A one-year intensified study of outbreaks of gastroenteritis in The Netherlands

In 2002, in The Netherlands a national study of gastroenteritis outbreaks was performed. Epidemiological information was collected by the Public Health Services (PHS) and the Food Inspection Services (FIS) using standardized questionnaires. Stool samples were collected for diagnostic testing. For foodborne outbreaks, food samples were taken. In total, 281 gastroenteritis outbreaks were included, mainly from nursing homes and homes for the elderly (57%), restaurants (11%), hospitals (9%) and day-care centres (7%). Direct person-to-person spread was the predominant transmission route in all settings (overall 78%), except for restaurant outbreaks where food was suspected in almost 90% (overall in 21% of outbreaks). The most common pathogen was norovirus (54%), followed by Salmonella spp. (4%), rotavirus group A (2%), Campylobacter spp. (1%) and only incidentally others. In conclusion, most outbreaks were reported from health and residential institutions, with norovirus as the dominant agent. Control should aim at reducing person-to-person spread. In foodborne outbreaks norovirus was common, due to contamination of food by food handlers. Salmonella, as the second foodborne pathogen, was mainly associated with raw shell eggs. These results stress the continuous need for food safety education, complementary to governmental regulation.     

Outbreaks of gastroenteritis due to infections with Norovirus in Switzerland, 2001-2003

Viral infections, especially those with noroviruses are the most common cause of acute gastroenteritis in Europe. To obtain information about the epidemic situation of noroviruses in Switzerland, an initial study was launched in the German-speaking part of the country to systematically compile Norovirus outbreak information between 2001 and 2003. In total, 73 outbreaks were registered. Most affected were closed settings, e.g. nursing homes (34%) and hospitals (25%). Transmission pathways were identified in 74% of Norovirus outbreaks. In 81% of these cases person-to-person transmission was the primary route of infection and on seven occasions (13%), a foodborne transmission was the possible cause. Furthermore, Norovirus outbreak characteristics of epidemiological importance are highlighted with a discussion of four selected events.     

Public health implications of a case of haemolytic-uraemic syndrome associated with a concomitant outbreak of mild gastroenteritis in a small rural community

The concomitant occurrence of a case of haemolytic-uraemic syndrome (HUS) and 62 cases of mild gastroenteritis in schools of a small rural community in southern Italy induced the health authorities to suspect a foodborne outbreak of shiga-toxin-producing Escherichia coli (STEC) infection. The schools were closed and the catering service involved was investigated. However, STEC were not isolated from the HUS case or from the 56 cases of gastroenteritis examined, and the HUS case and the outbreak of gastroenteritis were probably just coincidental. A retrospective cohort study failed to show any correlation with consumption of school meals and suggested that the outbreak probably started outside the school setting and then spread within the schools by person-to-person transmission. All the cases examined were negative for common enteric pathogens and the responsible agent for the cases of gastroenteritis was not identified. The concern raised in the small community by the occurrence of a severe case of HUS and the lack of a rapid epidemiological assessment excluding the occurrence of a STEC outbreak, turned an epidemic episode of mild gastroenteritis into a public health emergency with relevant socioeconomic consequences. Prompt intervention in outbreaks following timely and effective risk communication are crucial for taking the most appropriate control measures and avoiding the spread of fear and panic in the community.     

Norovirus activity--United States, 2006-2007

In late 2006, CDC began receiving requests from numerous state public health departments for information about a perceived increase in the number of outbreaks of acute gastroenteritis (AGE), especially those involving person-to-person transmission in long-term--care facilities. No national surveillance system exists for AGE outbreaks, including those caused by norovirus, unless foodborne transmission is suspected. In the absence of national surveillance data, CDC attempted to better characterize the outbreaks of AGE by analyzing information from the following sources: 1) detailed data on recent AGE outbreaks in three of the states that had contacted CDC about a possible increase (North Carolina, Wisconsin, and New York); 2) emergency department (ED) syndromic surveillance data from Boston, Massachusetts; 3) basic epidemiologic data on AGE outbreaks from a CDC survey of state health departments; and 4) laboratory data from CDC. The analysis suggests that a national increase has occurred in the frequency of AGE outbreaks caused by norovirus (including fatal cases in long-term-care facilities). Two new cocirculating GII.4 norovirus strains emerged nationwide in 2006 and likely accounted for this increase in activity. Improved national surveillance of outbreaks, including those with person-to-person transmission; development of accessible, affordable, and timely clinical tests; and increased access to a norovirus strain sequencing database at CDC will lead to more accurate assessment of the morbidity and mortality associated with norovirus and more rapid identification of newly emerging norovirus strains.     

