Norovirus activity--United States, 2002

During June-December 2002, an increased number of outbreaks of acute gastroenteritis (AGE) were reported on cruise ships sailing into U.S. ports. In addition, since October 2002, several states have noted an increase in outbreaks of AGE consistent clinically and epidemiologically with norovirus infection, particularly in institutional settings such as nursing homes (CDC, unpublished data, 2002). This report describes recent norovirus activity in two states and New York City (NYC) and data from CDC that indicate the possible emergence of a predominant, circulating norovirus strain.     

2005-2010年国际邮轮急性胃肠炎疾病暴发的流行病学分析

目的了解2005—2010年期间国际邮轮暴发急性胃肠炎疾病流行的状况与特征,探讨大型船舶暴发胃肠道传染病流行的规律和特点及应对措施。方法收集美国CDC国家环境卫生中心船舶卫生项目(VSP)及文献报道的邮轮急性胃肠炎疾病暴发等疫情报告资料,进行流行病学统计与分析。结果收集2005—2010年期间的暴发疫情中明确病原体的有100起,其中病毒性胃肠炎疾病94起(76.4%),细菌性及其他6起(4.9%);病原体未知及未获得样本有23起(18.7%)。诺如病毒、肠产毒性大肠杆菌、志贺氏菌和沙门菌在邮轮急性胃肠道疾病疫情病原体中占主要地位。每年的10月至次年5月为邮轮急性胃肠道疾病疫情发病高峰,其中诺如病毒引发的发病高峰季节是10月至次年3月。邮轮乘客胃肠炎发病率呈逐年上升趋势。结论邮轮发生胃肠道传染性疾病的频率及乘客发病率呈缓慢波动上升趋势,控制由诺如病毒引起的邮轮急性胃肠炎疾病暴发疫情对胃肠道疾病暴发相关性发病率的降低至关重要。     

Molecular diversity of noroviruses associated with outbreaks on cruise ships: comparison with strains circulating within the UK

The molecular diversity of norovirus (NV) strains associated with 26 outbreaks of NV gastroenteritis has been determined. The outbreaks occurred on 14 cruise ships from seven cruise lines, during the period from 1998 to 2002. The ships cruised in seas worldwide, including the Mediterranean, the Baltic and the Caribbean. Genogroup I NVs were more common in the cruise ship setting than in hospitals, with 38% of the cruise ship outbreaks associated with genotype I NVs, as compared to < 10% in hospital and other semi-closed institutions in the UK. Outbreaks on cruise ships were more common in the period April to September, than in the winter. Two mixed genogroup I and II outbreaks were detected, which suggested contaminated food or water as the source of the infection.     

Emergence of new norovirus variants on spring cruise ships and prediction of winter epidemics

In June 2006, reported outbreaks of norovirus on cruise ships suddenly increased; 43 outbreaks occurred on 13 vessels. All outbreaks investigated manifested person-to-person transmission. Detection of a point source was impossible because of limited investigation of initial outbreaks and data sharing. The most probable explanation for these outbreaks is increased norovirus activity in the community, which coincided with the emergence of 2 new GGII.4 variant strains in Europe and the Pacific. As in 2002, a new GGII.4 variant detected in the spring and summer corresponded with high norovirus activity in the subsequent winter. Because outbreaks on cruise ships are likely to occur when new variants circulate, an active reporting system could function as an early warning system. Internationally accepted guidelines are needed for reporting, investigating, and controlling norovirus illness on cruise ships in Europe.     

Enterotoxin-producing Escherichia coli O169:H41, United States

From 1996 to 2003, 16 outbreaks of enterotoxigenic Escherichia coli (ETEC) infections in the United States and on cruise ships were confirmed. E. coli serotype O169:H41 was identified in 10 outbreaks and was the only serotype in 6. This serotype was identified in 1 of 21 confirmed ETEC outbreaks before 1996.     

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.     

一起邮轮诺如病毒痰隋的病原学检测

[目的]总结诺如病毒实验室诊断经验,进一步完善诺如病毒的检测方法。（方法]针对上海口岸发生的又1起邮轮急性胃肠炎爆发疫情,应用酶联免疫吸附实验（ELISA）、逆转录-聚合酶链反应（RT—PCR）、电镜观察等技术,对送检的9份粪便标本进行检测。[结果]运用2种ELISA试剂盒在9份标本中分别检出4份和5份标本诺如病毒抗原阳性;运用逆转录-聚合酶链方法,发现9份标本中有7份扩增出诺如病毒特异性条带;运用电镜在镜下观察到诺如病毒颗粒。[结论]诺如病毒检测方法的建立将为口岸公共卫生突发事件应急体系的建设提供重要的技术支持。     

