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。     

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。     

2003年深圳市传染性非典型肺炎流行特征分析

目的 了解深圳市传染性非典型肺炎(SARS)的流行病学特征。方法 对2003年深圳市常住和流动人口中发生的SARS临床诊断、疑似和医学观察病例进行描述流行病学分析。结果2003年深圳市共发生53例SARS临床诊断病例、69例SARS疑似病例和206例SAPS医学观察病例,其中SARS临床诊断病例的发病率为0．76／10万,死亡4例,病死率为7．55％。分析53例SARS临床诊断病例,结果 显示全市6区均发生病例;发病主要集中在2月上旬和3月下旬;男女性别比为1：0．66,20～39岁年龄组发病人数最多,占54．72％,职业分布以干部职员、学生病例为主,分别占24．5％、20、8％,无医护人员感染;19例患者有明确接触史,41例为散发病例。SARS临床诊断、疑似与医学观察三类病例的发病时间、职业分布、住院时间分布并不相同。结论 深圳市SARS发病以散发为主。及早采取集中定点收治病例,分类隔离治疗和观察等措施可有效控制SARS疫情的传播。     

社区控制SARS的现状分析与对策

目的 采取有效的预防措施，防止传染性非典型肺炎(简称SARS)在社区蔓延，控制和阻断SARS病源，保障社区居民的生命安全和身体健康。方法 对SARS密切接触者、间接接触者、从发生SARS病例地区返沪人员实行医学观察；来沪人员实行健康检测。结果 在所有医学观察及健康检测人员中，没有一人发生类似SARS症状，同时在上海连续出现输入性SARS病人后，本社区没有出现可疑SARS病人。结论 时传染性疾病密切接触者实行隔离观察是阻断传播途径的有效方法。     

传染性非典型肺炎传播链案例分析

目的 研究SARS传播规律及发病特点，为制定防制措施提供理论依据。方法 采用北京市统一的非典型肺炎个案流行病学调查表、非典型肺炎密切接触的调查表逐一对病例和密切接触进行调查。对出院病例进行随访。利用SPSS ll．0软件进行描述性分析。结果 首例患A感染SARS后，引起与其有过接触的家人和医务人员8人发病(第二代)，这些患又引起第三代5人发病。同与患A的接触情况看，第二代发病的患均与患A有近距离密切接触。接触时间越长越容易感染。本传播链病例发病的病程：潜伏期平均5d；发病到首诊时间平均3d；首诊到确诊时间平均10d。结论 SARS传播为近距离飞沫传播，密切接触发病与接触时间有关，发病到首诊的时间对控制传染源有意义。     

湖南省2003年传染性非典型肺炎防治工作及效果评价

目的 评价湖南省2003年传染性非典型肺炎防治工作情况及其效果。方法 使用统一的调查表对湖南省2003年报告的传染性非典型肺炎临床诊断病例、疑似病例和医学观察病例的发病、诊治、报告、流行病学调查处理等情况进行调查，将调查结果用SPSS11．0录入和进行统计分析。结果 湖南省13例临床诊断病例和疑似病例发病到被发现的间隔时间中位数为4d；医学观察病例的中位数为1d；76．92％的临床诊断病例、疑似病例被发现后1h得到报告。64．92％的医学观察病例能在2h内报告；临床诊断病例和疑似病例100％得到及时隔离治疗，医学观察病例的病例隔离治疗率为79．57％；所有临床诊断病例和疑似病例的流行病学调查工作均在接到报告后1h内开展，81．95％的医学观察病例的流行病学调查工作在接到报告后2h内进行；所有疫点或可疑疫点均得到了消毒，消毒率100％；临床诊断病例和疑似病例的密切接触者调查率、医学观察率均为100％，医学观察病例的密切接触者被调查率和医学观察率分别为92．51％和78．00％。结论 湖南省2003年落实了“早发现、早报告、早隔离、早治疗”、严格疫情调查处理等措施，其防治工作是有效的。     

