avian influenza history

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  • 1. Avian InfluenzaA disease with a history

2. World Influenza Outbreaks1934Puerto RicoH1N1 3. World Influenza Outbreaks1995MexicoH5N2 4. World Influenza Outbreaks1997Hong KongH5N1The potential of spreading H5N1 to humanwas prevented by slaughtering all poultry inHong Kong in December 1997 5. World Influenza Outbreaks2001Hong KongH5N1 H5N1 reemerged again in Hong Kong in multiplegenotypes.Controlled, again, by slaughtering all poultry inHong Kong. 6. World Influenza Outbreaks2002Hong KongH5N1 H5N1 reemerged again in Hong Kong in multiplegenotypes.Controlled by slaughtering positive flocks andinfected poultry stalls in markets. 7. Avian InfluenzaA disease with a history 8. Hong Kong StoryStrategies to attempt tocontrol the emergence ofhighly pathogenic H5N1viruses in Hong Kongpoultry markets. 9. Hong Kong Story1997 All the poultry in Hong Kong were slaughtered. Slaughter of infected farms and live poultry markets.2002 Birds in the markets and birds due to go to themarkets were slaughtered.No farms in Hong Kong were shown to be infected.2001 10. Serological screening of eachtruckload of poultry sold from localfarms or entering Hong Kong.Removal of aquatic birds includingducks and geese from the livepoultry markets in 1998.Quail was identified as the poultryspecies that continued toreintroduce H6N1 and H9N2viruses into the Hong Kong poultrymarkets and were banned.Introduction of one clean dayper month when all poultrymarkets are simultaneously emptyand are cleaned. 11. What after Hong Kong Story These measures successfully removed the different H5N1influenza virus genotypes from Hong Kong poultry markets. They have so far not prevented reemergence of H5N1influenza viruses. 12. Avian InfluenzaA disease with a history 13. What after Hong Kong StoryAfter the third reintroduction ofH5N1/02 influenza virus in HongKong, the decision was made toinvestigate the use of inactivatedvaccine to reduce the H5N1 virusload and inhibit the furtherreemergence of H5N1 genotypes. 14. H5N2 The First UseInactivated vaccine wassuccessfully used to control theH5N2 outbreak in Mexico in1995 (Villard and Flores, 1997). 15. H5N2 The First Use We investigated the efficacy ofcommercially available H5N2influenza vaccine against H5N1/02influenza viruses from Hong Kong. The only commercially availableinactivated H5 influenza vaccine isagainst A/CK/Mexico/232/94(H5N2). 16. ASSESSMENT 17. H5N2 Immune ResponseAmino acid sequence identitybetween the HA of:A/Ck/Mexico/232/94 (H5N2)A/Ck/Hong Kong/86.3/02(H5N1)To evaluate the immuneresponse after single andmultiple doses of commercialinactivated H5N2 influenzavaccine.89.3% 18. H5N2 Immune ResponseProfile:8-day-old chickens were vaccinated vaccine.We have 3 groups of birds:1. Vaccinated chickens with single dose ofA/CK/Mexico/232/94 (H5N2)2. Unvaccinated in contact with the vaccinated chickens3. Unvaccinated chickens 19. H5N2 AssessmentInvestigations:Hemaggtutination inhibition (HI) titers:1. A/CK/Hidalgo/232/94 (H5N2)2. A/CK/HK/86.3/02 (H5N1)After two doses of vaccine, higher levels of prechallengeantibodies were induced that did not increase after viruschallenge. 20. Experiment 1Profile:Vaccinated group (19) Primary dose of vaccine at 8 day of age challenged.Unvaccinated in contact (10) Not vaccinated not challengedUnvaccinated group (9) Not vaccinated - challengedChallenge:Aggressive challenge dose of 10 CLD50 of A/CK/HK/86.3/02(H5N1). 21. Immune ResponseMean HI antibody titerH5N1 (H5N2)PreVaccinatedUnvaccinatedPost Pre Post20 53 100 150Unvaccinated incontact 22. Deaths And Virus SheddingDeath/total - 3 dpc Virus shedding - 3 dpcTrachea Cloaca0/19 0/196/196/9 0/3 1/3Vaccinated (19)Unvaccinated incontactUnvaccinated (4)0/10 0/10 1/10After 2-3 days 23. Experiment 2Profile:Vaccinated group (10) Primary dose of vaccine at 8 day of age, boosted 28 dayslater challenged.Unvaccinated in contact (6) Not vaccinated not challenged.Unvaccinated group (9) Not vaccinated challenged.Challenge:Aggressive challenge dose of 100 CLD50 of A/CK/HK/86.3/02(H5N1). 24. Immune ResponseMean HI antibody titerH5N1 (H5N2)PreVaccinated (10)Unvaccinated (4)Post Pre Post333 337 391 257Unvaccinated incontact (6) 25. Deaths And Virus SheddingDeath/total - 3 dpc Virus shedding - 3 dpcTrachea Cloaca1/10 3/100/10Hi Titer 1/809/9 ND NDVaccinated (10)Unvaccinated incontact (6)Unvaccinated (4)3/6 3/6 2/6After 2-3 days 26. Experiment 3Profile:Vaccinated group (10) Primary dose of vaccine at 8 day of age, which is boosted28 days laterUnvaccinated group (4) NothingChallenge:Exposed to birds infected with 100 CLD50 H5N1 27. Immune ResponseMean HI antibody titerH5N1 (H5N2)PreVaccinatedUnvaccinatedPost Pre Post282 252 388 3260 0 0 0 28. Deaths And Virus SheddingDeath/total - 3 dpc Virus shedding - 3 dpcTrachea Cloaca0/10 1/100/103/4 0/1 0/1Vaccinated (10)Unvaccinated (4) 29. CONCLUSION 30. ConclusionThus commercial inactivated oil-emulsion A/CK/Mexico/ 232/94(H5N2) provides protection against challenge with low doses ofA/CK/HK/86.3/02 (H5N1) virus but did not prevent virusshedding, which transmitted to contact birds. 31. Conclusion When the severity of challenge was increased in the secondexperiment, 1 of 10 vaccinated birds died but not in the thirdexperiment. However, virus shedding in vaccinates in the first experimentwas sufficient to infect 50% of unvaccinated contact controls. Despite high levels of HI antibody, the heavily challenged birdswere not fully protected, thus raising the question of lack ofgenetic similarity between the vaccine and challenge virus.