Epidemiology of gastroenteritis on cruise ships, 2001-2004

BACKGROUND: The incidence of diarrheal disease among cruise ship passengers declined from 29.2 cases per 100,000 passenger days in 1990 to 16.3 per 100,000 passenger days in 2000. In 2002, the Vessel Sanitation Program of the Centers for Disease Control and Prevention reported 29 outbreaks (3% or more passengers ill) of acute gastroenteritis on cruise ships, an increase from 3 the previous year. This analysis of gastroenteritis on cruise ships, conducted in 2005, details the increase in outbreak incidence rates during 2001 through 2004. METHODS: Using Gastrointestinal Illness Surveillance System data, investigators evaluated incidence rates of gastroenteritis on cruise ships calling on U.S. ports, carrying 13 or more passengers, by cruise length and reporting region during the study period. The investigators also evaluated the association between inspection scores, and gastroenteritis incidence and the frequency of outbreaks in 2001 through 2004. RESULTS: During the study period, the background and outbreak-associated incidence rates of passengers with acute gastroenteritis per cruise were 25.6 and 85, respectively. Acute gastroenteritis outbreaks per 1000 cruises increased overall from 0.65 in 2001 to 5.46 in 2004; outbreaks increased from 2 in 2001 to a median of 15 per year in 2002-2004. Median ship inspection scores remained relatively constant during the study period (median 95 on a 100-point scale), and were not significantly associated with either gastroenteritis incidence rates (risk ratio, 1.00; 95% confidence interval, 0.98-1.02) or outbreak frequency (Spearman's coefficient, 0.01, p=0.84). CONCLUSIONS: Despite good performance on environment health sanitation inspections by cruise ships, the expectation of passenger cases of gastroenteritis on an average 7-day cruise increased from two cases during 1990-2000 to three cases during the study period. This increase, likely attributable to noroviruses, highlights the inability of environmental programs to fully predict and prevent risk factors common to person-to-person and fomite spread of disease.     

上海口岸首例邮轮大规模诺如病毒感染爆发的应急处置

〔目的〕通过对某大型邮轮一起诺如病毒引起的急性胃肠炎疫情处置,关注国际间疫情变化,为国境口岸突发公共卫生事件快速反应提供对策依据。〔方法〕通过对来沪某大型邮轮的一起诺如病毒引起的急性胃肠炎的临床诊断、流行病学调查、实验室检测和卫生检疫措施的实施,探讨口岸突发公共卫生事件的快速反应对策。〔结果〕经过对邮轮上患者样本和食品样本的细菌学和病毒学检测,结合流行病学调查和临床表现确定为诺如病毒引起的急性胃肠炎,采取了以传染源控制和管理为重点、切断传播途径和保护易感人群等卫生检疫措施后控制了疫情的蔓延。〔结论〕国境卫生检疫应在排除检疫传染病的情况下,扩大疾病监测范围,以控制常见的、多发的、易引起突发公共卫生事件的传染病为重点。根据新的《国际卫生条例》的规定,调整国境口岸卫生检疫策略,加强口岸卫生检疫核心能力建设,建立应对突发公共卫生事件快速反应体系的新机制,为防止疾病的国际传播提供技术保障。     

Gastrointestinal illness on passenger cruise ships, 1975-1978.

Following investigations in 1972-1973 of outbreaks of enteric disease on cruise ships using American ports, a surveillance system was established which required that 24 hours before arrival in port, each ship report the number of persons with diarrheal illness seen by the ship's physician during the cruise. The reported data were found to be reliable; they established a baseline incidence for diarrhea on cruise ships. A significantly high portion of enteric disease outbreaks occurred on vessels that did not pass routine annual or semiannual sanitation inspections. The cruise ship sanitation program, developed with the cooperation of the cruise ship industry and the Centers for Disease Control, appears to have been successful in reducing the overall rate of cruise ship associated outbreaks of enteric illness.     

