avian influenza
TRANSCRIPT
Avian Influenza (Highly Pathogenic)Fowl plague, Fowl pest, Peste aviaire, Geflugelpest, Typhus exudatious gallinarium, Brunswick bird plague, Brunswick disease, Fowl disease, Fowl or bird grippe
Center for Food Security and Public Health, Iowa State University, 2008
OverviewOverview• Organism• Economic Impact• Epidemiology• Transmission• Clinical Signs• Diagnosis and Treatment• Prevention and Control • Actions to take
The Organism
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Influenza VirusInfluenza Virus
• Family Orthomyxoviridae−“myxo” means mucus
• Three main types−Type A
Multiple species−Type B
Humans−Type C
Humans and swine
Center for Food Security and Public Health, Iowa State University, 2008
Influenza AInfluenza A
• Multiple species−Humans, pigs, horses, birds, others
• Most virulent group• Classification by surface antigens
into subtypes−Hemagglutinin (H or HA)−Neuraminidase (N or NA)
Center for Food Security and Public Health, Iowa State University, 2008
Influenza AInfluenza A
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Influenza AInfluenza A
Center for Food Security and Public Health, Iowa State University, 2008
Center for Food Security and Public Health, Iowa State University, 2008
Influenza BInfluenza B
• Mostly humans• Common• Less severe than A• Epidemics occur less often than A• Human seasonal vaccine
−Two strains of type A−One strain of type B
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Influenza CInfluenza C
• Humans and swine• Different pattern of surface proteins• Rare
−Mild to no symptoms• By age 15, most have antibodies
Center for Food Security and Public Health, Iowa State University, 2008
Avian InfluenzaAvian Influenza
• Disease based on genetic features and/or severity of disease in poultry−Low pathogenic AI (LPAI)
H1 to H16 subtypes−Highly pathogenic AI (HPAI)
Some H5 or H7 subtypes LPAI H5 or H7 subtypes can mutate
into HPAI
Importance
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HistoryHistory
• 1878: First identified case in Italy• 1924-25: First U.S. cases• Mildly pathogenic avian influenza
first identified mid-twentieth century• 1970’s
−Migratory waterfowl carriers−Outbreaks in mink, seals and whales
Center for Food Security and Public Health, Iowa State University, 2008
Economic ImpactEconomic Impact
• Direct losses:− Depopulation and disposal− High morbidity and mortality− Quarantine and surveillance− Indemnities
• 1978-1996: Seasonal outbreaks in Minnesota cost taxpayers $22 million
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Economic ImpactEconomic Impact
• 1983: U.S. outbreak (H5N2) −$65 million in losses−Destruction of 17 million birds−30% increase in egg prices
• 1999-2000: Italy outbreak (H7N1)−$100 million in compensation to farmers−18 million birds destroyed− Indirect losses of $500 million
Center for Food Security and Public Health, Iowa State University, 2008
Economic ImpactEconomic Impact
• 1997: Hong Kong outbreak (H5N1)− $13 million for depopulation and indemnities− 1.4 million birds
• 2001: Hong Kong outbreak (H5N1)− 1.2 million birds− $3.8 million
• 2003: European outbreak (H7N7)− 30 million birds destroyed− $314 million
Epidemiology
Center for Food Security and Public Health, Iowa State University, 2008
Geographic DistributionGeographic Distribution• Worldwide distribution• Reservoir
− Free flying aquatic birds: Ducks, geese, shorebirds, gulls, terns, auks
• Outbreaks worldwide now• Similarity to Newcastle Disease makes
actual distribution difficult to define• Altered avian ecosystems have created
new niche for AI viruses
Center for Food Security and Public Health, Iowa State University, 2008
Epidemiology: BirdsEpidemiology: Birds
• Initial source of infection− Migrating ducks or other
waterfowl
• Spread by aerosol, shared drinking water, fomites− To other migratory waterfowl,
domestic poultry and pigs, pet birds
• Virus found in respiratory secretions and feces
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Epidemiology: PigsEpidemiology: Pigs
