1. West Nile Virus Surveillance Ingrid Garrison, DVM, MPH, DACVPM State Public Health Veterinarian September 16, 2015

2. West Nile Virus  Arthropod-borne virus (arbovirus) spread by infected mosquitoes  Culex species are the primary vector for West Nile virus (WNV) although it has been detected in 9 other species  Rarely transmitted by blood transfusion  All blood donors now screened for WNV

3. West Nile Virus the Disease  Incubation period – 3-15 days  Symptoms can include fever, headache, body aches, joint pains, vomiting, diarrhea, or rash  Most recover completely but fatigue and weakness can last for weeks or months  Less than 1% develop encephalitis or meningitis  10% of patients with serious neurological illness will die

5. West Nile Virus History  First isolated from a febrile patient from the West Nile district of Northern Uganda in 1937  WNV was first characterized in detail in the early 1950s and 1960s  First recognized epidemic of WNV occurred in Israel, 1951  Several large outbreaks in Egypt between 1951 and 1954

6. West Nile Virus History  In 1957, an outbreak in Israel was the first with severe neurologic manifestations  Between 1960 and mid 1970s, large outbreaks occurred in France, South Africa, Russia, Spain and India  Large outbreaks of WNV were very infrequent throughout the late 1970s and 1980s

7. West Nile Virus History  WNV was first identified in North America in New York City in 1999  An epizootic among birds associated with a high fatality rate was first noted; assessments did not detect common avian pathogens  NYC birds, infected mosquitoes, and human brain tissue from a fatal case of encephalitis identified WNV as the etiologic agent http://www.timesunion.com/news/article/Stone-role-raises-doubt-559620.php

8. Year of First Reported Human West Nile Virus Disease Case, By State – U.S., 1999-2008 Map Courtesy of CDC

9. West Nile Virus History  During the summer of 2002, North America had the largest outbreak of West Nile meningoencephalitits ever recorded  Factors contributing to outbreak remain unclear  KDHE began surveillance for WNV, 2001  First human case in Kansas, 2002

10. Mosquito Surveillance - Kansas In the early 2000s mosquito surveillance enjoyed robust funding Mosquito traps placed in all preparedness regions of Kansas Kansas State University trapped, identified, and tested mosquitoes for WNV

11. Mosquito Surveillance - Kansas As funding decreased the number of traps decreased Evaluation of the Kansas mosquito surveillance system (2001-2009) – Profound delay between mosquito collection, identification, WNV testing, and report to KDHE – Human cases of WNV occurred BEFORE WNV positive mosquitoes were identified – Not an ‘early warning’ system

12. Mosquito Surveillance - Kansas In 2011 Kansas Biological Survey new mosquito surveillance partner (collection, i.d.) Kansas Health and Environmental Lab performed WNV testing New methodology was established in 2013 – Concentrated mosquito surveillance in county with highest number of WNV cases (Sedgwick)

13. Methods

14. Mosquito Surveillance  Conducted weekly from June 13 to October 24, 2013 in Sedgwick County (24 weeks)  Kansas Biological Survey placed traps where mosquito transmission was most likely to occur  9 traps were set each week

15. Mosquito Surveillance  Encephalitis Vector Survey (EVS) traps were used  Emit carbon dioxide by using dry ice http://www.mosquitoturlock.com/surveillance.shtm

16. Mosquito Surveillance  Mosquitoes transported to Kansas Biological Survey for enumeration and identification  Culex spp. mosquitoes were tested for WNV http://i.usatoday.net/news/_photos/2012/08/30/Maryland-reports-1st-West- Nile-virus-death-PF267HV9-x-large.jpg

17. Human Surveillance  Reportable disease in Kansas  Cases entered in EpiTrax  Investigation conducted by local health department  Disease investigation guideline  Cases classified based on 2011 CDC case definition  Need clinical and laboratory data  Probable and confirmed cases reported  American Red Cross reports presumptive viremic blood donors for further investigation

18. ArboNet  KDHE reports human and mosquito surveillance data to ArboNet  National arboviral surveillance system managed by CDC and state health departments  Maintains data on:  Human disease (including presumptive viremic blood donors)  Veterinary disease cases  Mosquitoes  Dead birds  Sentinel animals

19. Surveillance Results

20. Results Mosquito enumeration and identification data from KBS to KDHE within 1 business day Mosquito WNV test data available within 7-10 business days Mosquito and human surveillance data posted weekly on KDHE’s website Data shared with Sedgwick County Health Department

21. Mosquito Abundance 26,690 mosquitoes collected 65% Culex spp.

22. 286 vials tested 10.5% positive for WNV

25. Measures to Predict WNV Cases Vector Index (VI) – Quantify potential risk of transmission of WNV from mosquitoes to humans – Requires three values to calculate Female mosquito vector presence Vector species density Vector species infection rate (need WNV lab data) Vector density – # female mosquito vectors/ # trap nights each week Vector density x infection rate = VI

26. Measures to Predict WNV Cases Need a measure that can be calculated quickly with the most current data We calculated 2 and 3 week prevalence estimates of Culex spp. and Vector Index (2013) Compared the number of human cases (Sedgwick County and the entire state) to the prevalence estimates

