Last data update: Oct 07, 2024. (Total: 47845 publications since 2009)
Records 1-24 (of 24 Records) |
Query Trace: Kahler AM[original query] |
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Sources and prevalence of Cyclospora cayetanensis in southeastern U.S. Growing environments
Kahler AM , Hofstetter J , Arrowood M , Peterson A , Jacobson D , Barratt J , Luiz Biscaia Ribeiro da Silva A , Rodrigues C , Mattioli MC . J Food Prot 2024 100309 Recent cyclosporiasis outbreaks associated with fresh produce grown in the United States highlight the need to better understand C. cayetanensis prevalence in U.S. agricultural environments. In this study, C. cayetanensis occurrence was assessed in municipal wastewater sludge, on-farm portable toilets, irrigation pond water, and spent packing house dump tank water in a Southeastern Georgia growing region over two years. Detection of the C. cayetanensis 18S rRNA qPCR gene target in pond samples was 0%, 28%, and 42% (N=217) depending on the detection definition used, and ≤ 1% in dump tank samples (N=46). However, no qPCR detections were confirmed by sequencing, suggesting false detection occurred due to cross-reactions. C. cayetanensis qPCR detections were confirmed in 9% of wastewater sludge samples (N=76). The human-specific fecal markers HF183 and crAssphage were detected in 33% and 6% of pond samples, respectively and 4% and 0% of dump tank samples, respectively. Despite community Cyclospora shedding and evidence of human fecal contamination in irrigation water, there was no correlation between C. cayetanensis and HF183 qPCR detections, further supporting that 18S gene target qPCR amplifications were due to cross reactions. When evaluating C. cayetanensis qPCR environmental detection data, the impact of assay specificity and detection criteria should be considered. Moreover, additional sequence-based testing may be needed to appropriately interpret Cyclospora qPCR environmental data. |
Case of primary amebic meningoencephalitis associated with surfing at an artificial surf venue: Environmental investigation
Miko S , Cope JR , Hlavsa MC , Ali IKM , Brown TW , Collins JP , Greeley RD , Kahler AM , Moore KO , Roundtree AV , Roy S , Sanders LL , Shah V , Stuteville HD , Mattioli MC . ACS ES T Water 2022 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. In September 2018, a 29-year-old man died of PAM after traveling to Texas. We conducted an epidemiologic and environmental investigation to identify the water exposure associated with this PAM case. The patients most probable water exposure occurred while surfing in an artificial surf venue. The surf venue water was not filtered or recirculated; water disinfection and water quality testing were not documented. N. fowleri and thermophilic amebae were detected in recreational water and sediment samples throughout the facility. Codes and standards for treated recreational water venues open to the public could be developed to address these novel venues. Clinicians and public health officials should also consider novel recreational water venues as a potential exposure for this rare amebic infection. Not subject to U.S. Copyright. Published 2023 by American Chemical Society. |
Outbreaks of acute gastrointestinal illness associated with a splash pad in a Wildlife Park - Kansas, June 2021
Aluko SK , Ishrati SS , Walker DC , Mattioli MC , Kahler AM , Vanden Esschert KL , Hervey K , Rokisky JJr , Wikswo ME , Laco JP , Kurlekar S , Byrne A , Molinari NA , Gleason ME , Steward C , Hlavsa MC , Neises D . MMWR Morb Mortal Wkly Rep 2022 71 (31) 981-987 In June 2021, Kansas state and county public health officials identified and investigated three cases of shigellosis (a bacterial diarrheal illness caused by Shigella spp.) associated with visiting a wildlife park. The park has animal exhibits and a splash pad. Two affected persons visited animal exhibits, and all three entered the splash pad. Nonhuman primates are the only known animal reservoir of Shigella. The splash pad, which sprays water on users and is designed so that water does not collect in the user area, was closed on June 19. The state and county public health codes do not include regulations for splash