AVIAN INFLUENZA AND IOWANS

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AVIAN INFLUENZA AND IOWANS

• Jim Gill, MD, PhD
• University of Iowa Hygienic Laboratory
• Iowa City, IA
• 319-335-4581
• james-gill_at_uiowa.edu

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Pandemic Influenza

• Natural event
• Worldwide consequences
• Rapid spread
• Unpredictable
• Zoonotic disease
• Influenza A

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Influenza A Wild waterfowl Humans
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Influenza A

• Infects humans, birds, pigs, horses, seals, and
  whales
• Wild water birds are natural hosts
• Two major surface proteins-HA NA
• 15 different HA subtypes
• 9 different NA subtypes

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Influenza A contd

• All combinations of HA NA in wild birds
• No disease in wild birds
• Domestic birds become ill
• Three subtypes currently circulating in humans
• H1N1, H1N2, H3N2
• Horses- H7N7, H3N8

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Influenza B and C

• Influenza B
• Found only in humans
• Associated with epidemics, not pandemics
• Not classified into subtypes
• Influenza C
• Found only in humans
• Not associated with wide-spread disease
• Not classified into subtypes

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Diagram of Influenza A
From www.ultranet.com/jkimball/BiologyPages/
F/FluVirion.gif
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How Influenza Viruses Change

• Antigenic Drift
• Small changes continually over time
• May take years to occur
• newer virus can infect people again
• Antigenic Shift
• Abrupt, major change in subtype (HA or NA)
• Responsible for pandemics

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Influenza Pandemics

• 1918-19 Spanish Flu
• H1N1
• Caused highest number of known flu deaths
• 500,000 in US
• 20-50 million worldwide
• About ½ of deaths were young, healthy adults

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Influenza Pandemics contd

• 1957-58 Asian Flu
• H2N2
• IDd in China in late Feb, 1957
• Spread to US by June, 1958
• 70,000 deaths in US

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Influenza Pandemics contd

• 1968-69 Hong Kong Flu
• H3N2
• Detected in Hong Kong in early 1968
• Spread to US later in 1968
• 34,000 deaths in US
• Still circulates today

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Influenza Pandemics contd

• The last three pandemic influenza viruses were
  the result of reassortment of a human strain of
  influenza A with an avian influenza
  virusAntigenic shift
• Human population is naive
• Virus becomes established
• Circulates for several years

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Spread of Influenza Virus Between Animals and
Humans

• Direct spread from birds or contaminated
  environment to humans
• Through an intermediate host--pig

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Reassortment in Pigs
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Avian Influenza Infections in Humans Since 1997

• H5N1, Hong Kong, 1997
• Direct transmission from poultry to humans
• 18 hospitalized
• 6 deaths
• 1.5 million chickens culled
• H9N2, China and Hong Kong, 1999
• Poultry to humans
• Two childrenboth recovered

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Infections contd

• N7N2, Virginia, 2002
• Outbreak among poultry
• Shenandoah Valley
• Serosurvey found 1 exposed person
• H5N1, China and Hong Kong, 2003
• Two cases in family that traveled from Hong Kong
  to China
• 1 death

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Infections contd

• H7N7, Netherlands, 2003
• Outbreak on several poultry farms
• 89 humans infected
• 78 cases conjunctivitis
• One death in visiting veterinarian
• H9N2, Hong Kong, 2003
• One childrecovered
• H7N2, New York, 2003
• One case in seriously ill patient--recovered

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Infections contd

• H7N3, Canada, 2004
• Outbreak among poultry
• Caused conjunctivitis in poultry workers
• H5N1, Thailand and Vietnam, 2004
• Jan-March35 cases, 23 deaths
• June-present10 cases, 9 deaths

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Outbreaks in US Among Poultry

• H5N2, HPAI, Texas, Feb 2004
• Gonzales County
• First outbreak of HPAI in US in 20 yrs
• Some birds sent to live markets in Houston
• Quarantine, culling, prevention successful
• H7N2, Maryland, March 2004
• Pocomoke City
• Quarantine, culling
• H2N2, Penn, Feb 2004
• 16 layer flocks
• H7N2, Delaware NJ, Feb 2004
• Two farms in Del. and 4 live markets in NJ

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Krauss, et al, Vector-borne, 2004
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Krauss, et al, 2004
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AIV in Iowa Ducks

• 80 ducks
• 20 mallards12 pos
• 60 wood ducks8 pos
• 100 Canada geese
• Not tested yet
• Hunter-killed ducks
• Not tested yet

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Influenza in Iowa Duck Hunters
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Future Work

• Isolate and identify AIV in all duck and goose
  samples
• Analyze human serum samples for AIV exposure
• Iowa duck hunters
• DNR workersFeb 17 at Springbrook St Pk
• NIH Grant
• AIV infections in wildlife professionals in US
  and Canada

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Acknowledgements

• Center for Health Effects of Environmental
  Contamination (CHEEC)
• Center for Emerging Pathogens
• University Hygienic Laboratory
• Iowa Department of Natural Resources