Factors affecting continued use of ceramic water purifiers distributed to Tsunami-affected Communities in Sri Lanka

Objectives  There is little information about continued use of point-of-use technologies after disaster relief efforts. After the 2004 tsunami, the Red Cross distributed ceramic water filters in Sri Lanka. This study determined factors associated with filter disuse and evaluate the quality of household drinking water. Methods  A cross-sectional survey of water sources and treatment, filter use and household characteristics was administered by in-person oral interview, and household water quality was tested. Multivariable logistic regression was used to model probability of filter non-use. Results  At the time of survey, 24% of households (107/452) did not use filters; the most common reason given was breakage (42%). The most common household water sources were taps and wells. Wells were used by 45% of filter users and 28% of non-users. Of households with taps, 75% had source water Escherichia coli in the lowest World Health Organisation risk category (<1/100 ml), vs. only 30% of households reporting wells did. Tap households were approximately four times more likely to discontinue filter use than well households. Conclusion  After 2 years, 24% of households were non-users. The main factors were breakage and household water source; households with taps were more likely to stop use than households with wells. Tap water users also had higher-quality source water, suggesting that disuse is not necessarily negative and monitoring of water quality can aid decision-making about continued use. To promote continued use, disaster recovery filter distribution efforts must be joined with capacity building for long-term water monitoring, supply chains and local production

Reduction of Norwalk Virus, Poliovirus 1, and Bacteriophage MS2 by Ozone Disinfection of Water

Norwalk virus and other human caliciviruses (noroviruses) are major agents of gastroenteritis, and water is a major route of their transmission. In an effort to control Norwalk virus in drinking water, Norwalk virus reduction by bench-scale ozone disinfection was determined using quantitative reverse transcription (RT)-PCR for virus assays. Two other enteric viruses, poliovirus 1 and coliphage MS2, were included for comparison, and their reductions were assayed by infectivity assays as well as by RT-PCR. Virus reductions by ozone were determined using a dose of 0.37 mg of ozone/liter at pH 7 and 5°C for up to 5 min. Based on two RT-PCR assays, the reductions of Norwalk virus were >3 log10 within a contact time of 10 s, and these were similar to the reductions of the other two viruses determined by the same assay methods. Also, the virus reductions detected by RT-PCR assays were similar to those detected by infectivity assays, indicating that the RT-PCR assay is a reliable surrogate assay for both culturable and nonculturable viruses disinfected with ozone. Overall, the results of this study indicate that Norwalk virus as well as other enteric viruses can be reduced rapidly and extensively by ozone disinfection and that RT-PCR is a useful surrogate assay for both culturable and nonculturable viruses disinfected with ozone

Bacterial Contamination on Household Toys and Association with Water, Sanitation and Hygiene Conditions in Honduras

There is growing evidence that household water treatment interventions improve microbiological water quality and reduce diarrheal disease risk. Few studies have examined, however, the impact of water treatment interventions on household-level hygiene and sanitation. This study examined the association of four water and sanitation conditions (access to latrines, improved sanitation, improved water and the plastic biosand filter) on the levels of total coliforms and E. coli on existing and introduced toys during an on-going randomized controlled trial of the plastic biosand filter (plastic BSF). The following conditions were associated with decreased bacterial contamination on children’s toys: access to a latrine, access to improved sanitation and access to the plastic BSF. Overall, compared to existing toys, introduced toys had significantly lower levels of both E. coliand total coliforms. Results suggest that levels of fecal indicator bacteria contamination on children’s toys may be associated with access to improved water and sanitation conditions in the home. In addition, the fecal indicator bacteria levels on toys probably vary with duration in the household. Additional information on how these toys become contaminated is needed to determine the usefulness of toys as indicators or sentinels of water, sanitation and hygiene conditions, behaviors and risks

Effects of Air Temperature and Relative Humidity on Coronavirus Survival on Surfaces