pads. Thus, these venues are not typically inspected, and environmental health expertise is limited. A case-control study identified two distinct outbreaks associated with the park (a shigellosis outbreak involving 21 cases and a subsequent norovirus infection outbreak involving six cases). Shigella and norovirus can be transmitted by contaminated water; in both outbreaks, illness was associated with getting splash pad water in the mouth (multiply imputed adjusted odds ratio [aOR(MI)] = 6.4, p = 0.036; and 28.6, p = 0.006, respectively). Maintaining adequate water disinfection and environmental health expertise and targeting prevention efforts to caregivers of splash pad users help prevent splash pad-associated outbreaks. Outbreak incidence might be further reduced when U.S. jurisdicitons voluntarily adopt CDC's Model Aquatic Health Code (MAHC) recommendations and through the prevention messages: "Don't get in the water if sick with diarrhea," "Don't stand or sit above the jets," and "Don't swallow the water."(†). |
Detection of Cyclospora cayetanensis in produce irrigation and wash water using large-volume sampling techniques
Kahler AM , Mattioli MC , da Silva AJ , Hill V . Food Waterborne Parisitol 2021 22 e00110 The recent increase of reported cyclosporiasis outbreaks associated with fresh produce has highlighted the need for understanding environmental transmission of Cyclospora cayetanensis in agricultural settings and facilities. Conducting such environmental investigations necessitates robust sample collection and analytical methods to detect C. cayetanensis in water samples. This study evaluated three sample collection methods for recovery of C. cayetanensis oocysts from water samples during seeded recovery experiments. Two filtration-based methods, dead-end ultrafiltration (DEUF) and USEPA Method 1623.1, were evaluated for oocyst recovery from irrigation water. A non-filter-based method, continuous flow centrifugation (CFC), was evaluated separately for recovery from creek water and spent produce wash water. Median C. cayetanensis recovery efficiencies were 17% for DEUF and 16–22% for Method 1623.1. The DEUF method proved to be more robust than Method 1623.1, as the recovery efficiencies were less variable and the DEUF ultrafilters were capable of filtering larger volumes of high-turbidity water without clogging. Median C. cayetanensis recovery efficiencies for CFC were 28% for wash water and 63% for creek water, making it a viable option for processing water with high turbidity or organic matter. The data from this study demonstrate the capability of DEUF and CFC as filter-based and non-filter-based options, respectively, for the recovery of C. cayetanensis oocysts from environmental and agricultural waters. |
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. |
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. |
Cholera epidemic - Lusaka, Zambia, October 2017-May 2018
Sinyange N , Brunkard JM , Kapata N , Mazaba ML , Musonda KG , Hamoonga R , Kapina M , Kapaya F , Mutale L , Kateule E , Nanzaluka F , Zulu J , Musyani CL , Winstead AV , Davis WW , N'Cho H S , Mulambya NL , Sakubita P , Chewe O , Nyimbili S , Onwuekwe EVC , Adrien N , Blackstock AJ , Brown TW , Derado G , Garrett N , Kim S , Hubbard S , Kahler AM , Malambo W , Mintz E , Murphy J , Narra R , Rao GG , Riggs MA , Weber N , Yard E , Zyambo KD , Bakyaita N , Monze N , Malama K , Mulwanda J , Mukonka VM . MMWR Morb Mortal Wkly Rep 2018 67 (19) 556-559 On October 6, 2017, an outbreak of cholera was declared in Zambia after laboratory confirmation of Vibrio cholerae O1, biotype El Tor, serotype Ogawa, from stool specimens from two patients with acute watery diarrhea. The two patients had gone to a clinic in Lusaka, the capital city, on October 4. Cholera cases increased rapidly, from several hundred cases in early December 2017 to approximately 2,000 by early January 2018 (Figure). In collaboration with partners, the Zambia Ministry of Health (MoH) launched a multifaceted public health response that included increased chlorination of the Lusaka municipal water supply, provision of emergency water supplies, water quality monitoring and testing, enhanced