实时荧光PCR检测诺瓦克病毒的应用研究

目的应用实时荧光PCR方法对诺瓦克病毒性急性胃肠炎进行快速检测，为疾病预防控制提供准确可靠的实验诊断依据。方法采集一起急性胃肠炎暴发流行患者的1份粪便、5份肛拭和1份呕吐物，进行实时荧光PCR检测。结果实时荧光PCR检测有1份病人粪便和1份病人肛拭样本中诺瓦克病毒核酸呈阳性。结论这是一起由诺瓦克病毒感染引起的急性胃肠炎暴发流行。     

诺瓦克病毒抗原检测在急性胃肠炎病原学诊断中的应用

目的为急性胃肠炎病原学诊断和预防控制提供科学依据。方法采用酶联免疫吸附试验（ELISA）法在急性胃肠炎患者粪便中查找诺瓦克病毒（NV）抗原，进行急性胃肠炎病原学诊断。结果2005年6月—2007年6月在梅州市6起群体性胃肠炎事件中，证实其中3起是由NV引起。结论采用ELISA法在急性胃肠炎患者粪便中查找NV抗原，方法灵敏度高，诊断快速，且较经济，在急性胃肠炎病原学诊断中具有重要的价值。     

Role of Norwalk virus in two foodborne outbreaks of gastroenteritis: definitive virus association

Two separate food-associated outbreaks of gastroenteritis occurred among Erie County, New York residents in June 1986. In one outbreak, cases of illness were estimated to have occurred in 50% of the approximately 700 persons in 13 groups who ate at an out-of-county restaurant during a seven-day period, and, in the second outbreak, illness occurred in 26 (30%) of 87 persons who attended a graduation party held in a private home. Laboratory investigation included serology (blocking radioimmunoassay) to determine seroconversion to Norwalk virus and an enzyme immunoassay for detection of Norwalk virus antigen in stools, which the investigators have found to be more specific for Norwalk virus than serology. Seroconversion to Norwalk virus occurred in 11 (79%) of 14 restaurant-related cases and seven (100%) of seven graduation party cases. Seroconversion to Norwalk virus antigen was also found in four (40%) of 10 food handlers at the restaurant and in two (100%) of two food handlers at the graduation party. Antigen was detected in the stools of three (20%) of 15 restaurant-related cases and four (67%) of six graduation party cases. No stools for viral analyses were available for testing from food handlers. All seven of the patients with Norwalk virus-positive stools were also positive by seroconversion. Widespread availability of reagents for stool antigen detection would result in confirmation of more outbreaks due to Norwalk virus and in a more timely manner.     

Norwalk Gastroenteritis Associated with a Water System in a Rural Georgia Community

An outbreak of acute gastroenteritis occurred during January 4–9, 1982, in a rural community in north Georgia. A systematic telephone survey revealed that 63% of persons living in homes served by the community water system had symptoms of acute gastroenteritis in contrast to 9% of persons in homes served by private wells or other sources (P < .001). A fourfold rise in antibody titer to the Norwalk virus occurred in 20 of 22 serum pairs obtained from ill persons. Fecal coliforms (> 16 MPN/100 ml) were detected in a spring which served as one water source for the community system. Surface runoff from a heavy rainfall, which preceded the outbreak, may have contaminated the system. Outbreaks of gastroenteritis should be promptly reported and investigated to facilitate corrective measures and to identify causative agents such as Norwalk virus.     

诺沃克病毒流行现状及预防措施

诺沃克病毒是一种分布很广泛的,可导致成人和儿童的急性腹泻的病毒,是除轮状病毒外引起腹泻的最主要的病毒病原,与食物、水源等的污染造成的急性胃肠炎爆发密切相关.为此,就诺沃克病毒的病原学、流行病学、临床表现、诊断治疗和预防等方面做一综述.     

桂林市诺瓦克病毒性腹泻暴发疫情调查

目的 了解诺瓦克病毒性腹泻流行特征,为制定防治对策提供依据.方法 应用现场流行病学方法调查疫情特征、临床表现,采集标本,用逆转录-聚合酶链反应(RT-PCR)进行病原学检测.结果 该疫情共发生病例54例,发病年龄8月86岁;主要临床表现为发热、呕吐、腹痛、腹泻;病程35 d;采集7份患者粪便标本,经RT-PCR检测,4份诺瓦克病毒阳性;进行传染源管理、饮用水消毒、和对村民进行健康教育等综合处理措施后疫情得到有效控制.结论 诺瓦克病毒性腹泻主要临床症状有腹泻、呕吐,少数病例低热,病例一般症状较轻,可自愈,患者粪便样诺瓦克病毒阳性;综合防控措施可有效控制疫情.     

An outbreak of food-borne gastroenteritis in two hospitals associated with a Norwalk-like virus.

Two connected outbreaks of gastroenteritis in separate hospitals associated with a small round structured virus morphologically indistinguishable from the Norwalk virus are described. The virus was most probably introduced on chicken sandwiches prepared by a member of the kitchen staff who was incubating the disease.     

