Last data update: Jun 03, 2024. (Total: 46935 publications since 2009)
Records 1-30 (of 72 Records) |
Query Trace: Hill VR [original query] |
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Wilderness Medical Society clinical practice guidelines on water treatment for wilderness, international travel, and austere situations
Backer HD , Derlet RW , Hill VR . Wilderness Environ Med 2023 10806032231218722 To provide guidance to medical providers, wilderness users, and travelers, the Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for treating water in situations where the potability of available water is not assured, including wilderness and international travel, areas impacted by disaster, and other areas without adequate sanitation. The guidelines present the available methods for reducing or eliminating microbiological contamination of water for individuals, groups, or households; evaluation of their effectiveness; and practical considerations. The evidence base includes both laboratory and clinical publications. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according to the criteria published by the American College of Chest Physicians. |
Estimating waterborne infectious disease burden by exposure route, United States, 2014
Gerdes ME , Miko S , Kunz JM , Hannapel EJ , Hlavsa MC , Hughes MJ , Stuckey MJ , Francois Watkins LK , Cope JR , Yoder JS , Hill VR , Collier SA . Emerg Infect Dis 2023 29 (7) 1357-1366 More than 7.15 million cases of domestically acquired infectious waterborne illnesses occurred in the United States in 2014, causing 120,000 hospitalizations and 6,600 deaths. We estimated disease incidence for 17 pathogens according to recreational, drinking, and nonrecreational nondrinking (NRND) water exposure routes by using previously published estimates. In 2014, a total of 5.61 million (95% credible interval [CrI] 2.97-9.00 million) illnesses were linked to recreational water, 1.13 million (95% CrI 255,000-3.54 million) to drinking water, and 407,000 (95% CrI 72,800-1.29 million) to NRND water. Recreational water exposure was responsible for 36%, drinking water for 40%, and NRND water for 24% of hospitalizations from waterborne illnesses. Most direct costs were associated with pathogens found in biofilms. Estimating disease burden by water exposure route helps direct prevention activities. For each exposure route, water management programs are needed to control biofilm-associated pathogen growth; public health programs are needed to prevent biofilm-associated diseases. |
Using Wastewater Surveillance Data to Support the COVID-19 Response - United States, 2020-2021.
Kirby AE , Walters MS , Jennings WC , Fugitt R , LaCross N , Mattioli M , Marsh ZA , Roberts VA , Mercante JW , Yoder J , Hill VR . MMWR Morb Mortal Wkly Rep 2021 70 (36) 1242-1244 Wastewater surveillance, the measurement of pathogen levels in wastewater, is used to evaluate community-level infection trends, augment traditional surveillance that leverages clinical tests and services (e.g., case reporting), and monitor public health interventions (1). Approximately 40% of persons infected with SARS-CoV-2, the virus that causes COVID-19, shed virus RNA in their stool (2); therefore, community-level trends in SARS-CoV-2 infections, both symptomatic and asymptomatic (2) can be tracked through wastewater testing (3-6). CDC launched the National Wastewater Surveillance System (NWSS) in September 2020 to coordinate wastewater surveillance programs implemented by state, tribal, local, and territorial health departments to support the COVID-19 pandemic response. In the United States, wastewater surveillance was not previously implemented at the national level. As of August 2021, NWSS includes 37 states, four cities, and two territories. This report summarizes NWSS activities and describes innovative applications of wastewater surveillance data by two states, which have included generating alerts to local jurisdictions, allocating mobile testing resources, evaluating irregularities in traditional surveillance, refining health messaging, and forecasting clinical resource needs. NWSS complements traditional surveillance and enables health departments to intervene earlier with focused support in communities experiencing increasing concentrations of SARS-CoV-2 in wastewater. The ability to conduct wastewater surveillance is not affected by access to health care or the clinical testing capacity in the community. Robust, sustainable implementation of wastewater surveillance requires public health capacity for wastewater testing, analysis, and interpretation. Partnerships between wastewater utilities and public health departments are needed to leverage wastewater surveillance data for the COVID-19 response for rapid assessment of emerging threats and preparedness for future pandemics. |
Detection and identification of Giardia species using real-time PCR and sequencing.