surveillance, epidemiologic investigations, a cholera vaccination campaign, aggressive case management and health care worker training, and laboratory testing of clinical samples. In late December 2017, a number of water-related preventive actions were initiated, including increasing chlorine levels throughout the city's water distribution system and placing emergency tanks of chlorinated water in the most affected neighborhoods; cholera cases declined sharply in January 2018. During January 10-February 14, 2018, approximately 2 million doses of oral cholera vaccine were administered to Lusaka residents aged >/=1 year. However, in mid-March, heavy flooding and widespread water shortages occurred, leading to a resurgence of cholera. As of May 12, 2018, the outbreak had affected seven of the 10 provinces in Zambia, with 5,905 suspected cases and a case fatality rate (CFR) of 1.9%. Among the suspected cases, 5,414 (91.7%), including 98 deaths (CFR = 1.8%), occurred in Lusaka residents. |
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. |
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. |
Using molecular characterization to support investigations of aquatic facility-associated outbreaks of cryptosporidiosis - Alabama, Arizona, and Ohio, 2016
Hlavsa MC , Roellig DM , Seabolt MH , Kahler AM , Murphy JL , McKitt TK , Geeter EF , Dawsey R , Davidson SL , Kim TN , Tucker TH , Iverson SA , Garrett B , Fowle N , Collins J , Epperson G , Zusy S , Weiss JR , Komatsu K , Rodriguez E , Patterson JG , Sunenshine R , Taylor B , Cibulskas K , Denny L , Omura K , Tsorin B , Fullerton KE , Xiao L . MMWR Morb Mortal Wkly Rep 2017 66 (19) 493-497 Cryptosporidiosis is a nationally notifiable gastrointestinal illness caused by parasitic protozoa of the genus Cryptosporidium, which can cause profuse, watery diarrhea that can last up to 2-3 weeks in immunocompetent patients and can lead to life-threatening wasting and malabsorption in immunocompromised patients. Fecal-oral transmission of Cryptosporidium oocysts, the parasite's infectious life stage, occurs via ingestion of contaminated recreational water, drinking water, or food, or following contact with infected persons or animals, particularly preweaned bovine calves (1). The typical incubation period is 2-10 days. Since 2004, the annual incidence of nationally notified cryptosporidiosis has risen approximately threefold in the United States (1). Cryptosporidium also has emerged as the leading etiology of nationally notified recreational water-associated outbreaks, particularly those associated with aquatic facilities (i.e., physical places that contain one or more aquatic venues [e.g., pools] and support infrastructure) (2). As of February 24, 2017, a total of 13 (54%) of 24 states reporting provisional data detected at least 32 aquatic facility-associated cryptosporidiosis outbreaks in 2016. In comparison, 20 such outbreaks were voluntarily reported to CDC via the National Outbreak Reporting System for 2011, 16 for 2012, 13 for 2013, and 16 for 2014. This report highlights cryptosporidiosis outbreaks associated with aquatic facilities in three states (Alabama, Arizona, and Ohio) in 2016. This report also illustrates the use of CryptoNet, the first U.S. molecularly based surveillance system for a parasitic disease, to further elucidate Cryptosporidium chains of transmission and cryptosporidiosis epidemiology. CryptoNet data can be used to optimize evidence-based prevention strategies. Not swimming when ill with diarrhea is key to preventing and controlling aquatic facility-associated cryptosporidiosis outbreaks (https://www.cdc.gov/healthywater/swimming/swimmers/steps-healthy-swimming.html). |
Aggregation of adenovirus 2 in source water and impacts on disinfection by chlorine