Norwalk virus enteric illness acquired by swimming exposure

In an epidemic of gastrointestinal illness strongly associated with swimming at a recreational park in Macomb County, Michigan, in July, 1979, the authors demonstrated the value of serologic testing to detect Norwalk virus infection. Rises in antibody titer to Norwalk virus were noted in all 11 individuals tested. Electron microscopy on stools from 20 ill individuals revealed only one with Norwalk virus-like particles. This particle was shown by radioimmunoassay and immune electron microscopy not to be Norwalk virus and not to have stimulated detectable antibodies in this individual. These results not only indicate that electron microscopy is insensitive in detecting Norwalk virus, but that it has the potential to mislead. A low rate of respiratory symptoms was associated with gastrointestinal illness in this Norwalk virus outbreak. The route of exposure might have been important for this. The outbreak was also noteworthy in that, although there was evidence of familial clusters of resistance, a very high percentage of the population was proved to be susceptible to the Norwalk virus.     

The frequency of a Norwalk-like pattern of illness in outbreaks of acute gastroenteritis.

Records of 642 outbreaks of acute gastroenteritis were reviewed to determine the proportion of outbreaks that were clinically and epidemiologically consistent with Norwalk-like virus infection. Using as our criteria stool cultures negative for bacterial pathogens, mean (or median) duration of illness 12-60 hours, vomiting in greater than or equal to 50 per cent of cases, and, if known, mean (or median) incubation period of 24-48 hours, we found that 23 per cent of waterborne outbreaks, 4 per cent of foodborne outbreaks, and 67 per cent, 60 per cent, and 28 per cent of outbreaks in nursing homes, in summer camps, and on cruise ships, respectively, satisfied the criteria for Norwalk-like pattern. Of 54 outbreaks that satisfied the criteria for Norwalk-like pattern, 14 were investigated for virus etiology. Ten of these (71 per cent) yielded serologic evidence of Norwalk-like virus infection. Norwalk-like viruses are probably an important cause of outbreaks of acute gastroenteritis. Investigation for Norwalk virus antibody in outbreaks that are clinically and epidemiologically consistent with Norwalk-like virus infection is likely to yield diagnostically useful results.     

A serosurvey of water-borne pathogens amongst canoeists in South Africa.

Certain health risks have been associated with recreational exposure to faecally polluted water. Canoeing in certain South African waters is considered to be a high risk activity with regard to schistosomiasis, gastroenteritis and possibly hepatitis. In a cross-sectional study, a serosurvey was conducted amongst canoeists to ascertain whether or not they had a higher seroprevalence to hepatitis A virus, Norwalk virus and Schistosoma spp. than non-canoeists. In comparisons between the two groups, a significant association could not be demonstrated between canoeing and antibody response to hepatitis A and Norwalk viruses (P-values for age-adjusted chi 2 were 0.083 and 0.219 respectively), but a significant association could be demonstrated between canoeing and the antibody response to Schistosoma spp. (P < 0.001; age-adjusted).     

A community waterborne gastroenteritis outbreak: evidence for rotavirus as the agent.

A community waterborne nonbacterial gastroenteritis outbreak occurred in Eagle-Vail, Colorado in March 1981. Illness (defined as vomiting and/or diarrhea) was statistically associated with water consumption (chi 2 for linear trend = 7.07, p less than .005). Five of seven persons associated with the outbreak were infected with rotavirus as shown by virus detection or serological methods. Bacterial pathogens, Giardia lamblia, and Norwalk virus were excluded as responsible agents. Rotavirus should be looked for as a cause of waterborne outbreaks.     

Norwalk virus gastroenteritis following raw oyster consumption

In January, 1980, six out of 13 persons (46%) attending a party in a small northwest Florida town near the Gulf of Mexico became ill with Norwalk virus gastroenteritis after eating raw oysters. Symptoms experienced by the ill persons were principally nausea (100%), vomiting (83%) and diarrhea (50%) and were of brief duration. The symptom complex and epidemiology of Norwalk virus infection closely resemble the gastrointestinal illness commonly referred to as the 24-hour intestinal flu or "stomach flu." Norwalk virus infection was identified in this outbreak by application of a recently developed sensitive and specific serologic radioimmunoassay. Oysters from the incriminated batch had fecal coliform levels above recommended standards; however, recent studies of oyster-harvesting waters have shown only a weak correlation between fecal coliforms and the presence of enteric viruses. Further studies are needed to determine whether modifications of monitoring modalities for oyster-harvesting waters are needed.     

