dr. julie louise gerberding director centers for disease control and prevention current status of...
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DR. JULIE LOUISE GERBERDINGDIRECTOR
CENTERS FOR DISEASE CONTROL AND PREVENTION
CURRENT STATUS OF AVIAN INFLUENZA AND PANDEMIC THREATPRESENTATION TO IOM, APRIL 2005
Influenza Pandemics Happen!
H1
H1
H3H2
1918SpanishFlu H1N1
1957Asian
Flu H2N2
1968Hong KongFlu H3N2
1915 1925 1935 1945 1955 1965 1975 1985 1995 2005
HumanHuman virusvirus
NewNewReassortedReassorted
virusvirus
Avian Avian virusvirus
Avian host
Swine
Mechanisms of Antigenic ShiftDirect Avian – Human Infection
0
200
400
600
800
1000
1900 1920 1940 1960 1980
Year
Mo
rta
lity
Ra
te p
er
100
,000
Source: Armstrong et al., JAMA;1999
Infectious Disease Mortality in the United States 1900 - 1996
Bacteriologic Findings among Patients with Influenzal Pneumonia 1918-1919
Sputum Blood
S. pneumoniae 1230/1609 (76%) 78/1507 (4.9%)
S. aureus 133/1485 (9%) 0/1535
Beta-hemolytic strep 254/2077 (12%) 32/1587 (2%)
H. Influenzae 436/729 (60%) 1/1400 (.1%)
Stevens KM: NEJM 1976; 1363-66
Potential Causes of Influenza-related Shock and Death
• Exacerbation of undiagnosed underlying conditions• Coincidental occurrence of an unrelated problem• Influenza pneumonia• Secondary bacterial pneumonia• Toxic shock syndrome / endotoxemia• Hypersensitivity response• Myopericarditis• Cytokine-induced shock syndrome
Avian Influenza is Emerging
H1
H1
H3H2
H7H5
H9
1918SpanishFlu H1N1
1957Asian
Flu H2N2
1968Hong KongFlu H3N2
1980 1996 2003
1997 2003 2004
1998 1999 Avian Flu
1915 1925 1935 1945 1955 1965 1975 1985 1995 2005
Outbreaks of Highly Pathogenic Avian Viruses Before 2004
Avian subtype Country Year
H5N3 U.S. 1983
H7N7 Australia 1985
H5N2 Mexico 1995/95
H7N3 Pakistan 1995
H5N1 Hong Kong 1997
H5N2 Italy 1997
H7N1 Italy 1999
H5N1 Hong Kong 2001-2003
H7N7 Netherlands 2003
Situation Report: Confirmed Human H5N1 CasesUpdated April 3, 2005
Country H5N1 cases
Deaths Case fatality
Thailand 17 12 71%
Vietnam 55 35 64%
Cambodia 2 2 100%
Total 74 49 66%
Risk Factors for Human H5N1 Illness in 1997
• Case control study primary risk factor for H5N1 illness• Exposure to live poultry in poultry stall or market in the week
prior to illness
• Studies on poultry workers in Hong Kong markets• 20% chickens infected with H5N1• Seroprevalence for H5 antibody = 10%• Seroprevalence in general population = 0%• Occupational risk factors for poultry workers:
• Butchering• Exposure to sick birds
1997 H5N1 Field Studies
• Most cases likely contracted influenza after exposure to infected poultry
• Human-to-human transmission occurred but was uncommon
• Groups with greatest risk of H5-antibody • Household contacts and poultry workers
• Although poultry workers had highest antibody rate, none found ill with H5
• May have been protected based on prior exposures to avian H5
Avian Influenza Poultry Outbreaks, Asia, 2003-04
H5N1 enzootic of unprecedented size and complexity now established– Poultry outbreaks in 9 or more countries– Ongoing poultry outbreaks and human cases– Substantial economic and social impact– Continuing risk of emergence of a pandemic
Situation Report: Avian Influenza 2005
Situation Report: Avian Influenza 2005H5N1 seasonal pattern for avian flu in Asia
– Expect increased activity in winter monthsOngoing human cases
– Most in young and healthy– Extremely high apparent case-fatality – No sustained person-to-person transmission
Human isolates (Vietnam, Cambodia & Thailand and 1 group of Vietnamese avian isolates– Resistant to adamantane drugs– Sensitive to oseltamivir
Probable human-to-human transmission in Thailand; family clusters in Vietnam– ? increasing
Antigenic heterogeneity among current H5N1 viruses (unlike 2003 Hong Kong H5N1 virus)– How variable are the 2005 H5N1 viruses?– How immunogenic? – Must compare human and avian isolates
Situation Report: Avian Influenza 2005
Countries containing at least 1 WHO influenza laboratoryWHO Collaborating Centers - Atlanta, London, Melbourne, and Tokyo
WHO Collaborating Centers for Influenza
HHS Response: Partnership with WHO
Support Global Influenza Pandemic Preparedness
Enhance Collaboration with Animal Influenza Health Authorities
Enhance Global Influenza Surveillance
Training - Laboratory, epidemiology, and biosafety
HHS / CDC Contributions to Preparedness and Response in Asia: HHS/CDC
A $5.5 M initiative to build surveillance capacity – Surveillance networks with bilateral funding to 9 countries in
Asia– WHO HQ and Western Pacific Regional Office – CDC’s IEIP in Thailand and NAMRU-2 in Jakarta– WHO’s Animal Influenza Network – Communications between public health and veterinary agencies– Shipment of isolates and specimens
Enhancing Influenza Surveillance: HHS/CDC
Pakistan
Malaysia
ThailandIndia
China
Mongolia
South Korea
Philippines
Indonesia
FY04
Quarantine Stations
Field Epidemiology/ Laboratory Training Programs
CDC Field Stations
International Business Connectivity
New CDC Sentinel Sites
New Quarantine Stations
New International LRN Sites
New CDC Sentinel Sites
International Health Protection Network
FY06
Global Biosurveillance: International Health Protection Network
Global Health ProtectionNetwork
Bio Sense &Biointelligence
Center
FY04 Laboratory Response Network (LRN)
National Clinical Lab Orders
DoD/VA Dx & Rx Records
Biowatch Data
OTC Drug Sales
Private Clinical Care
Expanded Real-Time LRN Data
Expanded Quarantine Stations
New Data Streams
FY06
DATA
EXCHANGE
Quarantine Authorization
• Public Health Service Act (Title 42 U.S. Code 264(b), Section 316 of the Public Health Services Act amended -- "(c) Influenza caused by novel or reemergent influenza viruses that are causing, or have the potential to cause, a pandemic.”
• Quarantine and isolation tools were last used during the SARS 2003 outbreak
• Quarantine duration of one incubation period
CDC’s Research Priorities
• Ggenetic determinants of pathogenicity and transmissibility
• Testing for antiviral resistance, receptor binding properties, etc.
• Tracking antigenic changes in the circulating viruses to facilitate appropriate vaccine development
• Epidemiology of the current H5N1 epizootic– Why did it spread so rapidly?– How many people have been infected?– What is the extent of asymptomatic infection?– What is the actual death rate?
Commitment
CollaborationCoordination
Compassion
Communication Competency
Candor Clinical Laboratories
Consistency
Community Common Sense
Complacency is the enemy of preparedness!
www.cdc.gov