Kahler AM , Cromeans TL , Metcalfe MG , Humphrey CD , Hill VR . Food Environ Virol 2016 8 (2) 148-55 It is generally accepted that viral particles in source water are likely to be found as aggregates attached to other particles. For this reason, it is important to investigate the disinfection efficacy of chlorine on aggregated viruses. A method to produce adenovirus particle aggregation was developed for this study. Negative stain electron microscopy was used to measure aggregation before and after addition of virus particles to surface water at different pH and specific conductance levels. The impact of aggregation on the efficacy of chlorine disinfection was also examined. Disinfection experiments with human adenovirus 2 (HAdV2) in source water were conducted using 0.2 mg/L free chlorine at 5 degrees C. Aggregation of HAdV2 in source water (≥3 aggregated particles) remained higher at higher specific conductance and pH levels. However, aggregation was highly variable, with the percentage of particles present in aggregates ranging from 43 to 71 %. Upon addition into source water, the aggregation percentage dropped dramatically. On average, chlorination CT values (chlorine concentration in mg/L x time in min) for 3-log10 inactivation of aggregated HAdV2 were up to three times higher than those for dispersed HAdV2, indicating that aggregation reduced the disinfection rate. This information can be used by water utilities and regulators to guide decision making regarding disinfection of viruses in water. |
Outbreaks of illness associated with recreational water - United States, 2011-2012
Hlavsa MC , Roberts VA , Kahler AM , Hilborn ED , Mecher TR , Beach MJ , Wade TJ , Yoder JS . MMWR Morb Mortal Wkly Rep 2015 64 (24) 668-672 Outbreaks of illness associated with recreational water use result from exposure to chemicals or infectious pathogens in recreational water venues that are treated (e.g., pools and hot tubs or spas) or untreated (e.g., lakes and oceans). For 2011-2012, the most recent years for which finalized data were available, public health officials from 32 states and Puerto Rico reported 90 recreational water-associated outbreaks to CDC's Waterborne Disease and Outbreak Surveillance System (WBDOSS) via the National Outbreak Reporting System (NORS). The 90 outbreaks resulted in at least 1,788 cases, 95 hospitalizations, and one death. Among 69 (77%) outbreaks associated with treated recreational water, 36 (52%) were caused by Cryptosporidium. Among 21 (23%) outbreaks associated with untreated recreational water, seven (33%) were caused by Escherichia coli (E. coli O157:H7 or E. coli O111). Guidance, such as the Model Aquatic Health Code (MAHC), for preventing and controlling recreational water-associated outbreaks can be optimized when informed by national outbreak and laboratory (e.g., molecular typing of Cryptosporidium) data. |
Evaluation of an ultrafiltration-based procedure for simultaneous recovery of diverse microbes in source waters
Kahler AM , Johnson TB , Hahn DH , Narayanan J , Derado G , Hill VR . Water (Basel) 2015 7 (3) 1202-1216 In this study, hollow-fiber ultrafiltration (UF) was assessed for recovery of Escherichia coli, Clostridium perfringens spores, Cryptosporidium parvum oocysts, echovirus 1, and bacteriophages MS2 and Phi X174 from ground and surface waters. Microbes were seeded into twenty-two 50-L water samples that were collected from the Southeastern United States and concentrated to ~500 mL by UF. Secondary concentration was performed for C. parvum by centrifugation followed by immunomagnetic separation. Secondary concentration for viruses was performed using centrifugal ultrafilters or polyethylene glycol precipitation. Nine water quality parameters were measured in each water sample to determine whether water quality data correlated with UF and secondary concentration recovery efficiencies. Average UF recovery efficiencies were 66%-95% for the six enteric microbes. Average recovery efficiencies for the secondary concentration methods were 35%-95% for C. parvum and the viruses. Overall, measured water quality parameters were not significantly associated with UF recovery efficiencies. However, recovery of Phi X174 was negatively correlated with turbidity. The recovery data demonstrate that UF can be an effective method for concentrating diverse microbes from ground and surface waters. This study highlights the utility of tangential-flow hollow fiber ultrafiltration for recovery of bacteria, viruses, and parasites from large volume environmental water samples. |
Environmental surveillance for toxigenic Vibrio cholerae in surface waters of Haiti.