某市首起水源污染引起的诺瓦克病毒胃肠炎暴发的调查

目的调查分析某市429人出现以呕吐为主的群发性急性胃肠炎的原因,探讨区县生活饮用水卫生监督对策。方法现场流行病学调查与现场卫生学进行调查,应用ELISA、RT-PCR法对病例及水样标本进行实验室检测。结果采集的水厂A出厂水、末梢水及生活污水水体标本中,RT-PCR法检出诺瓦克病毒核酸阳性;现场调查发现水源受排污口污水污染,水厂卫生管理情况较差,水处理工艺较落后。结论这是某市首起水源污染引起的诺瓦克病毒所致的急性胃肠炎暴发事件,提示卫生监督部门应重点加强基层生活饮用水水源水监管力度,加强出厂水与末梢水的监测,提高水厂卫生管理水平,改进区县水厂水处理工艺。     

肇庆市某幼儿园Norwalk样病毒性胃肠炎爆发的流行病学调查研究

目的对肇庆市某幼儿园爆发Norwalk样病毒性胃肠炎进行调查和分析.方法应用流行病学方法调查疫情发生经过、分布特征、临床表现,并采集标本用酶联免疫吸附试验(ELISA)和逆转录-聚合酶链反应(RT-PCR)来进行实验室病原学的检测.结果共发生病例73例,主要临床表现发热、呕吐、腹痛、腹泻,病程一般2～3 d.在采集的10份粪便标本中,8份RT-PCR结果为Norwalk样病毒阳性,ELISA Norwalk病毒抗原阳性5份.通过加强宣传教育、环境消毒和个人卫生等综合处理措施,疫情得到有效控制.结论本次疫情是因感染Norwalk样病毒而引起的群体性急性胃肠炎爆发.     

An outbreak of acute infectious nonbacterial gastroenteritis in a high school in Maryland

An outbreak of acute infectious nonbacterial gastroenteritis (AING) occurred in a high school in Maryland in 1984. Thirty-six percent of students surveyed met the case definition of gastroenteritis, as did 24 percent of school employees. Eating lunch in the cafeteria on January 30 was significantly associated with illness. After controlling for other food items consumed during the January 30 lunch, only the sandwiches were significantly associated with illness, but the source of the contamination was not identified. Four of 17 serum pairs from sick students and none of the 8 serum pairs from exposed controls (a nonsignificant difference) showed at least a 4-fold rise in antibody titre to Norwalk virus between acute- and convalescent-phase specimens. This outbreak of AING is believed to be the first to implicate epidemiologically sandwiches as vehicles of transmission. The outbreak highlights the need for investigators to look for a viral etiology in gastroenteritis outbreaks.     

Risk factors for secondary transmission in households after a common-source outbreak of Norwalk gastroenteritis

In November 1984, a foodborne outbreak of Norwalk gastroenteritis occurred in a K-12 public school in northern Vermont. The outbreak offered an opportunity to systematically study in detail secondary transmission rates in households. Eating salad at Tuesday's school-sponsored Thanksgiving Banquet was associated with illness among students and staff members (p less than 0.025). Seven of 11 serum pairs from ill persons showed a fourfold or greater rise in antibody titer to Norwalk virus compared with one of nine controls (p = 0.028). The study of secondary household transmission revealed that households with persons with primary illness were 5.5 times more likely to experience secondary illness than households with well school children or adults. As the number of individuals with primary illness in the household increased, the secondary illness rates increased. Pre-school children were twice as likely as adults to develop secondary illness.     

An outbreak of gastroenteritis in a psycho-geriatric hospital associated with a small round structured virus

An outbreak of gastroenteritis in a psycho-geriatric hospital is described. Small round structured viruses, morphologically similar to Norwalk agent, were seen in stool samples from four patients. Although the illness was mild, 67 patients and 30 nurses on four wards were affected over a period of 4 weeks. Because of shortage of staff and isolation facilities, difficulty was experienced in introducing effective control measures.     

诺瓦克样病毒胃肠炎集体性爆发的证实与思考

目的通过对诺瓦克样病毒胃肠炎集体爆发的调查和证实,总结处理不明原因疾病的经验.方法运用流行病学方法对3所幼儿园和1所小学发生的急性胃肠炎集体爆发进行调查,对病人粪便样本进行诺瓦克样病毒核酸检验.结果4起集体爆发的胃肠炎均以恶心呕吐为主要表现,有2个发病高峰,病程较短,有自愈倾向,没有明显的年龄、班级、楼层分布的集中趋势.对第4起爆发的22份病人粪便样本进行诺瓦克病毒的PCR检测,其中19份阳性,同时有4份经DNA测序证实与诺瓦克样病毒同源.结论此一系列不明原因的胃肠炎是由诺瓦克样病毒引起的.这是我国证实由诺瓦克样病毒感染而引起的集体性急性胃肠炎的爆发.     

一起学校宋内志贺菌群体感染中荧光PCR辅助检测及意义

目的:对一起学校疑似水源性群体感染事件相关标本进行荧光PCR检测,为明确病原、处置疫情提供参考依据。方法:采集现场病例及可疑水源标本,与常规检测同步,以实时荧光PCR试剂盒筛检可疑肠道病毒(诺瓦克病毒)与细菌(产毒素大肠杆菌、沙门菌、痢疾杆菌、副溶血弧菌)。结果:病例标本荧光PCR均检出痢疾杆菌,部分水样增菌4 h检出痢疾杆菌阳性,8 h后则均为阳性。常规检测从病例标本中分得宋内志贺菌。结论:荧光PCR用于暴发疫情实验室辅助检测,准确快速,有利于及早明确病原和及时处理疫情。