West Nile Virus

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West Nile Virus

• Whats New in the Wildlife Arena?
• November 2003

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Emi Kate Saito
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• Background
• Born/raised Pittsburgh PA
• BS, 1993 U. of WI Madison
• Zoology, Biological Aspects of Conservation
• VMD, 1997 U. of PA
• MSPH, 2001 Emory U.
• Epidemiology
• WNV-related work
• Dekalb Co. Board of Health, Atlanta GA (2001)
• NWHC, Madison WI (since 2002)

(Im the one on the far left INCDNCM 2003, AZ)
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Famous last words in Emis life
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• From a guidance counselor in high school
• Why dont you become a veterinarian? They work
  a nice M-F, 9-5 job.
• Ha.
• Upon graduating from college
• I want to be a field biologist. Ill get my
  veterinary degree so I can treat my subjects if
  they get sick/injured.
• little sleep little pay
• Upon graduating from vet school
• My head hurts. I think my brain is full.

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Basic Virus Review
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• Family Flaviviridae
• Genus Flavivirus Japanese Encephalitis Antigenic
  Complex
• Complex includes
• Japanese Encephalitis
• St. Louis Encephalitis
• Usutu - Austria 2002, 2003
• West Nile

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Transmission
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Role of Wildlife in Maintenance of WNV
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Clinical Signs
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• Found Dead
• General weakness, lethargy
• Emaciation
• Sedentary
• Difficulty maintaining balance, trembling
• Inability to walk, perch, stand, or fly
• Do not respond normally to danger

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Dead bird mortality, 2003
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• As of 11/3/2003
• approximately 13,000 dead birds found positive
• 44 states DC
• Although state of MD not testing birds, positive
  birds found from military installations in MD
• ID, NV, OR, WA
• 7 Canadian Provinces
• Manitoba, Ontario, Quebec, Saskatchewan, Alberta,
  New Brunswick, Nova Scotia

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Also in the Western Hemisphere
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• Resident/non-migratory birds
• Mexico
• Dominican Republic
• Jamaica
• El Salvador?

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Species Affected
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• at least 171 dead avian species
• another 35 antibody-positive
• 23 mammals (including equids)
• another 6 antibody-positive
• prairie dogs? unconfirmed
• 1 reptile
• another antibody-positive

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2003 WNV-Related Wildlife Mortality Events
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• American White Pelicans
• Raptors
• Black Vultures
• Squirrels
• Captive/Farmed
• Alligators

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Other Wildlife Mortality
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• Cotton-tail rabbits -- WY
• Crows- WA

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Testing Methods
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• Specimens
• Organs
• Oropharyngeal/cloacal swabs
• Immature feathers (blood quills)
• Tests
• Virus Isolation
• RT-PCR
• VecTest

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Utility of Continuing Dead Bird Testing and
Reporting
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• Dead (positive) birds continue to serve as early
  indicator of human risk of infection
• Arboviral panel/Diagnostic evaluation of dead
  wildlife can lead to discovery of other agents of
  concern
• Dead bird reporting (or lack of) may indicate
  higher risk areas, as well as indicate areas
  where need to target more education campaigns
• Further understanding of epidemiology and ecology
  of virus in North America

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Why to stop testing
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• Cost of shipping, testing, staff to collect
• Inconvenience lots of phone calls, particularly
  after the 1st positive
• If its known to be in the area, could solely
  focus on mosquito testing
• VecTest useful designed for mosquito testing,
  cheaper, considered to have acceptable
  sensitivity/specificity for surveillance purposes

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Research Update
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Some studies to mention
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• Crows in IL
• Crows in OK
• Blue Jays in OH
• Herps
• Bird Counts
• Bird vaccination studies

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Thank you for your attention!
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• Any questions?
• esaito_at_usgs.gov
• 608-270-2456