一起疑为杯状病毒腹泻暴发的流行病学调查

目的　调查四川省广安市感染性腹泻暴发的流行情况 ,分析发病原因。方法　采用随机抽样的方法对广安市经济技术开发区、广安区机关单位、居委会和农村进行感染性腹泻的流行病学调查。所采粪便标本进行常规检测和肠道致病菌培养 ,用PAGE、ELISA和RT PCR方法进行腹泻病毒病原检测。结果　在调查的 4 5 6 7人中 ,发病 94 2例 ,罹患率为 2 0 .6 3% ,无死亡病例。发病率农村高于城区 (χ2 =2 2 .2 9,P <0 .0 0 5 ) ,5月 10～ 2 5日为发病高峰。 2 6份标本中 ,ELISA方法检出 4份杯状病毒阳性 ,RT PCR方法确认 1例。结论　本次感染性腹泻暴发流行的病原可能为杯状病毒     

一起诺如病毒性胃肠炎暴发的队列研究

目的调查分析某村一起诺如病毒性胃肠炎暴发的发病原因。方法采用历史性队列研究方法，应用ELISA对标本进行实验室检测。结果该起暴发共报告病例34例，发病与接触腹泻病人（X^2=6．51，P=0．00）、食物暴露于苍蝇（X^2=4．61，P=0．00）及村民暴露于患者呕吐物或粪便1m内（X^2=3．09，P=0．00）有统计学意义上的关联，与饮用水来源（X^2=1．68，P=0．14）没有统计学意义上的关联。在采集的8份肛拭子样本中1份ELISA法检出诺如病毒抗原阳性：4份粪便样本中2份ELISA法检出诺如病毒抗原阳性。结论这是一起由诺如病毒感染所致的急性胃肠炎暴发．密切接触是此次暴发的主要传播途径。     

2006-2015年成都地区5岁以下病毒性腹泻住院患儿病原学特征分析CSCD

目的 对成都地区5岁以下急性腹泻病患儿进行病毒学监测,了解引起腹泻常见病毒的流行特征,为指导病毒性腹泻的防控提供科学依据.方法 采集成都市妇女儿童中心医院儿童消化科2006年3月至2015年6月5岁以下腹泻住院患儿粪便标本,并送四川省疾病预防控制中心进行病毒RNA提取与检测,并记录患儿临床资料.采用ELISA、RT-PCR方法对轮状病毒抗原进行检测与分型;采用RT-PCR方法对杯状病毒、星状病毒、腺病毒进行检测与分型.结果 共收集1-59月龄腹泻住院患儿粪便标本份共2 331份（男1 446份,女885份）,阳性检出率58.0％,以7-12月龄为好发年龄.轮状病毒阳性检出率28.3％,11 -12月份为流行季节.杯状病毒阳性检出率23.3％,9月份为流行季节,诺如病毒GII为主要感染株,未发现暴发流行.星状病毒阳性检出率1.5％,主要于1-3月份检出.腺病毒阳性检出率5.1％,主要于5-8月份检出,2011年有过小流行.2007年以后,轮状病毒的检出率较前明显下降,而同时杯状病毒检出率逐年升高,2010-2015年杯状病毒成为引起5岁以下患儿腹泻的主要病毒之一.绝大多数病毒性腹泻患儿为急性病程（91.2％）,以轻度脱水为主,其次为中度脱水,无重度脱水.可伴消化道外表现,轮状病毒的消化道外表现较杯状病毒多见,但在随访中均恢复正常.结论 病毒性腹泻是5岁以下儿童急性腹泻病常见原因,成都地区以轮状病毒、杯状病毒为主要病原体.     

一起诺如病毒Ⅰ型Ⅱ型混合感染急性胃肠炎暴发疫情调查分析

目的 对湖州市某中学发生的一起以腹泻、呕吐为特征的暴发疫情进行调查和分析,查找病因、分析危险因素.方法 采用现场流行病学调查方法,结合临床表现及实验室检测结果进行调查与综合分析.结果该校共发生急性胃肠炎病例578例,罹患率为23.58%;临床表现主要为腹泻、呕吐、腹痛、恶心,少见发热,大多症状较轻,病程1～3 d;各班均有发病,无明显聚集性;共采集患者粪便标本15份,采用RT-PCR方法检出诺如病毒阳性标本11份,其中Ⅱ型6份,Ⅰ型阳性3份,Ⅰ型、Ⅱ型混合阳性2份(同一学生,两次采样).病例对照研究显示,饮用未加热桶装水是此次发病的危险因素(OR=2.46,95% CI=1.19～5.23),且饮水量与发病存在剂量反应关系(X2=24.18,P<0.01).通过采取隔离治疗传染源、改桶装水为供应开水、卫生消杀及健康教育等综合措施后,疫情迅速得到控制.结论 本次疫情是由诺如病毒引起的急性胃肠炎暴发,可疑的传播途径为饮用未加热的桶装水与日常接触.     

