诺如病毒胃肠炎暴发后环境中病毒检测情况分析

目的 了解诺如病毒胃肠炎暴发后,病例临床症状消失、末例病例发病日期经过最长潜伏期(72 h)且无续发病例的情况下,病例家庭环境及外环境水标本中病毒存在情况.方法 在末例病例发病日期经过最长潜伏期(72h)后,采集病例肛拭标本、家庭环境标本、外环境水标本,采用RT-PCR方法 检测病毒,阳性标本测序分析.结果 9份病例肛拭标本中3份呈阳性;46份家庭环境拭子中2份呈阳性,分别是来自两户已无现症病例的家庭厕所马桶表面;5份外环境水标本中1份呈阳性,即村民粪便直接排入的河涌.病例肛拭、家庭环境拭子及河涌水三者检出的病毒株核苷酸序列一致,提示病毒同源.结论 诺如病毒胃肠炎暴发后期,病例肛拭、病例家庭环境及外环境水标本中仍能检出病毒,因此有必要加强病例的粪便管理及疫情后期的环境消毒,以防粪便污染引起二代病例.     

Waterborne outbreak of Norwalk-like virus gastroenteritis at a tourist resort,Italy

In July 2000, an outbreak of gastroenteritis occurred at a tourist resort in the Gulf of Taranto in southern Italy. Illness in 344 people, 69 of whom were staff members, met the case definition. Norwalk-like virus (NLV) was found in 22 of 28 stool specimens tested. The source of illness was likely contaminated drinking water, as environmental inspection identified a breakdown in the resort water system and tap water samples were contaminated with fecal bacteria. Attack rates were increased (51.4%) in staff members involved in water sports. Relative risks were significant only for exposure to beach showers and consuming drinks with ice. Although Italy has no surveillance system for nonbacterial gastroenteritis, no outbreak caused by NLV has been described previously in the country.     

An outbreak of Salmonella Typhimurium 9 at a school camp linked to contamination of rainwater tanks

In March 2007, an outbreak of gastroenteritis was identified at a school camp in rural Victoria, Australia, affecting about half of a group of 55 students. A comprehensive investigation was initiated to identify the source. Twenty-seven attendees were found to have abdominal pain, diarrhoea and nausea (attack rate 49%). Of 11 faecal specimens tested all were positive for Salmonella Typhimurium definitive phage type 9 (DT9). Of four samples taken from the untreated private water supply, two were positive for DT9. Drinking water from containers filled from rainwater tanks [relative risk (RR) 3.2, P=0.039] and participation in two recreational activities - flying fox (RR 5.3, P=0.011), and beam-balance (RR 3.9, P=0.050) - were indicative of a link with illness. Environmental and epidemiological investigations suggested rainwater collection tanks contaminated with DT9 as being the cause of the outbreak. Increased use of rainwater tanks may heighten the risk of waterborne disease outbreaks unless appropriate preventative measures are undertaken.     

Snow Mountain agent gastroenteritis from clams

A 1983 investigation of two clambake-related gastroenteritis outbreaks in Rochester, New York, showed that 84 (43%) of 196 persons interviewed had an acute illness characterized by watery diarrhea, vomiting, and abdominal cramps. None of the ill persons were hospitalized or had complications. Illness was associated with eating raw (p = 0.002) or baked (p less than 0.01) hard-shell clams, with the risk of illness increasing with the total number of clams consumed (p less than 0.01). The median incubation period and duration of illness were 36 and 44 hours, respectively. Stool samples obtained 2-4 days after onset of illness were negative for commonly recognized bacterial and viral pathogens. However, of 31 persons whose stools were tested, the stool of only one ill person was positive by enzyme-linked immunosorbent assay for the Snow Mountain agent, one of the Norwalk-like viruses. Paired serum specimens from six (67%) of nine ill and two (29%) of seven well persons showed a fourfold or greater rise in antibody titer to Snow Mountain agent. Persons who ate clams were more likely to seroconvert to Snow Mountain agent (eight of 12) than were those who did not eat clams (zero of four) (p = 0.04). The clams were harvested off the coast of southern Massachusetts in late October, when harvest waters were documented to be contaminated by untreated municipal sewage. This report describes the first documented outbreak of shellfish-associated gastroenteritis attributed to Snow Mountain agent of which we are aware.     

