Respiratory Diseases

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Avian Influenza
Joanne Walsh-Weeks DVM SW Field
Veterinarian Emergency Programs NC Department of
Agriculture and Consumer Services
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Overview

• The Disease
• Organism
• Transmission
• Clinical Signs
• Diagnosis and Treatment
• Economic Impact
• Prevention and Control

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Types of Influenza Viruses

• Influenza A
• epidemic or pandemic
• animals and humans
• divided into subtypes
• based on surface proteins

• Influenza B
• epidemic
• humans (primarily)
• not divided into subtypes
• Influenza C
• humans
• mild respiratory illness

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Reservoirs of Influenza A Virus
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Influenza Type A
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Avian Influenza Virus

• Influenza Type A virus
• Classification by
  surface proteins
• Hemagglutinin (H)-15 subtypes
• Neuraminidase (N)-9 subtypes

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Influenza A Virus Subtypes
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Virulence of Strains

• Classified by surface antigens
• Differences in symptoms and severity
• At least 15 known subtypes
• Most outbreaks due to H5 or H7 viruses
• Vaccination of one subtype is not cross
  protective to other subtypes.

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Types of Influenza
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Animal 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

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Human Transmission

• Farm Employees
• Visitors
• Owners
• 2004 LT (Laryngotracheitis)
  outbreak (another poultry virus)-
• 4 farms common connection is a convenience store!

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Highly pathogenic dead birds
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Swollen head, blue comb and wattles
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Hemorrhages on legs
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How does LPAI affect poultry?

• Chickens
• May have no signs of disease
• Decreased egg production
• Poor egg shell quality

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How does LPAI affect poultry?

• Turkeys
• Respiratory signs
• Snicking (coughing)
• Mucous in the trachea
• Decreased egg production
• Poor egg shell quality
• Decreased food and water intake

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Diagnosis

• NC Dept. Agriculture and Consumer Services
  Rollins Animal Disease Diagnostic Laboratory
• Agar gel immunoprecipitation
• Directagen
• Virus Isolation
• Real-time reverse-transcriptase PCR
• National Veterinary Services Laboratory
• All positives sent for confirmation
• Located in Ames Iowa not Plum Island

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Diagnosis

• Newcastle disease has same clinical signs
• Need laboratory tests to differentiate
• Lab results available in same day
• If H5 or H7 NVSL will do bird inoculation to
  determine pathogenicity index

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Treatment

• No specific treatment
• Supportive care and antibiotics for secondary
  infections
• Antivirals (Amantadine) effective in reducing
  mortality
• Not approved
• Resistant viruses

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AI Surveillance In NC Since 1985

• All birds submitted with respiratory complaint
• All birds over 4 weeks-old that have a blood
  sample collected
• Portion of all blood samples submitted every 4th
  week

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National Poultry Improvement ProgramAvian
Influenza Monitoring Program

• Multiplier flocks every 180 days
• Egg Layer flocks every 90 days
• Breeding flocks every 90 days
• Meat birds within 10 days of slaughter
• Approximate number of flocks tested
• Egg layers/breeders 2 million
• Broilers/breeders 74 million
• Turkeys/breeders 696

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Avian Influenza Detection at NVSL 2005
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Northeastern LBM System

• At least 18 million birds annually
• 160 Markets
• PA is the biggest supplier 400 monitored flocks
• 30 types of birds

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Live Bird Market System
Production Farms
Markets
Wholesalers and Distributors
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H7N2 Outbreaks Linked to Live-bird Markets

• 1996-98 PA (21 flocks, 2.5 M birds)
• 2001 CT (1 flock, 16,000 birds)
• 2001-2002 PA (7 flocks)
• 2002 VA, WV, NC (210 flocks, 4.7 M birds)
• 2003 CT (3.9 million layers)
• 2004 DE, MD (200,000 birds)

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NCDACS Threat Assessments

• Transportation assessments
• Pet bird assessments
• Game Bird Assessments

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USPS Quantities of birds

• High -- Charlotte
• 1275 birds and 40 containers.
• Low -- Raleigh
• 80 birds and 4 containers.
• Greensboro
• 152 birds and 7 containers

