萍乡市一起咽结膜热暴发疫情调查报告

目的分析萍乡市一起咽结膜热暴发的流行特征和病因,为今后此类传染病防控提供参考。方法制定病例定义进行病例搜索,对所有病例进行个案调查,对游泳馆进行现场卫生学调查,对患者咽拭子标本和游泳池水进行实验室检测。结果本起疫情累计病例84例,发病高峰在8月1～5日;年龄以5～13岁最多,占总病例数的77.38%。患者发病前均有游泳史,临床表现主要为发热伴咽痛、扁桃体红肿、眼结膜充血等。8份现症病人咽拭子标本经Real-time PCR方法检测,确定为腺病毒感染。结论本起咽结膜热暴发疫情的病原体为腺病毒,暴发可能是通过被污染的游泳池水造成传播。     

浙江省奉化市一起腺病毒感染暴发疫情调查

目的 对奉化市一起腺病毒暴发疫情进行流行病学调查和实验室检测,为及时采取有效控制措施提供依据.方法 对2016年奉化市某游泳池腺病毒暴发疫情进行现场调查,描述分析病例发病过程及流行病学特征.采集病例样本进行实时荧光定量PCR检测,并对阳性样本进行病毒分离.以腺病毒六邻体基因(Hexon gene)为目的基因,对分离株进行扩增测序.将测序结果提交GenBank进行BLAST比对,MEGA 5.2软件对腺病毒的六邻体基因序列构建进化树,确定其型别.结果 该起疫情历时15d,共出现18例住院患儿,临床症状以发热、扁桃体化脓和眼红为主,在发病前1～5天内有某游泳馆暴露史j 10份患儿咽拭子样本的PCR检测结果显示,均为呼吸道腺病毒(RADV)阳性,CT值在17～26之间.测序比对结果表明分离到的6株腺病毒序列相同,基因亲缘关系树显示该批分离株均为腺病毒B亚群,与人腺病毒3型参考株同处一支,同源性为99.1％～99.8％.结论 此次游泳池暴露的疫情系人腺病毒3型引起.     

Adenovirus Type 3 Epidemic Associated with Intermittent Chlorination of a Swimming Pool

A sharp outbreak of pharyngoconjunctival fever due to adenovirus type 3 occurred in two swimming teams shortly alter exposure to unchlorinated water. Children swimming in the chlorinated water suffered no similar illness. The attack rate was 65% and 67% for each team, Attempts to isolate the virus from the water after the outbreak failed. In ten of 19 affected families, transmission to other family members was demonstrated; the secondary attack rate for children was 63%, for adults 19%. The majority of infected children suffered fever, pharyngitis, and conjunctivitis; symptoms in adults were milder, with conjunctivitis predominating. Diarrhea was more common among children infected at home. The median incubation period for swimmers was estimated at seven days; the median case-to-case interval in the families was 11 days.     

驻陕某部呼吸道腺病毒7型暴发166例疫情分析

目的分析某部一起军营急性呼吸道腺病毒7型感染暴发的临床特征和病原学诊断,为此类疫情的防控提供依据。方法参训官兵共663人,采用统一的流行病学个案调查表,对166例患者进行现场调查,描述疾病特征;对其中32例急性期患者咽拭子标本进行病原学检测,82例患病进行病毒血清抗体检测。结果 166例患者分布在整个营区,有明显的宿舍聚集现象,发病率为25.0%。166例患者全部有发热症状,其中伴咳嗽占15.7%、咽痛占38.0%、头痛占20.5%、肺炎占1.8%、结膜炎占1.2%。咽拭子标本经PCR检测腺病毒基因阳性占53.1%;经HepG2、Hela细胞培养,50.0%出现细胞病变;30例患者经IgM抗体筛查明确为腺病毒感染(36.6%);中和试验证实20例(24.4%)腺病毒抗体恢复期比急性期有4倍以上升高。隔离患者、全面消毒后10 d,无新发病例。结论此次暴发疫情由腺病毒7型引起,经过及时而合理的预防措施能快速控制疾病的流行。     

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.     

Health effects of attending a public swimming pool: follow up of a cohort of pupils in Paris.