Outbreak of Norwalk virus in a Caribbean island resort: application of molecular diagnostics to ascertain the vehicle of infection

In 1998, an outbreak of gastroenteritis affected at least 448 persons including 122 staff at a resort hotel in Bermuda. A survey among staff indicated that gastroenteritis was associated with eating or drinking at the hotel (OR = 60, 95% CI = 2.4-15.1). Multiple specimens of drinking water had elevated faecal coliform levels and Escherichia coli present, suggestive of faecal contamination. Stools from 18 of the 19 persons with gastroenteritis that were tested were positive for genogroup-II Norwalk-like viruses (NLVs). RT-PCR analysis of a 31 specimen of water produced a genogroup-II NLV genome with a sequence identical to that of NLVs in the stools of three ill persons. This outbreak shows the value of new molecular diagnostics to link illness with a contaminated source through the use of sequence analysis. The risk of outbreaks such as these could be reduced in tourism dependent regions like Bermuda and the Caribbean by regular evaluation of data from the inspection and monitoring of drinking water supplies and waste water systems, by ensuring the chlorination of supplemental drinking water supplies and by establishing food-safety initiatives.     

Wading pool water contaminated with both noroviruses and astroviruses as the source of a gastroenteritis outbreak

In July 2001, an outbreak of gastroenteritis occurred in Helsinki among children and adults after bathing in an outdoor wading pool. The epidemiological survey revealed that at least 242 persons were affected. Microbiological testing of both patient stool samples and of the pool water revealed the presence of two different gastroenteritis viruses: a norovirus (NV) and an astrovirus. Amplicon sequencing of the NV samples showed nucleotide sequence identity between the virus from patients and the water. After changing the pool water and the sand at the bottom of the pool followed by shock chlorination, no virus could be detected in the water. However, NV was continuously detected in the water outlet well as much as 8 months after the incident. Here we show how molecular methods aided in tracing the source of the epidemic and in finding the causative pathogens both in patients and in the environment.     

Outbreak of acute gastroenteritis due to a washwater-contaminated water supply, Switzerland, 2008

An operating error in a sewage treatment plant led to severe drinking water contamination in a well-defined district of a suburban municipality of Zurich, Switzerland. Despite the alert issued to the local population on the same day advising people not to consume the contaminated water, cases of acute gastroenteric diseases were subsequently observed. Considerable faecal contamination was detected the day after the incident in water samples taken up to 500 m from the sewage plant. In a retrospective epidemiological study involving 240 persons living in the affected area, 126 cases of acute gastrointestinal illness were documented. The epidemic curve revealed a peak incidence two days after the event. Stool samples from 11 of 20 patients were positive for noroviruses or Campylobacter jejuni. Although these microorganisms were not detected in the contaminated water, the subsequently conducted case–control study among the surveyed population showed that consumption of contaminated drinking water was associated with gastrointestinal illness (odds ratio 29.1; 95% confidence interval: 9.8–86.4; p = 0.001). The study also revealed the very probable time period of infection. We present the dimension and chronology of this outbreak and discuss the reasons for its localised and temporary spread.     

An outbreak of gastroenteritis on a passenger cruise ship.

In an outbreak of gastroenteritis on board a cruise ship 251 passengers and 51 crew were affected and consulted the ship''s surgeon during a 14-day period. There was a significant association between consumption of cabin tap water and reported illness in passengers. Enterotoxigenic Escherichia coli were isolated from passengers and crew and coliforms were found in the main water storage tank. Contamination of inadequately chlorinated water by sewage was the most likely source of infection. A low level of reported illness and late recognition of the outbreak delayed investigation of what was probably the latest in a series of outbreaks of gastrointestinal illness on board this ship. There is a need for a national surveillance programme which would monitor the extent of illness on board passenger cruise ships as well as a standard approach to the action taken when levels of reported illness rise above a defined level.     

An outbreak of gastroenteritis on a passenger cruise ship

In an outbreak of gastroenteritis on board a cruise ship 251 passengers and 51 crew were affected and consulted the ship's surgeon during a 14-day period. There was a significant association between consumption of cabin tap water and reported illness in passengers. Enterotoxigenic Escherichia coli were isolated from passengers and crew and coliforms were found in the main water storage tank. Contamination of inadequately chlorinated water by sewage was the most likely source of infection. A low level of reported illness and late recognition of the outbreak delayed investigation of what was probably the latest in a series of outbreaks of gastrointestinal illness on board this ship. There is a need for a national surveillance programme which would monitor the extent of illness on board passenger cruise ships as well as a standard approach to the action taken when levels of reported illness rise above a defined level.     

