariable logit regression analyses applied to explore associations. Results A total of 1159 adolescent girls with a mean age of 15 years (SD = 1.8) participated. Most girls (90.8%, 95% confidence interval (95% CI) = 79.7–96.1) had reached menarche. Over half (64.1%, 95% CI = 49.9–76.2) reported poor MHM practices, and 11.1% (95% CI = 8.1–15.2) had missed one or more days of school during their most recent menstrual period. Poor MHM practices were associated with rural residence (Adjusted odds ratio (AOR) = 1.73, 95% CI = 1.13–2.64), province (various AOR), lower school grade (AOR = 1.69, 95% CI = 1.05–2.74) and low knowledge of menstruation (AOR = 3.49, 95% CI = 1.61–7.58). Absenteeism was associated with living in rural areas (AOR = 3.96, 95% CI = 3.02–5.18), province (various AOR), higher school grade (AOR = 3.02, 95% CI = 2.08–4.38), believing menstruation should be kept secret (AOR = 1.47, 95% CI = 1.03–2.11), experiencing serious menstrual pain (AOR = 1.68, 95% CI = 1.06–2.68) and showed mixed associations with school WASH facilities. Conclusions High prevalence of poor MHM and considerable school absenteeism due to menstruation among Indonesian girls highlight the need for improved interventions that reach girls at a young age and address knowledge, shame and secrecy, acceptability of WASH infrastructure and menstrual pain management.

We compared host-associated Bacteroidales qPCR assays developed in the continental United States and Europe for the purpose of measuring the effect of improved sanitation on human fecal exposure in rural Indian communities where both human and animal fecal loading are high. Ten candidate Bacteroidales qPCR assays were tested against fecal samples (human, sewage, cow, buffalo, goat, sheep, dog and chicken) from a test set of 30 individual human, 5 sewage, and 60 pooled animal samples collected in coastal Odisha, India. The two universal/general Bacteroidales assays tested (BacUni, GenBac3) performed equally well, achieving 100% sensitivity on the test set. Across the five human-associated assays tested (HF183 Taqman, BacHum, HumM2, BacH, HF183 SYBR), we found low sensitivity (17 to 49%) except for HF183 SYBR (89%), and moderate to high cross-reactivity with dog (20 to 80%) and chicken fecal samples (60 to 100%). BacHum had the highest accuracy (67%), amplified all sewage samples within the range of quantification (ROQ), and did not cross-react with any fecal samples from cows, the most populous livestock animal in India. Of the ruminant- and cattle-associated assays tested (BacCow, CowM2), BacCow was more sensitive in detecting the full range of common Indian livestock animal fecal sources, while CowM2 only detected cow sources with 50% sensitivity. Neither assay cross-reacted with human sources. BacCan, the dog-associated assay tested, showed no cross-reactivity with human sources, and high sensitivity (90%) for dog fecal samples. Overall, our results indicate BacUni, BacHum, HumM2, BacCan and BacCow would be the most suitable MST assays to distinguish and quantify relative amounts of human-associated and livestock/domestic animal-associated contributions to fecal contamination in Odisha, India.