• Susceptible to infection with all subtypes of avian influenza A−Called a “mixing vessel”
• Receptors for both avian and human influenza virus
• In US H1N1 stable for almost 30 years
• Now H1N1, H3N2, H1N2
Transmission
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Animal TransmissionAnimal Transmission
• Initial source of infection− Other poultry, migratory
waterfowl, domestic pigs, pet birds
• Spread by aerosol, shared drinking water, fomites
• Virus in respiratory secretions and feces
• Virus present in eggs but eggs unlikely to survive and hatch
Center for Food Security and Public Health, Iowa State University, 2008
Human TransmissionHuman Transmission
• Previously considered non-pathogenic for humans
• 1997, Hong Kong− 18 humans infected, 6 died− H5N1 virus linked to outbreak in live bird
market and area farms
• 2003, the Netherlands− 83 confirmed cases in humans, 1 death− H7N7 strain
• Swine are proposed “mixing vessel”
Center for Food Security and Public Health, Iowa State University, 2008
Interspecies Transmission of Influenza A Viruses
Interspecies Transmission of Influenza A Viruses
Avian Influenzain Animals
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Avian InfluenzaAvian Influenza
• Incubation period: 3-14 days • Birds found dead• Drop in egg production• Neurological signs• Depression, anorexia,
ruffled feathers• Combs swollen, cyanotic• Conjunctivitis and respiratory signs
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Post Mortem LesionsPost Mortem Lesions
• Lesions may be absent with sudden death
• Severe congestion of the musculature
• Dehydration• Subcutaneous
edema of head and neck area
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Post Mortem LesionsPost Mortem Lesions
• Nasal and oralcavity discharge
• Petechiae onserosal surfaces
• Kidneys severely congested
• Severe congestion of the conjunctivae
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Avian Influenza in CatsAvian Influenza in Cats
• H5N1 avian influenza in Asia infected cats fed infected dead chickens
• H5N1 experimentally− Respiratory − Systemic disease− Transmits cat to cat
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SamplingSampling
• Before collecting or sending any samples, the proper authorities should be contacted
• Samples should only be sent under secure conditions and to authorized laboratories to prevent the spread of the disease
• HP AI samples may be zoonotic
Center for Food Security and Public Health, Iowa State University, 2008
DiagnosisDiagnosis
• Clinically indistinguishablefrom virulent Newcastle Disease (END)
• Suspect with:− Sudden death− Drop in egg production− Facial edema, cyanotic combs and wattles− Petechial hemorrhages
• Virology and serology necessary for definitive diagnoses
Center for Food Security and Public Health, Iowa State University, 2008
Differential DiagnosisDifferential Diagnosis
• Virulent Newcastle disease• Avian pneumovirus• Infectious laryngotracheitis• Infectious bronchitis• Chlamydia• Mycoplasma• Acute bacterial diseases
−Fowl cholera, E. coli infection
Center for Food Security and Public Health, Iowa State University, 2008
DiagnosisDiagnosis
• Laboratory Tests−HP AI is usually diagnosed by virus
isolation• Presence of virus confirmed by
−AGID−ELISA−RT-PCR
• Serology may be helpful
Center for Food Security and Public Health, Iowa State University, 2008
Treatment Treatment
• No specific treatment• Supportive care and antibiotics for
secondary infections• Antivirals (amantadine) effective in
reducing mortality−Not approved in food
animals−Results in resistant
viruses
Avian Influenza in Humans
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Clinical Signs in HumansClinical Signs in Humans
• 1997: Hong Kong (H5N1)−Fever, respiratory, vomiting, diarrhea,
pain −Fatal cases: severe bilateral pneumonia,
liver dysfunction, renal failure, septic shock
• 1979: MP AI in harbor seals (H7N7)−Conjunctivitis
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Clinical Signs in HumansClinical Signs in Humans
• 2003: Netherlands (H7N7)−Conjunctivitis−Mild influenza or respiratory symptoms −Fatal case: Acute respiratory distress