Kahler AM , Haley BJ , Chen A , Mull BJ , Tarr CL , Turnsek M , Katz LS , Humphrys MS , Derado G , Freeman N , Boncy J , Colwell RR , Huq A , Hill VR . Am J Trop Med Hyg 2014 92 (1) 118-25 Epidemic cholera was reported in Haiti in 2010, with no information available on the occurrence or geographic distribution of toxigenic Vibrio cholerae in Haitian waters. In a series of field visits conducted in Haiti between 2011 and 2013, water and plankton samples were collected at 19 sites. Vibrio cholerae was detected using culture, polymerase chain reaction, and direct viable count methods (DFA-DVC). Cholera toxin genes were detected by polymerase chain reaction in broth enrichments of samples collected in all visits except March 2012. Toxigenic V. cholerae was isolated from river water in 2011 and 2013. Whole genome sequencing revealed that these isolates were a match to the outbreak strain. The DFA-DVC tests were positive for V. cholerae O1 in plankton samples collected from multiple sites. Results of this survey show that toxigenic V. cholerae could be recovered from surface waters in Haiti more than 2 years after the onset of the epidemic. |
Recreational water-associated disease outbreaks - United States, 2009-2010
Hlavsa MC , Roberts VA , Kahler AM , Hilborn ED , Wade TJ , Backer LC , Yoder JS . MMWR Morb Mortal Wkly Rep 2014 63 (1) 6-10 Recreational water-associated disease outbreaks result from exposure to infectious pathogens or chemical agents in treated recreational water venues (e.g., pools and hot tubs or spas) or untreated recreational water venues (e.g., lakes and oceans). For 2009-2010, the most recent years for which finalized data are available, public health officials from 28 states and Puerto Rico electronically reported 81 recreational water-associated disease outbreaks to CDC's Waterborne Disease and Outbreak Surveillance System (WBDOSS) via the National Outbreak Reporting System (NORS). This report summarizes the characteristics of those outbreaks. Among the 57 outbreaks associated with treated recreational water, 24 (42%) were caused by Cryptosporidium. Among the 24 outbreaks associated with untreated recreational water, 11 (46%) were confirmed or suspected to have been caused by cyanobacterial toxins. In total, the 81 outbreaks resulted in at least 1,326 cases of illness and 62 hospitalizations; no deaths were reported. Laboratory and environmental data, in addition to epidemiologic data, can be used to direct and optimize the prevention and control of recreational water-associated disease outbreaks. |
Influence of inorganic ions on aggregation and adsorption behaviors of human adenovirus
Wong K , Mukherjee B , Kahler AM , Zepp R , Molina M . Environ Sci Technol 2012 46 (20) 11145-53 In this study, we investigated the influence of inorganic ions on the aggregation and deposition (adsorption) behavior of human adenovirus (HAdV). Experiments were conducted to determine the surface charge and size of HAdV and viral adsorption capacity of sand in different salt conditions. The interfacial potential energy was calculated using extended Derjaguin and Landau, Verwey and Overbeek (XDLVO) and steric hindrance theories to interpret the experimental results. Results showed that different compositions of inorganic ions have minimal effect on varying the iso-electric point pH (pH(iep)) of HAdV (ranging from 3.5 to 4.0). Divalent cations neutralized/shielded virus surface charge much more effectively than monovalent cations at pH above pH(iep). Consequently, at neutral pH the presence of divalent cations enhanced the aggregation of HAdV as well as its adsorption to sand. Aggregation and adsorption behaviors generally agreed with XDLVO theory; however, in the case of minimal electrostatic repulsion, steric force by virus' fibers can increase the energy barrier and distance of secondary minimum, resulting in limited aggregation and deposition. Overall, our results indicated that subsurface water with low hardness residing in sandy soils may have a higher potential of being contaminated by HAdV. |
Primary amebic meningoencephalitis deaths associated with sinus irrigation using contaminated tap water
