Mosquito-borne Arbovirus Surveillance in West Virginia

1. Mosquito-borne Arbovirus Surveillance in West Virginia Rachel Radcliffe, DVM, MPH CDC Career Epidemiology Field Officer Division of Infectious Disease Epidemiology

2. Objectives • Describe arbovirus surveillance in WV • Historical methods • Plans for 2011 • Describe 2010 arbovirus surveillance data

3. Components of Mosquito-borne Arbovirus Surveillance • Species • Humans • Mosquitoes • Dead birds • Horses • Viruses • WNV • LAC • EEE • SLE

4. Human Surveillance • Local health departments receive reports from laboratories and healthcare providers • Conduct follow up to determine patient case status • Environmental investigation to provide education on mosquito-borne disease prevention

5. Arbovirus Case Definition — Clinical Criteria • Neuroinvasive disease • Fever (≥100.4°F or 38°C) AND • Meningitis, encephalitis, acute flaccid paralysis, or other acute signs of central or peripheral neurologic dysfunction, as documented by a physician, AND • Absence of a more likely clinical explanation. • Non-neuroinvasive disease • Fever (≥100.4°F or 38°C) AND • Absence of neuroinvasive disease AND • Absence of a more likely clinical explanation

6. Arbovirus Case Definition — Laboratory Criteria • Confirmatory Laboratory Criteria • Isolation of virus or demonstration of specific viral antigen or nucleic acid from tissue, blood, CSF, or other body fluid • Four-fold or greater change in virus-specific quantitative antibody titers in paired sera • Virus-specific IgM antibodies in serum with confirmatory virus-specific neutralizing antibodies in the same or a later specimen • Virus-specific IgM antibodies in CSF and a negative result for other IgM antibodies in CSF for arboviruses endemic to the region where exposure occurred • Probable Laboratory Criteria • Virus-specific IgM antibodies in CSF or serum

7. Arbovirus Case Classification — Confirmed • Neuroinvasive disease • Meets clinical criteria for neuroinvasive disease • One or more of the 4 confirmatory laboratory criteria • Non-neuroinvasive disease • Meets clinical criteria for non-neuroinvasive disease • One or more of the 4 confirmatory laboratory criteria

8. Arbovirus Case Classification — Probable • Neuroinvasive disease • Meets clinical criteria for neuroinvasive disease • Only has virus specific IgM antibodies in CSF or serum with no other testing • Non-neuroinvasive disease • Meets clinical criteria for non-neuroinvasive disease • Only has virus-specific IgM antibodies in CSF or serum with no other testing

9. 2010 Human Surveillance Data • 8 cases of LAC reported from 5 counties • 4 confirmed and 4 probable • All neuroinvasive • Illness onsets occurred June–October • Median age of cases=7.5 years • 50% were female • No cases of WNV, SLE, or EEE reported

10. Travel-Associated Cases • Dengue • 2 cases • Travel included Honduras and Phillipines • Both hospitalized • Malaria • 3 cases • Travel included Nigeria and India • One hospitalization

11. Mosquito Surveillance • Routine mosquito trapping began in 2007 • Trapping occurred May–October in most years • Trapping historically focused in Jackson and Kanawha counties • Cabell and Ohio counties have also participated • Mosquitoes tested for arboviruses depending on species • Culex spp. tested for WNV and SLE • Non-Culex spp. tested for WNV, LAC, SLE, and EEE

12. 2010 Mosquito Surveillance Data • Trapping only occurred May–August in 3 counties • 36,731 mosquitoes from 459 pools collected • 26 (5.7%) of 459 pools tested positive for WNV • Positive pools found in all 3 counties where trapping conducted • No pools positive for SLE, LAC, or EEE

14. 2011 Plans for Mosquito Surveillance • New entomologist in DIDE • Regular mosquito trapping postponed • Assessing previous trapping methods and locations • May do larval studies in a portion of the state • Would like to see surveillance expanded to more parts of state

15. Dead Bird Surveillance • Collection kits sent to local health departments each spring • Freshly dead birds suitable specimens • Swab oral cavity of bird and send swab to OLS • ID numbers obtained from DIDE prior to OLS submission • Specimens tested for WNV, SLE, and EEE

16. 2010 Dead Bird Surveillance Data • 9 dead bird samples tested • 0 were positive for WNV, SLE, and EEE • Specimens submitted from 8 counties

18. 2011 Dead Bird Surveillance • Dead bird testing will continue • Specimen collection and suitable specimens are the same • Specimens should be sent to OLS • OLS will send to Southeastern Cooperative Wildlife Disease Study for testing

19. Horse Surveillance • Veterinarians submitted horse serum samples to OLS • OLS sends specimens to National Veterinary Services Laboratory for WNV and EEE testing • Free testing service

20. 2010 Horse Surveillance Data • 3 horse specimens submitted and tested • 0 were positive for WNV and EEE • Specimens received from 2 counties

22. 2011 Horse Surveillance • Testing service will continue • Specimen collection and submission to OLS will remain the same • Advertising testing services through WV Veterinary Medical Association

23. Enhanced Passive Surveillance • HAN sent at beginning of season to healthcare providers • Letter sent to hospital laboratories • Communication with local health departments • More outreach to veterinarians in 2011

24. 2011 Surveillance Activities • May 2 — Email memo • May 9 — Hospital laboratory letter • May 16 — HAN to healthcare providers

25. Arbovirus Surveillance Summary • LAC continues to be the major arbovirus affecting humans in WV • WNV continues to be detected in mosquitoes • Previous surveillance methods being reviewed • Want to expand surveillance • No arboviral cases detected in dead birds or horses • Submission numbers of both are declining • Assistance needed to increase submission numbers