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.     

上海市传染性非典型肺炎流行病学特征分析

[目的 ]　分析上海市 2 0 0 3年传染性非典型肺炎 (SARS)流行病学特征 ,初步评价防制效果。　 [方法 ]　采用统一的流行病学调查表对病例进行流行病学调查 ,描述和分析流行病学、病原学等相关资料和控制措施。　 [结果 ]　2 0 0 3年 3月下旬至 5月上旬 ,19个区县有 5个区报告SARS病例共 8例 ,发病率为 0 .0 5 / 10万 ,其中 5例由疑似转为临床病人 ,发病主要集中在 4月份 ,均为 2 0岁以上成年人。除 1例为接触感染 ,其余 7例均为非本地感染病人。经治疗 6例治愈出院 ,2例死亡 (为 60岁以上者 )。病人密切接触者 3 3 3人中发生 1例病人 ,续发病率为 0 .3 %。医务人员中无一人感染 ,家庭和社区内未发生集聚性发病。　 [结论 ]　上海市SARS病人以非本地感染为主 ,续发病率低 ,采取及时有效地隔离病人 ,对密切接触者医学观察和采取个人防护措施 ,是切断传播链的有效途径     

Severe acute respiratory syndrome, Beijing, 2003

The largest outbreak of severe acute respiratory syndrome (SARS) struck Beijing in spring 2003. Multiple importations of SARS to Beijing initiated transmission in several healthcare facilities. Beijing's outbreak began March 5; by late April, daily hospital admissions for SARS exceeded 100 for several days; 2,521 cases of probable SARS occurred. Attack rates were highest in those 20-39 years of age; 1% of cases occurred in children <10 years. The case-fatality rate was highest among patients >65 years (27.7% vs. 4.8% for those 20-64 years, p < 0.001). Healthcare workers accounted for 16% of probable cases. The proportion of case-patients without known contact to a SARS patient increased significantly in May. Implementation of early detection, isolation, contact tracing, quarantine, triage of case-patients to designated SARS hospitals, and community mobilization ended the outbreak.     

Epidemiologic study and containment of a nosocomial outbreak of severe acute respiratory syndrome in a medical center in Kaohsiung, Taiwan.

OBJECTIVE: We conducted an epidemiologic investigation at the beginning of a nosocomial outbreak of severe acute respiratory syndrome (SARS) to clarify the dynamics of SARS transmission, the magnitude of the SARS outbreak, and the impact of the outbreak on the community. METHODS: We identified all potential cases of nosocomially acquired SARS, linked them to the most likely infection source, and described the hospital containment measures. SETTING: A 2,300-bed medical center in Kaohsiung, Taiwan. RESULTS: A total of 55 cases of SARS were identified, and 227 hospital workers were quarantined. The index patient and neighboring patients were isolated. A chest physician team reviewed medical charts and chest radiographs and monitored the development of SARS in patients staying in the ward. The presence of underlying lung disease and immunocompromise in some patients made the diagnosis of SARS difficult. Some cases of SARS were diagnosed after the patients had died. Medical personnel were infected only if they cared for patients with unrecognized SARS, and caretakers played important roles in transmission of SARS to family members. As the number of cases of nosocomial SARS increased, the hospital closed the affected ward and expedited construction of negative-pressure rooms on other vacated floors for patient cohorting, and the last case in the hospital was identified 1 week later. CONCLUSIONS: Timely recognition of SARS is extremely important. However, given the limitations of SARS testing, possible loss of epidemic links, and the nonspecific clinical presentations in hospitalized patients, it is very important to establish cohorts of persons with low, medium, and high likelihoods of SARS acquisition. Rapid closure of affected wards may minimize the impact on hospital operations. Establishment of hospitals dedicated to appropriate treatment of patients with SARS might minimize the impact of the disease in future epidemics.     

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.     