OBJECTIVES--This study aimed to determine the health effects of attending a well-kept school swimming pool maintained according to French public health regulations. METHODS--This prospective month long study was carried out on a randomised sample of pupils aged 5 to 18 years who attended a private French school with two swimming pools. The children surveyed, helped by their parents, had to fill in questionnaires about their bathing habits and symptoms during the survey period. Inspections of the pool complex were made and these included physicochemical and bacteriological analyses of the pools' water. PARTICIPATION--The response rates achieved were 70% at primary and middle school levels but only 25% in the high school pupils. Because of this older teenagers were excluded from the final analysis (of 246 children). RESULTS--Compared with non-bathers, bathers experienced fatigue and eye irritation significantly more often (p < 0.001). The eyes were red (38% of bathers) and/or watery (16%) after swimming but this resolved spontaneously within 24 hours. Bathing behaviour (bath duration, head immersion, wearing swimming goggles) did not affect these incidence rates noticeably. There were no differences between bathers and non-bathers with regard to other symptoms, especially otolaryngological ones. This survey does not allow definite conclusions to be made about verrucas because 22% of non-bathers were exempted from swimming because of verrucas that they might have caught previously in a pool. CONCLUSIONS--Except for verrucas, the methodology was adequate and daily self reporting of symptoms was feasible. This college largely recruits pupils from higher social classes and is not therefore representative of schools in Paris.     

Swimming-associated cryptosporidiosis.

In July and August 1988, an outbreak of gastroenteritis affected 44 of 60 (73%) persons from 5 separate swimming groups who had used the same swimming pool in Los Angeles. Cryptosporidium was identified in 5 of 8 (63%) stool specimens, and the clinical picture was consistent with Cryptosporidium infection. Resistance of Cryptosporidium to chlorine, an inadequately maintained pool filtration system, repeated exposure to pool water, and possible continuing pool contamination may have contributed to ongoing transmission. Cryptosporidium should be considered a potential etiologic agent of gastroenteritis associated with recreational water use.     

Microbiological and chemical analyses of indoor swimming pools and virucidal effect of chlorine in these waters

Virological and bacteriological examinations and chemical analysis were made of 24 water samples from 6 public indoor swimming pools in Aichi Prefecture. In 3 of these swimming pools, sodium hypochlorite was used as a disinfectant and in the remainder trichloroisocyanurates. All samples were negative for adenovirus per 20 liters. Coliform group was detected in one sample with 26.7 mg/l cyanuric acid. Total plate counts ranged from 0 to 1 per ml in the swimming pools treated with sodium hypochlorite and 0 to 51 in those with trichloroisocyanurates. Turbidity, pH and potassium permanganate concentrations in the samples were within allowable limits. Seven of 24 samples did not meet the recommended value of 0.4 mg/l for free chlorine residuals. Ammonium nitrogen was detected in one pool water with trichloroisocyanurates. In 11 of 12 water samples of swimming pools using sodium hypochlorite, poliovirus 1 (2 x 10(4) PFU/0.2 ml) was inactivated within 1 min under the condition of 1.0 mg/l free available chlorine and 25 degrees C. In 11 of 12 water samples of 3 swimming pools using trichloroisocyanurates, poliovirus type 1 survived after 2 min contact while in 5 samples poliovirus type 1 survived after 5 min contact. This shows that the risk of viral infection is greater in swimming pool water treated with chlorinated isocyanurics than that with sodium hypochlorite. The operator of the swimming pool should pay special attention to the control of water quality and free residual chlorine value.     

A foodborne outbreak of Campylobacter jejuni (O:33) infection associated with tuna salad: a rare strain in an unusual vehicle.

