An outbreak of cryptosporidiosis associated with a swimming pool.

In August 1988 an increase was noted in the number of cases of cryptosporidiosis identified by the microbiology laboratory at Doncaster Royal Infirmary. By 31 October, 67 cases had been reported. Preliminary investigations implicated the use of one of two swimming pools at a local sports centre and oocysts were identified in the pool water. Inspection of the pool revealed significant plumbing defects which had allowed ingress of sewage from the main sewer into the circulating pool water. Epidemiological investigation confirmed an association between head immersion and illness. The pools were closed when oocysts were identified in the water and extensive cleaning and repair work was undertaken. The pool water was retested for cryptosporidial oocysts and found to be negative before the pool reopened.     

An outbreak of cryptosporidiosis associated with a resort swimming pool.

An outbreak of cyptosporidiosis occurred in late April 1993 among resort hotel guests which was temporally associated with, but geographically distant from, a massive waterborne outbreak of cryptosporidiosis in Milwaukee, Wisconsin, that occurred in late March and early April of 1993. A case-control study was performed among groups with members who reported illness and among a systemic sample of groups who stayed at the resort hotel during the risk period. Of 120 persons interviewed, 51 (43%) met the case definition. Swimming in the resort hotel''s pool was significantly associated with case status (OR = 9.8; 95% Cl 3.4, 29.7), as was consumption of ice from the hotel''s ice machines (OR = 2.3; 95% Cl 1.01, 5.2). When analysis was restricted only to laboratory-confirmed cases and controls, swimming pool use was the only risk factor significantly associated with illness (OR = 13.0; 95% Cl 2.6, 88.7). Following waterborne outbreaks of cryptosporidiosis associated with water supplies, swimming pools should be considered as possible ongoing sources for transmission regionally.     

An outbreak of viral meningitis associated with a public swimming pond

From July to October 2001, 215 cases of aseptic meningitis occurred among the inhabitants of the German city of Kassel and neighbouring counties. A matched case-control study identified bathing in a public, nature-like pond during the beginning of the outbreak as a risk factor for disease [matched odds ratio (mOR) 44.8, 95% confidence interval (CI) 3.9-515.6]. Among bathers, patients with meningitis spent more time in the water (mOR 18.8, 95% CI 2.0-174.1) and swallowed water more frequently (mOR = 7.3, 95% CI 0.7-81.8). Of 30 cerebrospinal fluid samples tested, echovirus 30 was cultured from 16, and echovirus 13 from seven. An echovirus 30 sequence obtained from one pond water sample showed a 99% nucleotide and 100% amino-acid homology with patient isolates. This outbreak demonstrates the potential of nature-like swimming ponds to cause widespread community infection with substantial public health impact.     

A community outbreak of Cryptosporidium infection associated with a swimming pool complex

A case-control study was conducted to investigate the cause of a sudden increase in cases of cryptosporidiosis notified to the Brisbane Southside Public Health Unit from January to March 1998. Fifty-two eligible cases were identified over a three-week period early in 1998. Thirty-one of these cases and 21 control subjects participated in the study. Swimming in the 2 weeks before onset of illness was identified as a likely risk factor for cryptosporidiosis infection (OR 3.1, CI 0.8-12.6, P = 0.06). Analysis of swimming pool attendance identified swimming at Pool Complex A as a significant risk factor for the acquisition of cryptosporidiosis (OR 8.9, CI 1.5-67.4, P = 0.004). No other potential risk factors were significantly associated with illness. The detection of cryptosporidium oocysts in three of the four pools at Pool Complex A supported the findings of the case-control study. As a response to this outbreak, Queensland Health has developed a Code of Practice outlining measures for the control and prevention of future outbreaks of swimming pool-associated cryptosporidiosis and/or giardiasis.     