Yoder JS , Straif-Bourgeois S , Roy SL , Moore TA , Visvesvara GS , Ratard RC , Hill VR , Wilson JD , Linscott AJ , Crager R , Kozak NA , Sriram R , Narayanan J , Mull B , Kahler AM , Schneeberger C , da Silva AJ , Poudel M , Baumgarten KL , Xiao L , Beach MJ . Clin Infect Dis 2012 55 (9) e79-85 BACKGROUND: Naegleria fowleri is a climate-sensitive, thermophilic ameba found in the environment, including warm, freshwater lakes and rivers. Primary amebic meningoencephalitis (PAM), which is almost universally fatal, occurs when N. fowleri-containing water enters the nose, typically during swimming, and N. fowleri migrates to the brain via the olfactory nerve. In 2011, 2 adults died in Louisiana hospitals of infectious meningoencephalitis after brief illnesses. METHODS: Clinical and environmental testing and case investigations were initiated to determine the cause of death and to identify the exposures. RESULTS: Both patients had diagnoses of PAM. Their only reported water exposures were tap water used for household activities, including regular sinus irrigation with neti pots. Water samples, tap swab samples, and neti pots were collected from both households and tested; N. fowleri were identified in water samples from both homes. CONCLUSIONS: These are the first reported PAM cases in the United States associated with the presence of N. fowleri in household plumbing served by treated municipal water supplies and the first reports of PAM potentially associated with the use of a nasal irrigation device. These cases occurred in the context of an expanding geographic range for PAM beyond southern tier states with recent case reports from Minnesota, Kansas, and Virginia. These infections introduce an additional consideration for physicians recommending nasal irrigation and demonstrate the importance of using appropriate water (distilled, boiled, filtered) for nasal irrigation. Furthermore, the changing epidemiology of PAM highlights the importance of raising awareness about this disease among physicians treating persons showing meningitislike symptoms. |
Surveillance for waterborne disease outbreaks and other health events associated with recreational water --- United States, 2007--2008
Hlavsa MC , Roberts VA , Anderson AR , Hill VR , Kahler AM , Orr M , Garrison LE , Hicks LA , Newton A , Hilborn ED , Wade TJ , Beach MJ , Yoder JS . MMWR Surveill Summ 2011 60 (12) 1-32 PROBLEM/CONDITION: Since 1978, CDC, the U.S. Environmental Protection Agency, and the Council of State and Territorial Epidemiologists have collaborated on the Waterborne Disease and Outbreak Surveillance System (WBDOSS) for collecting and reporting data on waterborne disease outbreaks associated with recreational water. This surveillance system is the primary source of data concerning the scope and health effects of waterborne disease outbreaks in the United States. In addition, data are collected on other select recreational water--associated health events, including pool chemical--associated health events and single cases of Vibrio wound infection and primary amebic meningoencephalitis (PAM). REPORTING PERIOD: Data presented summarize recreational water--associated outbreaks and other health events that occurred during January 2007--December 2008. Previously unreported data on outbreaks that have occurred since 1978 also are presented. DESCRIPTION OF THE SYSTEM: The WBDOSS database includes data on outbreaks associated with recreational water, drinking water, water not intended for drinking (excluding recreational water), and water use of unknown intent. Public health agencies in the states, the District of Columbia, U.S. territories, and Freely Associated States are primarily responsible for detecting and investigating waterborne disease outbreaks and voluntarily reporting them to CDC using a standard form. Only data on outbreaks associated with recreational water are summarized in this report. Data on other recreational water--associated health events reported to CDC, the Agency for Toxic Substances and Disease Registry (ATSDR), and the U.S. Consumer Product Safety Commission (CPSC) also are summarized. RESULTS: A total of 134 recreational water--associated outbreaks were reported by 38 states and Puerto Rico for 2007--2008. These outbreaks resulted in at least 13,966 cases. The median outbreak size was 11 cases (range: 2--5,697 cases). A total of 116 (86.6%) outbreaks were associated with treated recreational water (e.g., pools and interactive fountains) and resulted in 13,480 (96.5%) cases. Of the 134 outbreaks, 81 (60.4%) were outbreaks of acute gastrointestinal illness (AGI); 24 (17.9%) were outbreaks of dermatologic illnesses, conditions, or symptoms; and 17 (12.7%) were outbreaks of acute respiratory illness. Outbreaks of AGI resulted in 12,477 (89.3%) cases. The etiology was laboratory-confirmed for 105 (78.4%) of the 134 outbreaks. Of the 105 outbreaks with a laboratory-confirmed