A foodborne outbreak of Norwalk virus gastroenteritis. Evidence for post-recovery transmission

From November 10-16, 1982, 220 (57%) of 383 attendees at eight banquets for which food had been prepared at a single hotel restaurant and the employees of the hotel had onset of Norwalk virus gastroenteritis. Epidemiologic investigation of the three largest banquets confirmed consumption of potato and fruit salads (banquet A), coleslaw (banquet B), and tossed salad (banquet C) to be significantly associated with illness. Between November 8-19, similar illness occurred in seven (54%) of 13 hotel kitchen employees. The foods implicated in banquets A and B were prepared by one salad worker during her acute illness and up to 48 hours following her recovery. A second salad worker prepared the implicated tossed salad for banquet C 24 hours following her recovery. To the authors' knowledge, this is the first foodborne outbreak investigation demonstrating Norwalk viral excretion and transmission by a food handler after recovery from illness and either person-to-person or vehicle-borne transmission between food handlers with subsequent transmission by more than one food handler to patrons.     

Sensor, a population-based cohort study on gastroenteritis in the Netherlands: incidence and etiology

A prospective population-based cohort study with a nested case-control study was conducted to estimate the incidence of gastroenteritis and the associated pathogens in the general Dutch population. Follow-up of two consecutive cohorts was performed by weekly reporting cards from December 1998 to December 1999. Cases and controls in the case-control study supplied a questionnaire and stool samples. The standardized gastroenteritis incidence was 283 per 1,000 person-years. The incidence rose with increasing level of education and was higher for persons with a history of diarrhea and for young children. Bacterial pathogens accounted for 5% of cases, bacterial toxins for 9%, parasites for 6%, and viral pathogens for 21%, with Norwalk-like virus (NLV) as the leading pathogen in 11% of cases. The gastroenteritis incidence was higher than that reported for England, but lower than for the United States. In community cases, viral pathogens are the leading cause of gastroenteritis, with NLV being the number one cause of illness in all age groups but one. In many countries, preventive measures are implemented to decrease bacterial infections. However, additional prevention of viral infections, especially NLV, might significantly decrease the number of gastroenteritis cases in the community.     

用文献综述法估计我国食源性副溶血性弧菌病发病率

目的估计副溶血性弧菌在我国导致的食源性疾病发病率。方法利用文献综述方法估计我国急性腹泻发病率以及腹泻人群中副溶血性弧菌感染的比例,利用食源性疾病监测网获得副溶血性弧菌感染疾病的腹泻发生比例,参考国外研究推算副溶血性弧菌感染的食源性比例,结合腹泻发病率及各项乘数获得副溶血性弧菌导致食源性疾病发病率。结果在我国,每年因副溶血性弧菌导致急性腹泻665.5万人,导致急性胃肠炎病例估计为728.1万人,副溶血性弧菌感染的食源性比例为68.0%,推算我国食源性副溶血性弧菌病每年约发生495.1万人次。副溶血性弧菌导致急性胃肠炎的比例远高于发达国家,低于我国食源性疾病监测网的报告比例。结论副溶血性弧菌在我国仍是主要的食源性致病菌,对我国造成的疾病负担较为严重。     

肇庆市某幼儿园诺瓦克样病毒性胃肠炎爆发情况调查

目的:对肇庆市某幼儿园一起诺瓦克样病毒引起的群体性胃肠炎进行调查和分析。方法:采取面对面或电话问卷调查的方法收集病例发病时间、班级分布、性别年龄分布等资料,进行流行病学分析。结果:89例病例中幼儿园学生56人,教师、保育员9人,学生家长24人,罹患率分别为9.3%、12.7%、8.3%;学生发病主要集中在6个班级,年龄集中在6岁以下,平均病程3.7天。实验室检测10份粪便ELISA诺瓦克病毒抗原阳性5份,PCR检测阳性8份。结论:本起群体性胃肠炎是由诺瓦克样病毒引起,今后要加强幼托机构对新发传染病的防治工作。     

A large hotel outbreak of Norwalk-like virus gastroenteritis among three groups of guests and hotel employees in Virginia

A large outbreak of acute gastroenteritis occurred among three different groups of guests and the employees of a Virginia hotel within a 2-week period in November 2000. At least 76 of the hotel's guests and 40 hotel employees had acute gastroenteritis during this period. All tested ill persons were infected with the same strain of Norwalk-like virus, as shown by cloning and sequencing of virus detected in stool specimens from the three guest groups and the employees. Epidemiologic investigation suggested food as the probable source for the guests. Most of the employees, including those sick, did not eat in the hotel, suggesting that environmental contamination and person-to-person transmission could have contributed to the outbreak. The disease continued to spread in the hotel, passing from one guest group to another, by food, environmental contamination, and/or by person-to-person transmission through infected employees and guests. The study describes procedures implemented to control the outbreak and makes recommendations for future outbreak control.     