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。     

广东省传染性非典型肺炎流行病学特征分析

目的 了解广东省局部地区流行的传染性非典型肺炎(SARS)的流行病学特征，为制定预防控制对策和措施提供科学依据。方法 采用统一的流行病学个案调查表对SARS，临床确诊病例进行调查。分析SARS病例在广东省的流行过程、地区、时间、人群分布及聚集性等特征。结果 截止2003年6月6日，广东省21个地级市有15个市报告SARS病例1511例，发病率为1．98／10万，病死率为3．77％。发病主要集中在1月下旬到2月下旬(2月上旬达到高峰)，占病例总数的54．00％，。首例发病时间为2002年11月16日，末例发病时间为2003年2003年5月9日。病例主要集中在广州、深圳、江门、中山、佛山5个市，占96．03％，其中广州占86．04％。20～49岁发病占病例总数的65．45％；医务人员发病较多，占病例总数的22．90％；聚集性病例占31.97％(483／1511)。潜伏期1～12d，中位数4d。结论 广东省SARS疫情波及面广，发病相对集中，有明显的家庭和医院聚集现象；传播途径主要为近距离飞沫和密切接触传播。     

广州市医务人员传染性非典型肺炎流行情况及预防控制效果分析

目的 分析广州市医务人员传染性生非典型肺炎(SARS)流行的基本特征，探讨流行因素，评价防制措施，为医疗卫生单位开展SARS收治及预防控制工作提供指导。方法 采用统一调查表对医务人员SARS患进行流行病学调查，采用定性生研究方法对医院SARS流行影响因素、预防控制措施及其效果进行调查，资料采用描述性流行病学方法分析。结果 广州市医务人员首例SARS患发病时间为2003年1月13日，截止5月5日共有29家医疗卫生单位报告医护人员发病280例，占全市总病例数的26．07％。医务人员发病高峰在2月上、中旬，共有167例，占医务人员发病总数的59．64％，呈明显聚集性。4月后病例为零星散发。病例主要集中在1月下旬前开始收治SARS患(对SARS尚缺乏认识的时期)的6家医院，占总病例数的73．2％(2c15／280)。调查180例医务人员SARS患中92．22％直接参与过SARS患的救治工作。采取定点收治患、加强医院病区通风、加强医护人员自身的个人防护等综合措施后，2月下旬开始，医务人员的新发SARS病例明显减少。结论 控制SARS在医务人员中流行的关键措施是：(1)要对出现SARS症状的患高度警惕，及时诊断并隔离患；(2)严格按照操作规范做好个人防护措施；(3)收治区要合理布局，严格区分污染区、半污染区和清洁区；(4)加强病区通风换气；(5)严格按照有关指引做好污染物、空气及环境的消毒工作。     

广州市2006年禽流感患者未造成密切接触者传播的调查

目的 探讨人感染禽流感的密切接触者传播的可能性。方法 根据卫生部公布的定义和办法，发现和确定密切接触者，开展流行病学调查和医学观察，并检测部分接触者的血清抗体。结果 2006年广州市发生的禽流感患者，在发病前1个月未离开过该地，且无病、死禽的接触史；共发现了56名密切接触者，包括其女友、医务人员、亲属、朋友。经过7天的医学观察，未发现密切接触者被感染的现象。结论 与SARS传播不同，广州市禽流感患者在潜伏期末和发病期间，未发现可能通过飞沫、唾液、黏膜、皮肤伤口直接接触等方式造成人间传播，提示目前禽流感病毒引起人间传播的能力不强。     

Efficiency of quarantine during an epidemic of severe acute respiratory syndrome--Beijing, China, 2003

During March--July 2003, an epidemic of severe acute respiratory syndrome (SARS) in Beijing, China, accounted for 2,521 probable cases (attack rate: 19 per 100,000 population). To control the epidemic, public health officials initiated enhanced surveillance, isolation of SARS patients, use of personal protective equipment (PPE) by health-care workers, and quarantine of contacts of known SARS patients. Approximately 30,000 Beijing residents were quarantined in their homes or quarantine sites. To guide future quarantine policy, the Chinese Field Epidemiology Training Program (China FETP) of the Chinese Center for Disease Control and Prevention (China CDC) conducted a survey to estimate the risk for acquiring SARS among quarantined residents of Haidian District (2001 population: 2.24 million), Beijing, in May 2003, 1 month after the epidemic peaked. This report summarizes the results of that survey, which indicate that, as a component of a comprehensive SARS-control program, quarantine should be limited to persons who have contact with an actively ill SARS patient in the home or hospital, allowing for better focus of resources in future outbreaks.     