Narayanan J , Murphy JL , Hill VR . J Microbiol Methods 2021 189 106279 We report a specific region of Giardia spp. 18S ribosomal RNA (18S rDNA) that serves as an ideal target for quantitative PCR (qPCR) detection and sequencing to identify Giardia species, including the clinically-relevant G. duodenalis, in clinical and environmental samples. The presence of multiple copies of the 18S rDNA gene and variations in the selected 18S genomic region enabled the development of a rapid, sensitive qPCR screening method for the detection of Giardia spp. The analytical sensitivity of the Giardia qPCR assay was determined to be a cyst equivalent of 0.4 G. duodenalis cysts per PCR reaction. Amplicon sequencing of the PCR product confirmed Giardia spp. detection and among the 35 sequences obtained, 31, 3 and 1 isolates were classified as belonging to G. duodenalis, G. microti and G. muris, respectively. The TaqMan assay reported here may be useful for the detection of low levels of Giardia in clinical and environmental samples, and further enables the effective use of direct sequencing of the PCR product for Giardia confirmation and to identify major species of Giardia, including G. duodenalis. |
Outbreaks Associated with Treated Recreational Water - United States, 2015-2019
Hlavsa MC , Aluko SK , Miller AD , Person J , Gerdes ME , Lee S , Laco JP , Hannapel EJ , Hill VR . MMWR Morb Mortal Wkly Rep 2021 70 (20) 733-738 Outbreaks associated with treated recreational water can be caused by pathogens or chemicals in aquatic venues such as pools, hot tubs, water playgrounds, or other artificially constructed structures that are intended for recreational or therapeutic purposes. For the pseriod 2015-2019, public health officials from 36 states and the District of Columbia (DC) voluntarily reported 208 outbreaks associated with treated recreational water. Almost all (199; 96%) of the outbreaks were associated with public (nonbackyard) pools, hot tubs, or water playgrounds. These outbreaks resulted in at least 3,646 cases of illness, 286 hospitalizations, and 13 deaths. Among the 155 (75%) outbreaks with a confirmed infectious etiology, 76 (49%) were caused by Cryptosporidium (which causes cryptosporidiosis, a gastrointestinal illness) and 65 (42%) by Legionella (which causes Legionnaires' disease, a severe pneumonia, and Pontiac fever, a milder illness with flu-like symptoms). Cryptosporidium accounted for 2,492 (84%) of 2,953 cases resulting from the 155 outbreaks with a confirmed etiology. All 13 deaths occurred in persons affected by a Legionnaires' disease outbreak. Among the 208 outbreaks, 71 (34%) were associated with a hotel (i.e., hotel, motel, lodge, or inn) or a resort, and 107 (51%) started during June-August. Implementing recommendations in CDC's Model Aquatic Health Code (MAHC) (1) can help prevent outbreaks associated with treated recreational water in public aquatic venues. |
Estimate of burden and direct healthcare cost of infectious waterborne disease in the United States
Collier SA , Deng L , Adam EA , Benedict KM , Beshearse EM , Blackstock AJ , Bruce BB , Derado G , Edens C , Fullerton KE , Gargano JW , Geissler AL , Hall AJ , Havelaar AH , Hill VR , Hoekstra RM , Reddy SC , Scallan E , Stokes EK , Yoder JS , Beach MJ . Emerg Infect Dis 2021 27 (1) 140-149 Provision of safe drinking water in the United States is a great public health achievement. However, new waterborne disease challenges have emerged (e.g., aging infrastructure, chlorine-tolerant and biofilm-related pathogens, increased recreational water use). Comprehensive estimates of the health burden for all water exposure routes (ingestion, contact, inhalation) and sources (drinking, recreational, environmental) are needed. We estimated total illnesses, emergency department (ED) visits, hospitalizations, deaths, and direct healthcare costs for 17 waterborne infectious diseases. About 7.15 million waterborne illnesses occur annually (95% credible interval [CrI] 3.88 million-12.0 million), results in 601,000 ED visits (95% CrI 364,000-866,000), 118,000 hospitalizations (95% CrI 86,800-150,000), and 6,630 deaths (95% CrI 4,520-8,870) and incurring US $3.33 billion (95% CrI 1.37 billion-8.77 billion) in direct healthcare costs. Otitis externa and norovirus infection were the most common illnesses. Most hospitalizations and deaths were caused by biofilm-associated pathogens (nontuberculous mycobacteria, Pseudomonas, Legionella), costing US $2.39 billion annually. |
Characteristics Associated with Adults Remembering to Wash Hands in Multiple Situations Before and During the COVID-19 Pandemic - United States, October 2019 and June 2020.
Haston JC , Miller GF , Berendes D , Andújar A , Marshall B , Cope J , Hunter CM , Robinson BM , Hill VR , Garcia-Williams AG . MMWR Morb Mortal Wkly Rep 2020 69 (40) 1443-1449 Washing hands often, especially during times when one is likely to acquire and spread pathogens,* is one important measure to help prevent the spread of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), as well as other pathogens spread by respiratory or fecal-oral transmission (1,2). Studies have reported moderate to high levels of self-reported handwashing among adults worldwide during the COVID-19 pandemic (3-5)(†); however, little is known about how handwashing behavior among U.S. adults has changed since the start of the pandemic. For this study, survey data from October 2019 (prepandemic) and June 2020 (during pandemic) were compared to assess changes in adults' remembering to wash their hands in six situations.(§) Statistically significant increases in reported handwashing were seen in June 2020 compared with October 2019 in four of the six situations; the odds of remembering to wash hands was 2.3 times higher among respondents after coughing, sneezing, or blowing their nose, 2.0 times higher before eating at a restaurant, and 1.7 times higher before eating at home. Men, young adults aged 18-24 years, and non-Hispanic White (White) adults were less likely to remember to wash hands in multiple situations. Strategies to help persons remember to wash their hands frequently and at important times should be identified and implemented, especially among groups reporting low prevalence of remembering to wash their hands. |
Calculation and uncertainty of zeta potentials of microorganisms in a 1:1 electrolyte with a conductivity similar to surface water
Polaczyk AL , Amburgey JE , Alansari A , Poler JC , Propato M , Hill VR . Colloids Surf A Physicochem Eng Asp 2020 586 The electrophoretic mobilities (EPM's) of fifteen different microbes (6 viruses, 5 vegetative bacteria, 2 bacterial endospores, 2 protozoa) and one microbial particle surrogate (Polystyrene microspheres) were measured, and five models were used to convert EPM's of these microorganisms to zeta potentials. The Helmholtz-Smoluchowski, Huckel-Onsager, Henry, modified Booth, and O'Brien and Hunter models were compared over their ranges of applicability for various microbes in a weak electrolyte solution intended to simulate the conductivity of surface water. The results from each of the models were compared by assessing the magnitude of the error due to inherent limitations of the models and comparing it to the error associated with the measurement of the EPM. Results indicated that differences imparted to the calculated zeta potentials by double layer distortion corrections were typically smaller than the uncertainty of the EPM measurement from which the zeta potential value was calculated. Based on our analyses, the Helmholtz-Smoluchowski equation was most appropriate for application to bacteria (vegetative and endospores) and parasites, while the Henry or modified Booth models were necessary for viruses. Zeta potential calculations with corresponding uncertainty values are presented for each of the microbes and the surrogate for each of the five models studied. A zone chart was created to help avoid unnecessary error in calculating microbial zeta potentials that can exceed 50%. |
A New Solid Matrix for Preservation of Viral Nucleic Acid from Clinical Specimens at Ambient Temperature.