We report a foodborne outbreak of Campylobacter jejuni infection in a summer camp. Outbreak-related cases occurred in 79 persons including 3 secondary cases in campers. Campylobacter jejuni was isolated from stool specimens from 16 of 21 patients who submitted a sample; 13 viable isolates were serotyped and all were serotype O:33 (somatic O scheme) or HL:18 (heat-labile scheme), and biotype III (Lior scheme). This serotype is widely distributed geographically but rarely isolated from humans. Samples of water from the wells supplying the camp were negative for faecal coliforms, and raw milk had not been served in the camp. A matched (1:1) case-control study identified tuna salad served for lunch on 19 July as the likely food item associated with illness (matched odds ratio=22; 95% confidence intervals (CI)=3.6-908). Swimming in the camp pool and other recreational water use in area lakes by the campers were not statistically associated with illness. The precise mechanism of introduction of the organism into the tuna salad remains unknown; contamination most likely occurred through cross-contamination with another food product, the hands of a food handler, or a work surface. Several deficiencies in the operation of the camp kitchen were identified. In Wisconsin, kitchens of such camps are subject to different inspection rules than restaurants. Camp staff, administrators, counselors, food managers, and infirmary staff, should fulfil important roles in their respective areas to prevent future outbreaks.     

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.     

Ocular and respiratory illness associated with an indoor swimming pool--Nebraska, 2006

On December 26, 2006, the Nebraska Department of Health and Human Services (NDHHS) received a report of a child hospitalized in an intensive care unit for severe chemical epiglottitis and laryngotracheobronchitis after swimming in an indoor motel swimming pool. The pool was inspected the same day and immediately closed by NDHHS because of multiple state health code violations. NDHHS initiated an outbreak investigation to identify additional cases and the cause of the illness. This report describes the results of that investigation, which indicated that 24 persons became ill, and the outbreak likely was the result of exposure to toxic levels of chloramines that had accumulated in the air in the enclosed space above the swimming pool. This outbreak highlights the potential health risks from chemical exposure at improperly maintained pools and the need for properly trained pool operators to maintain water quality.     

An outbreak of cryptosporidiosis in an urban swimming pool: why are such outbreaks difficult to detect?

OBJECTIVE: To describe an outbreak of Cryptosporidium gastroenteritis in a swimming pool in Melbourne in early 1998 that was not detected through routine surveillance, and discuss difficulties in identifying such outbreaks. METHODS: The Water Quality Study (WQS) was a large community-based study of gastroenteritis. Following suspicion of an outbreak of cryptosporidiosis within the study group, due to pool "X", a nested case control study was performed. Each case of Cryptosporidium gastroenteritis was matched with six controls and data from weekly Health Diaries from the WQS were reviewed. The Department of Human Services also instigated active surveillance among patrons at pool "X" using a systematic sample of 50 people from the pool's swim-school enrollment list. RESULTS: There were seven cases of Cryptosporidium gastroenteritis in the case control study. Five cases and eight controls swam at pool "X" during the outbreak period. The adjusted odds of developing cryptosporidial diarrhoea if an individual swam at pool "X" was 34.5 (CI 2.3-2548). DHS identified another 11 laboratory confirmed cases associated with pool "X" as well as cases not linked to pool "X". 125 cases were identified throughout Melbourne with the suspected involvement of seven swimming pools. CONCLUSIONS: Despite a high odds ratio of developing cryptosporidiosis this outbreak was not detected by routine surveillance methods. Current outbreak detection methods lack sensitivity, specificity or timeliness. IMPLICATIONS: Improved surveillance systems are required if outbreaks of gastroenteritis are to be detected early so an intervention can be instigated to reduce the amount of subsequent illness.     

Investigation of an outbreak of adenovirus type 3 infection in a boys' boarding school.

An outbreak of pharyngoconjunctival fever caused by adenovirus type 3 was studied in a boarding school for 800 boys aged 11-18 years. A total of 96 clinical cases were confirmed by laboratory tests. Clinical infection rates were higher in the younger boys but total infection rate did not vary with age. Previous infection provided 88% protection against reinfection. The techniques of virus isolation, complement fixation and neutralization were compared in the diagnosis of cases. Virus isolation diagnosed 86% of confirmed cases. Where acute sera (collected at onset) and convalescent sera (collected within one month) were available complement fixation and neutralization tests each diagnosed 96% of cases.     