Quarantine for SARS, Taiwan

During the 2003 outbreak of severe acute respiratory syndrome (SARS) in Taiwan, >150,000 persons were quarantined, 24 of whom were later found to have laboratory-confirmed SARS-coronavirus (SARS-CoV) infection. Since no evidence exists that SARS-CoV is infective before the onset of symptoms and the quarantined persons were exposed but not symptomatic, we thought the quarantine's effectiveness should be investigated. Using the Taiwan quarantine data, we found that the onset-to-diagnosis time of previously quarantined confirmed case-patients was significantly shortened compared to that for those who had not been quarantined. Thus, quarantine for SARS in Taiwan screened potentially infective persons for swift diagnosis and hospitalization after onset, thereby indirectly reducing infections. Full-scale quarantine measures implemented on April 28 led to a significant improvement in onset-to-diagnosis time of all SARS patients, regardless of previous quarantine status. We discuss the temporal effects of quarantine measures and other interventions on detection and isolation as well as the potential usefulness of quarantine in faster identification of persons with SARS and in improving isolation measures.     

SARS control and psychological effects of quarantine, Toronto, Canada

As a transmissible infectious disease, severe acute respiratory syndrome (SARS) was successfully contained globally by instituting widespread quarantine measures. Although these measures were successful in terminating the outbreak in all areas of the world, the adverse effects of quarantine have not previously been determined in a systematic manner. In this hypothesis-generating study supported by a convenience sample drawn in close temporal proximity to the period of quarantine, we examined the psychological effects of quarantine on persons in Toronto, Canada. The 129 quarantined persons who responded to a Web-based survey exhibited a high prevalence of psychological distress. Symptoms of posttraumatic stress disorder (PTSD) and depression were observed in 28.9% and 31.2% of respondents, respectively. Longer durations of quarantine were associated with an increased prevalence of PTSD symptoms. Acquaintance with or direct exposure to someone with a diagnosis of SARS was also associated with PTSD and depressive symptoms.     

Determination of the appropriate quarantine period following smallpox exposure: an objective approach using the incubation period distribution

Determination of the most appropriate quarantine period for those exposed to smallpox is crucial to the construction of an effective preparedness program against a potential bioterrorist attack. This study reanalyzed data on the incubation period distribution of smallpox to allow the optimal quarantine period to be objectively calculated. In total, 131 cases of smallpox were examined; incubation periods were extracted from four different sets of historical data and only cases arising from exposure for a single day were considered. The mean (median and standard deviation (SD)) incubation period was 12.5 (12.0, 2.2) days. Assuming lognormal and gamma distributions for the incubation period, maximum likelihood estimates (and corresponding 95% confidence interval (CI)) of the 95th percentile were 16.4 (95% CI: 15.6, 17.9) and 16.2 (95% CI: 15.5, 17.4) days, respectively. Using a non-parametric method, the 95th percentile point was estimated as 16 (95% CI: 15, 17) days. The upper 95% CIs of the incubation periods at the 90th, 95th and 99th percentiles were shorter than 17, 18 and 23 days, respectively, using both parametric and non-parametric methods. These results suggest that quarantine measures can ensure non-infection among those exposed to smallpox with probabilities higher than 95-99%, if the exposed individuals are quarantined for 18-23 days after the date of contact tracing.     

北京市海淀区403例传染性非典型肺炎的流行病学分析

目的　分析北京市海淀区常住人口传染性非典型肺炎 [严重急性呼吸综合征 (SARS) ]的流行病学特征。方法　对海淀区常住人口中发生的SARS病例进行个案调查和描述性分析。结果2 0 0 3年 3月 1 8日至 5月 31日 ,海淀区常住人口中共发生SARS病例 40 3例 ,发病率约为 1 8.0 1 0万 ,死亡 2 7例 ,病死率为 6 .7%。患者中青壮年占 70 .4% ,尤以 2 0～ 2 9岁组高发。全区除一个乡外均受累 ,多以散发为主 ,只有 3个街道呈现明显的家庭或学校内爆发。流行基本可以划分为初始增长期(2 7天 )、高峰期 (2 1天 )和快速下降期 (2 6天 )。患者中有密切接触史的比例随各期呈递减趋势 (趋势χ2 =8.80 0 ,P =0 .0 0 3) ;初期接触地点主要在医院 (72 .7% ) ,而迅速下降期则以家中接触为主(85 .7% ) ;各期的职业构成谱也明显不同 (χ2 =36 .41 ,P <0 .0 1 )。无明确接触史的患者中 2 6 .6 %有外出史 ,其中又有 47.6 %是去医院 ,并且 65 %在流行的高峰期光顾医院。结论　海淀区常住人口SARS流行强度与全市持平 ,医院内获得感染是SARS流行的主要原因     