Cromeans T , Jothikumar N , Lee J , Collins N , Burns CC , Hill VR , Vinje J . J Virol Methods 2019 274 113732 Stabilizing paper matrix methods for retaining nucleic acid from inactivated clinical specimens offer a solution for molecular diagnostics when specimens may be stored or shipped at ambient temperature. We developed cellulose disks (UNEXP) saturated with a total nucleic acid extraction buffer (UNEX) modified from a previously developed lysis buffer for multiple enteric pathogens. Infectivity of hepatitis A virus, adenovirus and poliovirus was destroyed after 2-3 h incubation at room temperature on the UNEXP disks. Norovirus RNA could be detected in UNEXP-eluted nucleic acids by reverse transcription-quantitative PCR (RT-qPCR) from 54 stool samples after 2 weeks storage at room temperature on disks; a subset of seven samples were positive after 3 months storage. Genotyping was successful in 76% of 54 samples tested including six of seven samples stored on the UNEXP disks for up to one month. Comparison of UNEXP with the FTA elute card in a subset of 10 samples demonstrated similar detection and genotyping rates after two weeks of storage at room temperature. UNEXP disks could be useful for epidemiologic investigations of disease outbreaks in resource-limited areas by simplifying specimen transport to regional diagnostic laboratories or shipment to international centers without the need to ship samples on dry ice. |
Wilderness Medical Society Clinical Practice Guidelines for Water Disinfection for Wilderness, International Travel, and Austere Situations
Backer HD , Derlet RW , Hill VR . Wilderness Environ Med 2019 30 S100-S120 To provide guidance to clinicians, the Wilderness Medical Society convened experts to develop evidence-based guidelines for water disinfection in situations where the potability of available water is not ensured, including wilderness and international travel, areas affected by disaster, and other areas without adequate sanitation. The guidelines present the available methods for reducing or eliminating microbiologic contamination of water for individuals, groups, or households; evaluation of their effectiveness; and practical considerations. The evidence evaluation includes both laboratory and clinical publications. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks or burdens, according to the criteria published by the American College of Chest Physicians. |
Antibiotic resistant Salmonella in swine wastes and farm surface waters
Casanova LM , Hill VR , Sobsey MD . Lett Appl Microbiol 2019 71 (1) 117-123 Hog production takes place mostly in large concentrated animal feeding operations (CAFOs) where waste is managed by storing in lagoons prior to land application of lagoon liquid. Salmonella, including antibiotic resistant Salmonella, have been found in the farm environment and lagoons. The objective of this research was to determine whether Salmonella resistant to clinically relevant antibiotics were present in wastewaters and surface waters from hog CAFOs. Samples of hog waste and on farm environmental waters were analysed for Salmonella, which were tested for antimicrobial susceptibility. The highest percentage of resistant isolates were found in raw waste flushed from hog houses and in lagoon wastewater; few resistant isolates were found in on-farm surface water. Resistance to sulfamethoxazole was most common, mostly in waste samples and less commonly in surface water, followed by chloramphenicol and ampicillin. No resistance to cephalosporin or fluoroquinolones was found. Resistance to clinically relevant antibiotics was commonly found in Salmonella from hog waste but was less extensive in farm surface waters. Management of wastes from hog CAFOs should be designed to further reduce the risk of human exposures resulting from environmental contamination with Salmonella. |
Response and remediation actions following the detection of Naegleria fowleri in two treated drinking water distribution systems, Louisiana, 2013-2014
Cope JR , Kahler AM , Causey J , Williams JG , Kihlken J , Benjamin C , Ames AP , Forsman J , Zhu Y , Yoder JS , Seidel CJ , Hill VR . J Water Health 2019 17 (5) 777-787 Naegleria fowleri causes the usually fatal disease primary amebic meningoencephalitis (PAM), typically in people who have been swimming in warm, untreated freshwater. Recently, some cases in the United States were associated with exposure to treated drinking water. In 2013, a case of PAM was reported for the first time in association with the exposure to water from a US treated drinking water system colonized with culturable N. fowleri. This system and another were found to have multiple areas with undetectable disinfectant residual levels. In response, the water distribution systems were temporarily converted from chloramine disinfection to chlorine to inactivate N. fowleri and reduced biofilm in the distribution systems. Once >1.0 mg/L free chlorine residual was attained in all systems for 60 days, water testing was performed; N. fowleri was not detected in water samples after the chlorine conversion. This investigation highlights the importance of maintaining adequate residual disinfectant levels in drinking water distribution systems. Water distribution system managers should be knowledgeable about the ecology of their systems, understand potential water quality changes when water temperatures increase, and work to eliminate areas in which biofilm growth may be problematic and affect water quality. |
Detection of Cryptosporidium recovered from large-volume water samples using dead-end ultrafiltration