A salmonellosis outbreak linked to internally contaminated pork meat

In August 1995, we investigated an outbreak of salmonellosis among patrons who attended a church camp in southern Sydney. Of the 73 attendees interviewed, 22 reported a gastroenteritis illness within two days of the conclusion of the camp, with one attendee hospitalised. Two stool specimens, one from each of two attendees, were both positive for Salmonella typhimurium phage type 9. A cohort study of 68 attendees established a statistically significant association between illness and the consumption of de-boned roast pork (estimated relative risk infinite, p=0.03) and between illness and the degree of cooking of the pork meat (x² for trend 5.8, p<0.02). The outbreak was most likely caused by consumption of roast pork that had been internally contaminated during the de-boning process. Meat and meat products that may be internally contaminated, such as de-boned meats, should be thoroughly cooked. Guidelines about minimum cooking temperatures of meats liable to internal contamination should be developed for commercial food handlers in Australia.     

Multi-pathogen waterborne disease outbreak associated with a dinner cruise on Lake Michigan

We report an outbreak associated with a dinner cruise on Lake Michigan. This took place on the same day as heavy rainfall, which resulted in 42·4 billion liters of rainwater and storm runoff containing highly diluted sewage being released into the lake. Of 72 cruise participants, 41 (57%) reported gastroenteritis. Stool specimens were positive for Shigella sonnei (n=3), Giardia (n=3), and Cryptosporidium (n=2). Ice consumption was associated with illness (risk ratio 2·2, P=0·011). S. sonnei was isolated from a swab obtained from the one of the boat's ice bins. Environmental inspection revealed conditions and equipment that could have contributed to lake water contaminating the hose used to load potable water onto the boat. Knowledge of water holding and distribution systems on boats, and of potential risks associated with flooding and the release of diluted sewage into large bodies of water, is crucial for public health guidance regarding recreational cruises.     

南宁市某公司因蓄水池被诺如病毒污染引起急性胃肠炎暴发调查

目的 对H公司1起诺如病毒感染引起的急性胃肠炎暴发开展调查,分析感染原因和传播途径。方法 根据病例定义开展病例搜索,对供水系统进行卫生学调查,对危险因素进行病例对照研究,采集病例肛拭子、自来水、桶装水进行诺如病毒核酸检测。结果 疫情历时4d,共搜索到病例184例,罹患率10.09%（184/1823）;临床症状主要为腹泻（100%）、腹痛（65.76%）、恶心（50.07%）、呕吐（50.35%）、发热（40.21%）;市政供水进入蓄水池A、B前余氯为0.17mg/L,浊度正常;蓄水池A供应的综合楼6楼和18楼末梢水浊度分别为11.7NTU和11.5NTU,有臭味,余氯均为0mg/L;4份现症病例肛拭子和5份蓄水池A样品均检出GⅡ型诺如病毒,而桶装水和蓄水池B均未检出。食用蓄水池A水洗过的水果和用蓄水池A水洗杯子后装桶装水喝是急性胃肠炎发病的危险因素（OR=6.295,95%CI:4.018~9.862;OR=2.665,95%CI:1.424~4.987）。结论 本次急性胃肠炎暴发是由于污水管道堵塞导致生活饮用水受诺如病毒污染引起的,应加强饮用水卫生管理。     

A school waterborne outbreak involving both Shigella sonnei and Entamoeba histolytica

In an outbreak of gastroenteritis affecting 730 students, Shigella sonnei and Entamoeba histolytica were isolated from the stool specimens of patients. Environmental investigations revealed the source of infection to be contamination of underground well water by sewage from a toilet. The outbreak ended with the closure of the well water supply. To avoid such problems, institutions and other groups that maintain their own wells, including schools and summer camps, need to be vigilant about maintenance and check for potential contamination.     

1起疑似食源性诺如病毒感染暴发疫情的流行病学调查

摘要:目的 调查1起小学内出现多名急性胃肠炎病例的感染事件,提出预防控制措施。方法 按照病例定义开展病例搜索,采用描述性流行病学方法和病例对照研究方法进行分析;样本采用RT-PCR方法进行肠道病毒核酸检测。结果 武进区某小学2015年3月2日-11日,出现149例以呕吐症状为主的学生,罹患率为9.0%,3月2日出现发病高峰,病例发病急、班级分布广。现场采集患者肛拭子或呕吐物、对照及食堂工作人员肛拭子、食物和环境样本等共42份,其中2名患者肛拭子、2名患者呕吐物及1名食堂工作人员肛拭子检测出诺如病毒GII型。结论 这是1起由诺如病毒GII型引起的急性胃肠炎暴发疫情,暴发原因可能是由带毒食堂工作人员污染部分食物所致,以食源性传播为主。     

