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2009甲流疫情发生概况

2009年4月24日：墨西哥出现“猪流感”患者约800例， 包括60例死亡病例 美国出现7例确诊病例 世卫组织要求各国卫生部门提高警惕 4月25日：世卫组织确认该病毒属H1N1毒株族， 具有“潜在大流行”能力 4月27日：世卫组织宣布将警戒级别从3级提升至4 级。欧洲证 实出现最早 3例确诊病例

4月28日：拉丁美洲和中东地区证实出现确 诊病例 4月29日：美国出现首例死亡病例 同日，世卫组织宣布再次提升警戒级别 4月30日：世卫组织采用“甲型H1N1流感病毒” 替代 原有猪流感一说 6月11日：世卫组织宣布流感大流行，提升警戒级别至 最高一级的6级水平

The pandemic phase is characterized by community level

• utbreaks in at least one other country in a different

WHO region in addition to the criteria defined in Phase 5. A global pandemic is under way.

在中国

截止到2010年3月31日，全国累计报告确诊甲流病 例12.7万余例，其中境内感染12.6万余例，境外输入 1228例；已治愈12.2万余例，在院治疗4859例，居家 治疗46例，死亡病例800例。

1.1 H1N1

Swine influenza virus ( SIV) is a kind of pigs’

• rthomyxoviridae which can cause local influenza .

World Health Organization renamed this new type of deadly

swine flu as H1N1 influenza virus (influenza A (H1N1))on April 30 ,2009.

Influenza A( H1N1) virus is a kind of influenza virus

type A, carrying the H1N1 subtype swine influenza virus strains which contains gene fragments of avian flu, swine flu and human influenza virus. It also carries the characteristics of influenza viruses of pigs in Asia and Africa .

Medical tests show that the current mainstream of

antiviral drugs effective against this strain.

Antigenic shift is the process by which at least two

different strains of a virus (or different viruses), especially influenza, combine to form a new subtype having a mixture of the surface antigens of the two

• riginal strains. The term antigenic shift is more often

applied specifically (but is not limited) to the influenza literature, as it is the best known example (e.g. visna virus in sheep). Antigenic shift is a specific case of reassortment or viral shift that confers a phenotypic change.

1.2 symptoms of H1N1 flu

fever Cough Sore throat Body aches headache chills runny nose feeling very tired diarrhea Vomiting Symptoms last from a

few days to up to a week

• r more

1.3 High risk groups for severe illness

Children younger than 2

years old

Pregnant woman up to 2

weeks post partum (regardless how the pregnancy ended)

Adult, 65 years of age or

• lder

Persons younger than 19

years who are receiving long‐ term aspirin therapy.

Persons with medical

condition including asthma, neurological and neurodevelopmental conditions (including disorder of the brain, spinal cord, peripheral nerve, and muscle such as cerebral palsy) chronic obstructive lung disease, cardiac disease, diabetes mellitus, immunosuppressive conditions (including HIV/AIDS, and cancer)

1.4 How does H1N1 flu spread?

wet spray (droplets of saliva and mucous) that comes out

• f the nose and mouth of someone who coughs or sneezes.

The virus can also live for a short time on things you touch like doorknobs, phones and toys.

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2 Pre-existing immunity against swine-origin H1N1 influenza viruses in the general human population

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there is concern that little protective immune memory exists

in the general human population. this concern was confirmed by reports that neutralizing antibodies against S-OIV are found nearly exclusively in persons born before 1957

together with reports of differences in athogenicity of the

virus in animal models compared with seasonal human H1N1 strains

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the incidence of clinically severe cases so far appears to be similar to that experienced for seasonal flu why? the possibility that some level of immunity against S-OIV sequences might exist in the general population

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The experiments demonstrate that a significant level of T-cell immunity might pre-exist in the general population against epitope sequences that are found totally conserved in S- OIV.

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with only 17% (1/6) conserved in the HAand NA surface proteins,a new vaccine based on the specific S-OIV HA and NA proteins is likely to be required to prevent infection

vaccine for H1N1 flu

Two types： One is a “shot” that is given with a needle, usually in the arm. The other is a “nasal spray” (a spray inhaled through the nose).

Narayan, O (1977). "Antigenic shift of visna virus in persistently

infected sheep". Science)197 (4301): 376–378. doi:10.1126/science.195339. PMID 195339. )

Treanor, John (2004-01-15). "Influenza vaccine--outmaneuvering

antigenic shift and drift". New England Journal of Medicine350 (3): 218–220. doi:10.1056/NEJMp038238. PMID14724300. http://content.nejm.org/cgi/content/full/350/3/218. Retrieved 2008- 01-07.

Al Hajjar, S. and K. McIntosh (2010). "The first influenza pandemic

• f the 21st century." Ann Saudi Med 30(1): 1-10.

Gordon, S. M. (2009). "Update on 2009 pandemic influenza A

(H1N1) virus." Cleve Clin J Med 76(10): 577-582.

Joshi, S. R., A. C. Shaw, et al. (2009). "Pandemic influenza H1N1

2009, innate immunity, and the impact of immunosenescence on influenza vaccine." Yale J Biol Med 82(4): 143-151

http://qe.qe.cn/HTML/296856.shtml

“Pre-existing immunity against swine-origin H1N1 influenza

viruses in the general human population,” Jason A. Greenbaum, Maya F. Kotturi, Yohan Kim, Carla Oseroff, Kerrie Vaughan, Nima Salimi, Randi Vita, Julia Ponomarenko, Richard H. Scheuermann, Alessandro Sette， Bjoern Peters

Lopez-Cervantes, M., A. Venado, et al. (2009). "On the spread

• f the novel influenza A (H1N1) virus in Mexico." J Infect Dev

Ctries 3(5): 327-330

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