Shigellosis from swimming in a park pond in Michigan

In July 1989 an outbreak of shigellosis occurred among visitors to a recreational park in Oakland County, MI. An epidemiologic investigation discovered an association between illness and swimming in a pond at the park, especially for those who had put their head underwater. No other factors were epidemiologically incriminated. A total of 65 cases were identified; nine were culture confirmed, all Shigella sonnei. Several water samples evaluated for fecal coliform counts shortly after the outbreak were found satisfactory. Cultures of water samples were negative for Shigella species. Inspection of the park's sewage disposal and toilet facilities found all equipment in proper working condition and no evidence of a sewage contamination event from these potential sources. No other commercial or residential sources of potential sewage contamination existed near the pond. Investigators concluded that Shigella contamination of the pond by a swimmer or swimmers on one or more occasions was a strong possibility. Factors supporting this conclusion included elevated incidence of S. sonnei in the community during the 2 months prior to the outbreak, greater use of the pond, warm water and air temperatures, and inadequate water exchange in the pond. This report adds one of the few documented outbreaks of shigellosis implicating bather contamination to the literature on the growing number of incidents that have been associated with recreational use of water.     

Follicular dermatitis outbreak caused by Pseudomonas aeruginosa associated with a motel's indoor swimming pool

Fourteen cases of pustular dermatitis occurred in members of a snowmobile club who swam in a motel pool in West Yellowstone, Mont., in February 1978. Survey questionnaires identified seven additional cases in guests at the motel the same weekend. All those with rashes had used the swimming pool and dry sauna on February 17 or 18. Among 56 survey respondents, swimming pool and sauna use were significantly associated with illness (P = .0002 by Fisher's exact test). Pseudomonas aeruginosa serotype 0:11 was isolated from a pustule on the skin of one club member and from four samples of the indoor-outdoor carpet that surrounds the pool. A specific precipitating event for the outbreak was not identified, but disinfection practices at this facility (a single daily chlorination, no measurement of chlorine levels, toleration of grossly cloudy water, soggy poolside carpet) may have established conditions in which P. aeruginosa could grow intermittently and cause disease. These cases are the first documented outbreak of P. aeruginosa dermatitis in which a whirlpool bath has not been implicated.     

An outbreak of Shigellosis in an ultra-orthodox Jewish community

An outbreak of Shigellosis due to Shigella sonnei, S. flexnerii and S. boydii in an ultra-religious Jewish community in Southern Israel is described. The source of epidemic was traced to vegetables bought from a single source.The importance of epidemic and endemic modes of spread of Shigella is discussed.     

A statewide outbreak of cryptosporidiosis in New South Wales associated with swimming at public pools

From December 1997 to April 1998, 1060 laboratory-confirmed cryptosporidiosis cases were reported in New South Wales, Australia. In a case-control study, compared with 200 controls, the 100 cases were younger (mean age 42 versus 71 years; P < 0.0001), more likely to report swimming at a public pool (59% versus 38%; adjusted OR and 95% CI = 27; 1.4-5.1) and swimming in a dam, river or lake (OR = 48; 1.1-20.3) but less likely to report drinking bottled water (OR = 0.4; 0.2-0.9). In subgroup analyses, in rural areas illness was associated mainly with contact with another person with diarrhoea, and in urban areas illness was associated with swimming in a public pool. Cryptosporidium oocysts were more commonly detected in pools to which at least two notified cases had swum (P = 004). Outbreaks of cryptosporidiosis can be prolonged, involve multiple pools and be difficult to control.     

一起痢疾暴发菌株脉冲场凝胶电泳分型研究

目的：探讨一起痢疾暴发中所分离菌株间的内在联系及变异,探明暴发原因。方法：用限制性内切酶NotI对2007年江苏省一起痢疾暴发中的15株福氏4c型志贺菌和3株地方散发株进行PFGE分型,用非加权配对算术平均法（UPGMA）进行聚类分析,相似性系数采用Dice系数。结果：15株暴发株呈9种带型,2种优势带型占46．7％,带型问差异主要在336．5～310．1bp呈现1～3条不等条带,相似性系数92％～100％;食品加工人员菌株带型与主要带型CNJZXN11．01仅存在1条之差,相似性系数97％;3株散发株呈现3种带型,与暴发株相似性系数82％～87％。结论：暴发分离株之间遗传关系紧密,可认为该起暴发由同一克隆群菌株引起;食品加工点的病原携带者是该起暴发的可疑传染源。     