Kahler AM , Hill VR . Methods Mol Biol 2020 2052 23-41 The procedure described here provides instructions for detection of Cryptosporidium recovered from large-volume water samples. Water samples are collected by dead-end ultrafiltration in the field and ultrafilters are processed in a laboratory. Microbes recovered from the filters are further concentrated and subjected to Cryptosporidium isolation or nucleic acid extraction methods for the detection of Cryptosporidium oocysts or Cryptosporidium DNA. |
Efficacy of a solar concentrator to Inactivate E. coli and C. perfringens spores in latrine waste in Kenya
Murphy JL , Ayers T , Foote A , Woods E , Wamola N , Fagerli K , Waiboci L , Mugoh R , Mintz ED , Zhao K , Marano N , O'Reilly CE , Hill VR . Sci Total Environ 2019 691 401-406 Alternative sanitation options are needed for effective waste management in low-income countries where centralized, large-scale waste treatment is not easily achievable. A newly designed solar concentrator technology utilizes solar thermal energy to treat feces contained in drums. This pilot study assessed the efficacy of the new design to inactivate microbes in 13 treatment drums under field conditions in Kenya. Three-quarters of the drums contained <1000E. coli/g of total solids following 6h of solar thermal treatment and inactivation of thermotolerant C. perfringens spores ranged from <1.8 to >5.0log10. Nearly all (94%) samples collected from treatment drums achieved thermophilic temperatures (>50 degrees C) during the treatment period, however this alone did not ensure samples met the WHO E. coli guideline; higher, sustained thermophilic temperatures tended to be more effective in reaching this guideline. The newly designed solar concentrator was capable of inactivating thermotolerant, environmentally-stable microorganisms as, or possibly more, efficiently than a previous design. Additional data are needed to better characterize how temperature, time, and other parameters affect the ability of the solar concentrator to inactivate microbes in feces. |
Pool chemical injuries in public and residential settings - United States, 2008-2017, and New York, 2018
Vanden Esschert KL , Haileyesus T , Tarrier AL , Donovan MA , Garofalo GT , Laco JP , Hill VR , Hlavsa MC . MMWR Morb Mortal Wkly Rep 2019 68 (19) 433-438 Pool chemicals are added to water in treated recreational water venues (e.g., pools, hot tubs/spas, and water playgrounds) primarily to protect public health. Pool chemicals inactivate pathogens (e.g., chlorine or bromine), optimize pH (e.g., muriatic acid), and increase water clarity, which helps prevent drowning by enabling detection of distressed swimmers underwater. However, pool chemicals can cause injuries if mishandled. To estimate the annual number of U.S. emergency department (ED) visits for pool chemical injuries, CDC analyzed 2008-2017 data from the National Electronic Injury Surveillance System (NEISS), operated by the U.S. Consumer Product Safety Commission (CPSC). During 2015-2017, pool chemical injuries led to an estimated 13,508 (95% confidence interval [CI] = 9,087-17,929) U.S. ED visits; 36.4% (estimated 4,917 [95% CI = 3,022-6,811]) of patients were aged <18 years. At least 56.3% (estimated 7,601 [95% CI = 4,587-10,615]) of injuries occurred at a residence. Two thirds of the injuries occurred during the period from Memorial Day weekend through Labor Day. This report also describes a toxic chlorine gas incident that occurred at a public pool in New York in 2018. Pool chemical injuries are preventable. CDC's Model Aquatic Health Code (MAHC) is an important resource that operators of public treated recreational water venues (e.g., at hotels, apartment complexes, and waterparks) can use to prevent pool chemical injuries. |
Good pool chemistry keeps swimming healthy and safe
Hlavsa MC , Laco JP , Hill VR . J Environ Health 2019 81 (9) 32-34 Many pool chemicals are used to protect the health and safety of swimmers and aquatics staff. For example, to help prevent outbreaks of infectious diseases, chlorine or bromine is added as a barrier to pathogen transmission. Muriatic (hydrochloric) acid is added to maintain pH at 7.2–7.8. Clarifiers are added to maximize water clarity, which enable lifeguards and others to identify distressed swimmers underwater and help prevent drownings. | | Maximizing the positive public health impact of pool chemicals calls for minimizing the risk of pool chemical injuries. State and local environmental health practitioners are on the frontline of prevention through educating pool operators about pool chemical safety, inspecting on pool code elements that minimize the risk of pool chemical injuries, investigating pool chemical injuries to identify their root cause(s), and informing the development of optimized measures to prevent future events. This month's column looks at pool chemical injuries and how they can be prevented. |
Water quality, availability, and acute gastroenteritis on the Navajo Nation - a pilot case-control study
Grytdal SP , Weatherholtz R , Esposito DH , Campbell J , Reid R , Gregoricus N , Schneeberger C , Lusk TS , Xiao L , Garrett N , Bopp C , Hammitt LL , Vinje J , Hill VR , O'Brien KL , Hall AJ . J Water Health 2018 16 (6) 1018-1028 The Navajo Nation includes approximately 250,000 American Indians living in a remote high desert environment with limited access to public water systems. We conducted a pilot case-control study to assess associations between acute gastroenteritis (AGE) and water availability, use patterns, and quality. Case patients with AGE and non-AGE controls who presented for care to two Indian Health Service hospitals were recruited. Data on demographics and water use practices were collected using a standard questionnaire. Household drinking water was tested for presence of pathogens, coliforms, and residual chlorine. Sixty-one subjects (32 cases and 29 controls) participated in the study. Cases and controls were not significantly different with respect to water sources, quality, or patterns of use. Twenty-one percent (n = 12) of study participants resided in dwellings not connected to a community water system. Eleven percent (n = 7) of subjects reported drinking hauled water from unregulated sources. Coliform bacteria were present in 44% (n = 27) of household water samples, and 68% (n = 40) of samples contained residual chlorine concentrations of <0.2 mg/L. This study highlights issues with water availability, quality, and use patterns within the Navajo Nation, including sub-optimal access to community water systems, and use of water hauled from unregulated sources. |
