Viral Zoonoses

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INFLUENZA
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Influenza



                                                             
Outbreaks g Widespreadg Regionalg Localg Sporadicg Negligibal or no surveillance Outbreaks g Widespreadg Regionalg Localg Sporadicg Negligibal or no surveillance                                                              
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Influenza

• Type A, B, or C
• family Orthomyxoviridae

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Type A influenza

• contagious ???????? ????????? acute respiratory
  disease ????????????????? ???????????
• ?? ??? ??? ??????????????????????
• ?????????????? ????? cattle
• sporadic influenza A virus ?????????????????????
  ???????? ?????????????

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Type B and C influenza

• ?????????????
• influenza B ????????????????????????????????????
  ???????????????????????? pandemic ??????
  influenza A ???????????????????????????

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??????? influenza virus

• type (A, B, C)
• ???????? origin
• ????????????? origin
• strain number
• ???????????????? ???
• antigenic subtype designations ??? hemagglutinin
  ??? neuraminidase glycoproteins

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???????? A/swine/Iowa/15/30 (H1N1)

• type A influenza virus ?????????????? Iowa
  ?????.?. 1930, ???????????????? laboratory
  reference number 15 ????? hemagglutinin subtype
  1 ??? neuraminidase subtype 1 surface
  glycoproteins
• ?????????????? host-of-origin ???????????????????
  ??

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Etiology
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????????????????? antigenic ???????? HA ??? NA

• Antigenic drift ?????????????????? point mutation
  ?? viral RNA segment ??? coding ?????? HA ??? NA
  ????????????? antigenic change ??? minor
  ???surface glycoprotein
• Antigenic shift ????????????????????????????????
  ?? type A influenza virus ???????? ????? subtype
  A ???????????????????? ????????????????????????
  subtype HA ??? NA

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• Antigenic shift ??????????????????????????????????
  ? (reassortment) ??? viral RNA segment ??????????
  maturation ??? progeny ???????? ????????????????
  infect ???? influenza virus 2 ???????????????????
  subtype HA ??? NA ?????????????
• ????? antigenic shift ?????????? ??? establish
  ??? influenza virus ??????????????????????????????
  ???????????? H1N1 human influenza ???? 1971

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• swine mixing vat ??????????????????????
  influenza A viruses
• ???????????????????????????? ??????????????
  ???????? avian-origin influenza viruses ????????

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Pandemic influenza

• ????????????? ???? pandemic 3 ????? Spanish Flu
  (????? 40 ?????????? 1918-1919), Asian influenza
  (?? 1957), Hong Kong influenza (?? 1968)
• ???????????????????????????? gene ??????????
  H-component

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Spanish influenza
pandemic ???? 1918-19 ??????? H1N1
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?? 20 ????????? ?? 1918 clinical swine
influenza ??????????
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• Asian flu pandemic ???? 1957 ??????????????
  69,800 ????????????? 1957-58
• ???? 1957 H1N1 ????????????? H2N2 ???? serotype
  ????????????????????????? Asian flu pandemic
• 11 ??????? (1968) ???? influenza virus
  ????????????? H3N2 ???????????? the Hong Kong flu
  pandemic

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Asia Week 1998
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20 ??.?. 40 (1997) influenza vaccine 97-98
??????????

• A/Wuhan/359/95 (H3N2) -like strain
• A/Bayern/7/95 (H1N1) -like strain
• B/Beijing/184/93 -like strain
• ?? 1997 ?????????????????????? H5N1

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????????????????? (??)

• ?????????? 1-3 ???
• ????????????? ???????????? ???????? ??
  ???????????????????????
• ????????????????????? 5 ??? ??????? ??????
• ?????????????????????? ???????????????????????????

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• Influenza ???????????????????????
  ??????????????????????????????????????? 14 ???
• point prevalence ??? incidence ???????????????????
  ???????????????????????? pandemic, epidemic ????
  inter-epidemic

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• ??????????????????????? ??? ???? just
  ??????????????????????
• Virus shedding ???? expose 1-3 ??? ??????????????
  1 ??????? 2-3 ??????? ????????????????????????
  ???????? ?????? 2-3 ???????? ???????????? 14-20
  ??????? exposure

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Transmission

• Inhalation ??????????????????????????????????
  conjunctival
• ????????????????? fomite-associated virus
• ???? ???????? ???/???? ????????????? fomites
  ??????????????? fecal material

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Prevention

• Bio-security programs ?????????????????????????
  ???????????? ?????????????? ?????????? contact
  ??????????????????????????????????
  ???????????????????????????????????
  ??????????????????????????? 30 ???
  ???????????????
• ????????

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Strain ?????????? inactivated vaccine

• ??????????? 3 ?????
• influenza A 2 ???? (H3N2, H1N1) ??? influenza B
  1 ????
• ??????????????? most recent antigenic variant
• ????????????? embryonated eggs ??? noninfectious

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??????????

• ????????????????? ?????????????????????????
  strain ?????????? ????????????????????????????????
  ???????????? ?????????????????????
  ??????????????????????????????? ??? strain
  ?????????????????????
• ?????????????????????????????? ???????????????????
  ?????????????? (?????? ?????????? ??? ???????)

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Family trees for type A viral strains from 11
consecutive flu seasons with each branch
representing a new mutant strain. (Robin Bush)
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influenza vaccine 1997-1998 ??????????

• A/Wuhan/359/95 (H3N2) -like strain
• A/Bayern/7/95 (H1N1) -like strain
• B/Beijing/184/93 -like strain
• ?? 1997 ?????????????????????? H5N1

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influenza vaccine 1999-2000 ??????????

• A/Sidney/5/97 (H3N2)-like
• A/Beijing/262/95 (H1N1)-like
• B/Yamanashi/166/98 (B/Beijing/184/93-like)

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influenza vaccine 2001-2002(2544-2545) ??????????

• A/New Caledonia/20/99 (H1N1)
• A/Misco/10/99 (H3N2)
• B/Sichuan/3/79/99

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influenza vaccine 2003-2004(2546-2547) ??????????

• A/New Caledonia/20/99(H1N1)-like virus
• A/Moscow/10/99(H3N2)-like virus
• B/Hong Kong/330/2001-like virus
• ???????????????????? A/Panama/2007/99.
  ????????????????????? B/Shandong/7/97, B/Hong
  Kong/330/2001, B/Hong Kong/1434/2002.

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?????????????????????????????

• ????????? WHO
• ??? Detect ???????????????? (throat secretion,
  paired sera) ????? ref. Lab. ??? Atlanta, USA
  London, UK Melbourne, Australia
• ??????????????????
• ???????????????????????????? ?????????????????????
  ?????????????????????????????