1起诺如病毒引起的急性胃肠炎暴发调查及实验室检测分析

目的调查了解1起诺如病毒引起的急性胃肠炎暴发疫情的流行病学特点、传播途径及病原体,为制定预防控制对策提供依据。方法设立病例定义,在深圳市发生疫情的村子进行病例搜索,使用感染性腹泻个案调查表对所有搜索到的病例进行回顾性调查,并分别调查58例病例及74例对照的生活习惯;采用逆转录-聚合酶链反应（RT—PCR）和实时荧光PCR方法分别对病人粪便、肛拭子标本及村民饮用的水样进行诺如病毒核糖核酸（RNA）检测,分析其流行特征及可能传播途径。结果该起疫情首例病例发病时间为2009年10月23日,疫情历时11d,共搜索到97例病例,全村罹患率为9．41％（97／1031）,以2岁以下的儿童为多,占53．1％。病例临床症状以腹泻、腹痛、腹胀、恶心、呕吐为主。病例组饮用生的山泉水及就餐前用生的山泉水冲洗碗筷的比例均高于对照组（P〈0．05或P〈0．01）;13份病例粪便和肛拭子标本中,检测出12例诺如病毒阳性,阳性率为92．3％;检测7份水样（包括1份水源水、1份水池水、3份病例家中水龙头水和2份洗碗水）,其中2份水龙头水和1份洗碗水检出诺如病毒,其余均为阴性。结论此起群体性胃肠炎暴发疫情是由诺如病毒感染引起;传播途径可能主要因水源污染和生活接触传播所致。     

A prolonged outbreak of Norwalk-like calicivirus (NLV) gastroenteritis in a rehabilitation centre due to environmental contamination

An outbreak of Norwalk-like calicivirus (NLV) gastroenteritis occurred in a rehabilitation centre in southern Finland between December 1999 and February 2000. An epidemiological investigation was conducted to determine the source and extent of the outbreak. More than 300 guests and staff members became ill during the outbreak. No food or activity in the centre could be linked epidemiologically to illness. NLV genogroup II was detected by RT-PCR in stool samples of symptomatic guests and employees. All strains reacted similarly with the microplate hybridization probe panel and showed the same nucleotide sequence, indicating that they represented the same NLV strain. Food and water samples were negative for NLV, whereas NLV was detected in three environmental specimens. The strains from patients and environment were identical based on microplate hybridization probes, suggesting that environmental contamination may have been important for the spread of calicivirus and the protracted course of the outbreak.     

Infectious gastroenteritis in Norfolk Island and recovery of viruses from drinking water

A high incidence of gastroenteritis in both islanders and tourists has been recorded in recent years on Norfolk Island--a popular tourist resort for Australians and New Zealanders. No bacterial cause has been found. However, electron microscopic examination of 28 faecal specimens revealed viruses associated with gastroenteritis in 21 (75%). No viruses were isolated in cell cultures. Bore water is used for drinking purposes on the island and 32 samples from 15 bores were examined for viruses by electron microscopy and culture as well as for bacterial contamination. Seven polioviruses (all type 1 vaccine strain) and adenoviruses 1 and 5 were isolated in cell cultures. In addition one rotavirus, one adenovirus and two small round viruses were detected by electron microscopy. Six of 21 samples tested showed unacceptably high levels of bacteria for drinking water. The deep ground water has apparently become contaminated with sewage effluent and is almost certainly the main cause of the high level of gastroenteritis on the island.     

Infectious gastroenteritis in Norfolk Island and recovery of viruses from drinking water.

A high incidence of gastroenteritis in both islanders and tourists has been recorded in recent years on Norfolk Island--a popular tourist resort for Australians and New Zealanders. No bacterial cause has been found. However, electron microscopic examination of 28 faecal specimens revealed viruses associated with gastroenteritis in 21 (75%). No viruses were isolated in cell cultures. Bore water is used for drinking purposes on the island and 32 samples from 15 bores were examined for viruses by electron microscopy and culture as well as for bacterial contamination. Seven polioviruses (all type 1 vaccine strain) and adenoviruses 1 and 5 were isolated in cell cultures. In addition one rotavirus, one adenovirus and two small round viruses were detected by electron microscopy. Six of 21 samples tested showed unacceptably high levels of bacteria for drinking water. The deep ground water has apparently become contaminated with sewage effluent and is almost certainly the main cause of the high level of gastroenteritis on the island.