Diarrheal disease on cruise ships, 1990-2000: the impact of environmental health programs

BACKGROUND: In 1975, the then-Center for Disease Control (CDC) established the Vessel Sanitation Program (VSP) to minimize the risk for diarrheal disease among passengers and crew aboard ships by assisting the cruise ship industry in developing and implementing comprehensive environmental health programs. OBJECTIVES: To evaluate the relationship between cruise ship sanitation scores and diarrheal disease incidence and outbreaks among cruise ship passengers. METHODS: Retrospective cohort study of ship inspection and diarrheal disease data from 1990 through 2000 from the National Center for Environmental Health, CDC database, for cruise ships entering the United States. OUTCOMES: Yearly trends in number of ships inspected, number of inspections conducted, inspection scores, and risks of failing inspections; rates of diarrheal disease among passengers, by inspection year, cruise duration, incidence of outbreaks, and passing- or failing-score status of the associated ship. RESULTS: From 1990 through 2000, inspection scores gradually increased from a median of 89 in 1990 to 93 in 2000 (p<0.001), with an associated statistically significant 21% increase in likelihood of passing. The total baseline level of diarrhea among passengers was 2.0 cases per cruise (13243/6485), or 23.6 cases per 100,000 passenger-days (13243/56129096). The latter rate declined significantly from 29.2 in 1990 to 16.3 in 2000 (p<0.0001). Diarrheal disease incidence rates among passengers sailing on ships that passed environmental inspections were significantly lower than rates among passengers sailing on ships that failed inspections (21.7 vs 30.1; RR = 1.39; 95% CI: 1.31-1.47). Diarrheal disease outbreak-related illnesses decreased from 4.2 to 3.5 per 100000 passenger-days from 1990-1995 to 1996-2000. CONCLUSIONS: Environmental sanitation inspections conducted among ships sailing into the United States appear to continue to decrease diarrheal disease rates and outbreaks among passengers.     

世界船舶传染性疾病爆发的流行病学分析

目的了解世界航行船舶发生传染性疾病流行的状况与特征;探寻航海传染病流行的规律和特点。方法收集世界卫生组织公布的1994～2004年符合定义的132起世界船舶传染病爆发的疫情资料,进行流行病学统计与分析。结果世界船舶传染病爆发疫情呈波动升高趋势,新发传染病增加迅速。疫情中明确病原体的87起,其中病毒性传染病占81.61%,细菌性传染病占16.09%、其他传染病占2.30%;不明原因和未获得样本的共45起,占34.09%,且多在近年出现。诺沃克病毒、肠道毒素型大肠杆菌、沙门氏菌、志贺氏菌在船舶传染病疫情中占主要位置。1～4月为疫情发生的高峰期,其他月份发病较为平均。各传染病的海上流行规律较陆地有较大不同。结论海上航行船舶传染性疾病爆发流行具有其特殊的特征和规律。食物和水源是船舶传染病传播流行的主要途径。     

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.     

上海口岸首例邮轮大规模诺如病毒感染爆发的实验室快速诊断

〔目的〕总结上海出入境检验检疫局快速确认口岸首例邮轮大规模诺如病毒感染疫情的成功经验,完善口岸公共卫生突发事件应急处置体系的建设。〔方法〕在上海口岸,对发生疫情的邮轮通过检疫查验和流行病学调查明确疫情性质后,通过实验室有针对性的系统检测,对邮轮上发生的群体性急性胃肠炎进行快速诊断,从而实施有效的预防控制措施。〔结果〕通过实验室多种方法检测,确认引发急性胃肠炎的病原体为诺如病毒。〔结论〕对口岸首例邮轮大规模诺如病毒感染疫情的快速准确诊断将为口岸公共卫生突发事件应急体系的建设提供宝贵经验。     

Successful Control of an Onboard COVID-19 Outbreak Using the Cruise Ship as a Quarantine Facility,Western Australia,Australia

Onboard quarantining has been only partially effective to control outbreaks of coronavirus disease on cruise ships. We describe the successful use of the ship as a quarantine facility during the response to the outbreak on the MS Artania, which docked in Western Australia, Australia. The health-led 14-day quarantine regime was based on established principles of outbreak management and experiences of coronavirus disease outbreaks on cruise ships elsewhere. The attack rate in the crew was 3.3% (28/832) before quarantine commencement and 4.8% (21/441) during quarantine on board. No crew members became symptomatic after completion of quarantine. Infection surveillance involved telephone correspondence, face-to-face visits, and testing for severe acute respiratory syndrome coronavirus 2. No serious health issues were reported, no response staff became infected, and only 1 quarantine breach occurred among crew. Onboard quarantine could offer financial and operational advantages in outbreak response and provide reassurance to the shore-based wider community regarding risk for infection.     

