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Avian Influenza A (H5N1)
“Bird Flu”
TRCPA
November 18, 2005
Charles W. Mackett III, MD FAAFP
Executive Vice Chair
Department of Family Medicine
University of Pittsburgh Medical Center
Etiology
• Viral disease
• Avian Influenza (HPAI)
– H5 and H7 – highly pathogenic
– Human case fatality estimated to be as high has 50%, but
not definitely known
Cycle of Avian Influenza viruses
in animals & humans
T ranmi ssi on
to
p eop le.
Direct bird to human
transmission is also common
Domestic birds
Natural avian
influenza cycle
Shore
birds
Pandemic
disease cycle
Waterfowl
Mammals
(primarily swine)
Humans
al so
d
How is bird flu monitored?
• WHO and CDC maintain regional labs that test
both bird and human specimens
• Periodic updates are provided
• The lab surveillance permits implementation of
control measures if needed
• Vaccine trials are underway for the H5N1 strain,
but are in early phases
WHO Pandemic Alert Phase Plan
Map of current outbreak
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
Bird flu by the numbers
Human cases since date of onset (12/26/03)
125
Human deaths
64
Suspected human-to-human transmissions
2
Number of countries affected (since Dec 04)
12
Est. international airline passengers yearly
1.6B
Types of potential antivirals for bird flu
2
Known bird flu types
15
Bird flu that can be fatal to humans
1
Best case global deaths in pandemic
2-7M
Worst case potential global deaths
40-100M
*Source: World Health Organization
First case of bird flu in the U.S.
Previous avian flu in the U.S.
• Delaware (H7N2)
– Reported February 6, 2003
– 12,000 chickens
– Low pathogenicity
• Texas (H5N2)
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–
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Reported February 23, 2004
1st such case in U.S. in 20 years
7,000 chickens
Highly pathogenic
• No H5N1
Human H5N1
• Incubation: 3-5 days
• Few URI symptoms
• Severe viral pneumonia picture
–
–
–
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Fever
Lymphopenia
Pulmonary infiltrates
Hypoxia
• Diarrhea (50%)
• Time to death: 10 days (mean)
Transmission
•
•
•
•
Respiratory droplets vs. aerosol
Hand to hand
Fomites
Viral shedding starts 24 hours before
clinical illness and lasts 5-7 days
Prerequisites for a pandemic
• Novel virus with no immunity
• Able to cause significant disease in humans
• Efficient human to human transmission
– Re-assort during co-infection with H3N2
– Evolve in a human by spontaneous mutation
Common pandemic features
• Herald wave (warning): up-tick in mortality
at end of prior year
• Increased mortality
• Mortality shift to younger ages
• Multiple waves of increased mortality for
several years
Potential for influenza pandemics
• All influenza viruses can mutate
• Avian flu can cause illness in humans
• Little to no herd immunity to avian strains among
humans
• If avian viruses acquire human genes
– Facilitate efficient person-to-person transmission
• H5N1 of particular concern
• No one can predict when a pandemic might occur
How is bird flu in humans treated?
• The H5N1 virus currently infecting birds in Asia
that has caused human illness and death is
resistant to amantadine and rimantadine
• Neurominidase inhibitors
– oseltamavir (Tamiflu)
– zanamavir (Relenza) inhaled, not stocked in house
– Resistance can develop
• Additional studies are needed to prove the
effectiveness of these medicines.
Defenses
•
•
•
•
•
Vaccination
Prophylaxis
Rapid diagnosis
Treatment
Infection control
–
–
–
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Respiratory etiquette
Hand washing
Disinfection
Droplet precautions in hospitals
CDC recommendations
• Enhanced surveillance in the U.S. of H5N1.
• Travelers to countries with known outbreaks of
influenza A (H5N1) should avoid:
– Poultry farms
– Contact with animals in live food markets
– Surfaces that appear to be contaminated with feces
from poultry or other animals.
• CDC does not recommend any travel restrictions
to affected countries at this time.
• For more information, visit Travelers' Health
CDC pandemic preparation
Providing leadership and working with:
• National Pandemic Influenza Preparedness and Response Task
Force, created in May 2005 by the Secretary of the U.S.
Department of Health and Human Services
• Association of Public Health Laboratories on training workshops
for state laboratories
• Council of State and Territorial Epidemiologists and others to help
states with their pandemic planning efforts
• Department of Defense and the Veterans Administration on
antiviral stockpile issues
• World Health Organization (WHO) and Vietnamese Ministry of
Health to investigate influenza H5N1 in Vietnam and provide help
in laboratory diagnostics and training
CDC pandemic preparation
• Offering laboratory testing for H5N1 viruses
• Funding a $5.5 million initiative to improve influenza surveillance
in Asia
• Holding or taking part in training sessions to improve local
capacities to conduct surveillance for possible H5N1 human cases
• Developing and distributing reagents kits to detect the currently
circulating influenza A H5N1 viruses
• Working together with WHO and the National Institutes of Health
(NIH) on safety testing of vaccine seed candidates and to develop
additional vaccine virus seed candidates for influenza A (H5N1)
and other subtypes of influenza A virus
UPMC Avian Flu Task Force
Under the Direction of Loren Roth, MD, MPH
Sr. V.P., Quality Care & Chief Medical Officer
• Comprised of experts in :
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infectious disease
critical care
emergency management
pathology
medical laboratory
human resources
corporate security
-virology
-epidemiology
-emergency medicine
-mental health
-medical logistics
-public affairs
-Center for Biosecurity of UPMC;
• The Task Force works closely in cooperation with the Allegheny
County Health Department and Region 13 emergency management
in facilitating and guiding UPMC’s preparations
• Preparation for a possible pandemic has been ongoing since early
this year
Thank You!
Many thanks to :
UPMC Avian Flu Task Force
Center for Biosecurity of UPMC
Questions?