一起传染性非典型肺炎爆发的“超级传播者”和传播链分析

目的：了解严重急性呼吸综合征(SARS)爆发案例的传播过程，分析SARS病例不同阶段的传染性和不同接触方式的危险性。方法：设计统一调查表，用查阅病历、面对面调查和电话调查相结合的方式进行，以指征病例为起点进行线索追踪和个案调查。用传播链示意图分析传播关系，用接触史分析示意图分析传染性。结果：共追查到与该案例传播链相关的接触者207人，发病36例，死亡1例，总罹患率为17％。其中指征病例和1名二代病例分别直接传播了12例和13例续发病例，其传播过程可以用清晰的传播链加以描述；所有36例病例均与前代病例的症状期有密切接触史，家族传播链中85％的病例都与前代病例症状期的第3—5天有过接触，发病前后均接触和仅发病后接触者罹患率分别为70％和67％，差异无显著性；仅与前代病例潜伏期接触的15名同柜台同事、29名同班同学无发病，38名与医护人员发病前或发病初期密切接触的家属无发病。结论：该案例所有的续发病例都有与症状期病例密切接触史；未观察到SARS患者在其潜伏期内存在传染性。     

一起小学校内乙型流感暴发的调查

2004年9月下旬，浙江省江山市某乡镇中心小学发生了一起由乙型流感病毒引起流行性感冒暴发。经调查本次乙型流感共发现患者65例，罹患率15．26％。     

SARS-associated coronavirus transmission, United States

To better assess the risk for transmission of the severe acute respiratory syndrome-associated coronavirus (SARS-CoV), we obtained serial specimens and clinical and exposure data from seven confirmed U.S. SARS patients and their 10 household contacts. SARS-CoV was detected in a day-14 sputum specimen from one case-patient and in five stool specimens from two case-patients. In one case-patient, SARS-CoV persisted in stool for at least 26 days after symptom onset. The highest amounts of virus were in the day-14 sputum sample and a day-14 stool sample. Residual respiratory symptoms were still present in recovered SARS case-patients 2 months after illness onset. Possible transmission of SARS-CoV occurred in one household contact, but this person had also traveled to a SARS-affected area. The data suggest that SARS-CoV is not always transmitted efficiently. Routine collection and testing of stool and sputum specimens of probable SARS case-patients may help the early detection of SARS-CoV infection.     

一起院内传染性非典型肺炎感染的传播链分析

目的：调查一起严重急性呼吸综合征(SARS)院内感染的传播过程，分析造成院内感染的原因和流行病学特点，为预防和控制院内SARS感染提供可借鉴的资料。方法：采用统一的流行病学调查表，通过座谈了解，查看病案和感染现场调查相结合进行追踪和个案调查。绘制传播链说明本次院内感染的传播过程，描述发病时间分布、接触史和接触方式。结果：传染源为1名输入性病例，与该案例传播相关接触者54人，发病5人，总罹患率为9．26％。其中指征病例传播了1例和这名二代病例又传播了4例续发病例，其传播过程可以用清晰的传播链加以描述；此5例病例均与前代病例的症状期有密切接触史，发病潜伏期长，潜伏期平均10d以上；后对在症状期所有接触者进行隔离，无发病。结论：本案例中所有续发病例都有与症状期病例明确的近距离密切接触史，但密切接触者并非全部发病；病原体传播与环境条件有关；急诊科护士是SARS感染高危人群；院内SARS感染可防可制。     

Severe acute respiratory syndrome (SARS) in Singapore: clinical features of index patient and initial contacts

Severe acute respiratory syndrome (SARS) is an emerging viral infectious disease. One of the largest outbreaks of SARS to date began in Singapore in March 2003. We describe the clinical, laboratory, and radiologic features of the index patient and the patient's initial contacts affected with probable SARS.     

SARS transmission in Vietnam outside of the health-care setting

To evaluate the risk of transmission of SARS coronavirus outside of the health-care setting, close household and community contacts of laboratory-confirmed SARS cases were identified and followed up for clinical and laboratory evidence of SARS infection. Individual- and household-level risk factors for transmission were investigated. Nine persons with serological evidence of SARS infection were identified amongst 212 close contacts of 45 laboratory-confirmed SARS cases (secondary attack rate 4.2%, 95% CI 1.5-7). In this cohort, the average number of secondary infections caused by a single infectious case was 0.2. Two community contacts with laboratory evidence of SARS coronavirus infection had mild or sub-clinical infection, representing 3% (2/65) of Vietnamese SARS cases. There was no evidence of transmission of infection before symptom onset. Physically caring for a symptomatic laboratory-confirmed SARS case was the only independent risk factor for SARS transmission (OR 5.78, 95% CI 1.23-24.24).     

