Slide1: Where Health Care Meets Policy with Dr. Mike Magee


Slide2: The Threat of Bird Flu


• 3 types of the influenza virus: A, B and C reflect differences in the M protein on the envelope that contains the virus• ‘A’ influenza viruses cause human and bird flu outbreaks  – contain 8-segment RNA strand – segments break apart during replication to mix and reassort – potential for constant evolution is built in – sub-typed based on activity in envelope’s glycoproteins: 1] hemagglutinin activity (H): 16 known varieties  2] neuraminidase activity (N): 9 known varieties • Shorthand names have an “H” and “N” number (H1N1): • 3 types of the influenza virus: A, B and C reflect differences in the M protein on the envelope that contains the virus • ‘A’ influenza viruses cause human and bird flu outbreaks – contain 8-segment RNA strand – segments break apart during replication to mix and reassort – potential for constant evolution is built in – sub-typed based on activity in envelope’s glycoproteins: 1] hemagglutinin activity (H): 16 known varieties 2] neuraminidase activity (N): 9 known varieties • Shorthand names have an “H” and “N” number (H1N1) Understanding Bird Flu and the Influenza Virus Sources: Infectious Diseases Society of America Web site. Avian Influenza (Bird Flu): Implications for Human Disease. Centers for Disease Control and Prevention Web site. Information about Avian Influenza (Bird Flue) and Avian Influenza A (H5N1) Virus. Hien TT. De Jong M, Farrar J. Avian influenza – a challenge to global health care structures. NEJM. 2004;351:2363-2365.


3 influenza A viruses associated with 20th century human pandemics all have genetic components originally housed in viruses in birds: 3 influenza A viruses associated with 20th century human pandemics all have genetic components originally housed in viruses in birds Bird Flu and Human Flu Have a Complex and Inter-related Story • 1918 H1N1 virus killed 20 to 40 million people worldwide • 1957 H2N2 and 1968 H3N2 viruses each responsible for more than 1 million deaths • Now, in 2005, all eyes are focused on H5N1 — bird flu Source: Hien TT. De Jong M, Farrar J. Avian influenza – a challenge to global health care structures. NEJM. 2004;351:2363-2365. Hastings M, Guteri F. Bird-Flu Challenge. MSNBC.com. Dec. 13, 2004.


Slide5: The Influenza A Virus Appears Most In Wild Bird Populations • Spreads rapidly through exchange of mucus or feces, without creating sickness or death in these species • Once transferred to domestic birds (chickens, ducks and turkeys), spreads explosively — is frequently lethal • Virus mutates rapidly in large groups of closely contained birds – Has ability to jump to other species, such as pigs Secondary carriers become mixing pots for more varieties, increasing chances that other mammals, including humans, will become vulnerable. Sources: Centers for Disease Control and Prevention Web site. Information about Avian Influenza (Bird Flue) and Avian Influenza A (H5N1) Virus. Fouchier R, Kuiken T, Rimmelzwaan G, Osterhaus A. Global task force for influenza. Nature. 2005;435:419-420.


Slide6: The H5N1 Bird Flu Has Infected Humans and Continues to Evolve • First identified in South African wild terns in 1961 • Spread naturally among global bird populations over 4 decades • Appeared in poultry populations in 2003 – outbreak in 8 countries in Asia: Cambodia, China, Indonesia, Japan, Laos, South Korea, Thailand, and Vietnam – loss of more than 100 million domestic birds • Outbreak appeared under control until June of 2004 when it reappeared in 4 of the same countries and Malaysia Sources: Infectious Diseases Society of America Web site. Avian Influenza (Bird Flu): Implications for Human Disease. Centers for Disease Control and Prevention Web site. Information about Avian Influenza (Bird Flue) and Avian Influenza A (H5N1) Virus. WNYC. The Leonard Lopate Show. Underreported: Avian Flu. July 14, 2005.


