Male Specific Coliphages as an Indicator of Fecal Contamination of Drinking Waters and as Model Organisms for the Reduction of Viruses by Water Treatment Processes

This study field-tested a new membrane filter method (MF) for the enumeration of F-specific RNA coliphages in source waters and treated drinking waters to assess the potential use of these organisms as a viral indicator. Simultaneous testing for F-specific coliphage by the Single Agar Layer Method (SAL) as well as for E. coli and enterococci permitted comparisons between the two phage detection methods as well as the evaluation of F-specific coliphages as an indicator of fecal pollution. Mean concentrations of coliphages enumerated by the SAL and MF methods were comparable and correlation analysis resulted in a Pearson's correlation coefficient of 0.85. F-specific phages were reasonably well correlated with both bacterial indicators as well as with the presence or absence of upstream, permitted, wastewater discharges suggesting the usefulness of these coliphages in assessing fecal contamination of natural waters. The reduction of F-specific coliphages by water treatment processes was observed at four drinking water treatment facilities. No phages were detected in any of the treated, or partially treated samples. Coliphage reductions of up to 5 logs were observed with an average reduction of >3.3 log[10]. Source waters were found to contain a mixed population of Somatic Salmonella phages as well as the F-specific coliphages. The presence of these phages interferes with the relationship between the F-specific phages and the human enteric viruses. This study demonstrates the applicability of the membrane filter method to natural waters and the usefulness of F-specific coliphages as an indicator of fecal contamination. Further modifications in the host bacterium may be required to compensate for the interference by somatic Salmonella phages.Master of Science in Public Healt

Selection of reliable biomarkers from PCR array analyses using relative distance computational model: Methodology and proof-of-concept study

10.1371/journal.pone.0083954PLoS ONE812-POLN

Ascaris and Escherichia coli Inactivation in an Ecological Sanitation System in Port-au-Prince, Haiti.

The goal of this study was to evaluate the microbial die-off in a latrine waste composting system in Port-au-Prince, Haiti. Temperature data and samples were collected from compost aged 0-12+ months. Samples collected from compost bin centers and corners at two depths were assessed for moisture content, E. coli concentration, and Ascaris spp. viability. Center temperatures in compost bins were all above 58 °C, while corner temperatures were 10 - 20 °C lower. Moisture content was 67 ± 10% in all except the oldest compost. A 4-log reduction in E. coli was observed over the first sixteen weeks of composting at both locations and depths, after which E. coli was undetectable (LOD: 142 MPN g(-1) dry weight). In new compost, 10.4% and 8.3% of Ascaris eggs were viable and fully embryonated, respectively. Percent viability dropped to zero in samples older than six weeks. These findings indicate that the Haitian EcoSan composting process was effective in inactivating E. coli and Ascaris spp. in latrine waste within sixteen weeks. This study is one of the first to document efficacy of an ecological sanitation system under field conditions and provides insight into composting methods and monitoring for other international settings

Epidemiologic and Environmental Investigation of a Recreational Water Outbreak Caused by Two Genotypes of Cryptosporidium Parvum in Ohio in 2000

In August 2000, the Ohio Department of Health requested assistance to investigate a cryptosporidiosis outbreak with more than 700 clinical case-patients. An epidemiologic and environmental investigation was conducted. Stool specimens, pool water, and sand filter samples were analyzed. A community-based case-control study showed that the main risk factor was swimming in pool A (odds ratio [OR] = 42, 95% confidence interval [CI] = 12.3-144.9). This was supported by results of polymerase chain reaction (PCR) analysis, which showed the presence of both the human and bovine genotypes of Cryptosporidium parvum in case-patients and samples from the filter of pool A. A pool-based case-control study indicated that the highest risk was related to exposure to pool water via the mouth (OR = 5.1, 95% CI = 2.1-12.5) or to pool sprinklers (OR = 2.5, 95% CI = 1.3-4.7). Fecal accidents at the pool were documented. Records indicated that the pool met local health regulations. The outbreak, caused by co-infection with two C. parvum genotypes (human and bovine), underscores the need for concerted action to improve public health policies for recreational water facilities and enhanced education regarding the potential for disease transmission through pools

Soap is not enough: handwashing practices and knowledge in refugee camps, Maban County, South Sudan

BACKGROUND: Refugees are at high risk for communicable diseases due to overcrowding and poor water, sanitation, and hygiene conditions. Handwashing with soap removes pathogens from hands and reduces disease risk. A hepatitis E outbreak in the refugee camps of Maban County, South Sudan in 2012 prompted increased hygiene promotion and improved provision of soap, handwashing stations, and latrines. We conducted a study 1 year after the outbreak to assess the knowledge, attitudes, and practices of the refugees in Maban County. METHODS: We conducted a cross sectional survey of female heads of households in three refugee camps in Maban County. We performed structured observations on a subset of households to directly observe their handwashing practices at times of possible pathogen transmission. RESULTS: Of the 600 households interviewed, nearly all had soap available and 91 % reported water was available “always” or “sometimes”. Exposure to handwashing promotion was reported by 85 % of the respondents. Rinsing hands with water alone was more commonly observed than handwashing with soap at critical handwashing times including “before eating” (80 % rinsing vs. 7 % washing with soap) and “before preparing/cooking food” (72.3 % vs 23 %). After toilet use, 46 % were observed to wash hands with soap and an additional 38 % rinsed with water alone. CONCLUSIONS: Despite intensive messaging regarding handwashing with soap and access to soap and water, rinsing hands with water alone rather than washing hands with soap remains more common among the refugees in Maban County. This practice puts them at continued risk for communicable disease transmission. Qualitative research into local beliefs and more effective messaging may help future programs tailor handwashing interventions