卢龙县1998年婴幼儿腹泻轮状病毒血清型调查

目的 对河北省卢龙县农村人口中儿童轮状病毒腹泻流行情况进行调查。方法 采用病毒核酸电泳和酶免疫方法对卢龙县1998年轮状病毒腹泻发病季节采集的非菌性腹泻粪便标本进行轮状病毒检测,采用酶免疫和RT-PCR方法对轮状病毒阳性标本进行血清型调查。结果 120份婴幼儿腹泻样本轮状病毒阳性率为39.2%,病毒电泳型全为长型,血清分型发现G3型为流行优势株,占61.7%,其次为G1型占36.2%,G4型占6.4%,轮状病毒腹泻病人最小年龄为2月龄,最大为2岁,男女之比库存1：1.47,结论 卢龙县1998年轮状病毒腹泻流行规律与全国情况基本一致,但流行毒株以G3型为主,与全国以G1型为主不同。     

广州市一起登革热家族聚集性暴发事件的调查与分析

目的探讨登革热家庭聚集性发病的流行病学特点及传播效率，为今后进行有效的预防和控制登革热暴发提供参考。方法采用现场流行病学调查方法对广州市一起登革热家庭聚集性暴发事件进行调查和分析；采用ELISA、RT-PCR和病毒分离的方法对标本进行检测。结果2006年8月广州市荔湾区发生一起登革热家庭聚集性暴发事件，该家族15名家庭成员先后共有6人发病，罹患率40．0％，其中6例患者登革热抗体IgM或IgG阳性3例，病毒分离阳性3例，荧光PCR检测阳性者1例，基因序列测序和病毒分离结果最终确定为登革I型病毒。结论根据临床表现、实验室检测结果以及流行病学调查．虽然该家族部分患者登革热抗体为阴性，但病例发病均在一个最长潜伏期内，因此可以确定该家族发生了登革热聚集性暴发，荔湾区龙津中路龙兴里最有可能是共同感染地．感染来源不明，感染时间为家庭聚会日可能性大。     

3起老人院诺如病毒胃肠炎暴发疫情分析

目的分析3起发生在老人院内的诺如病毒胃肠炎局部暴发疫情的流行特征,为今后预防类似事件的发生提供参考依据。方法收集2007年佛山市老人院诺如病毒胃肠炎暴发疫情现场流行病学调查报告．采用描述性流行病学方法对疫情调查处理情况进行分析。结果2007年佛山市共报告3起老人院诺如病毒胃肠炎暴发疫情,共发病56例,无死亡病例;疫情集中发生在2～3月份;每起疫情均从部分患者粪便标本中检测诺如病毒Ⅱ型核酸;3起疫情主要以人-人密切接触的途径传播。结论早发现、早报告、早处理疫情．以及日常加强院内卫生,强化护工的规范操作,是预防和控制诺如病毒胃肠炎在老人院发生的关键。     

一起发生在医院病房的诺如病毒胃肠炎的调查

目的对一起发生在某医院内科病区的群体性胃肠炎进行调查和分析。方法应用现场流行病学调查方法进行调查，对标本进行ELISA检测。结果共报告病例14例，包括7名住院病人和7名医护人员，在3人的粪便标本中检出诺如病毒抗原阳性。通过隔离治疗病人、加强消毒和卫生宣教等综合措施，疫情得到有效控制。结论本次胃肠炎暴发疫情由诺如病毒引起，感染来源尚不明确。     