Slide7: Bird Flu in Humans • H5N1 first infected a human population in Hong Kong in 1997 – 18 documented cases, 6 deaths – reappeared in 2 cases, causing 1 death in 2003 – soon broke out in Vietnam, Thailand and Cambodia • As of June 2005: 100 documented human cases – 54 percent mortality rate – transmission is result of direct contact with infected poultry • What constitutes a pandemic? 1] highly virulent organism 2] lack of human immunity to the organism 3] ability to easily transmit from human to human Sources: Infectious Diseases Society of America Web site. Avian Influenza (Bird Flu): Implications for Human Disease. Centers for Disease Control and Prevention Web site. Information about Avian Influenza (Bird Flue) and Avian Influenza A (H5N1) Virus. Hien TT. De Jong M, Farrar J. Avian influenza – a challenge to global health care structures. NEJM. 2004;351:2363-2365. H5N1 has the first two, but not the third (at least not yet)


Slide8: Concerns Are High: Studies Demonstrate Continued Evolution • Host range of H5N1 is expanding – includes pigs, horses, cats, tigers, leopards, whales and seals • Expansion of the domestic bird population in Asia – China: domestic chicken population increase: 8 million to 13 billion • More domestic pigs, which are catalytic mixers of genetic brews • Human-to-human transmission has occurred in a documented case of child to mother to aunt in Thailand Spread stopped there, suggesting virus does not yet have capability to readily jump from one human to the next. Sources: Infectious Diseases Society of America Web site. Avian Influenza (Bird Flu): Implications for Human Disease. Hien TT. De Jong M, Farrar J. Avian influenza – a challenge to global health care structures. NEJM. 2004;351:2363-2365. WNYC. The Leonard Lopate Show. Underreported: Avian Flu. July 14, 2005. Ungchusak K, Auewarakul P, Dowell SF, Kitphati R, Auwanit W, et al. Probable person-to-person transmission of avian influenza A (H5N1). NEJM. 2005;352:333-340.


Slide9: Our Capacity to Diagnose and Manage an H5N1 Pandemic is Less than Adequate Needs • Excellent surveillance: clinical, scientific and technologic capacity • Knowledge sharing • The will to act (quickly) at first sign of human-to-human transmission Concerns • H5N1 is already resistant to two of four common anti-viral drugs • Our supply of the two non-resistant drugs is woefully inadequate Sources: Centers for Disease Control and Prevention Web site. Information about Avian Influenza (Bird Flue) and Avian Influenza A (H5N1) Virus. World Health Organization. Report by the Secretariat. Avian influenza and human health. April 8, 2004.


Slide10: The Good News Aug. 7: Health officials announced success in an initial test of a human vaccine Realities • Existence of vaccine is not enough to prevent a worldwide pandemic • More testing is required before vaccine can be offered to public • Vaccine made in chicken eggs: successful mass production dependent on available eggs • Obstacles include organizational system for distribution Sources: Altman LK. Avian Flu Vaccine Called Effective in Human Testing. The New York Times. Aug. 7, 2005. Altman LK, Bradsher K. A Successful Vaccine Alone Is Not Enough to Prevent Avian Flu Epidemic. The New York Times. Aug. 8, 2005.


Slide11: Managing the Real Risk of Bird Flu Requirements • Global cooperation • Expanded surveillance • Expanded capacity • H5N1 tracking worldwide • Agree on a research plan • Share knowledge • Be ready to intervene Poultry • Surveillance of all subtypes • Modifying production and distribution, and strict enforcement Humans • Broad surveillance / detection • Cluster investigation • Contact tracking • Targeted use of anti-virals • Continued vaccine R&D • Travel restrictions when appropriate Human transmission of bird flu is predictable and therefore manageable. Failure to take action could be a mistake of historic proportions.


Slide12: Release Date: 8/24/2005 www.healthpolitics.com with Dr. Mike Magee The Threat of Bird Flu