syndrome
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Avian Influenza in HumansAvian Influenza in Humans
• Risk is low• Strains vary in ability
to infect humans• Close contact
with infected birds−High occupational exposure,
cultural practices may increase risk• April 2008: 31 cases, 24 deaths
Year Cases Deaths
2003 4 4
2004 46 32
2005 98 43
2006 115 79
2007 88 59
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H5N1 AI in Poultry, Birds since 2003
H5N1 AI in Poultry, Birds since 2003
Prevention and Control
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Recommended ActionsRecommended Actions
• Notification of Authorities−Federal:
Area Veterinarian in Charge (AVIC) www.aphis.usda.gov/vs/area_offices.htm
−State veterinarian www.aphis.usda.gov/vs/sregs/official.htm
• Quarantine
Center for Food Security and Public Health, Iowa State University, 2008
Recommended ActionsRecommended Actions
• Confirmatory diagnosis• Depopulation may
occur− Infected premises−Contact-exposed
premises−Contiguous premises
Center for Food Security and Public Health, Iowa State University, 2008
Control and EradicationControl and Eradication
• Eliminate insects and mice• Depopulate flock and
destroy carcasses• Remove manure down
to bare concrete• High pressure spray
to clean equipment and surfaces
• Spray with residual disinfectant
Center for Food Security and Public Health, Iowa State University, 2008
PreventionPrevention
• Appropriate biosecurity−Control human traffic− Introduction of new birds into flock−Avoid open range rearing in waterfowl
prevalent areas• Education of the poultry industry• Prompt response to MP AI outbreaks
Center for Food Security and Public Health, Iowa State University, 2008
Vaccination of PoultryVaccination of Poultry
• Emergency situations −Preserve breeding stock
• Vaccines−Killed and fowl-pox vectored−DIVA – Differentiating Infected from
Vaccinated Animals• US Vaccine bank with 40 mil doses
−20 million for H5−20 million for H7
Center for Food Security and Public Health, Iowa State University, 2008
USDA Prevention ActivitiesUSDA Prevention Activities
• Import restrictions−No live birds or bird products from
infected countries• Increasing surveillance of wild birds• National H5 and H7 control program• Training for disease recognition• Improving diagnostics for
rapid detection
Center for Food Security and Public Health, Iowa State University, 2008
Protection of Humans from H5N1 Avian Influenza
Surveillance
Avoid contact with poultry
U.S. Border
AI ResponsePlan
Food Safety Inspection Service
Biosecurity
Proper food handling and preparation
Center for Food Security and Public Health, Iowa State University, 2008
Prevention: HumansPrevention: Humans• Personal Protective Equipment
− Gloves, masks− If working with poultry or wild birds
• Vaccine− April 17, 2007
US FDA approved an avian influenza vaccine for humans
Not commercially available Part of National Strategic Stockpile
• For distribution during public health emergency
• Antivirals
Additional Resources
Center for Food Security and Public Health, Iowa State University, 2008
For More InformationFor More Information
• Centers for Disease Control and Prevention (CDC)− http://www.cdc.gov/flu/avian/
• World Health Organization (WHO)− http://www.who.int/csr/disease/avian_influenza/en/
• World Organization for Animal Health (OIE)− www.oie.int
• Center for Food Security and Public Health− www.cfsph.iastate.edu
Center for Food Security and Public Health, Iowa State University, 2008
AcknowledgmentsAcknowledgments
Development of this presentationwas funded by grants from
the Centers for Disease Control and Prevention, the Iowa Homeland Security and Emergency
Management Division, and the Iowa Department of Agriculture and Land Stewardship
to the Center for Food Security and Public Health at Iowa State University.
Contributing Authors: Danelle Bickett-Weddle, DVM, MPH, DACVPM; Glenda Dvorak, DVM, MPH, DACVPM; Katie Steneroden, DVM, MPH; Anna Rovid Spickler, DVM, PhD; Radford Davis, DVM, MPH, DACVPM; Bindy Comito Sornsin, BS.