A review of outbreaks of foodborne disease associated with passenger ships: evidence for risk management

OBJECTIVE: Foodborne disease outbreaks on ships are of concern because of their potentially serious health consequences for passengers and crew and high costs to the industry. The authors conducted a review of outbreaks of foodborne diseases associated with passenger ships in the framework of a World Health Organization project on setting guidelines for ship sanitation. METHODS: The authors reviewed data on 50 outbreaks of foodborne disease associated with passenger ships. For each outbreak, data on pathogens/toxins, type of ship, factors contributing to outbreaks, mortality and morbidity, and food vehicles were collected. RESULTS: The findings of this review show that the majority of reported outbreaks were associated with cruise ships and that almost 10,000 people were affected. Salmonella spp were most frequently associated with outbreaks. Foodborne outbreaks due to enterotoxigenic E. coli spp, Shigella spp, noroviruses (formally called Norwalk-like viruses), Vibrio spp, Staphylococcus aureus, Clostridium perfringens, Cyclospora sp, and Trichinella sp also occurred on ships. Factors associated with the outbreaks reviewed include inadequate temperature control, infected food handlers, contaminated raw ingredients, cross-contamination, inadequate heat treatment, and onshore excursions. Seafood was the most common food vehicle implicated in outbreaks. CONCLUSIONS: Many ship-associated outbreaks could have been prevented if measures had been taken to ensure adequate temperature control, avoidance of cross-contamination, reliable food sources, adequate heat treatment, and exclusion of infected food handlers from work.     

Enteric disease outbreak reporting, New South Wales, Australia, 2000 to 2005

OBJECTIVE: To review enteric disease outbreaks reported to the NSW Department of Health. METHODS: Data from existing electronic enteric disease outbreak summary databases were used to describe the number and type of outbreaks reported, burden of illness and cause of the outbreaks. RESULTS: Between 2000 and 2005, 998 enteric disease outbreaks were reported (148 foodborne and 850 non-foodborne), affecting 24 260 people and associated with 771 hospitalisations and 21 deaths. Salmonella was confirmed in 28 per cent of foodborne outbreaks, and norovirus in 18 per cent of non-foodborne outbreaks. CONCLUSIONS: Enteric disease outbreaks cause a substantial burden of disease in NSW.     

Outbreaks of diarrhoeal illness on passenger cruise ships, 1975-85

We reviewed data from the Vessel Sanitation Program (VSP), established by the US Public Health Service in 1975, to describe the epidemiology of shipboard diarrhoeal outbreaks, determine the risk of outbreak-related illness among cruise ship passengers, and evaluate changes in rates and patterns of shipboard diarrhoeal illness since the VSP was implemented. When the programme began, none of the cruise ships passed periodic VSP sanitation inspections; since 1978, more than 50% of ships have met the standard each year. On cruises lasting 3-15 days and having at least 100 passengers, diarrhoeal disease outbreaks investigated by the Centers for Disease Control decreased from 8.1 to 3.0 per 10 million passenger days between 1975-79 and 1980-85. The proportion of outbreaks due to bacterial pathogens (36%) did not change. Seafood cocktail was implicated in 8 of 13 documented food-borne outbreaks. The risk of diarrhoeal disease outbreaks on cruise ships appears to have decreased since implementation of the VSP but has not been eliminated.     

Use of Norovirus Genotype Profiles to Differentiate Origins of Foodborne Outbreaks

Because secondary transmission masks the connection between sources and outbreaks, estimating the proportion of foodborne norovirus infections is difficult. We studied whether norovirus genotype frequency distributions (genotype profiles) can enhance detection of the sources of foodborne outbreaks. Control measures differ substantially; therefore, differentiating this transmission mode from person-borne or food handler–borne outbreaks is of public health interest. Comparison of bivalve mollusks collected during monitoring (n = 295) and outbreak surveillance strains (n = 2,858) showed 2 distinguishable genotype profiles in 1) human feces and 2) source-contaminated food and bivalve mollusks; genotypes I.2 and I.4 were more frequently detected in foodborne outbreaks. Overall, ≈21% of all outbreaks were foodborne; further analysis showed that 25% of the outbreaks reported as food handler–associated were probably caused by source contamination of the food.     

Outbreaks of noroviral gastroenteritis in Florida, 2006-2007

Noroviruses are an important cause of sporadic cases and outbreaks of acute gastroenteritis. During 2006-2007, widespread increases in acute gastroenteritis outbreaks consistent with norovirus were observed in the United States. We conducted a statewide survey to characterize norovirus outbreak activity in Florida during a 1-year period. From July 2006 to June 2007, 257 outbreaks of norovirus gastroenteritis were identified in 39 of Florida's 67 counties. About 44% of outbreaks were laboratory confirmed as norovirus and 93% of these were due to genogroup GII. About 63% of outbreaks occurred in long-term care facilities and 10% of outbreaks were classified as foodborne. The median number of ill persons per outbreak was 24, with an estimated total of 7880 ill persons. During the study period, norovirus outbreak activity in Florida was widespread, persistent, and consistent with increased activity observed in other parts of the country.