湖北省传染性非典型肺炎流行病学分析

目的了解湖北省传染性非典型肺炎流行病学特征及其影响因素．为制订预防控制对策提供依据。方法根据传染性非典型肺炎病例个案调查表、密切接触者调查表和国家法定传染病监测系统资料,使用Excel软件进行统计分析。结果湖北省2003年报告7例传染性非典型肺炎病例,其中死亡1例,发病率0．012／10万,病死率14．3％以输入病例为主,其中2例为继发病例,呈点状散发。结论估计病例潜伏期为1～10天,一般潜伏期在1周内,未观察到病例发病前有传染性。     

Analysis of Japanese encephalitis epidemic in Western Nepal in 1997

We conducted an epidemiological study of a Japanese encephalitis (JE) outbreak in the southwestern part of Nepal in 1997. A high density of JE infections was found and it was estimated that 27.9% the total population were infected with JE virus in the study area. The fatality rate was 13.2% and there was no difference in the fatality rate between males and females over 5 years old. However, the case fatality rate was 2.1 times higher in females than in males (14.6% vs. 6.9%) among children under 5 years of age. Fifty-three blood samples were collected from suspected JE cases during the epidemic period in 1998. Findings for JE specific IgM revealed that clinical diagnoses of JE were serologically confirmed in an average 78% (70-93%) of patients in three collaborating hospitals. These studies demonstrated that JE was highly prevalent in the area and clinical diagnoses were reliable. Effective preventive measures should be taken against this vaccine-preventable disease.     

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     

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。     

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。     

广东省传染性非典型肺炎流行病学特征初步调查

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病例进行调查。利用EPI6．0软件分析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 SARS在广东省的发病率为1．72／10万，病死率为3．64％。发病主要集中在1月下旬至2月下旬(2月上旬达到高峰)，占病例总数的61．88％。地区分布以经济发达、人口流动频繁的珠江三角洲地区为主，占病例总数的96．66％；患者以青壮年居多；医务人员是高发人群，占病例总数的24．9％；有明显的家庭和医院聚集，聚集性病例占37．1％。结论 SARS是一种呼吸道传播为主的传染病，目前发现传染源是人，潜伏期1—12天，中位数4天；通过短距离飞沫和密切接触传播；人群普遍易感，病例主要集中在经济发达、人口流动频繁的珠江三角洲地区。     

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％。     

37例传染性非典型肺炎流行病学分析

目的 了解传染性非典型肺炎(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病例进行调查并分析。结果 深圳市福田区共报告37例散发SARS病例，患以青壮年为主，平均年龄23．1a；发病率为4．38／10万，病死率为5．4％，有一定的家庭聚集性，无医务人员感染。结论 SARS是一种以呼吸道传播为主的传染病。目前发现传染源是SARS病人，潜伏期1～12d，通过短距离飞沫和密切接触传播，人群普遍易感。     

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。     

严重急性呼吸综合征（SARS）调查分析

目的 了解严重急性呼吸综合征(SARS)流行病学的特点，提出相应的预防和控制措施。方法 采取现场调查、网上电子病历审查、电话询问等方法。结果 认真贯彻落实消毒隔离制度，医院内无任何人员感染发病。SARS住院病人治愈率为89．2％，病死率5．4％，有接触史患占37．8％。结论 SARS病例在年龄上以青壮年为主，职业以商业餐饮服务人员为多。     

焦作市解放区新型冠状病毒肺炎聚集性疫情流行病学特征分析

目的:通过对焦作市解放区新型冠状病毒肺炎聚集性疫情进行描述和分析,探讨其流行病学特征,为有效防控新型冠状病毒肺炎提供科学依据。方法:根据国家卫生健康委员会《新型冠状病毒感染的肺炎防控方案(试行第五版)》流行病学调查指引,采用描述性分析的方法,探讨焦作市解放区新型冠状病毒肺炎聚集性疫情的流行病学特征。结果:焦作市解放区自2020年2月1日确诊首例新型冠状病毒肺炎病例以来,确诊病例数共7例,无死亡病例。其中6例来自3起聚集性疫情,这3起聚集性病例均为家庭暴露引发,1起聚集性病例存在明显的病例代际。结论:焦作市解放区新型冠状病毒肺炎聚集性疫情以家庭暴露为主,在居家生活中应注意个人防护,患者应避免与其他家庭成员密切接触,做好自我隔离。     

