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Monitoring population effects of an emergent disease in wild birds.

Monitoring population effects of an emergent disease in wild birds. Shannon L. LaDeau Postdoctoral fellow Smithsonian Institution National Zoo-Migratory Bird Center Advisor: Peter Marra. Disease emergence in U.S. avifauna:. Avian tuberculosis (1986) Newcastle disease (1992)

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Monitoring population effects of an emergent disease in wild birds.

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  1. Monitoring population effects of an emergent disease in wild birds. Shannon L. LaDeau Postdoctoral fellow Smithsonian Institution National Zoo-Migratory Bird Center Advisor: Peter Marra

  2. Disease emergence in U.S. avifauna: Avian tuberculosis (1986) Newcastle disease (1992) House Finch conjunctivitis (1994) West Nile virus (1999) H5N1-Avian flu (??) STEPHEN JAFFE/AFP US Army specialist Steve Richards captures mosquitos “Ready or not, here it comes. It is being spread much faster than first predicted from one wild flock of birds to another, an airborne delivery system that no government can stop. “ from coverage of M. Leavitt speech. March 2006

  3. © Peter Weber. © Chan Robbins. Objective Identify impacts of West Nile virus in wild bird populations.

  4. 1999 2000 2001 2004 2002 2003 West Nile virus 1999 emergence in Queens, NY. Primary avian host. Mosquito vector 284 avian species in 48 states Positive bird surveillance: by county From CDC/USGS

  5. North American Breeding Bird Survey (BBS) • Citizen scientists • 1966 to current • Over 4100 survey routes • 24.5 mile along secondary roads Sauer, J. R., J. E. Hines, and J. Fallon. 2005. The North American Breeding Bird Survey, Results and Analysis 1966 - 2004. Version 2005.2. USGS Patuxent Wildlife Research Center, Laurel, MD

  6. Route selection • Mid-Atlantic states • Temporal coverage: At least 80% data coverage from • 1980 – 2005 with observations in 5 of 6 years after 1999. 2004 Population (people/per sq Mile < 3500 3500-8850 8851-20850 20851 - 55775

  7. http://www.mbr-pwrc.usgs.gov West Nile Footprint • Crows experience high mortality. • Komar et al. 2003 • Eidson et al. 2001

  8. Data Mean of OBSERVED counts Average count WNV emergence in NY

  9. 1999 2000 2001 2004 2002 2003 Spread of West Nile virus

  10. http://www.mbr-pwrc.usgs.gov West Nile Footprint • Crows experience high mortality. • Komar et al. 2003 • Eidson et al. 2001 2. Population effects will be patchy and greater near urban areas. Kilpatrick et al. unpub Hochachka et al. 2004 Caffrey and Peterson 2003

  11. Data model For a given species, individual counts are conditionally Poisson where subscripts i and j refer to observer and route identity, respectively, and t denotes year. The expected value for a given annual count after accounting for route and observer effects is with random effects for variation among routes, years and observers.

  12. Data Mean of OBSERVED counts WNV exposure? Average count

  13. Data versus Predicted Mean of PREDICTED counts Mean of OBSERVED counts Average count

  14. Mid-Atlantic states Observations > Predicted Observations < Predicted Unusual routes after 2000

  15. Observations > Predicted Observations < Predicted Unusual routes before 1999

  16. Summary • 1. Monitoring disease in wildlife populations demands analyses that can accommodate natural stochasticity, census data and unplanned experiments without replication. • We may not be collecting data at scales useful for monitoring avian disease. [Consistent sampling across rural to urban] • Modeling/Analyses future: • other species • state-space approach • using human or crow data as prior information regarding spatial exposure.

  17. Special thanks to…. • USGS and BBS volunteers • Wayne Thogmartin, Bill Link, John Sauer, Michael Lavine, and Jim Clark for discussion and modeling input.

  18. Extra slides

  19. Monitoring wildlife disease is difficult: Can’t see the disease - Follow mortality Often there is no population data prior to disease How disease regulates/limits wildlife is largely unknown. Disease emergence in U.S. avifauna: Avian tuberculosis (1986) Newcastle disease (1992) House Finch conjunctivitis (1994) West Nile virus (1999) H5N1-Avian flu (??)

  20. Do we have the data we need? WNV exposure rates WNV-related mortality rates Population size prior to disease emergence Monitoring of populations at scale of disease ecology

  21. Average count HOFI ©Gerhard Hofmann AMRO Average count © Chan Robbins. MODO © Peter LaTourrette Data

  22. Trend Analysis Identify routes where trend before WNV emergence differs from post 2000 trend.

  23. Trend analysis Change in trend from 20 year mean Increase in trend Decrease in trend

  24. 1999 2000 2001 2004 2002 2003 Spread of West Nile virus

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