Investigation of an outbreak of adenovirus type 3 infection in a boys' boarding school

An outbreak of pharyngoconjunctival fever caused by adenovirus type 3 was studied in a boarding school for 800 boys aged 11-18 years. A total of 96 clinical cases were confirmed by laboratory tests. Clinical infection rates were higher in the younger boys but total infection rate did not vary with age. Previous infection provided 88% protection against reinfection. The techniques of virus isolation, complement fixation and neutralization were compared in the diagnosis of cases. Virus isolation diagnosed 86% of confirmed cases. Where acute sera (collected at onset) and convalescent sera (collected within one month) were available complement fixation and neutralization tests each diagnosed 96% of cases.     

Outbreaks of short-incubation ocular and respiratory illness following exposure to indoor swimming pools

OBJECTIVES: Chlorination destroys pathogens in swimming pool water, but by-products of chlorination can cause human illness. We investigated outbreaks of ocular and respiratory symptoms associated with chlorinated indoor swimming pools at two hotels. MEASUREMENTS: We interviewed registered guests and companions who stayed at hotels X and Y within 2 days of outbreak onset. We performed bivariate and stratified analyses, calculated relative risks (RR), and conducted environmental investigations of indoor pool areas. RESULTS: Of 77 guests at hotel X, 47 (61%) completed questionnaires. Among persons exposed to the indoor pool area, 22 (71%) of 31 developed ocular symptoms [RR = 24; 95% confidence interval (CI), 1.5-370], and 14 (45%) developed respiratory symptoms (RR = 6.8; 95% CI, 1.0-47) with a median duration of 10 hr (0.25-24 hr). We interviewed 30 (39%) of 77 registered persons and 59 unregistered companions at hotel Y. Among persons exposed to the indoor pool area, 41 (59%) of 69 developed ocular symptoms (RR = 24; 95% CI, 1.5-370), and 28 (41%) developed respiratory symptoms (RR = 17; 95% CI, 1.1-260) with a median duration of 2.5 hr (2 min-14 days). Four persons sought medical care. During the outbreak, the hotel X's ventilation system malfunctioned. Appropriate water and air samples were not available for laboratory analysis. CONCLUSIONS AND RELEVANCE TO PROFESSIONAL PRACTICE: Indoor pool areas were associated with illness in these outbreaks. A large proportion of bathers were affected; symptoms were consistent with chloramine exposure and were sometimes severe. Improved staff training, pool maintenance, and pool area ventilation could prevent future outbreaks.     

Outbreak of cryptosporidiosis at a California waterpark: employee and patron roles and the long road towards prevention

In August-September 2004, a cryptosporidiosis outbreak affected >250 persons who visited a California waterpark. Employees and patrons of the waterpark were affected, and three employees and 16 patrons admitted to going into recreational water while ill with diarrhoea. The median illness onset date for waterpark employees was 8 days earlier than that for patrons. A case-control study determined that getting water in one's mouth on the waterpark's waterslides was associated with illness (adjusted odds ratio 7.4, 95% confidence interval 1.7-32.2). Laboratory studies identified Cryptosporidium oocysts in sand and backwash from the waterslides' filter, and environmental investigations uncovered inadequate water-quality record keeping and a design flaw in one of the filtration systems. Occurring more than a decade after the first reported outbreaks of cryptosporidiosis in swimming pools, this outbreak demonstrates that messages about healthy swimming practices have not been adopted by pool operators and the public.     

"Lifeguard lung": endemic granulomatous pneumonitis in an indoor swimming pool.

OBJECTIVES: Two sequential outbreaks of respiratory disease among lifeguards at an indoor swimming pool with water spray features were investigated. METHODS: Questionnaires were administered to recreation center employees following each outbreak. Respondents reporting 2 or more pool-related symptoms were offered clinical evaluation, including bronchoscopy with bronchoalveolar lavage and transbronchial biopsy. Pool air and water were sampled for fungi, bacteria, amoebae, endotoxin, and respirable particulates. RESULTS: Thirty-three lifeguards had noncaseating granulomas on biopsy and/or bronchoalveolar lavage lymphocytosis. Attack rates for the outbreaks were 27% and 65%. Case patients had higher cumulative hours of work and tended to work more hours per week. Analyses indicated increased levels of endotoxin in pool air and water (relative to control pools) and gram-negative bacterial colonization of water sprays. Use of water spray features generated a 5.2-fold increase in the number of respirable particles and up to an 8-fold increase in air endotoxin levels. CONCLUSIONS: Lifeguards in this indoor swimming pool developed granulomatous lung disease associated with endotoxin-containing respirable bioaerosols from water spray features, which ventilation system improvements did not prevent.     

