Transcript Avian Influenza – What does it mean for list state?

Avian Influenza –
What does it all mean?
Important Background Information
Island Paravets and Residents
Avian Influenza: Background
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Waterbirds are the natural reservoir of all Influenza
“A” viruses. Wild birds and these diseases have
evolved together naturally over time
Many subtypes of AI already exist in wild bird
populations in North America – but currently not
HPAI H5N1
Avian Influenza: Background
Influenza strains are named
for their specific types of
protein spikes that act as a
“lock and key” mechanism with
host cells
H = hemagglutinin (16 types)
N = neuraminidase (9 types)
H5N1
Source: Horimoto and Kawaoka, 2005.
is one of the 144 possible
combinations. One
subtype (HPAI H5N1) is of
concern worldwide.
Avian Influenza: Background
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Pathogenicity refers to the ability of the virus to
produce disease and is based on the impacts to
domestic poultry
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Low pathogenic = few clinical signs, mostly respiratory
and digestive problems
High pathogenic = attack many organs, can cause high
mortality
HPAI = kills >75% of chickens
AI viruses can become very pathogenic when they
enter a new host (domestic poultry, humans, some
carnivores). This is the suspected origin of HPAI
strains.
Avian Influenza: Background
Significant Variation within current HPAI
H5N1 subtypes
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Juvenile mallards were inoculated with 23
different isolates of HPAI H5N1
Results ranged from no clinical signs (n=8 virus
isolates) to high lethality in inoculated ducklings
22/23 virus isolates were efficiently transmitted
from inoculated ducklings to susceptible contacts
Sturm-Ramirez et al. 2005
Avian Influenza: Background
Why are we so worried about “bird flu”?
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HPAI H5N1 is spreading rapidly across the globe
HPAI H5N1 has killed 132 out of 230 people
infected (57%)
If avian influenza combines genetically with human
influenza it can become very infectious among
humans
The risk of H5N1 changing to become global
pandemic influenza is unknown
Avian Influenza: Background
Avian Influenza: Current Situation
HPAI H5N1 Human cases
Dec. 2003 to May 2006
Country
Indonesia
Thailand
Vietnam
Cases
32
22
93
147
Deaths
24
14
42
80
Population
207 million
65 million
84 million
356 million
Average = 1 case per 2.4 million people
Average = 1 death per 4.5 million people
Avian Influenza: Current Situation
Compared to 230 human cases of HPAI
H5N1 worldwide in nearly a decade…..
Each year in the U.S. 5-20% of the
population will get HUMAN seasonal flu
> 200,000 people hospitalized
 ~ 36,000 people die
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Avian Influenza: Current Situation
Almost all human infections have
resulted from direct contact w/
live or dead domestic poultry
Avian Influenza: Current Situation
How could HPAI H5N1 reach islands ?
Infected People
Commercial /Illegal Trade of
Birds, Poultry Meat, Eggs
Wild Birds
Efforts to “stamp out” HPAI H5N1 in Asia and
Europe proving to be difficult
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Culling infected flocks
Quarantine infected areas
Enclosing poultry operations
Vaccinating birds
Avian Influenza: What You Should Know
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Reporting mortalities -> Culling -> Loss of
income unless governments compensate
farmers for culled poultry
Compensation for flocks is essential for accurate
reporting
Sale or slaughter
of sick birds is
known to spread
HPAI in Asia
Avian Influenza: What is Your Role?
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Be “eyes and ears” of animal health
authorities
Keep informed about AI via the internet
Become connected with those on- and offisland who will make decisions about
responding to HPAI
Know how to respond appropriately
Communicate effectively with the public and
government about risks and realities of
HPAI H5N1