*H1N11342H1N1

H1N1

(H1N1)

Influenza Surface ProteinsM1 protein

Influenza A virus RNA segment and protein

RNA segmentProteinFunction/Activity1PB2Cap-binding, endonuclease2PB1RNA polymerase3PAProteolysis4HAAttachment to sialic acid, fusion5NPStructural protein6NASialidase, release of virus7M1, M2Structural protein, Ion channel8NS1, 2RNA transport, splicing, translate

Antigenic ShiftSwine cell

Influenza virusFamily Orthomyxoviridae(segmented negative strand RNA virus)Influenza A: 8 segmentsInfluenza B: 8 segmentsInfluenza C: 7 segmentsTyping: CF antibody against core proteinsM1: matrix proteinNP: nucleoprotein

ABC

H1N1, H3N2, B,Immune protectionH5N1,Immune destruction

YearsFluVirusMortality1918-1919SpanishType A (H1N1) 20 million worldwide 550,000 US1957-1958AsianType A (H2N2)70,000 US1968-1969Hong KongType A (H3N2)34,000 US1977-1978Russian Type A (H1N1)negligableGlezen WP. Epidemiol Rev. 1996;18:65. Centers for Disease Control and Prevention. Influenza Prevention and Control. Influenza. Available at: http://www.cdc.gov/ncidod/diseases/flu/fluinfo.htm.Influenza Pandemics in the 20th Century

WHO

(Inter-pandemic)Phase 1Phase 2(Pandemic alert)Phase 3Phase 4Phase 5(Pandemic)Phase 6

WHOOH5H7 1.2.Phase 1Phase 2Phase 3A1Phase 4Phase 5A2Phase3~phase5 BPhase 5CPhase 6 Post-peak Post-pandemic

17173

H1N1

() 1.:2.3.2 4. 5.:

() H1N1 1 275 3 H1N1

() H1N1 1. H1N1 72. H1N1 1.2.3. H1N1

Mask

(..)

N95

H1N1N95()H1N1

Benefits of fit testingStudy: 25 volunteers, 21 models of N-95 respiratorsWithout fit testing, 95% of the tests had up to 33% leakageWith fit testing, 95% of the tests had no more than 4% leakage

(Tamiflu)(Relenza)H1N1

3 2 2 1

192206-6333080 http//www.cdc.gov.tw

*[Keywords] ###Two glycoproteins jut out from the surface of the influenza virus: hemagglutinin (HA) and neuraminidase (NA). Both of these antigenic surface proteins play key roles in viral infection and dissemination.Slide 11Lecture Notes*[Keywords] ###In contrast to the gradual evolution of strains subject to antigenic drift, antigenic shift occurs as soon as a type A influenza virus with a completely novel hemagglutinin or neuraminidase formation moves into humans from other host species. The primary source is birds, certain species of which carry a reservoir of 15 influenza A subtypes.16 These subtypes either genetically reassort themselves with circulating human influenza virus or are transmitted directly into humans, typically via intermediate hosts such as swine.15Antigenic shift of type A influenza viruses occurs less frequently than antigenic drift, but with more dramatic impact. The result of global immunologic susceptibility to a new influenza virus is often pandemic. The influenza pandemics of both 1957 and 1968, for example, were caused by genetic reassortment between human and avian influenza A virus.16To date, influenza type B viruses have not been subject to antigenic shift.15Slide 16Lecture Notes*[Keywords] ###Three influenza pandemics have occurred in the 20th century.The Spanish flu of 1918-1919 killed over 550,000 people in the United States.6 Some virologists refer to this as swine flu. 18 The population of young healthy adults was particularly affected: one of every 100 persons aged 20-39 years died of influenza-related causes.6 Some historians believe that World War I ended in part because of this pandemic.19The Asian flu occurred with the transmission into humans of the avian influenza virus type A (H2N2), causing 70,000 deaths in the United States in 1957-1958.13 The H2N2 virus no longer circulates in humans. The most recent pandemic was the Hong Kong flu (H3N2), which occurred in 1968-1969 and killed approximately 34,000 people in the United States.13

Slide 18Lecture Notes*WHO20056 Phase1 phase2Inter-pandemic phase phase1 Phase2Phase3~5 Phase3Phase425 Phase5 25~502~4 Phase6 phase3*A NIOSH scientist recently did some testing of 21 commercially available N-95 respirators. He used 25 volunteers to test each model 4 times, or 100 per respirator, and he measured leakage and penetration. His criteria for pass were that 95% of the time, a respirator should allow exposure to less than 10% of the hazard outside the respirator. He found some interesting things:-without fit testing, 95% of the tests had more than 33% leakage-17 of the 21 had acceptable fits for less than half the 25 volunteers- for some respirators, 95% of the time the wearer had 88% leakage - almost no protection.With fit testing, you can see which respirator fits you badly so you can choose another size or model. After fit testing, 95% of the tests had no more than 4% leakage. Thats a lot better protection!