Surveillance for Waterborne-Disease Outbreaks--United States, 1999-2000

PROBLEM/CONDITION: Since 1971, CDC, the U.S. Environmental Protection Agency (EPA), and the Council of State and Territorial Epidemiologists (CSTE) have maintained a collaborative surveillance system for the occurrences and causes of waterborne-disease outbreaks (WBDOs).This surveillance system is the primary source of data concerning the scope and effects of waterborne diseases on persons in the United States. REPORTING PERIOD COVERED: This summary includes data regarding outbreaks occurring during January 1999-December 2000 and previously unreported outbreaks occurring in 1995 and 1997. DESCRIPTION OF THE SYSTEM: The surveillance system includes data for outbreaks associated with drinking water and recreational water. State, territorial, and local public health departments are primarily responsible for detecting and investigating WBDOs and voluntarily reporting them to CDC on a standard form. The unit of analysis for the WBDO surveillance system is an outbreak, not an individual case of a waterborne disease. Two criteria must be met for an event to be defined as a WBDO. First, \u3e or = 2 persons must have experienced a similar illness after either ingestion of drinking water or exposure to water encountered in recreational or occupational settings. This criterion is waived for single cases of laboratory-confirmed primary amebic meningoencephalitis and for single cases of chemical poisoning if water-quality data indicate contamination by the chemical. Second, epidemiologic evidence must implicate water as the probable source of the illness. RESULTS: During 1999-2000, a total of 39 outbreaks associated with drinking water was reported by 25 states. Included among these 39 outbreaks was one outbreak that spanned 10 states. These 39 outbreaks caused illness among an estimated 2,068 persons and were linked to two deaths. The microbe or chemical that caused the outbreak was identified for 22 (56.4%) of the 39 outbreaks; 20 of the 22 identified outbreaks were associated with pathogens, and two were associated with chemical poisoning. Of the 17 outbreaks involving acute gastroenteritis of unknown etiology, one was a suspected chemical poisoning, and the remaining 16 were suspected as having an infectious cause. Twenty-eight (71.8%) of 39 outbreaks were linked to groundwater sources; 18 (64.3%) of these 28 groundwater outbreaks were associated with private or noncommunity wells that were not regulated by EPA. Fifty-nine outbreaks from 23 states were attributed to recreational water exposure and affected an estimated 2,093 persons. Thirty-six (61.0%) of the 59 were outbreaks involving gastroenteritis. The etiologic agent was identified in 30 (83.3%) of 36 outbreaks involving gastroenteritis. Twenty-two (61.1%) of 36 gastroenteritis-related outbreaks were associated with pools or interactive fountains. Four (6.8%) of the 59 recreational water outbreaks were attributed to single cases of primary amebic meningoencephalitis (PAM) caused by Naegleria fowleri. All four cases were fatal. Fifteen (25.4%) of the 59 outbreaks were associated with dermatitis; 12 (80.0%) of 15 were associated with hot tubs or pools. In addition, recreational water outbreaks of leptospirosis, Pontiac fever, and chemical keratitis, as well as two outbreaks of leptospirosis and Pontiac fever associated with occupational exposure were also reported to CDC. INTERPRETATION: The proportion of drinking water outbreaks associated with surface water increased from 11.8% during 1997-1998 to 17.9% in 1999-2000. The proportion of outbreaks (28) associated with groundwater sources increased 87% from the previous reporting period (15 outbreaks), and these outbreaks were primarily associated (60.7%) with consumption of untreated groundwater. Recreational water outbreaks involving gastroenteritis doubled (36 outbreaks) from the number of outbreaks reported in the previous reporting period (18 outbreaks). These outbreaks were most frequently associated with Cryptosporidium parvum (68.2%) in treated water venues (e.g., swimming pools or interactive fountains) and by Escherichia coli O157:H7 (21.4%) in freshwater venues. The increase in the number of outbreaks probably reflects improved surveillance and reporting at the local and state level as well as a true increase in the number of WBDOs. PUBLIC HEALTH ACTION: CDC and others have used surveillance data to identify the types of water systems, their deficiencies, and the etiologic agents associated with outbreaks and evaluated current technologies for providing safe drinking water and safe recreational water. Surveillance data are used also to establish research priorities, which can lead to improved water-quality regulations. Only the groundwater systems under the influence of surface water are required to disinfect their water supplies, but EPA is developing a groundwater rule that specifies when corrective action (including disinfection) is required. CDC and EPA are conducting epidemiologic studies to assess the level of waterborne illness attributable to municipal drinking water in nonoutbreak conditions. Rules under development by EPA--the Ground Water Rule (GWR), the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), and Stage 2 Disinfection Byproduct Rules (DBPR)--are expected to further protect the public from contaminants and disinfection byproducts in drinking water. Efforts by EPA under the Beaches Environmental Assessment, Closure, and Health (BEACH) program are aimed at reducing the risks for infection attributed to ambient recreational water by strengthening beach standards and testing; providing faster laboratory test methods; predicting pollution; investing in health and methods research; and improving public access to information regarding both the quality of the water at beaches and information concerning health risks associated with swimming in polluted water. EPA\u27s Beach Watch (available at http://www.epa.gov/waterscience/beaches) provides online information regarding water quality at U.S. beaches, local protection programs, and other beach-related programs. CDC partnered with a consortium of local and national pool associations to develop a series of health communication materials for the general public who attend treated recreational water venues and to staff who work at those venues. CDC has also developed a recreational water outbreak investigation toolkit that can be used by public health professionals. All of the CDC materials are accessible at the CDC Healthy Swimming website (http://www.cdc.gov/healthyswimming)