Outbreaks associated with untreated recreational water - United States, 2000-2014
Graciaa DS , Cope JR , Roberts VA , Cikesh BL , Kahler AM , Vigar M , Hilborn ED , Wade TJ , Backer LC , Montgomery SP , Secor WE , Hill VR , Beach MJ , Fullerton KE , Yoder JS , Hlavsa MC . MMWR Morb Mortal Wkly Rep 2018 67 (25) 701-706 Outbreaks associated with untreated recreational water can be caused by pathogens, toxins, or chemicals in fresh water (e.g., lakes, rivers) or marine water (e.g., ocean). During 2000-2014, public health officials from 35 states and Guam voluntarily reported 140 untreated recreational water-associated outbreaks to CDC. These outbreaks resulted in at least 4,958 cases of disease and two deaths. Among the 95 outbreaks with a confirmed infectious etiology, enteric pathogens caused 80 (84%); 21 (22%) were caused by norovirus, 19 (20%) by Escherichia coli, 14 (15%) by Shigella, and 12 (13%) by Cryptosporidium. Investigations of these 95 outbreaks identified 3,125 cases; 2,704 (87%) were caused by enteric pathogens, including 1,459 (47%) by norovirus, 362 (12%) by Shigella, 314 (10%) by Cryptosporidium, and 155 (5%) by E. coli. Avian schistosomes were identified as the cause in 345 (11%) of the 3,125 cases. The two deaths were in persons affected by a single outbreak (two cases) caused by Naegleria fowleri. Public parks (50 [36%]) and beaches (45 [32%]) were the leading settings associated with the 140 outbreaks. Overall, the majority of outbreaks started during June-August (113 [81%]); 65 (58%) started in July. Swimmers and parents of young swimmers can take steps to minimize the risk for exposure to pathogens, toxins, and chemicals in untreated recreational water by heeding posted advisories closing the beach to swimming; not swimming in discolored, smelly, foamy, or scummy water; not swimming while sick with diarrhea; and limiting water entering the nose when swimming in warm freshwater. |
Outbreaks associated with treated recreational water - United States, 2000-2014
Hlavsa MC , Cikesh BL , Roberts VA , Kahler AM , Vigar M , Hilborn ED , Wade TJ , Roellig DM , Murphy JL , Xiao L , Yates KM , Kunz JM , Arduino MJ , Reddy SC , Fullerton KE , Cooley LA , Beach MJ , Hill VR , Yoder JS . MMWR Morb Mortal Wkly Rep 2018 67 (19) 547-551 Outbreaks associated with exposure to treated recreational water can be caused by pathogens or chemicals in venues such as pools, hot tubs/spas, and interactive water play venues (i.e., water playgrounds). During 2000-2014, public health officials from 46 states and Puerto Rico reported 493 outbreaks associated with treated recreational water. These outbreaks resulted in at least 27,219 cases and eight deaths. Among the 363 outbreaks with a confirmed infectious etiology, 212 (58%) were caused by Cryptosporidium (which causes predominantly gastrointestinal illness), 57 (16%) by Legionella (which causes Legionnaires' disease, a severe pneumonia, and Pontiac fever, a milder illness with flu-like symptoms), and 47 (13%) by Pseudomonas (which causes folliculitis ["hot tub rash"] and otitis externa ["swimmers' ear"]). Investigations of the 363 outbreaks identified 24,453 cases; 21,766 (89%) were caused by Cryptosporidium, 920 (4%) by Pseudomonas, and 624 (3%) by Legionella. At least six of the eight reported deaths occurred in persons affected by outbreaks caused by Legionella. Hotels were the leading setting, associated with 157 (32%) of the 493 outbreaks. Overall, the outbreaks had a bimodal temporal distribution: 275 (56%) outbreaks started during June-August and 46 (9%) in March. Assessment of trends in the annual counts of outbreaks caused by Cryptosporidium, Legionella, or Pseudomonas indicate mixed progress in preventing transmission. Pathogens able to evade chlorine inactivation have become leading outbreak etiologies. The consequent outbreak and case counts and mortality underscore the utility of CDC's Model Aquatic Health Code (https://www.cdc.gov/mahc) to prevent outbreaks associated with treated recreational water. |
Pool water quality and prevalence of microbes in filter backwash from metro-Atlanta swimming pools
Murphy JL , Hlavsa MC , Carter BC , Miller C , Jothikumar N , Gerth TR , Beach MJ , Hill VR . J Water Health 2018 16 (1) 87-92 During the 2012 summer swim season, aquatic venue data and filter backwash samples were collected from 127 metro-Atlanta pools. Last-recorded water chemistry measures indicated 98% (157/161) of samples were from pools with >/=1 mg/L residual chlorine without stabilized chlorine or >/=2 mg/L with stabilized chlorine and 89% (144/161) had pH readings 7.2-7.8. These water quality parameters are consistent with the 2016 Model Aquatic Health Code (2nd edition) recommendations. We used previously validated real-time polymerase chain reaction assays for detection of seven enteric microbes, including Escherichia coli, and Pseudomonas aeruginosa. E. coli was detected in 58% (93/161) of samples, signifying that swimmers likely introduced fecal material into pool water. P. aeruginosa was detected in 59% (95/161) of samples, indicating contamination from swimmers or biofilm growth on surfaces. Cryptosporidium spp. and Giardia duodenalis were each detected in approximately 1% of samples. These findings indicate the need for aquatics staff, state and local environmental health practitioners, and swimmers to each take steps to minimize the risk of transmission of infectious pathogens. |
