Avian Influenza in Avians (Poultry & Wild Birds)

Transcription

1 Avian Influenza in Avians (Poultry & Wild Birds) Separating Fact From Fiction: Current Situation, Surveillance & Response Dr. Julie Helm Clemson University Livestock Poultry Health Division Columbia, SC September 20, 2006

2 Clemson University Livestock Poultry Health Division Clemson University The CULPH Division: 1) South Carolina Meat & Poultry Inspection Department 2) Veterinary Diagnostic Laboratory 3) Animal Health Regulatory Programs Enforce state and federal animal health laws and regulations, and protect animal and public health through control of endemic, foreign and emerging diseases. Animal Emergency Response ESF-17; SCEMD

3 The Asian Bird Flu Public Perception Asian Bird Flu is in U.S. now Pandemic has already begun Can get Bird Flu from eating chicken or turkey in U.S. WRONG!

4 Influenza (Flu) Virus Influenza Virus Type A (avian, swine, equine & human viruses) Typically Influenzas are species-specific: specific: avian flu > birds swine flu > pigs, etc. Sometimes they cross to other species: swine flu > turkeys swine swine flu > humans equine flu > dogs It is rare for avian flu >> humans

5 Avian Influenza (AI) Effects many avian species Disease was first reported in Italy, 1878 as fowl plague U.S. first reported in NY live bird marketing system (LBMS) Worldwide distribution

6 What s in a Name? Type A Viruses -- many different subtypes H N Named by 2 surface proteins on the virus H (hemagglutinin)) = H1 H16 N (neuraminidase) = N1 N9 AI Virus 144 different possible combinations = H5N1, H7N2 H5N1 H5N1 H5N1 ( Don t t judge a book by its cover. )

7 What s in a Name? Pathogenicity: : (ability to produce disease) Low-path (LPAI) = mild or moderate disease No clinical disease (waterfowl) Have these strains in the U.S. High-path (HPAI) = severe, highly fatal disease Considered a Foreign Animal Disease (FAD) in U.S. Do not have these strains in U.S.

8 Avian Influenza Genetic material is unstable and is subject to change = mutate Mutations = Low-Path form can change into High-Path form H5 & H7 subtypes tend to mutate more frequently

9 Avian Influenza -- Different Situations One category does not automatically lead into another Low Path High Path High Path Pandemic? Zoonotic In U.S.

10 Avian Influenza Transmission Natural Reservoirs Waterfowl & shore birds Can carry virus in GI without getting sick Normally LPAI types Uncommon to be H5 & H7 subtypes Rare to see HPAI Perfect spreaders of AI worldwide migrate for long distances spreading viruses through feces

11 Avian Influenza Transmission How the Disease is spread: Bird to bird -- thru inhalation or ingestion of the virus. Feces contain high levels of virus -- fecal contamination of equipment, vehicles, personnel. People tracking virus around (Acting as fomites or moving infected birds/equipment)

12 Avian Influenza Transmission How the Disease is spread: Bird to bird -- thru inhalation or ingestion of the virus. Feces contain high levels of virus -- fecal contamination of equipment, vehicles, personnel. Dress For Success People tracking virus around (as fomites or moving infected birds/equipment)

13 Avian Influenza Survivability Virus can survive long periods in cool, moist environments: In feces: 35 days at 4 degrees C (~39 deg F) 6 days at 37 degrees C. (~98 deg F) Easily killed with heat, drying, ph extremes, disinfectants

14 Avian Influenza Signs in Poultry Can see variable signs ranging from none to severe, depending on the strain Low-Path Strains No signs Respiratory signs Decreased egg production & poor shell quality Virus not found in meat or eggs

15 Avian Influenza Signs in Poultry High-Path Strains Severe respiratory & nervous signs Or found dead with few signs Can be 100% in 48 hrs Possible that virus can be found in meat or eggs

16 High-Path AI Outbreaks 24 outbreaks since 1959 (excluding current) Recent ones outside of the U.S.: 2004 BC, Canada 2003 Netherlands 2002 Chili Italy Australia Mexico 06 Asia >Europe > Africa H7N3 H7N7 H7N3 H7N1 H5N1 H7N4 H5N2

17 Find LPAI in non-commercial flocks routinely. Avian Influenza Outbreaks in U.S. Commercial Flocks Linked Back To LBMS 2004 DE, MD 0.5M birds LP H7N TX 48K birds LP H7N CT 4.5M birds LP H7N VA, WV, NC 4.7M birds LP H7N PA, CT (7 flocks) LP H7N PA 2.5M birds LP H7N PA, VA, NJ 17M birds HP H5N UT MN 1971 OR 1968 WI LP H7N2 LP several subtypes

18 Low-Path AI in U.S. Poultry Historically, turkeys were most commonly affected commercial poultry flocks due to range rearing & commingling with wild birds this practice is declining. Recently, commercial poultry infections have been linked back to Live Bird Marketing System (LBMS).

19 Low-Path AI in U.S. Poultry Backyard flocks are the greatest risk to commercial flocks because of their mobility & reduced Biosecurity practices. Both backyard and commercial flocks are equally at risk due to people negligence not using Biosecurity.

20 Risk of HP H5N1 Coming to U.S. How will it come? Legal & illegal movements of infected birds Tremendous trade in exotic & wild birds May be the biggest risk Legal & illegal movements of infected poultry products Migratory wild birds Intentional Agro-terrorism

21 Risk of High-Path H5N1 Coming to U.S. in Migratory Wild Birds Wild bird migration patterns do not favor easy spread to North American flyways..can it happen? Sure. Overlap in Alaska & Canada. Most routes run North & South.