Surveillance for Waterborne-Disease Outbreaks--United States, 1997-1998.

PROBLEM/CONDITION: Since 1971, CDC and the U.S. Environmental Protection Agency (EPA) have maintained a collaborative surveillance system for collecting and periodically reporting data relating to occurrences and causes of waterborne-disease outbreaks (WBDOs). REPORTING PERIOD COVERED: This summary includes data from January 1997 through December 1998 and a previously unreported outbreak in 1996. DESCRIPTION OF THE SYSTEM: The surveillance system includes data regarding outbreaks associated with drinking water and recreational water. State, territorial, and local public health departments are primarily responsible for detecting and investigating WBDOs and voluntarily reporting them to CDC on a standard form. RESULTS: During 1997-1998, a total of 13 states reported 17 outbreaks associated with drinking water. These outbreaks caused an estimated 2,038 persons to become ill. No deaths were reported. The microbe or chemical that caused the outbreak was identified for 12 (70.6%) of the 17 outbreaks; 15 (88.2%) were linked to groundwater sources. Thirty-two outbreaks from 18 states were attributed to recreational water exposure and affected an estimated 2,128 persons. Eighteen (56.3%) of the 32 were outbreaks of gastroenteritis, and 4 (12.5%) were single cases of primary amebic meningoencephalitis caused by Naegleria fowleri, all of which were fatal. The etiologic agent was identified for 29 (90.6%) of the 32 outbreaks, with one death associated with an Escherichia coli O157:H7 outbreak. Ten (55.6%) of the 18 gastroenteritis outbreaks were associated with treated pools or ornamental fountains. Of the eight outbreaks of dermatitis, seven (87.5%) were associated with hot tubs, pools, or springs. INTERPRETATION: Drinking water outbreaks associated with surface water decreased from 31.8% during 1995-1996 to 11.8% during 1997-1998. This reduction could be caused by efforts by the drinking water industry (e.g., Partnership for Safe Water), efforts by public health officials to improve drinking water quality, and improved water treatment after the implementation of EPA\u27s Surface Water Treatment Rule. In contrast, the proportion of outbreaks associated with systems supplied by a groundwater source increased from 59.1% (i.e., 13) during 1995-1996 to 88.2% (i.e., 15) during 1997-1998. Outbreaks caused by parasites increased for both drinking and recreational water. All outbreaks of gastroenteritis attributed to parasites in recreational water were caused by Cryptosporidium, 90% occurred in treated water venues (e.g., swimming pools and decorative fountains), and fecal accidents were usually suspected. The data in this surveillance summary probably underestimate the true incidence of WBDOs because not all WBDOs are recognized, investigated, and reported to CDC or EPA. ACTIONS TAKEN: To estimate the national prevalence of waterborne disease associated with drinking water, CDC and EPA are conducting a series of epidemiologic studies to better quantify the level of waterborne disease associated with drinking water in nonoutbreak conditions. The Information Collection Rule implemented by EPA in collaboration with the drinking water industry helped quantifythe level of pathogens in surface water. Efforts by CDC to address recreational water outbreaks have included meetings with the recreational water industry, focus groups to educate parents on prevention of waterborne disease transmission in recreational water settings, and publications with guidelines for parents and pool operators

Surveillance for Waterborne-Disease Outbreaks Associated with Drinking Water--United States, 2001-2002