Primary amebic meningoencephalitis associated with rafting on an artificial whitewater river: Case report and environmental investigation
Cope JR , Murphy J , Kahler A , Gorbett DG , Ali I , Taylor B , Corbitt L , Roy S , Lee N , Roellig D , Brewer S , Hill VR . Clin Infect Dis 2018 66 (4) 548-553 Background: Naegleria fowleri is a thermophilic ameba found in freshwater that causes primary amebic meningoencephalitis (PAM) when it enters the nose and migrates to the brain. Patient exposure to water containing the ameba typically occurs in warm freshwater lakes and ponds during recreational water activities. In June 2016, an 18-year-old woman died of PAM after traveling to North Carolina, where she participated in rafting on an artificial whitewater river. Methods: We conducted an epidemiologic and environmental investigation to determine the water exposure that led to the death of this patient. Results: The case patient's most probable water exposure occurred while rafting on an artificial whitewater river during which she was thrown out of the raft and submerged underwater. The approximately 11.5 million gallons of water in the whitewater facility were partially filtered, subjected to ultraviolet light treatment, and occasionally chlorinated. Heavy algal growth was noted. Eleven water-related samples were collected from the facility; all were positive for N. fowleri. Of 5 samples collected from the nearby natural river, 1 sediment sample was positive for N. fowleri. Conclusions: This investigation documents a novel exposure to an artificial whitewater river as the likely exposure causing PAM in this case. Conditions in the whitewater facility (warm, turbid water with little chlorine and heavy algal growth) rendered the water treatment ineffective and provided an ideal environment for N. fowleri to thrive. The combination of natural and engineered elements at the whitewater facility created a challenging environment to control the growth of N. fowleri. |
Surveillance for waterborne disease outbreaks associated with drinking water - United States, 2013-2014
Benedict KM , Reses H , Vigar M , Roth DM , Roberts VA , Mattioli M , Cooley LA , Hilborn ED , Wade TJ , Fullerton KE , Yoder JS , Hill VR . MMWR Morb Mortal Wkly Rep 2017 66 (44) 1216-1221 Provision of safe water in the United States is vital to protecting public health. Public health agencies in the U.S. states and territories report information on waterborne disease outbreaks to CDC through the National Outbreak Reporting System (NORS) (https://www.cdc.gov/healthywater/surveillance/index.html). During 2013-2014, 42 drinking water-associated outbreaks were reported, accounting for at least 1,006 cases of illness, 124 hospitalizations, and 13 deaths. Legionella was associated with 57% of these outbreaks and all of the deaths. Sixty-nine percent of the reported illnesses occurred in four outbreaks in which the etiology was determined to be either a chemical or toxin or the parasite Cryptosporidium. Drinking water contamination events can cause disruptions in water service, large impacts on public health, and persistent community concern about drinking water quality. Effective water treatment and regulations can protect public drinking water supplies in the United States, and rapid detection, identification of the cause, and response to illness reports can reduce the transmission of infectious pathogens and harmful chemicals and toxins. |
Waterborne disease outbreaks associated with environmental and undetermined exposures to water - United States, 2013-2014
McClung RP , Roth DM , Vigar M , Roberts VA , Kahler AM , Cooley LA , Hilborn ED , Wade TJ , Fullerton KE , Yoder JS , Hill VR . MMWR Morb Mortal Wkly Rep 2017 66 (44) 1222-1225 Waterborne disease outbreaks in the United States are associated with a wide variety of water exposures and are reported annually to CDC on a voluntary basis by state and territorial health departments through the National Outbreak Reporting System (NORS). A majority of outbreaks arise from exposure to drinking water (1) or recreational water (2), whereas others are caused by an environmental exposure to water or an undetermined exposure to water. During 2013-2014, 15 outbreaks associated with an environmental exposure to water and 12 outbreaks with an undetermined exposure to water were reported, resulting in at least 289 cases of illness, 108 hospitalizations, and 17 deaths. Legionella was responsible for 63% of the outbreaks, 94% of hospitalizations, and all deaths. Outbreaks were also caused by Cryptosporidium, Pseudomonas, and Giardia, including six outbreaks of giardiasis caused by ingestion of water from a river, stream, or spring. Water management programs can effectively prevent outbreaks caused by environmental exposure to water from human-made water systems, while proper point-of-use treatment of water can prevent outbreaks caused by ingestion of water from natural water systems. |
Environmental survey of drinking water sources in Kampala, Uganda during a typhoid fever outbreak