Foodborne illness acquired in the United States--unspecified agents

Each year, 31 major known pathogens acquired in the United States caused an estimated 9.4 million episodes of foodborne illness. Additional episodes of illness were caused by unspecified agents, including known agents with insufficient data to estimate agent-specific illness, known agents not yet recognized as causing foodborne illness, substances known to be in food but of unproven pathogenicity, and unknown agents. To estimate these additional illnesses, we used data from surveys, hospital records, and death certificates to estimate illnesses, hospitalizations, and deaths from acute gastroenteritis and subtracted illnesses caused by known gastroenteritis pathogens. If the proportions acquired by domestic foodborne transmission were similar to those for known gastroenteritis pathogens, then an estimated 38.4 million (90% credible interval [CrI] 19.8-61.2 million) episodes of domestically acquired foodborne illness were caused by unspecified agents, resulting in 71,878 hospitalizations (90% CrI 9,924-157,340) and 1,686 deaths (90% CrI 369-3,338).     

Norwalk-like gastroenteritis epidemic in a Toronto hospital.

An epidemic of gastroenteritis in a teaching hospital affected 57 patients and 69 staff over a 26-day period. The index case was a patient admitted with acute abdominal pain and diarrhea two days prior to the outbreak. The epidemic curve indicated person-to-person transmission. The incubation period, duration and types of symptoms were typical of Norwalk gastroenteritis, and Norwalk-like virus particles, serologically different from the prototype Norwalk virus strain, were observed in 17 of 20 fecal specimens examined by immune-electron microscopy.     

Norovirus transmission on cruise ship

An outbreak of norovirus gastroenteritis affected passengers on two consecutive cruises of ship X and continued on 4 subsequent cruises despite a 1-week sanitization. We documented transmission by food and person-to-person contact; persistence of virus despite sanitization onboard, including introductions of new strains; and seeding of an outbreak on land.     

国内诺如病毒胃肠炎疫情分子流行病学分析

目的 研究诺如病毒聚集性胃肠炎疫情在国内的流行现状. 方法 运用系统综述的方法在万方数据库、维普咨讯数据库、CNKI数据库、生物文献数据库及pubmed数据库中检索关于国内诺如病毒聚集性胃肠炎疫情的文献.结果 国内从2003年1月-2012年6月共发生83起诺如病毒胃肠炎疫情.从地点分布来看,疫情主要集中在广东省、浙江省,其次是北京市、广西省;从季节分布来说,诺如病毒胃肠炎疫情每季度均有发生,但秋冬季高发（10、1、2月份）;从发生场所来说,疫情主要发生在学校、医疗卫生保健机构;水源性、人与人密切接触传播为其主要传播途径.人与人密切接触传播多为GⅡ.4型感染所致. 结论 学校等作为诺如病毒胃肠炎疫情防控工作的重点场所,应加强诺如病毒防治知识培训,提高疫情报告敏感性和及时性.     

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.     

"Norwalk-like viruses". Public health consequences and outbreak management.

"Norwalk-like viruses" (NLVs) cause outbreaks of gastroenteritis and are spread frequently through contaminated food or water. Molecular diagnostics now enables detecting viruses in clinical and environmental specimens, linking of NLV strains causing outbreaks in multiple geographic locations, and tracing them to their sources in contaminated food or water. This report reviews recent advances in NLV detection and provides guidelines and recommendations for investigating NLV-related outbreaks, including specimen collection and disease prevention and control. This report also updates information provided in CDC's previously published, Viral Agents of Gastroenteritis: Public Health Importance and Outbreak Management (MMWR 1990;39 [No. RR-5]: 1-24). These CDC recommendations are intended for public health professionals who investigate outbreaks of acute gastroenteritis but could be useful in academic and research settings as well.     

A school outbreak of Norwalk-like virus: evidence for airborne transmission

An outbreak of gastroenteritis affected a school attended by children aged 4-11 years. Epidemiological features suggested this was due to Norwalk-like virus (NLV) and this was confirmed by polymerase chain reaction (PCR). Nucleotide sequence analysis of the PCR amplicons revealed identical strains in all five positive stool samples. Pupils were significantly more likely to become ill following an episode of vomiting within their classroom (adjusted odds ratio 4.1, 95% CI 1.8-9.3). The times from exposure to illness were consistent with direct infection from aerosolized viral particles where exposure to vomiting was high. Cleaning with quaternary ammonium preparations made no impact on the course of the outbreak. However, the outbreak stopped after the school closed for 4 days and was cleaned using chlorine-based agents. This study confirms the importance of vomiting in the transmission of NLV and provides evidence that direct infection with aerosolized viral particles occurs.