ONE WORLD . ONE HEALTHRockefeller University New York – 29 September 2004: ONE WORLD . ONE HEALTH Rockefeller University New York – 29 September 2004 "History of zoonotic avian influenza" By F.X. Meslin Co-ordinator, Strategy development and monitoring of Zoonoses, Foodborne Diseases and Kinetoplastidae World Health Organization WHO, Geneva


Slide2: Influenza A viruses: common to man and animals Wild birds: wild ducks, shorebirds e.g. terns, shearwaters and gulls All HA and NA


Avian influenza viruses causing human disease: Avian influenza viruses causing human disease Pre-1997: sporadic conjunctivitis – H7N7 1997: H5N1 (Hong Kong): 18 patients; 6 deaths 1998, 1999 and 2003: H9N2 (Hong Kong; Guangdong) 2003: H5N1: Fujian / Hong Kong: 2 patients, 1 death 2003: H7N7 (Holland) - 78 conjunctivitis, 7 with flu-like illness, 4 other, 1 death 2004 –H5N1 Asian outbreak (human cases in Vietnam & Thailand);


Previous outbreaks of highly pathogenic avian influenza worldwide: Previous outbreaks of highly pathogenic avian influenza worldwide Year Country/area Domestic birds affected Strain 1959 Scotland chicken H5N1 1963 England turkey H7N3 1966 Ontario (Canada turkey H5N9 1976 Victoria (Australia) chicken H7N7 1979 Germany chicken H7N7 1979 England turkey H7N7 1983–1985 Pennsylvania (USA)* chicken, turkey H5N2 1983 Ireland turkey H5N8 1985 Victoria (Australia) chicken H7N7 1991 England turkey H5N1 1992 Victoria (Australia) chicken H7N3 1994 Queensland (Australia) chicken H7N3 1994–1995 Mexico* chicken H5N2 1994 Pakistan* chicken H7N3 1997 New South Wales (Australia) chicken H7N4 1997 Hong Kong (China)* chicken H5N1 1997 Italy chicken H5N2 1999–2000 Italy* turkey H7N1 2002 Hong Kong (China) chicken H5N1 2002 Chile chicken H7N3 2003 Netherlands *chicken H7N7


The H5N1 "incident" of 1997: The H5N1 "incident" of 1997 Outbreaks of avian flu in chicken farms in Hong Kong in March / April 1997 May 1997: Child with flu like illness, died of complications Virus was H5N1


Mild human flu-like disease associated with avian H9N2 virus in Hong Kong: Mild human flu-like disease associated with avian H9N2 virus in Hong Kong 1999 Two children with mild self limited “flu like” illness in Hong Kong in 1999 caused by H9N2 Low prevalence of neutralizing antibody in general population and Health care workers. Up to 30% seroprevalence in poultry workers. 2003 1 child with H9N2 disease - unpublished


Slide8: H7N7 outbreak in Holland, 2003 - Reports of conjunctivitis by date of onset of symptoms - Date of onset June 12 Feb 28 0 5 10 15 20 25 # of cases Mar 7 Mar 14 Mar 21 Mar 28 Apr 4 Apr 11 Apr 18 Apr 25 May 2 May 9 May 16 May 23 May 30 Jun 6 453 suspect cases 89 confirmed as H7: 83 with conjunctivitis One death More infection, more disease, and different clinical presentation than expected! In particular a high proportion of case family members seropositive…!


Slide9: Indonesia Korea Vietnam Japan Thailand Cambodia Laos China


Slide10: Vietnam Thailand Indonesia China Malaysia


Confirmed human cases of avian influenza A(H5N1) as of 27 September 2004: Confirmed human cases of avian influenza A(H5N1) as of 27 September 2004 Tip of the Iceberg?


Brief descriptive analyses: Brief descriptive analyses Sex (n=23) 10 (43%) female Age (n=23) Mean 16 years, median 13 years Range 4 to 58 years Interval between onsets of symptoms and death Mean 13 days, median 13.5 days Range 5 to 31 days


Status of H5N1 Cases by Age groupThailand and Viet Nam (N= 40) : Status of H5N1 Cases by Age group Thailand and Viet Nam (N= 40)


Clinical features influenza A(H5N1) (Based on preliminary reports from Thailand and Viet Nam): Clinical features influenza A(H5N1) (Based on preliminary reports from Thailand and Viet Nam) Exposure history to ill or dead chickens No disease among cullers Main presenting features Sustained fever (> 38°C) Shortness of breath Dry, non-productive cough Rapid progression of severe respiratory distress Chest X-ray changes Mechanical ventilation Decreased WBC count with lymphocytopenia


Characterization of H5N1 viruses: Characterization of H5N1 viruses Li et al Nature July 8, 2004 Human and avian viruses of Vietnam and Thailand cluster closely together Indonesian viruses are distinct


Why is WHO concerned?: Why is WHO concerned? Increasing number of human avian influenza cases H5N1 virus circulation in animals is not under control and will last as infected countries not yet equipped to cop Co-circulating of human & avian influenza viruses will also continue (and increase as the cold season arrives) Risk of genetic reassortment increase Emergence of pandemic strain Majority of human population would lack immunity Reports of H5N1 viruses isolated from pigs Reports of HP H5N1 healthy carrier state in domestic ducks Reported family cluster with possible human to human transmission


Reassortment (in Human): Reassortment (in Human) Migratory water birds Source: WHO/WPRO


Reassortment (in Pigs): Reassortment (in Pigs) Source: WHO/WPRO Migratory water birds


Slide19: A(H1N1) A(H2N2) A(H3N2) 1918: “Spanish Flu” 1957: “Asian Flu” 1968: “Hong Kong Flu” 20 - 40 million deaths 1 - 4 million deaths 1 - 4 million deaths Credit: US National Museum of Health and Medicine Influenza Pandemics 20th Century Pandemic are major epidemics characterised by the rapid spread of a novel type of virus to all areas of the world resulting in an unusually high number of illnesses and deaths in most age groups for approximately 2 to 3 years. Next pandemic is "overdue"


control and prevention strategy: inter-agency responsibility: control and prevention strategy: inter-agency responsibility Risk reduction (avoid emergence of a new virus) Reduction of human exposure through disease control and elimination in the domestic animal reservoir (FAO, OIE and others) Culling, movement control, immunization Protection, immunization and monitoring of at-risk individuals (WHO) Cullers, health care personnel Strengthen surveillance & ensure timely reporting and response Domestic and wild Animals (FAO, OIE and others with WHO through rumours investigation: GLEWS) Humans and animals: improved diagnostic tests, national detection, global reporting (WHO/FAO/OIE and other partners) Improve pandemic preparedness (WHO) Ensure (H5N1) vaccine development, fair distribution and administration Increase production and access to antiviral drugs for prophylaxis or therapy Prepare for case isolation, contact confinement, border screening, travel advisories, travel restrictions (if appropriate)


Conclusions: Conclusions WHO is extremely concerned by the current situation WHO is in pandemic preparedness mode WHO needs to cooperate very effectively with other Organizations as major interventions to effectively reduce and detect human exposure to HPAI viruses are with the agricultural sector not the public health sector


Slide22: Thank you for your attention