Understanding, compliance and psychological impact of the SARS quarantine experience

This study examines a cohort of persons quarantined during the 2003 SARS outbreak in Canada and describes their understanding of, difficulties and compliance with, and the psychological impact of the quarantine experience. A mailed questionnaire was administered to 1912 eligible adults and included the Impact of Events Scale - Revised (IES-R) to assess symptoms of post-traumatic stress disorder (PTSD). Self-reported compliance with all required quarantine measures was low (15.8+/-2.3%), although significantly higher when the rationale for quarantine was understood (P=0.018). Health-care workers (HCW) experienced greater psychological distress, including symptoms of PTSD (P<0.001). Increasing perceived difficulty with compliance, HCW, longer quarantine and compliance with quarantine requirements were significant contributors to higher IES-R scores. The low compliance with quarantine requirements introduces concerns about the effectiveness of quarantine as a public health measure. Improvements in compliance and reduced psychological distress may be possible by minimizing duration, revising requirements, and providing enhanced education and support.     

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).     

Management of inpatients exposed to an outbreak of severe acute respiratory syndrome (SARS)

This is a prospective observational study of a cohort of inpatients exposed to a severe acute respiratory syndrome (SARS) outbreak. Strict infection control policies were instituted. The 70 patients exposed to the SARS outbreak were isolated from the rest of the hospital. They were triaged, quarantined and cohorted in three open plan wards. Selective isolation was carried out immediately when symptoms and signs suspicious of SARS manifested clinically. The patients' ages ranged from 21 to 90 years and 56% had surgery before the quarantine. Sixteen patients with unexplained fever during the period of quarantine were isolated, seven of whom were eventually diagnosed with probable SARS. The crude incidence of SARS in our cohort was 10%. The SARS case fatality was 14%. No secondary transmission of the SARS virus within the cohort was observed. Strict infection control, together with appropriate triaging, cohorting and selective isolation, is an effective and practical model of intervention in cohorts exposed to a SARS outbreak. Such a management strategy eases the logistic constraints imposed by demands for large numbers of isolation facilities in the face of a massive outbreak.     

Differential effects of pandemic (H1N1) 2009 on remote and indigenous groups, Northern Territory, Australia, 2009

Pandemic (H1N1) 2009 influenza spread through the Northern Territory, Australia, during June-August 2009. We performed 2 cross-sectional serologic surveys on specimens from Northern Territory residents, with 445 specimens obtained prepandemic and 1,689 specimens postpandemic. Antibody titers were determined by hemagglutination inhibition against reference virus A/California/7/2009 on serum samples collected opportunistically from outpatients. All specimens had data for patients' gender, age, and address, with patients' indigenous status determined for 94.1%. Protective immunity (titer >40) was present in 7.6% (95% confidence interval [CI] 5.2%-10.1%) of prepandemic specimens and 19.5% (95% CI 17.6%-21.4%) of postpandemic specimens, giving a population-standardized attack rate of 14.9% (95% CI 11.0%-18.9%). Prepandemic proportion of immune persons was greater with increasing age but did not differ by other demographic characteristics. Postpandemic proportion of immune persons was greater in younger groups and around double in indigenous persons. Postpandemic proportion immune was geographically heterogeneous, particularly among remote-living and indigenous groups.     

广州市传染性非典型肺炎危险因素及传播途径

目的 了解SARS流行的危险因素及传播途径。方法 选择广州市经血清学检测SARS抗体阳性病例236例，SARS抗体阴性的健康人206例，采用单因素和多因素Logistic回归分析方法进行比较。结果 医务人员感染SARS的危险性比非医务人员大，其OR值为9．63(3．67～25．26)，流行期问不到医院可明显降低感染的危险性，其OR值为0．39(0．18～0．83)，不接触动物者感染SARS的危险性亦降低，OR值0．29(0．14～0．61)。多人同办公室或多人同厂工作可增加感染的危险性，其OR值分别为4．05(1．34～12．20)和24．43(3．92～152．32)，工作场所通风不良的OR值为2．91(1．15～7．37)。无麻疹、流感等疫苗按种史者可能会增加感染SARS的危险性，OR值为2．03(0．93～4．41)，但无显著性差异。不吸烟者的OR值为2．43(0．79～7．44)，但无显著性差异。结论 除与病人密切接触或近距离接触是重要传播途径外，工作场所人口密集和通风不良是感染SARS的危险因素。动物接触史与SARS发生有密切关系，支持SARS病毒来源于动物的可能性。