Assessment of the risks posed by severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) on surfaces requires data on survival of this virus on environmental surfaces and on how survival is affected by environmental variables, such as air temperature (AT) and relative humidity (RH). The use of surrogate viruses has the potential to overcome the challenges of working with SARS-CoV and to increase the available data on coronavirus survival on surfaces. Two potential surrogates were evaluated in this study; transmissible gastroenteritis virus (TGEV) and mouse hepatitis virus (MHV) were used to determine effects of AT and RH on the survival of coronaviruses on stainless steel. At 4°C, infectious virus persisted for as long as 28 days, and the lowest level of inactivation occurred at 20% RH. Inactivation was more rapid at 20°C than at 4°C at all humidity levels; the viruses persisted for 5 to 28 days, and the slowest inactivation occurred at low RH. Both viruses were inactivated more rapidly at 40°C than at 20°C. The relationship between inactivation and RH was not monotonic, and there was greater survival or a greater protective effect at low RH (20%) and high RH (80%) than at moderate RH (50%). There was also evidence of an interaction between AT and RH. The results show that when high numbers of viruses are deposited, TGEV and MHV may survive for days on surfaces at ATs and RHs typical of indoor environments. TGEV and MHV could serve as conservative surrogates for modeling exposure, the risk of transmission, and control measures for pathogenic enveloped viruses, such as SARS-CoV and influenza virus, on health care surfaces

Identification of Particle Size Classes Inhibiting Protozoan Recovery from Surface Water Samples via U.S. Environmental Protection Agency Method 1623

Giardia species recovery by U.S. Environmental Protection Agency method 1623 appears significantly impacted by a wide size range (2 to 30 μm) of particles in water and organic matter. Cryptosporidium species recovery seems negatively correlated only with smaller (2 to 10 μm), presumably inorganic particles. Results suggest constituents and mechanisms interfering with method performance may differ by protozoan type

Gene Mapping and Phylogenetic Analysis of the Complete Genome from 30 Single-Stranded RNA Male-Specific Coliphages (Family Leviviridae)

Male-specific single-stranded RNA (FRNA) coliphages belong to the family Leviviridae. They are classified into two genera (Levivirus and Allolevivirus), which can be subdivided into four genogroups (genogroups I and II in Levivirus and genogroups III and IV in Allolevivirus). Relatively few strains have been completely characterized, and hence, a detailed knowledge of this virus family is lacking. In this study, we sequenced and characterized the complete genomes of 19 FRNA strains (10 Levivirus strains and 9 Allolevivirus strains) and compared them to the 11 complete genome sequences available in GenBank. Nucleotide similarities among strains of Levivirus genogroups I and II were 75% to 99% and 83 to 94%, respectively, whereas similarities among strains of Allolevivirus genogroups III and IV ranged from 70 to 96% and 75 to 95%, respectively. Although genogroup I strain fr and genogroup III strains MX1 and M11 share only 70 to 78% sequence identity with strains in their respective genogroups, phylogenetic analyses of the complete genome and the individual genes suggest that strain fr should be grouped in Levivirus genogroup I and that the MX1 and M11 strains belong in Allolevivirus genogroup III. Strains within each genus share >50% sequence identity, whereas between the two genera, strains have <40% nucleotide sequence identity. Overall, amino acid composition, nucleotide similarities, and replicase catalytic domain location contributed to phylogenetic assignments. A conserved eight-nucleotide signature at the 3′ end of the genome distinguishes leviviruses (5′ ACCACCCA 3′) from alloleviviruses (5′ TCCTCCCA 3′)

Efficacy of Hospital Germicides against Adenovirus 8, a Common Cause of Epidemic Keratoconjunctivitis in Health Care Facilities

