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SARS 与 H1N1 的流行概况

SARS 与 H1N1 的流行概况. 余运贤 流行病学与卫生统计学教研组. 传染病和流行病学的概念. 传染病是由病原体（细菌、病毒和寄生虫）引起的能在人与人或人与动物之间传播的疾病。 流行病学是研究 人群 中疾病与健康状况的分布及其影响因素，并研究防制疾病及促进健康的策略和措施的科学。. 传染病流行的基本环节. 传染源 ： 散播病原体的人或动物 传播途径： 病原体离开传染源到达健康人所经过的途径 易感人群： 对某种传染病缺乏免疫力而容易感染该病的人群. 传染病的预防措施：. 1 、控制传染源. 2 、切断传播途径. 3 、保护易感人群.

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SARS 与 H1N1 的流行概况

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  1. SARS与H1N1的流行概况 余运贤 流行病学与卫生统计学教研组

  2. 传染病和流行病学的概念 • 传染病是由病原体（细菌、病毒和寄生虫）引起的能在人与人或人与动物之间传播的疾病。 • 流行病学是研究人群中疾病与健康状况的分布及其影响因素，并研究防制疾病及促进健康的策略和措施的科学。

  3. 传染病流行的基本环节 • 传染源 ：散播病原体的人或动物 • 传播途径：病原体离开传染源到达健康人所经过的途径 • 易感人群：对某种传染病缺乏免疫力而容易感染该病的人群

  4. 传染病的预防措施： 1、控制传染源 2、切断传播途径 3、保护易感人群

  5. 描述性研究（descriptive study） • 通过描述疾病或健康状况的三间分布情况，找出某些因素与疾病或健康状况间的关系，提供病因线索。 • 又称描述性流行病学。指根据日常记录资料或通过特殊调查所得的资料，包括实验室检查结果。按不同地区、不同时间及不同人群特征分组，将一个社区人群疾病或健康状态分布情况进行简单描述，常常是流行病学调查的第一步，也是分析流行病学的基础。它主要描述分布的三大特征，即：地区特征、时间特征和人群特征。

  6. Severe Acute Respiratory Syndrome (SARS） • The 2002-2003 SARS outbreak infected 8,422 individuals leading to 916 deaths in eight affected areas • The first case was identified on 16 November 2002 in the southern Chinese city of Foshan. • The epidemic then spread within Guangdong province before a large superspreading event in Hong Kong seeded the global outbreak. • On 5 July 2003, the World Health Organization (WHO) announced the last affected area Taiwan to be transmission free and declared the last human-to-human transmission chain successfully interrupted

  7. SARS 传染源 • SARS coronavirus (CoV), was identified as the infectious agent in the syndrome. • The origin of this pandemic remains unclear. ？

  8. SARS Epidemiology The first wave • a chef from Heyuan who worked at a restaurant in Shenzhen was reported to have atypical pneumonia； • His wife, two sisters, and seven medical staff were infected； • SARS was outbreak in Heyuen in early Dec, 2002; • The outbreak happened in Zhongshan. 28 case were recognised. 13 of the 28 patients were health-care workers.

  9. SARS Epidemiology The second wave—since Jan 12, 2003 • A 46-year-old male seafood merchant who was admitted to the Second Affiliated Hospital of Zhongshan University on Jan 31, 2003. • The patient stayed in the hospital for only 18 h, but caused more than 30 hospital staff to become infected. • During transfer, ambulance driver, two doctors, and two nurses were infected. • Within the next 8 days, 20 more medical staff and 19 family members who had been in contact with the patient became infected. • And then resulted in outbreak in Guangzhou. • In mid-February, one doctor working at the Second Affiliated Hospital of Zhongshan travelled to Hong Kong, and became the major source of the SARS The outbreak was characterised by infection within hospitals and family clusters, suggesting that transmission arises through close contact with infected patients.

  10. Characteristics of SARS patients in Hong Kong, Beijing and Taiwan. Lau et al. BMC Infectious Diseases 2010, 10:50

  11. Figure 2A shows the epidemic curve in each region

  12. SARS Incubation • The estimated means of the incubation distributions were 4.4 days in Hong Kong, 5.7 days in Beijing and 6.9 in Taiwan. • The mean delay from onset to admission were 3.6, 2.7 and 2.8 days respectively for Hong Kong, Beijing and Taiwan.

  13. 传播途径 • water-borne • Food-borne • blood-borne • vector-borne • Air-borne • others

  14. SARS病毒的传播 主要经过紧密接触传播，以近距离飞沫传播为主，也可通过手接触呼吸道分泌物，经口鼻眼传播，另有研究发现存在粪-口传播的可能。

  15. 危险人群： 1、医务人员 2、家庭成员、共同生活者 3、关系密切的朋友 4、接触病人者 密切接触

  16. Nanshan Zhong. BMJ 2006;333;389-391

  17. H1N1 Epidemic • WHO declared a pandemic in June 2009, a total of 74 countries and territories had reported laboratory confirmed infections. • As of October 2009, worldwide H1N1 virus has been implicated in over318 925 laboratory-confirmed human cases and 3917deaths. • As of 20 May 2009, 10 243 laboratory-confirmed cases of new influenza A (H1N1) virus infection, including 80 deaths, had been reported to WHO from 41 countries. • Most of these cases were from North America (USA, 5469; Mexico, 3734; Canada, 496). • The majority of fatal cases were reported from Mexico • Approximately 2–5% of confirmed cases in the United States and Canada, as well as 6% in Mexico, have been admitted to hospital.