Promotion of healthy swimming after a statewide outbreak of cryptosporidiosis associated with recreational water venues--Utah, 2008-2009

During the summer of 2007, Utah experienced a statewide outbreak of gastrointestinal illness caused by Cryptosporidium, a parasite transmitted via the fecal-oral route. Approximately 5,700 outbreak-related cases were identified across the state. Of 1,506 interviewed patients with laboratory-confirmed cryptosporidiosis, 1,209 (80%) reported swimming in at least one of approximately 450 recreational water venues during their potential 14-day incubation period. Cryptosporidium is extremely chlorine-tolerant, and secondary or supplemental disinfection with ultraviolet light or ozone can control but not prevent outbreaks. Because swimmers are the primary source of Cryptosporidium contamination, healthy swimming campaigns are needed to increase awareness and practice of healthy swimming behaviors, especially not swimming while ill with diarrhea (i.e., swimming while ill with diarrhea can lead to gross contamination of recreational water). Before the 2008 summer swimming season, Utah public health agencies launched a multimedia healthy swimming campaign. To assess knowledge of healthy swimming, a survey of Utah residents was conducted during July-September 2008. The results of that survey found that 96.1% of respondents correctly indicated that "it is not OK to swim if you have diarrhea." In a separate national survey in 2009, 100% of Utah residents but only 78.4% of residents of other states correctly indicated that "not swimming while ill with diarrhea protects others from recreational water illnesses (RWIs)." No recreational water-associated outbreaks were detected in Utah during 2008-2011. The healthy swimming campaign, as part of a multipronged prevention effort, might have helped prevent recreational water-associated outbreaks of cryptosporidiosis in Utah.     

An outbreak of E. coli O157 associated with a swimming pool: an unusual vehicle of transmission

Escherichia coli O157 causes a range of illnesses from mild diarrhoea to haemolytic uraemic syndrome (HUS) which carries a mortality rate of 3.7%. Infection is more common in the under-5s. Between 1995 and 2000, 106 outbreaks of E. coli O157 were reported in England and Wales. Recreational water is well documented as a transmission route for infectious diseases worldwide. In the United Kingdom there have been very few reported outbreaks associated with swimming pools due to the relative susceptibility of E. coli O157 to adequate levels of free chlorine. This report describes the investigation of an outbreak associated with a local leisure centre pool and makes recommendations about the safe management of such facilities.     

Tinea pedis outbreak in swimming pools in Japan

This study was conducted to show a higher prevalence of interdigital tinea pedis in athletes by comparing athletes and non-athletes, and to examine swimming pools as a route of infection. The subjects were 282 athletes, 137 non-athletes, and 140 students enrolled in a swimming class at the University of Tsukuba. This study included the taking of cotton-swab samples from the interdigital skin surfaces of both feet and cultures, microscopical examinations of scales collected from subjects with lesions, and questionnaires. There was a significant difference between athletes and non-athletes in the prevalence of the relevant pathogens, and a higher risk of infection was shown in athletes. The study also found that 63.6% of the swimming class students were carriers, and that 85.0% of their dermatophytes were Trichophyton mentagrophytes. In addition, dermatophytes were also isolated from the floors of the swimming pool and the public baths. The results of these controlled studies suggested that there was a significant risk of dermatophytosis in both athletes and non-athletes using the swimming pool.     