长春地区2010年度婴幼儿腹泻的病原学研究及流行病学特点

目的 了解长春地区四种主要腹泻病毒病原构成及流行病学特点.方法 收集长春市儿童医院5岁以下住院患儿腹泻样本共460例,轮状病毒采用ELISA试剂盒检测,杯状病毒、星状病毒采用逆转录-聚合酶链反应( RT-PCR)法,腺病毒采用聚合酶链反应(PCR)法进行鉴定.结果 460份标本中轮状病毒占35.22％( 162/460);杯状病毒占20.43％( 94/460),星状病毒占9.78％(45/460),腺病毒占3.70％(17/460),混合感染达7.17％(33/460),发病患儿以2岁以下婴幼儿为主.对162份轮状病毒阳性标本进行G/P分型,结果示G1P[8]为主要流行株,杯状病毒以GⅡ-4亚型为主要流行株,星状病毒为Ⅰ型,腺病毒为Ad41.结论 长春地区婴幼儿病毒性腹泻的病原中轮状病毒是最主要病原,其次为杯状病毒、星状病毒和腺病毒.     

一起由札如病毒引起的急性胃肠炎暴发疫情的分子流行病学研究

目的 调查深圳市某幼儿园发生的一起急性胃肠炎暴发疫情的病原体,并分析病原体的分子流行病学特征.方法 收集患病幼儿及相关人员的粪便标本16份,剩余食物6份,采用国家卫生行业标准规定方法检测肠道致病菌、实时荧光RT-PCR法检测诺如病毒、札如病毒、轮状病毒核酸,逆转录RT-PCR法对病毒衣壳区和聚合酶区序列进行扩增,对PCR产物进行序列测定.序列用Clustalx软件进行多重比对、Mega 5.0软件绘制系统进化树.结果 16份样本中检出11例札如病毒核酸阳性,对其中3例阳性标本进行札如病毒衣壳区和聚合酶区序列测定,3株札如病毒与GII.3型参考株AY603425衣壳区核苷酸同源性为86.3％,聚合酶区核苷酸同源性为90.2％,3株札如病毒与GII.3型参考株AY603425、AB455793同属于GII.3型遗传分支.结论 此起急性胃肠炎爆发是由GII.3型札如病毒导致,GII.3型引起的急性胃肠炎暴发属广东省首次报道.     

Probabilities in norovirus outbreak diagnosis.

BACKGROUND: Noroviruses are recognized as the most common cause of outbreaks of acute gastroenteritis. Yet, diagnostic testing for norovirus is based mostly on RNA detection by RT-PCR, which is not widely available. While antigen detection tests (ELISAs) are easier to perform, they are in general less sensitive. OBJECTIVES: Our aim was to provide a scientific basis for declaring norovirus as the causative agent of an outbreak of acute gastroenteritis. STUDY DESIGN: Statistical analysis used binomial distribution to determine the minimal number of positive samples, and the probability of detecting the required number of positive samples, for different tests, required to assign norovirus as the causative agent of an outbreak of acute gastroenteritis. RESULTS: For either a standard RT-PCR or a commercially available ELISA, finding only 1 sample positive out of 2, 3 or 4 samples is sufficient to assign norovirus as the causative agent of an outbreak of acute gastroenteritis. However, when ELISA is used, the probability of detecting this required minimum number of positive samples is low when small numbers of samples are tested (57% when 2 samples are tested; 72% when 3 samples are tested). In order to reach a 90% probability of detecting a norovirus outbreak (false negativity at outbreak level <10%), at least 3 samples should be tested using RT-PCR, and 6 samples when using an ELISA. CONCLUSIONS: The sensitivity for NoV outbreak diagnosis will increase from 57% to 92%, or from 84% to 96%, for ELISA or RT-PCR respectively, when sample size increases from 2 to 6. Thus, using ELISA instead of RT-PCR for the detection of norovirus in stool samples will result in considerable numbers of false negative outbreaks unless a minimum of 6 samples are tested per outbreak.     

Real-time PCR detection of salmonella in suspect foods from a gastroenteritis outbreak in kerr county,Texas

In June 2001, an outbreak of acute gastroenteritis among 109 attendees of a church picnic in Kerr County, Texas, was reported. A 5'-nuclease PCR assay was used to screen for Salmonella in nine food items from the buffet line. Barbeque chicken B tested positive for Salmonella, and no amplification was detected in the remaining food items. These PCR findings were consistent with culture results and were confirmed by direct nucleotide sequencing. Salmonella enterica serotype Panama was cultured from both food and patient stool samples.     

An outbreak of gastroenteritis associated with calicivirus in an infant home.