  18. H1N1 distribution by age http://www.who.int/wer

  19. High risk for hospitalization • Almost one-half of the patients hospitalized in the United States, and 21 of 45 (46%) fatal cases in Mexico have had underlying conditions, including pregnancy, asthma, other lung diseases, diabetes, morbid obesity, autoimmune disorders and associated immunosuppressive therapies, neurological disorders and cardiovascular disease. • Among 20 pregnant women in the United States confirmed to have been infected with new influenza A (H1N1) virus, 3 required hospitalization, 1 of whom died. • Among 30 patients hospitalized in California, 64% had underlying conditions and 2 of 5 pregnant women developed complications, including spontaneous abortion and premature rupture of membranes. http://www.who.int/wer

  20. Map: International Co-circulation of 2009 H1N1 and Seasonal Influenza(As of October 2, 2009; posted October 2, 2009, 11:00 AM ET)

  21. HINI Incubation • The median incubation period of the virus was 2 days (range, 1 to 7). Cao et al. N Engl J Med 2009;361:2507-17.

  22. 甲型流感病毒 • 病毒家族:正黏液病毒科 • 基因组为单股负链RNA病毒 • 呈球形，直径8O一120 nm，有囊膜 • 根据外膜蛋白血凝素抗原(HA)和神经氨酸酶(NA)，甲型流感病毒可以分为l5个H亚型 感谢: L. Stammard, 1995

  23. The pandemic H1N1 virus is spread from person to person, similar to seasonal influenza viruses. It is transmitted as easily as the normal seasonal flu and can be passed to other people by exposure to infected droplets expelled by coughing or sneezing that can be inhaled, or that can contaminate hands or surfaces. 传播途径

  24. Population Immunizationin 2008 Miller et al. Lancet. 2010 Mar 27;375(9720):1100-8.

  25. Baseline immunization in 2008 Miller et al. Lancet. 2010 Mar 27;375(9720):1100-8.

  26. The population immunization in 2009 Miller et al. Lancet. 2010 Mar 27;375(9720):1100-8.

  27. Special example for influenza • when an airplane that held 54 passengers, 1 of whom had influenza, was grounded for three hours with a failed air-circulation system, a clinical syndrome of influenza developed in 72 percent of all passengers during the next three days.

  28. Daniel M. Musher N Engl J Med 2003;348:1256-66.

  29. How to protect from H1N1 • Avoidance of infections that are spread by large droplets requires avoidance of close contact with ill persons. • In the case of infections that are spread by droplet nuclei, shared space should also be avoided unless ventilation is extremely good: attending a Broadway show during an outbreak of influenza is certainly not advisable for a person who has not been vaccinated. • Washing hands after greeting someone with a viral infection may be appropriate, because viruses may be transmitted by direct contact, • and self-inoculation is an important part of pathogenesis.

  30. 流感疫苗研究现状 6月8日，甲型H1N1流感疫苗生产用毒株，从美国运抵北京，标志着甲型H1N1流感疫苗的批量生产正式启动。

  31. Controlling communicable diseases (1) • Preparedness and prevention • training health and outreach staff • supplies and equipment for diagnosis, treatment and environmental health measures; • strengthening health surveillance systems and practicing protocols for managing information on certain diseases; • raising awareness among the population

  32. Health care worker infected in SARS outbreak • From November 2002 to July 2003, severe respiratory distress syndrome (SARS) quickly spread from Foshan (Shunde district), Guangdong Province in the People’s Republic of China to 33 other countries or regions on 5 continents. • There were 8447 cases, 21% occurring in health care workers (HCWs), and 813 deaths (9.6% overall mortality) by the time of July 2003. • In the Hong Kong and Hanoi outbreaks, 46% and 63% of cases occurred in HCWs, respectively.

  33. Controlling communicable diseases (2) • Public-health surveillance • Public-health surveillance is the collection, analysis and dissemination of health information to enable appropriate action to be taken. • Outbreak control • Suspected disease outbreaks, indicated by information from a health surveillance system, should be rapidly investigated using standards protocols for assessment • The two main strategies for controlling outbreaks of communicable disease are to reduce the number of cases through preventive activities and to reduce mortality due to the disease through early case detection and effective treatment

  34. Outbreak control • Preventive and curative measures work together • to reduce the sources of infection by rapidly isolating and treating patients and controlling animal reservoirs; • to protect susceptible groups through immunization, nutritional support and possibly chemoprophylaxis • to reduce transmission through improvements in hygiene conditions and hygiene behaviour.

  35. 医院是传染病管理的前哨 • 医院是传染病的集散地 • 医务人员是传染病的高暴露人群 • 医务人员要承担传染病管理的任务 • 传染病报告 • 病人管理 • 疾病监测

  36. Thanks！！！

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