Murphy JL , Kahler AM , Nansubuga I , Nanyunja EM , Kaplan B , Jothikumar N , Routh J , Gomez GA , Mintz ED , Hill VR . Appl Environ Microbiol 2017 83 (23) In 2015, a typhoid fever outbreak began in downtown Kampala, Uganda and spread into adjacent districts. In response, an environmental survey of drinking water source types was conducted in areas of the city with high case numbers. A total of 122 samples were collected from 12 source types and tested for E. coli, free chlorine, and conductivity. An additional 37 grab samples from seven source types and 16 paired large volume (20-L) samples from wells and springs were also collected and tested for the presence of Salmonella Typhi. Escherichia coli was detected in 60% of kaveras (drinking water sold in plastic bags) and 80% of refilled water bottles; free chlorine was not detected in either source type. Most jerry cans (68%) contained E. coli and had free chlorine residuals below the WHO recommended level of 0.5 mg/L during outbreaks. Elevated conductivity readings for kaveras, refilled water bottles, and jerry cans (compared to treated surface water supplied by the water utility) suggested they likely contained untreated ground water. All unprotected springs and wells and more than 60% of protected springs contained E. coli Water samples collected from the water utility were found to have acceptable free chlorine levels and no detectable E. coli While S Typhi was not detected in water samples, Salmonella spp. were detected in samples from two unprotected springs, one protected spring, and one refilled water bottle. These data provided clear evidence that unregulated vended water and ground water represented a risk for typhoid transmission.Importance Despite the high incidence of typhoid fever globally, relatively few outbreak investigations incorporate drinking water testing. During waterborne disease outbreaks, measurement of physical-chemical parameters, such as free chlorine residual and electrical conductivity, and microbiological parameters, such as the presence of E. coli or the implicated etiologic agent, in drinking water samples can identify contaminated sources. This investigation indicated that unregulated vended water and ground water sources were contaminated and were therefore a risk to consumers during the 2015 typhoid fever outbreak in Kampala. Identification of contaminated drinking water sources and sources that do not contain adequate disinfectant levels can lead to rapid targeted interventions. |
Removals of cryptosporidium parvum oocysts and cryptosporidium-sized polystyrene microspheres from swimming pool water by diatomaceous earth filtration and perlite-sand filtration
Lu P , Amburgey JE , Hill VR , Murphy JL , Schneeberger CL , Arrowood MJ , Yuan T . J Water Health 2017 15 (3) 374-384 Removal of Cryptosporidium-sized microspheres and Cryptosporidium parvum oocysts from swimming pools was investigated using diatomaceous earth (DE) precoat filtration and perlite-sand filtration. In pilot-scale experiments, microsphere removals of up to 2 log were obtained with 0.7 kg.DE/m2 at a filtration rate of 5 m/h. A slightly higher microsphere removal (2.3 log) was obtained for these DE-precoated filters when the filtration rate was 3.6 m/h. Additionally, pilot-scale perlite-sand filters achieved greater than 2 log removal when at least 0.37 kg/m2 of perlite was used compared to 0.1-0.4 log removal without perlite both at a surface loading rate of 37 m/h. Full-scale testing achieved 2.7 log of microspheres and oocysts removal when 0.7 kg.DE/m2 was used at 3.6 m/h. Removals were significantly decreased by a 15-minute interruption of the flow (without any mechanical agitation) to the DE filter in pilot-scale studies, which was not observed in full-scale filters. Microsphere removals were 2.7 log by perlite-sand filtration in a full-scale swimming pool filter operated at 34 m/h with 0.5 kg/m2 of perlite. The results demonstrate that either a DE precoat filter or a perlite-sand filter can improve the efficiency of removal of microspheres and oocysts from swimming pools over a standard sand filter under the conditions studied. |
Methodological approaches for monitoring opportunistic pathogens in premise plumbing: A review
Wang H , Bedard E , Prevost M , Camper AK , Hill VR , Pruden A . Water Res 2017 117 68-86 Opportunistic premise (i.e., building) plumbing pathogens (OPPPs, e.g., Legionella pneumophila, Mycobacterium avium complex, Pseudomonas aeruginosa, Acanthamoeba, and Naegleria fowleri) are a significant and growing source of disease. Because OPPPs establish and grow as part of the native drinking water microbiota, they do not correspond to fecal indicators, presenting a major challenge to standard drinking water monitoring practices. Further, different OPPPs present distinct requirements for sampling, preservation, and analysis, creating an impediment to their parallel detection. The aim of this critical review is to evaluate the state of the science of monitoring OPPPs and identify a path forward for their parallel detection and quantification in a manner commensurate with the need for reliable data that is informative to risk assessment and mitigation. Water and biofilm sampling procedures, as well as factors influencing sample representativeness and detection sensitivity, are critically evaluated with respect to the five representative bacterial and amoebal OPPPs noted above. Available culturing and molecular approaches are discussed in terms of their advantages, limitations, and applicability. Knowledge gaps and research needs towards standardized approaches are identified. |
A full-scale study of Cryptosporidium parvum oocyst and Cryptosporidium-sized microsphere removals from swimming pools via sand filtration