Cryptosporidiosis outbreak in a recreational swimming pool in Minnesota

On May 6, 1998, the Olmsted County Public Health Department initiated an investigation into an outbreak of diarrheal illness that had occurred among people who swam frequently at a local swimming pool. Interviews of swimmers and microbiological testing of stool samples and swimming pool filter material were conducted to determine the source of the outbreak. Twenty-six of 206 swimmers interviewed had illnesses that met the case definition. The most common symptoms were diarrhea (100 percent), abdominal cramps (81 percent), and nausea (77 percent). The median duration of symptoms was nine days. Four cases of cryptosporidiosis were confirmed by stool analysis. The outbreak was found to be associated with swimming at the pool. Public awareness-including an understanding that recreational water facilities should be avoided during diarrheal illness-and proper pool hygiene are vital in preventing cryptosporidiosis outbreaks. Health care providers also must consider testing specifically for cryptosporidiosis when a patient presents with persistent diarrhea.     

Shigellosis outbreak linked to canteen-food consumption in a public institution: a matched case-control study

On 13 November 2009, the authorities of Flemish Brabant, Belgium, received an alert concerning a potential outbreak of Shigella sonnei at a public institution. A study was conducted to assess the extent, discover the source and to implement further measures. We performed a matched case-control study to test an association between shigellosis and canteen-food consumption. Water samples and food handlers' faecal samples were tested. The reference laboratory characterized the retrospectively collected Shigella specimens. We found 52 cases distributed over space (25/35 departments) and time (2 months). We found a matched odds ratio of 3·84 (95% confidence interval 1·02-14·44) for canteen-food consumption. A food handler had travelled to Morocco shortly before detection of the first laboratory-confirmed case. Water samples and food handlers' faecal samples tested negative for Shigella. Confirmed cases presented PFGE profiles, highly similar to archived isolates from Morocco. Foodborne transmission associated with the canteen was strongly suspected.     

Acinetobacter calcoaceticus outbreak associated with peritoneal dialysis

Investigation of an outbreak of contamination of dialysis drainage fluid with Acinetobacter calcoaceticus var. anitratus identified a previously unrecognized source for dialysis associated infections. Over a 4-month period, 25 peritoneal dialysis treatments were administered to 13 hospital patients. Of the 25 treatments for which culture results were available, 14 were associated with dialysis drainage fluid cultures positive for A. calcoaceticus. A water bath used to warm bottles of peritoneal dialysate before use was the reservoir for the bacteria, and investigation showed in vitro that bath water could contaminate the dialysate. It appears likely that the dialysate became contaminated when the prong of the fluid administration set was inserted through the rubber bung on the dialysate bottles. This outbreak illustrates the potential importance of environmental reservoirs in infections complicating peritoneal dialysis.     

Salmonella Typhimurium outbreak associated with veterinary clinic

A Salmonella enterica serovar Typhimurium outbreak was associated with a veterinary clinic. Confirmed cases were in one cat, two veterinary technicians, four persons associated with clinic patients, and a nurse not linked to the clinic. This outbreak emphasizes the importance of strong public health ties to the animal health community.     

上海市细菌性痢疾疾病经济负担与无形负担研究

目的:研究上海市细菌性痢疾(菌痢)的疾病经济负担和无形负担,为科学制定菌痢的防治策略提供依据。方法:2009年4月至2010年4月,采用问卷调查上海市534名菌痢病例的直接费用和家庭支出费用,使用人力资本法测算间接费用;计算上海市菌痢病例的社会费用和个人费用,采用自评法评价无形负担。结果:上海市菌痢临床诊断病例和实验室确诊病例的人均直接费用分别为957.35元和1 095.79元,人均间接费用分别为215.97元和347.35元,人均家庭支出费用分别为555.84元和663.16元。人均社会费用分别为1 173.32元和1 443.13元,人均个人费用分别为771.81元和1 010.51元。上海市每年因菌痢产生的潜在总社会费用和潜在总个人费用分别为1 698 368.8元和1 142 602.2元。菌痢实验室确诊病例在行动、自我照顾、日常活动、焦虑或抑郁等四个方面无任何影响的比例略高于临床诊断病例,无统计学差异;菌痢临床诊断病例无任何疼痛或不舒服的比例高于实验室确诊病例,有统计学差异。结论:上海市菌痢疾病经济负担不容忽视,但无形负担较轻,应进一步完善医保制度,加强养成良好个人卫生习惯的健康教育。