2009—2011年清远市清城区泳池水水质的卫生状况

目的了解清远市清城区游泳池的水质卫生状况,预防感染性疾病暴发,为提高游泳池水质卫生质量提供科学依据。方法对清远市清城区游泳池水的pH值、浑浊度、尿素、游离性余氯、细菌总数和大肠菌群进行检验,并对2009—2011年游泳池水质检测结果进行分析。结果检测清远市清城区游泳池的水样676份,各项指标全部合格的273份,合格率为40.4%。合格率游泳淡季为42.5%,旺季为39.3%。检测指标合格率:pH值为100%,浑浊度为100%,尿素为45.6%,细菌总数为99.8%,大肠菌群为100%,游离性余氯为84.3%。结论游泳池水质的不合格项目主要是尿素和游离性余氯。有关部门须加强对游泳场所的监督管理,强化游泳池水消毒和定期换水。     

An outbreak of echovirus 13 meningitis in central Israel

Until recently, echovirus 13 has been a very rare cause of aseptic meningitis. We investigated an outbreak of echovirus 13 in central Israel during the summer of 2000 using a prospective case control study and a retrospective study. Echovirus 13 was isolated from 79 cerebrospinal fluid (CSF) specimens from different medical centres in central Israel. Patients' ages ranged from 10 days to 41 years (95% < 15 years, M/F ratio 62/38). A total of 128 patients with clinical aseptic meningitis were admitted to the Department of Pediatrics during the outbreak (aged 10 days to 18 years, mean 5.4 years), and 58 CSF samples were processed for viral cultures. Thirty of them did not grow any virus, 26 samples yielded echovirus 13, and 2 samples echovirus 7. The clinical features of patients with echovirus 13 in the CSF were similar to those in whom no virus was isolated or those infected with other enteroviral strains except for higher rate of fever on admission, and prolonged time with fever following the diagnosis in the echovirus 13 patients. CSF cell count varied from 4 to 2,333 cells/mm3 with polymorphonuclears (PMN) predominant in 90% of our patients. In a case-control study there was no significant difference between patients and matched controls with regard to parameters such as: day care attendance, recreation in summer camp, swimming pools and at the beach, and consumption of tap water. All the patients in our series recovered fully with no neurological abnormalities. The illness caused by echovirus 13 was benign and involved mainly patients younger than 15 year of age. Several features that characterized this outbreak include relatively high WBC in the blood and a minent CSF PMN response.     

广西某中学甲型副伤寒暴发的流行特征及原因

目的　调查甲型副伤寒暴发疫情的流行特征及原因。　方法　对发热病人进行个案调查、采样和疫点环境卫生学调查 ,运用描述性流行病学和卫生统计学方法对现场调查资料和实验室结果进行统计和分析。　结果　本起疫情共发生甲型副伤寒病例 3 2 2例 ,罹患率 9.2 1%。其中学生 3 2 1例 ,食堂从业人员 1例 ;内宿罹患率 (14 .3 8% )高于外宿(0 .2 9% ) (P <0 .0 1) ;男性罹患率 (12 .45 % )高于女性 (6.0 2 % ) (P <0 .0 1) ;流行时间为 3 6d ,流行过程有两个波峰 ;共分离出甲型副伤寒沙门氏菌 41株 ,其中发热病人血和粪便培养分别为 2 0株和 2株 ,无症状学生肛拭培养为 19株 ;2 3株菌株对 18种常用抗生素均敏感。流行原因为无安全饮用水、食堂卫生状况不良、学生有饮生水等不良卫生习惯等 ;传播途径流行前期极可能为水型传播所致 ,后期则为生活接触传播。　结论　加强学校水源及食堂卫生的管理和监督、改善学生卫生习惯是防止甲型副伤寒疫情暴发的关键措施 ;流行早期及时采取严格、有效的措施和保证资金投入是短期内疫情得到有效控制的保证。