广州市传染性非典型肺炎流行病学及预防控制效果的初步研究

目的 分析广州市2003年传染性非典型肺炎(SARS)流行的基本特征，探讨流行因素，评价防制措施。方法 对2003年广州市SARS患者进行流行病学调查，描述和分析流行病学、病原学和控制措施等相关资料。结果 2003年1月至4月17日，累计报告发病966例(男429例，女性537例)。首例广州市居民病例于1月2日发病；2月开始全市疫情呈上升趋势，2月上旬达到最高峰，此后疫情呈下降趋势，4月份后，平均每日新发病例降至10例以下；年龄分布以20—50岁发病数较多，低年龄组的发病数较少313个区(县级市)均有病例发生，但病例主要集中于7个中心城区，占总病例数的95％；职业以医务人员多发(占28．67％)；死亡36例，死者年龄在5—89岁之间，60岁以上占50％，死亡病例中原合并有其他疾患，如高血压、糖尿病、心脏病、肺气肿等占38.9％。发病有聚集性，42个家庭发生2例以上病例；28家医疗单位有277名医务人员发病；公共场所仅发生1起聚集性病例；学校未发生聚集性病例。流行病学特点：主要经呼吸道传播，可以气溶胶和飞沫的方式传播；接触性传播可能也是传播方式之一；传染力强，尤其是在密闭的空间内近距离接触病例获得感染的机会比较大；潜伏期1一11天，多数为3—8天，平均为5天；发病有明显的聚集性。主要控制措施及效果：病人隔离治疗，疑似病人隔离观察；加强病房通风换气；进行空气、物体表面消毒；医务人员加强个人防护。采取控制措施后，医务人员发病率显著下降。结论 根据广州市疫情控制的经验，SARS是可以预防和控制的。聚集性病例的控制应该作为重点，而控制医院内感染的发生，是非常关键的措施。     

SARS in hospital emergency room

Thirty-one cases of severe acute respiratory syndrome (SARS) occurred after exposure in the emergency room at the National Taiwan University Hospital. The index patient was linked to an outbreak at a nearby municipal hospital. Three clusters were identified over a 3-week period. The first cluster (5 patients) and the second cluster (14 patients) occurred among patients, family members, and nursing aids. The third cluster (12 patients) occurred exclusively among healthcare workers. Six healthcare workers had close contact with SARS patients. Six others, with different working patterns, indicated that they did not have contact with a SARS patient. Environmental surveys found 9 of 119 samples of inanimate objects to be positive for SARS coronavirus RNA. These observations indicate that although transmission by direct contact with known SARS patients was responsible for most cases, environmental contamination with the SARS coronavirus may have lead to infection among healthcare workers without documented contact with known hospitalized SARS patients.     

广东省SARS家庭聚集性病例流行病学分析

目的　了解广东省传染性非典型肺炎 (SARS)家庭聚集性病例的流行病学特征 ,探讨家庭因素在本病传播方面的作用。方法　采用统一个案调查表 ,用描述性流行病学方法对广东省SARS家庭聚集性病例进行分析。结果　截至 5月 1 5日止 ,在广东省 1 5 1 2例SARS病例中 ,6 0户家庭出现聚集性病例 ,共 1 91例 ,占全省病例总数的1 2 6 %。家庭聚集性病例的病死率为 9 9% ,高于全省平均病死率 (3 7% ) (P <0 0 1 )。家庭聚集性病例主要发生在2 0 0 3年 1月至 3月 ,占家庭聚集性病例总数的 90 6 % (1 73/ 1 91 )。病例以 30～ 4 9岁青壮年为主 ,占 5 2 9% (1 0 1 / 1 91 ) ;职业以干部职员为主 ,占 1 3 6 % (2 6 / 1 91 ) ,其次为饮食、服务人员 ,占 1 2 6 % (2 4 / 1 91 )。 4 1 7%家庭的首发病例在发病前两周有明确或可疑接触史。在 1 2 9例家庭聚集二代感染病例中可能因陪护或探病感染发病的有 4 2户 ,共 92例 ,占71 3%。首发病例与二代病例发病时间间隔中位数为 7d。结论　家庭聚集性病例的病死率较高 ,家庭聚集性病例有较大比例可能在医院内感染 ,但家庭密切接触也是造成疫情传播的原因之一 ,控制医院内感染和及早对病例进行家庭隔离可以减少聚集性病例的出现