In October 1977 an outbreak of acute infectious diarrhea occurred in an infant home in the city of Sapporo, Japan. Of 34 residents aged two to 20 months, 26 (77%) suffered from diarrhea. In ten of these patients the diarrhea was accompanied by vomiting. Electron microscopic examinations revealed typical calicivirus particles in eight faecal specimens, seven of which were from the group of 26 affected patients (28%) and one of which was from the group of eight infants without symptoms (13%). Immune electron microscopy tests for antibody responses against one of the isolated strains of calicivirus were carried out on 27 paired pre- and post-outbreak sera. Seroconversions were demonstrated in 18 of 19 (95%) affected infants and in six of eight (75%) unaffected infants. One patient with lack of antibody response was the youngest child--two months old. Periodic surveys on enteric viruses circulating in the home revealed that calicivirus was specifically associated with the outbreak of gastroenteritis. These observations provide further evidence for the causative role of calicivirus in acute gastroenteritis in children.     

Outbreak of human calicivirus gastroenteritis in a day-care center in Sydney, Australia.

Between January and March 1988, an outbreak of gastroenteritis occurred among children and staff at a day-care center in Sydney, New South Wales, Australia. Over an 11-week period, 53 persons had 101 episodes of gastroenteritis; some patients had 5 separate episodes. The principal etiologic agent in the outbreak, human calicivirus (HCV), was detected by electron microscopy in 32% of fecal specimens from children and staff members with symptoms but in only 8% of asymptomatic individuals (P less than 0.01). HCV was confirmed by both an enzyme immunoassay and solid-phase immune electron microscopy. HCV infection was a particular problem in infants, who had the highest age-specific attack rates, had the greatest symptomatic/asymptomatic infection ratio, and were most likely to have a second symptomatic episode. The mode of transmission of this virus was not identified, and extensive efforts to control the 11-week outbreak had little effect. Prolonged excretion of HCV by some symptomatic patients and high rates of asymptomatic infection may have contributed to the extended duration of the outbreak. HCV may be a common cause of gastroenteritis in children that is under-recognized because of insensitive methods of detection.     

Outbreak of acute gastroenteritis associated with group A rotavirus and genogroup I sapovirus among adults in a mental health care facility in Japan

An outbreak of acute gastroenteritis consisting of 57 cases occurred in a mental health care facility in Takasaki city, Japan during 6th February and 27th March 2002. A total of 18 fecal specimens collected from 17 residents and one member of the medical staff during this outbreak were tested for the presence of viral enteropathogens by RT-PCR and latex agglutination. Group A rotavirus and sapovirus were detected in 5 out of 18 fecal specimens (55.6%). To our knowledge, this is the first finding of an outbreak of gastroenteritis associated with co-circulation of different kinds of viruses such as group A rotavirus and sapovirus. All of group A rotaviruses were typed further as P[4]G2 strains. Both rotavirus and sapovirus were subjected to molecular analysis by sequencing. It was noteworthy that all rotaviruses and sapoviruses had high homologies, respectively, to each other and sapoviruses presented a potential novel sapovirus genogroup I (GI) genotype, which was obviously different from any GI genotypes (GI-a, b, c, and d). The outbreak associated with these viruses spread gradually from dormitory to dormitory, suggesting a spread by person-to-person contact, although investigation on the route of transmission of the outbreak is lacking. The findings confirm the presence of group A rotavirus and sapovirus are important in acute gastroenteritis among adults in Japan.     

Microtiter solid-phase radioimmunoassay for detection of human calicivirus in stools.

A microtiter solid-phase radioimmunoassay (RIA) was developed for detection of human calicivirus in stool specimens. Seventy-eight stool specimens were tested by RIA. All 17 specimens positive for human calicivirus by electron microscopy (EM) were also positive by RIA. In addition, of 21 specimens obtained from an outbreak of caliciviral gastroenteritis, 11 were positive by RIA but negative by EM. Of 20 specimens positive for rotavirus by EM and 20 nondiarrheic specimens with no virus, 2 and 1, respectively, were positive by RIA but were subsequently shown to be falsely positive by a blocking test. There was no cross-reaction between human and feline caliciviruses. Thus, the test was more sensitive than EM and, with an appropriate blocking test, was specific for human calicivirus. It might be especially useful for screening large numbers of stool specimens.