Lack of SARS transmission and U.S. SARS case-patient

In early April 2003, severe acute respiratory syndrome (SARS) was diagnosed in a Pennsylvania resident after his exposure to persons with SARS in Toronto, Canada. To identify contacts of the case-patient and evaluate the risk for SARS transmission, a detailed epidemiologic investigation was performed. On the basis of this investigation, 26 persons (17 healthcare workers, 4 household contacts, and 5 others) were identified as having had close contact with this case-patient before infection-control practices were implemented. Laboratory evaluation of clinical specimens showed no evidence of transmission of SARS-associated coronavirus (SARS-CoV) infection to any close contact of this patient. This investigation documents that, under certain circumstances, SARS-CoV is not readily transmitted to close contacts, despite ample unprotected exposures. Improving the understanding of risk factors for transmission will help focus public health control measures.     

Seroprevalence of SARS coronavirus antibody in household contacts

Between March and July 2003, 671 cases of severe acute respiratory syndrome (SARS) were diagnosed in Taiwan with a total of 84 fatalities. After the epidemic, a serological survey was conducted involving the asymptomatic household contacts. Household contacts of 13 index patients were enrolled in the study. Contact history and clinical symptoms of the household contacts were recorded by standardized questionnaires. Blood samples of patients and household contacts were collected at least 28 days after symptom onset in the index patients or household exposure in the contacts for SARS-associated coronavirus (SARS-CoV) IgG testing. On the basis of this investigation, 29 persons (25 adults and 4 children) were identified as having had unprotected exposure to the index cases before infection-control practices were implemented. Laboratory evaluation of clinical specimens showed no evidence of transmission of SARS-CoV infection to any contacts. This investigation demonstrated that subclinical transmission among household contacts was low in the described setting.     

北京市首例输入性传染性非典型肺炎家族内传播的流行病学分析

目的：描述传染性非典型肺炎[严重急性呼吸综合征(SARS)]传播链，以探讨该病在人群中传播的规律和特征。方法：对北京市第一起输入性疫情相关的病例及其密切接触者逐一进行流行病学调查，分析病例之间的关系，并采集相关标本进行实验室检测。结果：2003年3月5日北京市发生第一例输入性SARS病例，并在家庭内和医院造成9人感染，其中2例死亡；指示病例潜伏期为4天，第二代病例潜伏期为平均7天(4～17天)，第三代病例较少，潜伏期为8天。潜伏期越短，发热维持时间越长，病情越重。经及时采取综合控制措施，疫情得到控制。结论：SARS在传播过程中存在家庭及医院聚集性，主要为呼吸道飞沫传播和密切接触传播。     

一起SARS爆发的血清流行病学调查

目的 探讨SARS密切接触者的隐性感染和SARS患者血清中特异性抗体的消长情况。方法 采用中和试验法、间接酶联免疫吸附试验(ELISA)和免疫粘连法对北京一起SARS爆发案例中与重症SARS患者无防护密切接触的未发病者和续发SARS病例进行血清SARS特异性IgG抗体检测,采血时间为发病后或接触后24周左右。结果 共采集到32份血清,其中未发病密切接触者的血清19份,SARS康复期患者血清13份。三种方法检测结果:57份次未发病密切接触者的血清标本SARS-CoV抗体检测,结果均为阴性;39份次SARS康复期患者血清标本SARS-CoV抗体检测,38份次结果为阳性,1份次(用免疫粘连法检测)结果为阴性。病后24周左右的中和抗体效价为1:43(1:16～1:203)。结论 研究中未发现SARS密切接触者存在隐性感染;SARS患者病后24周左右血清IgG抗体仍维持在较高水平。     

天津市传染性非典型肺炎流行特点及主要控制措施效果评价

目的：分析天津市传染性非典型肺炎[严重急性呼吸综合征(SARS)]流行病学特征，对主要控制措施的效果进行初步评价。方法：采用自行设计的病例报告表，全市统一的流行病学个案调查表及病例接触者、密切接触者树状分布图，深入病房、家庭、社区、团体等对病例及接触者进行调查。结果：以发病时间计算，自2003年4月13日至5月8日，包括输入病例在内发病175例，发病率为1．9／10万，其中死亡14例，病死率达8．O％。整个流行过程不足1个月，流行特点：1例“超级传播者”直接或间接传染了全市94．3％的病例；呈现以A、B、C 3家医院聚集发病为特点的爆发性流行，占全市病例的68．6％，3家医院外的家庭聚集发病占全市病例的14．3％，同事间传播为2．3％，散发者为9．1％，这些散发者未造成接触者感染；早期医务人员发病较多，占总病例数的38．2％，流行全过程参加SARS救治工作的1975名医护人员的总感染率为3．4％；全部流行过程传染源明确，传染链清晰，全市仅3例患者未找到传染源，占病例总数的2％；在10例源头病例中仅“超级传播者”和另一病例传染了其接触者，其他传染源由于及时隔离未造成任何传播。结论：SARS是严重急性呼吸系统传染病，如能及时准确地掌握传染链并进行范围适当、及时有效的封闭及隔离措施，以科学的方法提高全民的警觉度，传染链可能在较短时间内被切断，从而控制传播。     

