Avian Influenza – What does it all mean? Important Background Information Island Paravets and Residents

Avian Influenza: Background Waterbirds are the natural reservoir of all Influenza “A” viruses. Wild birds and these diseases have evolved together naturally over time 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 Many subtypes of AI already exist in wild bird populations in North America – but currently not HPAI H5N1

Avian Influenza: Background Source: Horimoto and Kawaoka, H = hemagglutinin (16 types) N = neuraminidase (9 types) Influenza strains are named for their specific types of protein spikes that act as a “lock and key” mechanism with host cells H5N1 is one of the 144 possible combinations. One subtype (HPAI H5N1) is of concern worldwide.

Avian Influenza: Background Pathogenicity refers to the ability of the virus to produce disease and is based on the impacts to domestic poultry Pathogenicity refers to the ability of the virus to produce disease and is based on the impacts to domestic poultry Low pathogenic = few clinical signs, mostly respiratory and digestive problems Low pathogenic = few clinical signs, mostly respiratory and digestive problems High pathogenic = attack many organs, can cause high mortality High pathogenic = attack many organs, can cause high mortality HPAI = kills >75% of chickens 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. 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.

Significant Variation within current HPAI H5N1 subtypes Juvenile mallards were inoculated with 23 different isolates of HPAI H5N1 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 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 22/23 virus isolates were efficiently transmitted from inoculated ducklings to susceptible contacts Sturm-Ramirez et al Avian Influenza: Background

HPAI H5N1 is spreading rapidly across the globe HPAI H5N1 is spreading rapidly across the globe HPAI H5N1 has killed 132 out of 230 people infected (57%) 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 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 The risk of H5N1 changing to become global pandemic influenza is unknown Why are we so worried about “bird flu”? Avian Influenza: Background

Avian Influenza: Current Situation HPAI H5N1 Human cases Dec to May 2006 Country Cases Deaths Population Indonesia million Thailand million Vietnam million million million Average = 1 case per 2.4 million people Average = 1 death per 4.5 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

Almost all human infections have resulted from direct contact w/ live or dead domestic poultry Avian Influenza: Current Situation

Infected People How could HPAI H5N1 reach islands ? Wild Birds Commercial /Illegal Trade of Birds, Poultry Meat, Eggs

Efforts to “stamp out” HPAI H5N1 in Asia and Europe proving to be difficult Culling infected flocks Culling infected flocks Quarantine infected areas Quarantine infected areas Enclosing poultry operations Enclosing poultry operations Vaccinating birds Vaccinating birds

Avian Influenza: What You Should Know Reporting mortalities -> Culling -> Loss of income unless governments compensate farmers for culled poultry Reporting mortalities -> Culling -> Loss of income unless governments compensate farmers for culled poultry Compensation for flocks is essential for accurate reporting 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? Be “eyes and ears” of animal health authorities Be “eyes and ears” of animal health authorities Keep informed about AI via the internet Keep informed about AI via the internet Become connected with those on- and off- island who will make decisions about responding to HPAI Become connected with those on- and off- island who will make decisions about responding to HPAI Know how to respond appropriately Know how to respond appropriately Communicate effectively with the public and government about risks and realities of HPAI H5N1 Communicate effectively with the public and government about risks and realities of HPAI H5N1