PROBLEM/CONDITION: Since 1971, CDC, the U.S. Environmental Protection Agency, and the Council of State and Territorial Epidemiologists have maintained a collaborative surveillance system for collecting and periodically reporting data related to occurrences and causes of waterborne-disease outbreaks (WBDOs). This surveillance system is the primary source of data concerning the scope and effects of waterborne disease outbreaks on persons in the United States. REPORTING PERIOD COVERED: This summary includes data on WBDOs associated with drinking water that occurred during January 2001-December 2002 and on three previously unreported outbreaks that occurred during 2000. DESCRIPTION OF SYSTEM: Public health departments in the states, territories, localities, and the Freely Associated States are primarily responsible for detecting and investigating WBDOs and voluntarily reporting them to CDC on a standard form. The surveillance system includes data for outbreaks associated with both drinking water and recreational water; only outbreaks associated with drinking water are reported in this summary. RESULTS: During 2001-2002, a total of 31 WBDOs associated with drinking water were reported by 19 states. These 31 outbreaks caused illness among an estimated 1,020 persons and were linked to seven deaths. The microbe or chemical that caused the outbreak was identified for 24 (77.4%) of the 31 outbreaks. Of the 24 identified outbreaks, 19 (79.2%) were associated with pathogens, and five (20.8%) were associated with acute chemical poisonings. Five outbreaks were caused by norovirus, five by parasites, and three by non-Legionella bacteria. All seven outbreaks involving acute gastrointestinal illness of unknown etiology were suspected of having an infectious cause. For the first time, this MMWR Surveillance Summary includes drinking water-associated outbreaks of Legionnaires disease (LD); six outbreaks of LD occurred during 2001-2002. Of the 25 non-Legionella associated outbreaks, 23 (92.0%) were reported in systems that used groundwater sources; nine (39.1%) of these 23 groundwater outbreaks were associated with private noncommunity wells that were not regulated by EPA. INTERPRETATION: The number of drinking water-associated outbreaks decreased from 39 during 1999-2000 to 31 during 2001-2002. Two (8.0%) outbreaks associated with surface water occurred during 2001-2002; neither was associated with consumption of untreated water. The number of outbreaks associated with groundwater sources decreased from 28 during 1999-2000 to 23 during 2001-2002; however, the proportion of such outbreaks increased from 73.7% to 92.0%. The number of outbreaks associated with untreated groundwater decreased from 17 (44.7%) during 1999-2000 to 10 (40.0%) during 2001-2002. Outbreaks associated with private, unregulated wells remained relatively stable, although more outbreaks involving private, treated wells were reported during 2001-2002. Because the only groundwater systems that are required to disinfect their water supplies are public systems under the influence of surface water, these findings support EPA\u27s development of a groundwater rule that specifies when corrective action (including disinfection) is required. PUBLIC HEALTH ACTION: CDC and EPA use surveillance data 1) to identify the types of water systems, their deficiencies, and the etiologic agents associated with outbreaks and 2) to evaluate the adequacy of technologies for providing safe drinking water. Surveillance data are used also to establish research priorities, which can lead to improved water-quality regulations. CDC and EPA recently completed epidemiologic studies that assess the level of waterborne illness attributable to municipal drinking water in nonoutbreak conditions. The decrease in outbreaks in surface water systems is attributable primarily to implementation of provisions of EPA rules enacted since the late 1980s. Rules under development by EPA are expected to protect the public further from microbial contaminants while addressing risk tradeoffs of disinfection byproducts in drinking water

Surveillance for Waterborne-Disease Outbreaks Associated With Recreational Water--United States, 2001-2002

PROBLEM/CONDITION: Since 1971, CDC, the U.S. Environmental Protection Agency, and the Council of State and Territorial Epidemiologists have maintained a collaborative surveillance system for collecting and periodically reporting data related to occurrences and causes of waterborne-disease outbreaks (WBDOs) related to drinking water; tabulation of recreational water-associated outbreaks was added to the surveillance system in 1978. This surveillance system is the primary source of data concerning the scope and effects of waterborne disease outbreaks on persons in the United States. REPORTING PERIOD COVERED: This summary includes data on WBDOs associated with recreational water that occurred during January 2001-December 2002 and on a previously unreported outbreak that occurred during 1998. DESCRIPTION OF SYSTEM: Public health departments in the states, territories, localities, and the Freely Associated States are primarily responsible for detecting and investigating WBDOs and voluntarily reporting them to CDC on a standard form. The surveillance system includes data for outbreaks associated with both drinking water and recreational water; only outbreaks associated with recreational water are reported in this summary. RESULTS: During 2001-2002, a total of 65 WBDOs associated with recreational water were reported by 23 states. These 65 outbreaks caused illness among an estimated 2,536 persons; 61 persons were hospitalized, eight of whom died. This is the largest number of recreational water-associated outbreaks to occur since reporting began in 1978; the number of recreational water-associated outbreaks has increased significantly during this period (p INTERPRETATION: The 30 outbreaks involving gastroenteritis comprised the largest proportion of recreational water-associated outbreaks during this reporting period. These outbreaks were associated most frequently with Cryptosporidium (50.0%) in treated water venues and with toxigenic Escherichia coli (25.0%) and norovirus (25.0%) in freshwater venues. The increase in the number of outbreaks since 1993 could reflect improved surveillance and reporting at the local and state level, a true increase in the number of WBDOs, or a combination of these factors. PUBLIC HEALTH ACTION: CDC uses surveillance data to identify the etiologic agents, types of aquatics venues, water-treatment systems, and deficiencies associated with outbreaks and to evaluate the adequacy of efforts (e.g., regulations and public awareness activities) for providing safe recreational water. Surveillance data are also used to establish public health prevention priorities, which might lead to improved water-quality regulations at the local, state, and federal levels

