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Chet Moore

Introduction to vector-borne disease ecology; West Nile virus update; ArboNET structure and function. Chet Moore Environmental Health Advanced Systems Laboratory Dept. of Environmental & radiological Health Sciences Colorado State University. The Balkanization of Science. Epidemiology.

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Chet Moore

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  1. Introduction to vector-borne disease ecology; West Nile virus update; ArboNET structure and function Chet Moore Environmental Health Advanced Systems Laboratory Dept. of Environmental & radiological Health Sciences Colorado State University

  2. The Balkanization of Science Epidemiology Ornithology Organism Mammalogy Entomology Botany Microbiology Geological scale Landscape Ecology Community Ecology Population Ecology Scale Behavior Physiology Cell Biology Molecular Biology Agriculture Health Natural Resources Application VBCI

  3. Introduction to vector-borne disease ecology; ArboNET structure and function; West Nile virus update, 2003 Chet Moore Environmental Health Advanced Systems Laboratory Dept. of Environmental & radiological Health Sciences Colorado State University

  4. Vector n [fr. L., vectus] 2 a: an organism (as an insect) that transmits a pathogen. Webster

  5. Zoonosis n[Gk zo- animal + nosos disease] A disease that occurs naturally in animals other than humans, and often is communicable to humans.

  6. E H Suitable Environment Host Vector Pathogen The Vector-borne Disease System Unsuitable environment (matrix) B E P V H

  7. Arbovirus Transmission Cycle Vertebrate Host Virus Virus Vector Adults Eggs Terrestrial Aquatic Pupae Dead-end hosts Larvae

  8. Arbovirus Transmission Cycle Food, Space, Breeding sites Weather and Climate Vertebrate Host Predators and Pathogens Virus Virus Weather and Climate Vector Food, Space, Breeding sites Adults Eggs Terrestrial Aquatic Pupae Dead-end hosts Larvae

  9. Weather and Climate Affect the System in a Complex Fashion Impact of R.H. and temperature on adult survival Impact of rain on food supply of vertebrate host Impact of rain on larval habitats TIME Impact of temperature on host and vector winter survival Impact of temperature on larval growth and development Today

  10. Temporal pattern of arbovirus activity: vectors, birds, and humans Total females (e.g., light traps) Infected female mosquitoes Overwintering (diapause) females Infected birds Human cases Winter Spring Summer Fall

  11. ArboNET – Structure and Function The Arbonet Team Division of Vector-Borne Infectious Diseases Centers for Disease Control and Prevention Fort Collins, Colorado

  12. ArboNET Description • CDC’s system for national arboviral (WNV) surveillance • 57 state / metropolitan health depts. • 50 states and PR • NYC, DC, Philadelphia, Chicago, Houston, Los Angeles • Published guidelines • Case definitions / diagnostic methods

  13. ArboNET Description: National surveillance guidelines

  14. Funding for Surveillance • Emerging Infections Program - CDC • Enhanced Laboratory Capacity (ELC) program • Five year cycle • Cooperative Agreements (renewed yearly) • ELC and WNV funding expected to continue

  15. Enhanced Laboratory Capacity (ELC) Funding, 1999-2004 Awards (millions) Year Mean: $2,250,792 Range: $144, 311 – $11,201, 533

  16. Goals of national West Nile virus surveillance • Track geographic spread in the United States • Detect increasing virus activity before humans are at significant risk • Enable interventions and educational messages • Characterize secular trends • Provide basis for policy / resource allocation

  17. ArboNET Cast of players • State and local health departments • Collect field and clinical specimens • Conduct human epidemiologic investigations • Laboratory testing • Data entry and reporting • Commercial laboratories • human (equine) diagnostic testing

  18. ArboNET Cast of Players • CDC ArboNET staff • Atlanta (server support) – to Ft. Collins, 2004 • Fort Collins • Programmers (2 Access, 1 Java, 1 XML) • ArboNET technicians (3+) • Medical epidemiologists (7) • Laboratory diagnostic reference section (approx. 10)

  19. Arbonauts: The ArboNET Team Page 1… 2003 Jen Brown Peggy Collins Roy Campbell Nick Crall John Jones

  20. Stephanie Kuhn Krista Kniss Jen Lehman Tony Marfin Sue Montgomery Dan O’Leary …Page 2!

  21. ArboNET Cast of Players • Other U.S. agencies • Department of Defense • Mosquito collection and testing • Department of Agriculture • Equine diagnostic testing • Geological Survey • Dead bird diagnostic testing • Geospatial mapping