北京市SARS患者密切接触者发病及其危险因素分析

目的 了解SARS密切接触者的发病危险因素。方法 采用回顾性流行病学方法,分析已有的SARS疫情及密切接触者的流行病学资料,利用SPSS统计软件对现有资料进行统计学分析。结果 在北京市5个区县的2195个密切接触者中,转归为病例138例,罹患率为6.3％。与病例为同事、同学关系,罹患率仅为0.36％。家务待业病例的密切接触者罹患率为最高(15.33％),接触地点在家和医院的密切接触者罹患率为31.71％,接触地点在学校密切接触者罹患率为0.77％。而接触地点在工作单位的密切接触者459名中,无一例转为病例,罹患率为零。结论 密切接触者发病的影响因素与患者接触时间、接触程度与频率、接触地点、隔离方式、时间及密切接触者的年龄等有关。SARS的传播途径存在近距离密切接触传播及家庭聚集性感染。科学管理密切接触者是控制SARS疫情蔓延的有效措施。     

一起公共场所传染性非典型肺炎暴发的流行病学分析

目的 对一起公共场所传染性非典型肺炎(SARS)暴发的流行状况和因素进行调查分析，为制定预防控制措施提供依据。方法 用统一的个案调查表对一起公共场所聚餐所致的SARS暴发病例及相关的所有病例进行调查，采集部分病例咽漱液、血清分别用荧光定量PCR测定SARS抗原和用ELISA测定SARSIgG、IgM。结果 2003年2月21～28日广州市芳村区某酒楼9名就餐聚餐后全部陆续发病，其中1人死亡，所有病例临床表现符合卫生部SARS临床诊断标准。用荧光定量PCR测定3例患咽漱液，2例SARS冠状病毒阳性；用ELISA法测定5例患血清，3例SARS冠状病毒特异性IgG抗体阳性，1例(指示病例)IgM抗体阳性。本起暴发发生于通风不良小型餐厅包房内，聚餐停留玩纸牌和进餐，时间长达3h。首例患于聚餐后次日(21日)发病，聚餐前多次到过SARS收治医院的呼吸病区看护患肿瘤的父亲(父亲和曾去医院看护的另2名亲属也分别在指示病例发病同日及10d内发病)，其余8名聚餐病前除这次聚餐外无其他明确的接触史或暴露史。病例发病潜伏期为2～8d，平均5d。结论 证实本次暴发是因长时间在通风不良的公共场所聚会所导致的SARS暴发，主要传播途径可能为近距离的飞沫传播和密切接触传播，潜伏期末的病人具有传染性。     

Superspreading SARS events, Beijing, 2003

Superspreading events were pivotal in the global spread of severe acute respiratory syndrome (SARS). We investigated superspreading in one transmission chain early in Beijing's epidemic. Superspreading was defined as transmission of SARS to at least eight contacts. An index patient with onset of SARS 2 months after hospital admission was the source of four generations of transmission to 76 case-patients, including 12 healthcare workers and several hospital visitors. Four (5%) case circumstances met the superspreading definition. Superspreading appeared to be associated with older age (mean 56 vs. 44 years), case fatality (75% vs. 16%, p = 0.02, Fisher exact test), number of close contacts (36 vs. 0.37) and attack rate among close contacts (43% vs. 18.5%, p < 0.025). Delayed recognition of SARS in a hospitalized patient permitted transmission to patients, visitors, and healthcare workers. Older age and number of contacts merit investigation in future studies of superspreading.     