Lu P , Amburgey JE , Hill VR , Murphy JL , Schneeberger C , Arrowood MJ . Water Quality Research Journal 2017 52 (1) 18-25 Removal of Cryptosporidium parvum oocysts and Cryptosporidium-sized microspheres was evaluated in full-scale swimming pools via high-rate sand filtration (31–34 m/h) with coagulation. Results showed that at least 90% of C. parvum oocysts and microspheres were removed by filtration with an initial dosage of coagulant B (1.56 mg/L), D (1.9 mg/L or 305 g/m2), or F (1.56 mg/L) from each swimming pool. Filtration with an initial dosage of coagulant E (0.1 mg·Al/L) achieved 82% C. parvum oocyst removal and 97% microsphere removal. Coagulants B and F had a tendency to overdose over time with continuous feeding (based on corresponding pilot-scale experiments) and did not consistently achieve removals greater than 90% in the full-scale trials. As high as 99% of C. parvum oocysts and 98% of microspheres were removed with a continuous dosage of coagulant D. Up to 98% (1.7 log) of C. parvum oocysts and 93% (1.1 log) of microspheres were removed by continuous dosing of coagulant E at 27 m/h. Consistent oocyst and microsphere removal by aluminum-based coagulants (D and E) was achieved under the tested swimming pool conditions. |
Inter-laboratory evaluation and successful implementation of MS2 coliphage as a surrogate to establish proficiency using a BSL-3 procedure
Mapp L , Chambers Y , Takundwa P , Hill VR , Schneeberger C , Knee J , Raynor M , Klonicki P , Miller K , Pope M , Hwang N . Water (Basel) 2016 8 (6) 248 The U.S. Environmental Protection Agency's (EPA) Water Laboratory Alliance relies on the Centers for Disease Control and Prevention's ultrafiltration-based Water Processing Procedure (WPP) for concentration of biosafety level 3 (BSL-3) agents from 10 L to 100 L of drinking water. The WPP requires comprehensive training and practice to maintain proficiency, resulting in a critical need for quality control (QC) criteria. The aim of this study was to develop criteria using male-specific (MS2) coliphage (BSL-2 agent) to minimize safety hazards associated with BSL-3 agents and to use the criteria to evaluate analytical proficiency during a demonstration exercise. EPA Method 1602 with EasyPhage was used during the study to develop QC criteria for 100-mL, and 40-100 L samples. The demonstration exercise indicated that the MS2 criteria would allow laboratories to demonstrate proficiency using the WPP with 40-100 L samples. In addition, the QC criteria developed for 100-mL samples has broad applicability at laboratories that are using MS2 for other types of analyses, such as assessment of water treatment devices. The development of MS2 QC criteria allows laboratories to develop and confirm ongoing proficiency using the WPP. |
A large and persistent outbreak of typhoid fever caused by consuming contaminated water and street-vended beverages: Kampala, Uganda, January - June 2015
Kabwama SN , Bulage L , Nsubuga F , Pande G , Oguttu DW , Mafigiri R , Kihembo C , Kwesiga B , Masiira B , Okullo AE , Kajumbula H , Matovu J , Makumbi I , Wetaka M , Kasozi S , Kyazze S , Dahlke M , Hughes P , Sendagala JN , Musenero M , Nabukenya I , Hill VR , Mintz E , Routh J , Gomez G , Bicknese A , Zhu BP . BMC Public Health 2017 17 (1) 23 BACKGROUND: On 6 February 2015, Kampala city authorities alerted the Ugandan Ministry of Health of a "strange disease" that killed one person and sickened dozens. We conducted an epidemiologic investigation to identify the nature of the disease, mode of transmission, and risk factors to inform timely and effective control measures. METHODS: We defined a suspected case as onset of fever (≥37.5 degrees C) for more than 3 days with abdominal pain, headache, negative malaria test or failed anti-malaria treatment, and at least 2 of the following: diarrhea, nausea or vomiting, constipation, fatigue. A probable case was defined as a suspected case with a positive TUBEX(R) TF test. A confirmed case had blood culture yielding Salmonella Typhi. We conducted a case-control study to compare exposures of 33 suspected case-patients and 78 controls, and tested water and juice samples. RESULTS: From 17 February-12 June, we identified 10,230 suspected, 1038 probable, and 51 confirmed cases. Approximately 22.58% (7/31) of case-patients and 2.56% (2/78) of controls drank water sold in small plastic bags (ORM-H = 8.90; 95%CI = 1.60-49.00); 54.54% (18/33) of case-patients and 19.23% (15/78) of controls consumed locally-made drinks (ORM-H = 4.60; 95%CI: 1.90-11.00). All isolates were susceptible to ciprofloxacin and ceftriaxone. Water and juice samples exhibited evidence of fecal contamination. CONCLUSION: Contaminated water and street-vended beverages were likely vehicles of this outbreak. At our recommendation authorities closed unsafe water sources and supplied safe water to affected areas. |
Evaluation of alternative DNA extraction processes and real-time PCR for detecting Cryptosporidium parvum in drinking water
Kimble GH , Hill VR , Amburgey JE . Water Supply 2015 15 (6) 1295-1303 USEPA Method 1623 is the standard method in the United States for the detection of Cryptosporidium in water samples, but quantitative real-time polymerase chain reaction (qPCR) is an alternative technique that has been successfully used to detect Cryptosporidium in aqueous matrices. This study examined various modifications to a commercial nucleic acid extraction procedure in order to enhance PCR detection sensitivity for Cryptosporidium. An alternative DNA extraction buffer allowed for qPCR detection at lower seed levels than a commercial extraction kit buffer. In addition, the use of a second spin column cycle produced significantly better detection (P = 0.031), and the volume of Tris-EDTA buffer significantly affected crossing threshold values (P = 0.001). The improved extraction procedure was evaluated using 10 L of tap water samples processed by ultrafiltration, centrifugation and immunomagnetic separation. Mean recovery for the sample processing method was determined to be 41% using microscopy and 49% by real-time PCR (P = 0.013). The results of this study demonstrate that real-time PCR can be an effective alternative for detecting and quantifying Cryptosporidium parvum in drinking water samples. |
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