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Health Documentation by Container (NPIPNational
Poultry Improvement Plan)
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Container Origins
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Container Destinations
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Shooting Preserve Biosecurity
77,396 birds
335,245 birds
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Most likely routes of AI transmission in USA
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Influenza AGenetic Changes

• Antigenic drift
• Minor point mutation
• Gradual, continuous
• Change within a subtype epidemic
• Antigenic shift
• Major genetic reassortment
• Could occur with simultaneous infection with
  human and avian flu viruses
• Abrupt, infrequent
• Results in a new subtype pandemic

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Pandemic Influenza

• An influenza pandemic occurs when a new
  influenza virus appears against which the human
  population has no immunity, resulting in several,
  simultaneous epidemics worldwide with enormous
  numbers of deaths and illness.

WHO website
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Pandemic Prerequisites

• Novel virus emerges
• Novel virus causes disease in humans
• Novel virus can be efficiently transmitted person
  to person

Dr. Asamoa-Baah, Assistant Director General, WHO
Communicable Diseases
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Outbreaks of H5N1 in Poultry as of Oct. 11, 2005
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Smuggled Eagles
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Pandemic WatchEurasia

• H5N1 virus continues to circulate widely in
  poultry
• H5N1 virus continues to evolve
• new animals are becoming infected
• longer survival in the environment
• lethal to some migratory birds

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Avian Influenza in Humans

• Avian flu viruses typically do not infect humans
• Cases have been identified since 1997
• H5N1
• Hong Kong 1997 18 cases, 6 deaths
• Asia and Europe 2003 to present 125 cases, 64
  deaths
• H7N3
• Canada 2004 1 case
• H7N7
• Netherlands 2003 83 cases, 1 death
• H9N2
• Hong Kong 1999 2 cases
• Hong Kong 2003 1 case

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Avian Influenza A (H5N1) in HumansRisk Factor

• History of direct contact with poultry
• Plucking and preparing if diseased birds
• Handling fighting cocks
• Playing with poultry
• Consumption of ducks blood or possibly
  undercooked poultry
• not those involved in mass culling operations

WHO Consultation on Human Influenza A/H5, NEJM
October 5, 2005
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Avian Influenza A (H5N1) in Humans

• Incubation period
• 2 - 4 days (possibly up to 8 days)
• Transmission
• Bird-to-human
• Environment-to-human
• Limited human-to-human

WHO Consultation on Human Influenza A/H5, NEJM
October 5, 2005
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How can you protect yourself and prevent possible
spread of avian influenza?
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Be aware of how the virus is spread

• From the birds
• Saliva
• Nasal secretions
• Feces
• Spread in organic matter
• litter, feces
• Can live for 1 week to 3 months
• Spread by
• People shoes, clothes, nasal passages
• Vehicles especially in organic matter

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Wear Proper Personal Protective Equipment

• Bonnet
• N95 Respirator
• Tyvek suit
• Nitrile gloves
• Disposable boots

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National Strategy for Pandemic Influenza

• Preparedness and Communication
• Surveillance and Detection
• Response and Containment
• 7.1 Billion Requested for Program
• USDA/APHIS/Veterinary Services
• Requested 91 Million

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Agriculture Preparedness and Response

• 13 M Live bird market surveillance
• 17 M Wild bird flyway surveillance
• 18 M International efforts
• 10 M Double existing vaccine stockpile
• 9 M Planning and training
• 150 person Veterinary Reserve Corps/State

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Quiz

• What State has the third largest poultry
  production industry?

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Could this bird be infected with avian influenza?
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High or Low Pathogencity?
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Which bird might have avian influenza, Newcastle
disease or frost bite?
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Questions?
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Internet Resources

• www.oie.int
• www.vet.uga.edu/vpp/gray_book/index
• www.who.int
• www.poultrymed.com
• www.osha.gov/dsg/guidance/avian-flu.html
• www.cdc.gov/flu/avian/index.htm