广东省严重急性呼吸综合征的流行与控制

目的 分析广东省2003年严重急性呼吸综合征(severe acute respirstory syndrome,SARS)流行特征,探讨其危险因素,为有效控制该病的流行提供对策、依据与参考。方法 用描述流行病学方法对SARS流行病学及控制措施等相关资料进行描述与分析。结果 目前追溯到首例发病日期为2002年11月16日,家庭聚集发病5例;2003年1月2日,河源市为全国最早正式报告SARS病例的城市。至2003年6月15日止,广东省共有15个地级市报告SARS病例1511例,全省报告发病率为1．77／10万,主要集中在珠江三角洲的5个城市(佛山、广州、深圳、中山及江门),占病例总数的95．97％,广州市报告病例最多,占病例总数的85．81％;报告死亡数为58例,报告死亡率为0．07／10万,病死率为3．84％。发病高峰出现在1月28日至2月26日(占病例总数的50．69％),单日发病例数最多的为2月8日,共55例。发病年龄主要集中在青壮年(20—49岁),占65．86％。发病率随着年龄的增大而升高。有明显的医院和家庭聚集现象,医务人员的聚集性病例占病例总数的19．38％,家庭聚集性病例占12．04％。早期135例无明确接触史的社区散发患者中,从事与动物相关职业者11例,占8．14％。潜伏期为1—12d,中位数为4．5d。实行严格的SARS疫情监测报告制度,落实预防控制SARS的各项指引,切断SARS从患者到健康人的传播链,强化医院感染控制的技术指导和落实,做好消毒和个人防护工作是主要的控制措施。结论 切断SARS从患者到健康人的传播链是控制SARS流行的关键;重点控制医院内感染的发生;一些研究结果支持SARS病原可能来源于动物的假设。     

Detection of SARS coronavirus in patients with suspected SARS

Cases of severe acute respiratory syndrome (SARS) were investigated for SARS coronavirus (SARS-CoV) through RNA tests, serologic response, and viral culture. Of 537 specimens from patients in whom SARS was clinically diagnosed, 332 (60%) had SARS-CoV RNA in one or more clinical specimens, compared with 1 (0.3%) of 332 samples from controls. Of 417 patients with clinical SARS from whom paired serum samples were available, 92% had an antibody response. Rates of viral RNA positivity increased progressively and peaked at day 11 after onset of illness. Although viral RNA remained detectable in respiratory secretions and stool and urine specimens for >30 days in some patients, virus could not be cultured after week 3 of illness. Nasopharyngeal aspirates, throat swabs, or sputum samples were the most useful clinical specimens in the first 5 days of illness, but later in the illness viral RNA could be detected more readily in stool specimens.     

Contact Investigation for Imported Case of Middle East Respiratory Syndrome,Germany

On March 19, 2013, a patient from United Arab Emirates who had severe respiratory infection was transferred to a hospital in Germany, 11 days after symptom onset. Infection with Middle East respiratory syndrome coronavirus (MERS-CoV) was suspected on March 21 and confirmed on March 23; the patient, who had contact with an ill camel shortly before symptom onset, died on March 26. A contact investigation was initiated to identify possible person-to-person transmission and assess infection control measures. Of 83 identified contacts, 81 were available for follow-up. Ten contacts experienced mild symptoms, but test results for respiratory and serum samples were negative for MERS-CoV. Serologic testing was done for 53 (75%) of 71 nonsymptomatic contacts; all results were negative. Among contacts, the use of FFP2/FFP3 face masks during aerosol exposure was more frequent after MERS-CoV infection was suspected than before. Infection control measures may have prevented nosocomial transmission of the virus.     

北京市1 091例严重急性呼吸综合征临床诊断病例流行病学史再调查

目的　对北京市无明确流行病学史的 10 91例严重急性呼吸综合征 (SARS)临床诊断病例进行再次调查 ,了解其真实的流行病学史。方法　选择截止到 2 0 0 3年 6月 9日北京市全部无明确流行病学史的SARS临床诊断病例为调查对象 ,采用流行病学问卷调查法进行相关项目的调查。结果　调查时间为 2 0 0 3年 6月 9～ 30日 ,结果显示 ,10 91例临床诊断病例中 15 9%的患者通过补充调查找到了与SARS患者的接触史 ;10 5 %的患者存在续发史 ;4 6 5 %的患者找到了医院内感染史。流行病学史综合判定结果显示 ,在无明确流行病学史的临床诊断病例中有 4 6 6 %的患者通过补充调查找到了可能的流行病学史。结论　通过以流行病学史为主要内容的补充调查 ,部分患者可以找到相应的感染来源     

Late recognition of SARS in nosocomial outbreak, Toronto

Late recognition of severe acute respiratory syndrome (SARS) was associated with no known SARS contact, hospitalization before the nosocomial outbreak was recognized, symptom onset while hospitalized, wards with SARS clusters, and postoperative status. SARS is difficult to recognize in hospitalized patients with a variety of underlying conditions in the absence of epidemiologic links.