Rapidly Measured Indicators of Recreational Water Quality Are Predictive of Swimming-Associated Gastrointestinal Illness

Standard methods to measure recreational water quality require at least 24 hr to obtain results, making it impossible to assess the quality of water within a single day. Methods to measure recreational water quality in ≤ 2 hr have been developed. Application of rapid methods could give considerably more accurate and timely assessments of recreational water quality. We conducted a prospective study of beachgoers at two Great Lakes beaches to examine the association between recreational water quality, obtained using rapid methods, and gastrointestinal (GI) illness after swimming. Beachgoers were asked about swimming and other beach activities and 10–12 days later were asked about the occurrence of GI symptoms. We tested water samples for Enterococcus and Bacteroides species using the quantitative polymerase chain reaction (PCR) method. We observed significant trends between increased GI illness and Enterococcus at the Lake Michigan beach and a positive trend for Enterococcus at the Lake Erie beach. The association remained significant for Enterococcus when the two beaches were combined. We observed a positive trend for Bacteroides at the Lake Erie beach, but no trend was observed at the Lake Michigan beach. Enterococcus samples collected at 0800 hr were predictive of GI illness that day. The association between Enterococcus and illness strengthened as time spent swimming in the water increased. This is the first study to show that water quality measured by rapid methods can predict swimming-associated health effects

Spatial clustering of filarial transmission before and after a Mass Drug Administration in a setting of low infection prevalence

BACKGROUND: In the global program for the elimination of lymphatic filariasis (LF) longitudinal assessment of the prevalence of microfilaremia and antigenemia is recommended to monitor the effect of mass treatment on transmission. Additional monitoring tools such as entomologic and antibody methods may be useful in identifying residual foci of infection. In this study, we characterized serologic markers of infection and exposure spatially both before and after mass treatment, in an area of initial low Wuchereria bancrofti infection prevalence. METHODS: Consenting persons in the sentinel community were tested for circulating microfilaria and antigen (by immunochromatographic test) before and after the 1(st )annual mass drug administration of diethylcarbamazine and albendazole. A cohort of 161 persons provided serum specimens both years that were tested for antifilarial IgG (1 and 4) antibody. Every house was mapped using a differential Global Positioning System; this information was linked to the serologic data. W. bancrofti infection in the mosquito vector was assessed with year-round collection. Multiple linear regression was used to investigate the influence of antigen-positive persons on the antifilarial antibody responses of antigen-negative neighbors. RESULTS: After mass treatment, decreases were observed in the sentinel site in the overall prevalence of antigen (10.4% to 6.3%) and microfilaremia (0.9 to 0.4%). Of the persons in the cohort that provided serum specimens both years, 79% received treatment. Antigen prevalence decreased from 15.0% to 8.7%. Among 126 persons who received treatment, antigen and antifilarial IgG1 prevalence decreased significantly (p = 0.002 and 0.001, respectively). Among 34 persons who did not receive treatment, antifilarial IgG1 prevalence increased significantly (p = 0.003). Average antifilarial IgG1 levels decreased in households with high treatment coverage and increased in households that refused treatment. Each 10-meter increase in distance from the residence of a person who was antigen-positive in 2000 was associated a 4.68 unit decrease in antifilarial IgG1 level in 2001, controlling for other factors (p = 0.04). DISCUSSION: Antifilarial antibody assays can be used as a measure of filarial exposure. Our results suggest that micro-scale spatial heterogeneity exists in LF exposure and infection. Treatment appeared to be associated with reduced exposure at the sub-community level, suggesting the need to achieve high and homogeneous coverage. Public health messages should note the benefits of having one's neighbors receive treatment with antifilarial drugs

Field-free deterministic ultra fast creation of skyrmions by spin orbit torques

Magnetic skyrmions are currently the most promising option to realize current-driven magnetic shift registers. A variety of concepts to create skyrmions were proposed and demonstrated. However, none of the reported experiments show controlled creation of single skyrmions using integrated designs. Here, we demonstrate that skyrmions can be generated deterministically on subnanosecond timescales in magnetic racetracks at artificial or natural defects using spin orbit torque (SOT) pulses. The mechanism is largely similar to SOT-induced switching of uniformly magnetized elements, but due to the effect of the Dzyaloshinskii-Moriya interaction (DMI), external fields are not required. Our observations provide a simple and reliable means for skyrmion writing that can be readily integrated into racetrack devices