etiology, 68 (64.8%) were caused by parasites, 22 (21.0%) by bacteria, five (4.8%) by viruses, nine (8.6%) by chemicals or toxins, and one (1.0%) by multiple etiology types. Cryptosporidium was confirmed as the etiologic agent of 60 (44.8%) of 134 outbreaks, resulting in 12,154 (87.0%) cases; 58 (96.7%) of these outbreaks, resulting in a total of 12,137 (99.9%) cases, were associated with treated recreational water. A total of 32 pool chemical--associated health events that occurred in a public or residential setting were reported to WBDOSS by Maryland and Michigan. These events resulted in 48 cases of illness or injury; 26 (81.3%) events could be attributed at least partially to chemical handling errors (e.g., mixing incompatible chemicals). ATSDR's Hazardous Substance Emergency Events Surveillance System received 92 reports of hazardous substance events that occurred at aquatic facilities. More than half of these events (55 [59.8%]) involved injured persons; the most frequently reported primary contributing factor was human error. Estimates based on CPSC's National Electronic Injury Surveillance System (NEISS) data indicate that 4,574 (95% confidence interval [CI]: 2,703--6,446) emergency department (ED) visits attributable to pool chemical--associated injuries occurred in 2008; the most frequent diagnosis was poisoning (1,784 ED visits [95% CI: 585--2,984]). NEISS data indicate that pool chemical--associated health events occur frequently in residential settings. A total of 236 Vibrio wound infections were reported to be associated with recreational water exposure; 36 (48.6%) of the 74 hospitalized vibriosis patients and six (66.7%) of the nine vibriosis patients who died had V. vulnificus infections. Eight fatal cases of PAM occurred after exposure to warm untreated freshwater. INTERPRETATIONS: The 134 recreational water--associated outbreaks reported for 2007--2008 represent a substantial increase over the 78 outbreaks reported for 2005--2006 and the largest number of outbreaks ever reported to WBDOSS for a 2-year period. Outbreaks, especially the largest ones, were most frequently associated with treated recreational water and characterized by AGI. Cryptosporidium remains the leading etiologic agent. Pool chemical--associated health events occur frequently but are preventable. Data on other select recreational water--associated health events further elucidate the epidemiology of U.S. waterborne disease by highlighting less frequently implicated types of recreational water (e.g., oceans) and detected types of recreational water--associated illness (i.e., not AGI). PUBLIC HEALTH ACTIONS: CDC uses waterborne disease outbreak surveillance data to 1) identify the types of etiologic agents, recreational water venues, and settings associated with waterborne disease outbreaks; 2) evaluate the adequacy of regulations and public awareness activities to promote healthy and safe swimming; and 3) establish public health priorities to improve prevention efforts, guidelines, and regulations at the local, state, and federal levels. |
Toxigenic Vibrio cholerae O1 in water and seafood, Haiti
Hill VR , Cohen N , Kahler AM , Jones JL , Bopp CA , Marano N , Tarr CL , Garrett NM , Boncy J , Henry A , Gomez GA , Wellman M , Curtis M , Freeman MM , Turnsek M , Benner RA Jr , Dahourou G , Espey D , DePaola A , Tappero JW , Handzel T , Tauxe RV . Emerg Infect Dis 2011 17 (11) 2147-2150 During the 2010 cholera outbreak in Haiti, water and seafood samples were collected to detect Vibrio cholerae. The outbreak strain of toxigenic V. cholerae O1 serotype Ogawa was isolated from freshwater and seafood samples. The cholera toxin gene was detected in harbor water samples. |
Source water quality effects on monochloramine inactivation of adenovirus, coxsackievirus, echovirus, and murine norovirus
Kahler AM , Cromeans TL , Roberts JM , Hill VR . Water Res 2010 45 (4) 1745-51 There is a need for more information regarding monochloramine disinfection efficacy for viruses in water. In this study, monochloramine disinfection efficacy was investigated for coxsackievirus B5 (CVB5), echovirus 11 (E11), murine norovirus (MNV), and human adenovirus 2 (HAdV2) in one untreated ground water and two partially treated surface waters. Duplicate disinfection experiments were completed at pH 7 and 8 in source water at concentrations of 1 and 3 mg/L monochloramine at 5 and 15 degrees C. The Efficiency Factor Hom (EFH) model was used to calculate CT values (mg-min/L) required to achieve 2-, 3-, and 4-log(10) reductions in