22 Risk of High-Path H5N1 Coming to U.S. in Migratory Wild Birds Uncommon to find same AI virus lineages in New World & Old World Hemispheres. New World AI Lineages Old World AI Lineages

23 Risk of High-Path H5N1 Coming to U.S. in Migratory Wild Birds Targeted wild bird surveillance. Alaska initially. HP H5N1

24 Risk of High-Path H5N1 Coming to U.S. in Migratory Wild Birds Now sampling all 4 major U.S. flyways all 50 states. SC now. Get ready to find normal AI Don t t Panic! HP H5N1

25 Will High-Path H5N1 Come to U.S.? No one knows. We are use to fighting these fires -- firewalls in place: Poultry & poultry products from HPAI affected areas currently banned from entry into US Surveillance for AI in U.S. for 20+ years Management & biosecurity practices in US reduce the risk to commercial poultry

26 Avian Influenza -- Public Health Impact , 96, avian influenza infections in humans have occurred in 9 occasions No serious illness nor deaths 1997 Hong Kong chickens: high-path H5N1 First time avian strain proven to infect humans directly 18 human cases, 6 deaths

27 High-Path Avian Influenza Public Health Impact High-Path H5N Human cases of HP H5N1 (WHO: as of 8/23/06) Cases: 241 Deaths: 141 Azerbaijan 8 / 5 Cambodia 6 / 6 China 21 / 14 Djibouti 1 / 0 Egypt 14 / 6 Indonesia 60 / 46 Iraq 2 / 2 Thailand 24 / 16 Turkey 12 / 4 Viet Nam 93 / 42 Avian H5N1 Avian & Human H5N1

28 High-Path Avian Influenza Public Health Impact Human infections due to close contact with dead or sick birds Most in rural, semi-urban areas w/ small flocks These farmers live closely with their animals, eat sick or dead animals Poultry mix with other animals and wild birds Total contrast to how U.S. commercial poultry are raised

29 Avian Influenza - Public Health Impact Pandemic = a worldwide spread of a new virus History 3 Type A Flu pandemics in 20 th century 1918 (Spanish Flu) = million died (700,000 U.S.) Mother of all pandemics (Asian Flu) = million died (Hong Kong Flu) = 1 million died Why so deadly? People have no immunity to the new virus Depends on virus strain if deadly or mild pandemic

30 World Health Organization (WHO) Pandemic Alert Phases: 1 Inter-pandemic phase 2 New virus in animals 3 Pandemic Alert 4 5 New virus in humans 6 Pandemic Low risk human cases Higher risk human cases No or limited human-to to-human transmission Increased human-to to-human transmission Significant human-to to-human transmission Efficient & sustained human-to to-human transmission

31 High-Path Avian Influenza Pandemic Potential? The pandemic has not started yet. Will it?? No one knows. H5N1 bird virus still has to change to easily infect humans and then go human >> human. The longer the H5N1 bird virus is allowed to spread, the greater the chance it will change.

32 High-Path Avian Influenza Public Health Impact Last 8 years, 100+ people have died from AI. Last 8 years, ~288,000 Americans died from seasonal human flu. (~900 SC s s died in 2003) At this point, it is rare for people to get AI.

33 Avian Influenza Public Concern Eating poultry meat & eggs In U.S. no High-Path AI flock would go into the food chain = flock would be depopulated. Safe to eat properly cooked poultry meat and eggs. Do I eat chicken? Yes.

34 Avian Influenza Public Concern Hunters High-Path H5N1 not is U.S. yet Hunt healthy birds Use basic hygiene with game Don t t eat, drink, smoke Wear gloves, wash hands Wild Bird Feeders High-Path H5N1 not in U.S. yet Use basic hygiene Seed birds don t t share same habitat as waterfowl

35 SC Avian Influenza Surveillance in Wild Birds USDA Wildlife Services & SC Dept. Natural Resources Focus on geese, ducks & shorebirds that migrate between Alaska and Asia Investigate wild bird die offs Sample live birds shorebirds Sample hunter-killed birds ducks Sample environment

36 SC Avian Influenza Surveillance Necropsies (animal autopsies) & testing on commercial & backyard poultry submitted to Clemson Vet Diagnostic Lab Auctions, Flea Markets, Fairs & Shows inspections & testing New national program to sample commercial flocks (broilers, turkeys) Report large die-offs of poultry or wild birds

37 Avian Influenza Vaccination What about vaccinating poultry? Would only be used during an outbreak as a control measure. Vaccinated birds interfere with surveillance testing and trade issues.

38 Emergency Animal Disease Response Plan Farm quarantine Animals and equipment Zone quarantines? Mandatory Biosecurity measures implemented for people and vehicles to exit farm or zones.

39 Emergency Animal Disease Response Plan Zones surveillance & restricted movement

40 Emergency Animal Disease Response Plan Depopulation of flock or herd Disposal of carcasses need several options On-site Preferred to removing off the farm lower risk of spreading disease to other farms Compost Burial Off-site Landfill Rendering Incineration

41 Emergency Animal Disease Response Plan Farm buildings & equipment disinfected Litter heated / composted to kill virus Downtime Repopulation

42 Awareness SC Ag-Watch Program ( Producer & Responder Programs Using Biosecurity to protect our Industries Awareness of Diseases & Biosecurity Measures SC contact numbers

43 Training Biosecurity State & Federal Ag Personnel PPE & Surveillance Training Strike Teams

44 Home Team Advantage We are ready to respond. Plans for worse case scenario & hope for the best. Early detection Rapid Diagnosis Training in Personal Protective Equipment (PPE) Working with industry on detailing plans Experience with aggressive action on quarantine / depopulation / clean up

45 Clemson University Livestock Poultry Health Division (803) Hmmm? News & Updates Avian Influenza