The inactivation of virus-contaminated nonporous inanimate surfaces was investigated using adenovirus type 8, a common cause of epidemic keratoconjunctivitis. A 10-μl inoculum of adenovirus was placed onto each stainless steel disk (1-cm diameter), and the inoculum was allowed to air dry for 40 min. Twenty-one different germicides (including disinfectants and antiseptics) were selected for this study based on their current uses in health care. After a 1- or 5-minute exposure to 50 μl of the germicide, the virus-germicide test mixture was neutralized and assayed for infectivity. Using an efficacy criterion of a 3-log10 reduction in the titer of virus infectivity and regardless of the virus suspending medium (i.e., hard water, sterile water, and hard water with 5% fetal calf serum), only five disinfectants proved to be effective against the test virus at 1 min: 0.55% ortho-phthalaldehyde, 2.4% glutaraldehyde, 2.65% glutaraldehyde, ∼6,000 ppm chlorine, and ∼1,900 ppm chlorine. Four other disinfectants showed effectiveness under four of the five testing conditions: 70% ethanol, 65% ethanol with 0.63% quaternary ammonium compound, 79.6% ethanol with 0.1% quaternary ammonium compound, and 0.2% peracetic acid. Of the germicides suitable for use as an antiseptic, 70% ethanol achieved a 3-log10 reduction under four of the five test conditions. These results emphasize the need for proper selection of germicides for use in disinfecting noncritical surfaces and semicritical medical devices, such as applanation tonometers, in order to prevent outbreaks of epidemic keratoconjunctivitis

Environmental monitoring of antimicrobial resistant bacteria in North Carolina water and wastewater using the WHO Tricycle protocol in combination with membrane filtration and compartment bag test methods for detecting and quantifying ESBL E. coli

Antimicrobial resistance (AMR) threatens human and animal health; effective response requires monitoring AMR presence in humans, animals, and the environment. The World Health Organization Tricycle Protocol (WHO TP) standardizes and streamlines global AMR monitoring around a single indicator organism, extended-spectrum-β-lactamase-producing Escherichia coli (ESBL-Ec). The WHO TP culture-based method detects and quantifies ESBL-Ec by spread-plating or membrane filtration on either MacConkey or TBX agar (supplemented with cefotaxime). These methods require laboratories and trained personnel, limiting feasibility in low-resource and field settings. We adapted the WHO TP using a simplified method, the compartment bag test (CBT), to quantify most probable numbers (MPN) of ESBL-Ec in samples. CBT methods can be used correctly in the field by typical adults after a few hours’ training. We collected and analyzed municipal wastewater, surface water, and chicken waste samples from sites in Raleigh and Chapel Hill, NC over an 8-month period. Presumptive ESBL-Ec were quantified using MF on TBX agar supplemented with cefotaxime (MF+TBX), as well as using the CBT with chromogenic E. coli medium containing cefotaxime. Presumptive ESBL-Ec bacteria were isolated from completed tests for confirmation and characterization by Kirby Bauer disk diffusion tests (antibiotic sensitivity) and EnteroPluri biochemical tests (speciation). Both methods were easy to use, but MF+TBX required additional time and effort. The proportion of E. coli that were presumptively ESBL in surface water samples was significantly greater downstream vs upstream of wastewater treatment plant (WWTP) outfalls, suggesting that treated wastewater is a source of ESBL-Ec in some surface waters. The CBT and MF+TBX tests provided similar (but not identical) quantitative results, making the former method suitable as an alternative to the more complex MF+TBX procedure in some applications. Further AMR surveillance using MF+TBX and/or CBT methods may be useful to characterize and refine their performance for AMR monitoring in NC and elsewhere

An Environmental Science and Engineering Framework for Combating Antimicrobial Resistance

On June 20, 2017, members of the environmental engineering and science (EES) community convened at the Association of Environmental Engineering and Science Professors (AEESP) Biennial Conference for a workshop on antimicrobial resistance. With over 80 registered participants, discussion groups focused on the following topics: risk assessment, monitoring, wastewater treatment, agricultural systems, and synergies. In this study, we summarize the consensus among the workshop participants regarding the role of the EES community in understanding and mitigating the spread of antibiotic resistance via environmental pathways. Environmental scientists and engineers offer a unique and interdisciplinary perspective and expertise needed for engaging with other disciplines such as medicine, agriculture, and public health to effectively address important knowledge gaps with respect to the linkages between human activities, impacts to the environment, and human health risks. Recommendations that propose priorities for research within the EES community, as well as areas where interdisciplinary perspectives are needed, are highlighted. In particular, risk modeling and assessment, monitoring, and mass balance modeling can aid in the identification of “hot spots” for antibiotic resistance evolution and dissemination, and can help identify effective targets for mitigation. Such information will be essential for the development of an informed and effective policy aimed at preserving and protecting the efficacy of antibiotics for future generations