Setting priorities for humanitarian water, sanitation and hygiene research: a meeting report

Recent systematic reviews have highlighted a paucity of rigorous evidence to guide water, sanitation and hygiene (WASH) interventions in humanitarian crises. In June 2017, the Research for Health in Humanitarian Crises (R2HC) programme of Elhra, convened a meeting of representatives from international response agencies, research institutions and donor organisations active in the field of humanitarian WASH to identify research priorities, discuss challenges conducting research and to establish next steps. Topics including cholera transmission, menstrual hygiene management, and acute undernutrition were identified as research priorities. Several international response agencies have existing research programmes; however, a more cohesive and coordinated effort in the WASH sector would likely advance this field of research. This report shares the conclusions of that meeting and proposes a research agenda with the aim of strengthening humanitarian WASH policy and practice

Hepatitis E Epidemic, Uganda

In October 2007, an epidemic of hepatitis E was suspected in Kitgum District of northern Uganda where no previous epidemics had been documented. This outbreak has progressed to become one of the largest hepatitis E outbreaks in the world. By June 2009, the epidemic had caused illness in >10,196 persons and 160 deaths

The Public Health Response and Epidemiologic Investigation Related to the Opening of a Bacillus anthracis–Containing Envelope, Capitol Hill, Washington, D.C.

On October 15, 2001, a U.S. Senate staff member opened an envelope containing Bacillus anthracis spores. Chemoprophylaxis was promptly initiated and nasal swabs obtained for all persons in the immediate area. An epidemiologic investigation was conducted to define exposure areas and identify persons who should receive prolonged chemoprophylaxis, based on their exposure risk. Persons immediately exposed to B. anthracis spores were interviewed; records were reviewed to identify additional persons in this area. Persons with positive nasal swabs had repeat swabs and serial serologic evaluation to measure antibodies to B. anthracis protective antigen (anti-PA). A total of 625 persons were identified as requiring prolonged chemoprophylaxis; 28 had positive nasal swabs. Repeat nasal swabs were negative at 7 days; none had developed anti-PA antibodies by 42 days after exposure. Early nasal swab testing is a useful epidemiologic tool to assess risk of exposure to aerosolized B. anthracis. Early, wide chemoprophylaxis may have averted an outbreak of anthrax in this population

H. pylori-infection and antibody immune response in a rural Tanzanian population

BACKGROUND: Helicobacter pylori (H. pylori) infection is ubiquitous in sub-Saharan Africa, but paradoxically gastric cancer is rare. METHODS: Sera collected during a household-based survey in rural Tanzania in 1985 were tested for anti-H. pylori IgG and IgG subclass antibodies by enzyme immunoassay. Odds ratios (OR) and confidence intervals (CI) of association of seropositivity with demographic variables were computed by logistic regression models. RESULTS: Of 788 participants, 513 were aged ≤17 years. H. pylori seropositivity increased from 76% at 0–4 years to 99% by ≥18 years of age. Seropositivity was associated with age (OR 11.5, 95% CI 4.2–31.4 for 10–17 vs. 0–4 years), higher birth-order (11.1; 3.6–34.1 for ≥3(rd )vs. 1(st )born), and having a seropositive next-older sibling (2.7; 0.9–8.3). Median values of IgG subclass were 7.2 for IgG1 and 2.0 for IgG2. The median IgG1/IgG2 ratio was 3.1 (IQR: 1.7–5.6), consistent with a Th2-dominant immune profile. Th2-dominant response was more frequent in children than adults (OR 2.4, 95% CI 1.3–4.4). CONCLUSION: H. pylori seropositivity was highly prevalent in Tanzania and the immunological response was Th2-dominant. Th2-dominant immune response, possibly caused by concurrent bacterial or parasitic infections, could explain, in part, the lower risk of H. pylori-associated gastric cancer in Africa

Population-Based Biochemistry, Immunologic and Hematological Reference Values for Adolescents and Young Adults in a Rural Population in Western Kenya

BACKGROUND: There is need for locally-derived age-specific clinical laboratory reference ranges of healthy Africans in sub-Saharan Africa. Reference values from North American and European populations are being used for African subjects despite previous studies showing significant differences. Our aim was to establish clinical laboratory reference values for African adolescents and young adults that can be used in clinical trials and for patient management. METHODS AND FINDINGS: A panel of 298, HIV-seronegative individuals aged 13-34 years was randomly selected from participants in two population-based cross-sectional surveys assessing HIV prevalence and other sexually transmitted infections in western Kenya. The adolescent (/=18 years) ratio and the male-to-female ratio was 1ratio1. Median and 95% reference ranges were calculated for immunohematological and biochemistry values. Compared with U.S-derived reference ranges, we detected lower hemoglobin (HB), hematocrit (HCT), red blood cells (RBC), mean corpuscular volume (MCV), neutrophil, glucose, and blood urea nitrogen values but elevated eosinophil and total bilirubin values. Significant gender variation was observed in hematological parameters in addition to T-bilirubin and creatinine indices in all age groups, AST in the younger and neutrophil, platelet and CD4 indices among the older age group. Age variation was also observed, mainly in hematological parameters among males. Applying U.S. NIH Division of AIDS (DAIDS) toxicity grading to our results, 40% of otherwise healthy study participants were classified as having an abnormal laboratory parameter (grade 1-4) which would exclude them from participating in clinical trials. CONCLUSION: Hematological and biochemistry reference values from African population differ from those derived from a North American population, showing the need to develop region-specific reference values. Our data also show variations in hematological indices between adolescent and adult males which should be considered when developing reference ranges. This study provides the first locally-derived clinical laboratory reference ranges for adolescents and young adults in western Kenya