viral titers. In all water types, monochloramine disinfection was most effective for MNV, with 3-log(10) CT values at 5 degrees C ranging from 27 to 110. Monochloramine disinfection was least effective for HAdV2 and E11, depending on water type, with 3-log(10) CT values at 5 degrees C ranging from 1200 to 3300 and 810 to 2300, respectively. Overall, disinfection proceeded faster at 15 degrees C and pH 7 for all water types. Inactivation of the study viruses was significantly different between water types, but there was no indication that overall disinfection efficacy was enhanced or inhibited in any one water type. CT values for HAdV2 in two types of source water exceeded federal CT value recommendations in the US. The results of this study demonstrate that water quality impacts the inactivation of viruses and should be considered when developing chloramination plans. |
Source drinking water quality effects on chlorine disinfection of adenovirus, coxsackievirus, echovirus, and murine norovirus
Kahler AM , Cromeans TL , Roberts JM , Hill VR . Appl Environ Microbiol 2010 76 (15) 5159-64 More information is needed on the disinfection efficacy of chlorine for viruses in source drinking water. In this study, chlorine disinfection efficacy was investigated for USEPA Contaminant Candidate List viruses coxsackievirus B5 (CVB5), echovirus 1 (E1), murine norovirus (MNV), and human adenovirus 2 (HAdV2) in one untreated ground water source and two partially treated surface waters. Disinfection experiments using pH 7 and 8 source water were carried out in duplicate using 0.2 and 1 mg/L free chlorine at 5 and 15 degrees C. The efficiency factor Hom (EFH) model was used to calculate CT values (mg-min/L) required to achieve 2-, 3-, and 4-log10 reductions in viral titers. In all water types, chlorine disinfection was most effective for MNV, with 3-log10 CT values at 5 degrees C ranging from ≤ 0.020-0.034. Chlorine disinfection was least effective for CVB5 in all water types, with 3-log10 CT values at 5 degrees C ranging from 2.3-7.9. Overall, disinfection proceeded faster at 15 degrees C and pH 7 for all water types. Inactivation of the study viruses was significantly different between water types, but no single source water had consistently different inactivation rates than another. CT values for CVB5 in one type of source water exceeded the recommended CT values set forth by USEPA's Guidance Manual for Compliance with the Filtration and Disinfection Requirements for Public Water Systems Using Surface Water Sources. The results of this study demonstrate that water quality plays a substantial role in the inactivation of viruses and should be considered when developing chlorination plans. |
Inactivation of adenoviruses, enteroviruses, and murine norovirus in water by free chlorine and monochloramine
Cromeans TL , Kahler AM , Hill VR . Appl Environ Microbiol 2009 76 (4) 1028-33 Inactivation of infectious viruses during drinking water treatment is usually achieved with free chlorine. Many drinking water utilities in the United States now use monochloramine as a secondary disinfectant to minimize disinfectant byproduct formation and biofilm growth. The inactivation of adenoviruses 2, 40 and 41 (HAdV2, HAdV40 and HAdV41), coxsackieviruses B3 and B5 (CVB3 and CVB5), echoviruses 1 and 11 (E1 and E11) and murine norovirus (MNV), are compared in this study. Experiments were performed with 0.2 mg/L free chlorine or 1 mg/L monochloramine at pH 7 and pH 8 in buffered reagent grade water (RGW) at 5 degrees C. Ct values for 2-4-log10 (99-99.99%) reductions in viral titers were calculated using the Efficiency Factor Hom (EFH) model. The enteroviruses required the longest times for chlorine inactivation and MNV the least time. CVB5 required the longest exposure time, with Ct values of 7.4 and 10 mg-min/L (pH 7 and 8) for 4-log10 inactivation. Monochloramine disinfections was most effective for E1 (Ct values ranged from 8 to 18 mg-min/L for 2- and 3-log10 reductions, respectively). E11 and HAdV2 were the least susceptible to monochloramine disinfection, (Ct values of 1300 and 1600 mg-min/L for 3-log10 reductions, respectively). Monochloramine inactivation was most successful for the adenoviruses, CVB5, and E1 at pH 7. A greater variation in inactivation rates between viruses was observed during monochloramine disinfection than during chlorine disinfection. This data will be useful in drinking water risk assessment studies and disinfection system planning. |
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