27. Average Number Culex spp. and Human Cases of WNV Strong correlation (R=0.82, 0.78) between the 2 & 3 week average number Culex and human cases that occur 2 weeks later among residents of Sedgwick County Strong correlation between the 2 week average number Culex and human cases occurring throughout the entire state 2,3, and 4 weeks later

28. Vector Index and Human Cases of WNV Weak correlation between VI and human cases of WNV in Sedgwick County Strong correlation (R=0.93) between VI and human cases of WNV throughout the entire state 3 & 4 weeks later

29. Results Translated We compared the average number of Culex mosquitoes using the 2 & 3 week prevalence estimates to determine an ‘action level’ When the 3 week average number of Culex mosquitoes was above 44, human cases occurred 2 weeks later in Sedgwick County Therefore when the 3 week average approaches 44 some form of mitigation should take place

30. Limitations Unable to compare data before 2012 because of change in surveillance methodologies Difficult to make conclusions based on one year of data regarding a disease that has many factors that influence the number of cases (e.g. environmental factors, human behavior) Delay in reporting of human cases

31. Surveillance to Action

32. Mosquito Mitigation and Education Sedgwick County Health Department – Communicated mosquito surveillance data to City of Wichita – Mosquito surveillance results used to determine location of larvicide application No adulticide used – Fight the Bite Campaign 210 posters 1, 080 palm cards

35. 2012-13 WNV neuroinvasive cases Decreased 83% in U.S. Increased 70% in Kansas Decreased 60% in Sedgwick County

36. 2014 Count Rate Sedgwick County 0 N/A Kansas 18 0.62 West North Central 104 0.50 United States 1,347 0.42

37. What You Can Do… Review mosquito surveillance data – When Culex spp. > 40, issue press release Remind people to perform the 3 D’s Contact City Works Department – Determine what, if any, mosquito mitigation are performed Local mosquito surveillance ideal – Larval surveillance?

38. Acknowledgements KDHE Amie Worthington, BEPHI Brian Hart, KHEL Alyssa Bigler, KHEL KBS Dr. Christopher Rogers Sedgwick County Health Dept Christine Steward Adrienne Byrne-Lutz City of Wichita Scott Lindeback Code Enforcement Staff Citizens Media

39. www.kdheks.gov Amie Worthington, Medical Investigator Ingrid Garrison, State Public Health Veterinarian Bureau of Epidemiology and Public Health Informatics Kansas Department of Health and Environment 785-296-2898 AWorthington@kdheks.gov 785-296-2501 igarrison@kdheks.gov Healthy Kansans living in safe and sustainable environments.

40. References Selvar, MD, James M. "West Nile Virus: An Historical Overview." The Ochsner Journal 5.3 (2003): 6-10. Web. Centers for Disease Control and Prevention, Division of Vector-Borne Diseases. West Nile Virus in the United States: Guidelines for Surveillance, Prevention, and Control. 4 th Revision June 14, 2003. Accessed October 22, 2014. http://www.cdc.gov/westnile/resourcepages/pubs.htm l http://www.cdc.gov/westnile/resourcepages/pubs.htm l "Anopheles Mosquitoes." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention. Web. 29 Oct. 2014.

41. WNV Clinical Criteria (2011) Neuroinvasive disease – Fever (≥100.4°F or 38°C) as reported by the patient or a health-care provider, 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) as reported by the patient or a health-care provider, AND – Absence of neuroinvasive disease, AND – Absence of a more likely clinical explanation

42. WNV Lab Criteria (2011) Isolation of virus from, or demonstration of specific viral antigen or nucleic acid in, tissue, blood, CSF, or other body fluid, OR Four-fold or greater change in virus-specific quantitative antibody titers in paired sera, OR Virus-specific IgM antibodies in serum with confirmatory virus-specific neutralizing antibodies in the same or a later specimen, OR 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, OR Virus-specific IgM antibodies in CSF or serum.

43. Case Classification - Probable Neuroinvasive disease A case that meets the clinical criteria for neuroinvasive disease and the following laboratory criteria: Virus-specific IgM antibodies in CSF or serum but with no other testing. Non-neuroinvasive disease A case that meets the clinical criteria for non- neuroinvasive disease and the laboratory criteria for a probable case: Virus-specific IgM antibodies in CSF or serum but with no other testing.

44. Case Classification - Confirmed Neuroinvasive disease Meets clinical criteria for neuroinvasive disease and one or more the following laboratory criteria : Isolation of virus from, or demonstration of specific viral antigen or nucleic acid in, tissue, blood, CSF, or other body fluid, OR Four-fold or greater change in virus-specific quantitative antibody titers in paired sera, OR Virus-specific IgM antibodies in serum with confirmatory virus-specific neutralizing antibodies in the same or a later specimen, OR 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.

45. Case Classification - Confirmed Non-neuroinvasive disease Meets clinical criteria for non-neuroinvasive disease and one or more of the following laboratory criteria for a confirmed case: Isolation of virus from, or demonstration of specific viral antigen or nucleic acid in, tissue, blood, CSF, or other body fluid, OR Four-fold or greater change in virus-specific quantitative antibody titers in paired sera, OR Virus-specific IgM antibodies in serum with confirmatory virus- specific neutralizing antibodies in the same or a later specimen, OR 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.