  22. ArboNET Surveillance Categories • Human • Meningitis, encephalitis, AFP (neuroinvasive) • Uncomplicated fever (non-neuroinvasive) • Birds • Dead (wild) • Caged sentinel (chickens, pigeons) • Live-caught wild • Non-human mammals (horses) • Mosquitoes

  23. ArboNet Data Flow : State Health Department to CDC Human, mosquito, bird, horse specimens Suspect Human Case Investigations DOH WNV Coordinator State, Commercial, Reference Labs Public domain CDC

  24. Data flow through ArboNET • Reporting pathways (4) • ArboNET stand-alone software • CDC-developed • MS Access-based • XML data transfer format • Proprietary software • Commercial or locally-produced • XML data transfer format • Secure website • Combinations

  25. Data flow through ArboNET, 2002 • Use of reporting pathways • ArboNET (38%) • Proprietary software (16%) • Secure website (42%) • Combinations (4%)

  26. ArboNET data • Numerator (individual) • Human disease cases • Equine disease cases / other infected mammals • Infected birds (dead, sentinel, live-caught wild) • Infected mosquito pools • Denominator (aggregated) • Total individuals tested per week and county (avian and mosquito only)

  27. Numerator records (individual totals) 2000 (5,001) 2001 (9,324) 2002 (44,157) 2003 (?) Denominator records (aggregate totals) 2000 (18,881) 2001 (42,208) 2002 (54,375) 2003 (?) ArboNET data

  28. End-users of ArboNET data • Participating health departments • Weekly conference call and secure internet • USGS • Weekly data snapshot---surveillance maps • Public • Peer reviewed publications • CDC publications (MMWR weekly updates) • Maps (via CDC and USGS websites) • Media interviews • Senior public health officials

  29. ArboNET data limitations • Lag time • Delays in testing and reporting • Data quality • Adherence to national surveillance guidelines currently unknown • Case definitions (case misclassification) • Testing procedures (false positives & negatives) • Variabile emphasis on respective surveillance categories • Incomplete reporting & aggregation of denominator data

  30. Limitations: ‘first activity’ data • Do reporting delays permit timely interventions? • Low specificity of animal data, 2002 • 2,531 counties detected animal activity • Human cases in only 1,942 (23%) • Modification by early public health measures? • Human disease unrelated to animal disease?

  31. Percent of Cases 0-24 25-49 50-74 75-100 Percent of Reported West Nile Virus Cases Classified as West Nile Fever, United States, 2003 * Reported as of 5/20/2004

  32. Historical Perspective Progression of West Nile Virus Activity in the United States, 1999-2003

  33. 1999

  34. 2000

  35. 2001

  36. 2002

  37. 2003

  38. States and Counties Reporting WNV Activity, United States, 1999-2003* Reported to ArboNET as of 5/20/2004 ** Plus D.C.

  39. West Nile VirusBird Surveillance United States, 2003

  40. WNV Surveillance, United States, 2003*:Summary of Dead Bird Data • 97,905 dead birds reported • 25,339 tested (26%) • 12,066 WNV-positive birds reported • 10,200 corvids (85%) • 1,866 birds of other spp. (15%) (1999-2003: 229 spp. WNV-positive dead birds reported to CDC) * Reported as of 5/20/2004

  41. “Top Ten” WNV-Positive Bird Species Reported, United States, 2003* * Reported as of 5/20/2004

  42. Counties Reporting Bird and Human Surveillance (n=763) Human illness before bird collection (n=203, (27%)) Bird collection before human illness (n=560, (73%)) Timing of WNV-Positive Dead Bird Collection and Human WNV Case Onset, By County, United States, 2003* * Reported as of 5/20/2004

  43. West Nile VirusMosquito Surveillance United States, 2003

  44. U.S. Counties Reporting WNV-Positive Mosquitoes, 2003 8,385 pools 41 species 40 states and DC

  45. WNV Surveillance, United States, 2003*:Summary of Mosquito Data • 2.8 million individuals tested • 8,384 WNV-positive mosquito pools • Overall infection rate ~3 per 1,000 • 50 positive species • Earliest: 18 JAN, Cx. pipiens, Monmouth Co., NJ • (overwintering mosquito), • then 7 MAR, Cx. quinquefasciatus, St. Tamany Parish, LA • Latest: 19 NOV, Cx. quinquefasciatus, Travis Co., TX * Reported as of 5/20/2004

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