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

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

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

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

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

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

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

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

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

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

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

ArboNET Description: National surveillance guidelines

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

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

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

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

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) ArboNET Cast of Players

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

Krista Kniss Stephanie Kuhn Jen Lehman Tony MarfinSue Montgomery Dan O’Leary …Page 2!

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

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

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

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

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

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)

ArboNET data 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 (?)

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

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

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?

Percent of Reported West Nile Virus Cases Classified as West Nile Fever, United States, 2003 * Reported as of 5/20/ Percent of Cases

Historical Perspective Progression of West Nile Virus Activity in the United States,

1999

2000

2001

2002

2003

Reported to ArboNET as of 5/20/2004 Year# States# CountiesDate Range AUG – 15 NOV **1456 FEB – 17 NOV **3598 APR – 26 DEC **2,5313 JAN – 19 DEC **2,358 1 JAN – 31 DEC States and Counties Reporting WNV Activity, United States, * ** Plus D.C.

West Nile Virus Bird Surveillance United States, 2003

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%) ( : 229 spp. WNV-positive dead birds reported to CDC) * Reported as of 5/20/2004

“Top Ten” WNV-Positive Bird Species Reported, United States, 2003* Species# positive birds% of Total American Crow4,18035 Blue Jay3,79331 Crow Species1,76615 Other Species5014 Black-Billed Magpie3193 House Sparrow2502 Northern Cardinal1812 Fish Crow1001 Red-tailed Hawk961 Common Grackle911 * Reported as of 5/20/2004

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

West Nile Virus Mosquito Surveillance United States, 2003

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

2.8 million individuals tested 8,384 WNV-positive mosquito pools –Overall infection rate ~3 per 1, 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 WNV Surveillance, United States, 2003*: Summary of Mosquito Data * Reported as of 5/20/2004

CulexAedesOchlerotatusAnophelesOther cont. erraticusaegyptiatlanticus nigromaculis atroposCs. melanura erythrothoraxalbopictusatropalpus provocans barberiCs. morsitans nigripalpuscinereuscanadensis sollicitans cruciansCq. perturbans pipiensvexanscantator sticticus franciscanusDe.cancer quinquefasciatusdorsalis stimulans punctipennisOr. signifera restuansfitchiitaeniorhynchusquadrimaculatusPs. ciliata salinariusgrossbeckitriseriatuswalkeriPs. columbiae tarsalisinfirmatustrivittatus Other Ps. ferox territansjaponicusCs. impatiensPs. howardii Cs. inornataUr. sapphirina

“Top 10” WNV-Positive Mosquito Species Reported, By Number of WNV-Positive Pools, United States, * * Reported as of 5/20/ Cx. pipiens (349) Cx. species (2124) Cx. species (1904) Cx. species (184) Cx. pipiens (1536) Cx. tarsalis (1746) Cx. pip/rest (119) Cx. pip/rest (1186) Cx. pipiens (1152) Cx. restuans (76) Cx. quinq (625) Cx. quinq (1060) Cx. salinarius (70) Cx. restuans (298) Cx. restuans (850) Cs. melanura (26) Cx. tarsalis (249) Cx. pip/rest (625) Oc. triseriatus (13) Cx. salinarius (119) Cx. pip complex (272) Cx. quinq (13) Ae. albopictus (66) Cx. salinarius (247) Oc. japonicus (8) Oc. triseriatus (63) Ae. vexans (126) Oc. sollicitans (6) Ae. vexans (62) Cs. melanura (69)

* Reported as of 5/20/2004 Counties Reporting Mosquito and Human Surveillance (n=333) Human illness before mosquito collection (n=103, (31%)) Mosquito collection before human illness (n=230, (69%)) Timing of WNV-Positive Mosquito Pool Collection and Human WNV Case Onset, By County, United States, 2003*

West Nile Virus Equine Surveillance United States, 2003

U.S. Counties Reporting Equine WNV Disease Cases, ,251 cases 1,294 counties 43 states

Equine WNV Disease Cases Reported, United States, * Total: 20,643 cases * Reported as of 5/20/2004

West Nile Virus Human Disease Surveillance United States, 2003

Reported WNV Disease Cases in Humans, United States, * * Reported as of 5/20/2004 Year# Cases# States# CountiesOnset Date Range AUG – 24 SEP JUL – 27 SEP JUL – 7 DEC 20024,15639**74019 MAY – 19 DEC 20039,86245** APR – 5 DEC ** Plus D.C.

U.S. Counties Reporting Human WNV Disease Cases, ,862 cases 1,079 counties 45 states and DC

WNND County Level Incidence per Million, United States, 2002* Incidence per million >=100 * Reported as of 4/15/2003

WNND County Level Incidence per Million, United States, 2003* *Reported as of 5/20/2004 Incidence per million >=100

Conclusions Continuing need for WNV surveillance –Detecting first activity –Secular trends –Allocation of resources Funding stable for forseeable future Continuing data challenges –Quality? –What type is appropriate? –What is available?

Questions?

* Reported as of 5/20/ (All) 2002 (Fatal) 2003 (All)* 2003 (Fatal)* N Clinical category 4, , WNND71%97%28%88% WN Fever28%2%70%7% Other ClinicalN/AN/A<1%2% Unknown1%<1% 3% Age (yr) median range0 – – 99 0 – 99 0 – 97 Males53%64% 64% Mortality7%**3%*** ** 9% of WNND Cases WNV Human Disease Cases, Demographics & Mortality, United States, 2002 vs 2003* *** 8% of WNND Cases

Common Arboviruses in the United States California Serogroup Eastern equineWestern equine St. Louis

SpringFallSummer Winter Total females (e.g., light traps) Infected female mosquitoes Overwintering (diapause) females Human cases Infected birds Temporal pattern of arbovirus activity: vectors, birds, and humans Larvicide, source reduction Adult control

Aedes aegypti, the yellow fever mosquito

A Favored Breeding Place for Aedes aegypti

ArboNET and the Arbonauts ArboNET and the Arbonauts: Rapid Reporting Systems for Vector-borne and Zoonotic Disease

Summary of West Nile Virus Activity in the United States, 2003 The Arbonet Team Division of Vector-Borne Infectious Diseases Fort Collins, Colorado