West Nile Virus and Eastern Equine Encephalitis (EEE)
2022 Kentucky's Equine West Nile Virus (Updated 10/25/2022)
One (1) Case(s) Reported Y-T-D
Animal's Disposition: One (1) Alive
Animal's West Nile Vaccination Status: One (1) Not Vaccinated
Affected Counties: McLean (1)
2021 Kentucky's Equine West Nile Virus (Updated 11/10/2021)
Six (6) Case(s) Reported Y-T-D
Animal's Disposition: Four (4) Alive, Two (2) Deceased
Animal's West Nile Vaccination Status: One (1) Current, One (1) Partially Vaccinated, Four (4) Not Vaccinated
6 Affected Counties: Ballard (1), Christian (1), Graves (1), Todd (1), Trigg (1) and Woodford (1)
2020 Kentucky's Equine West Nile Virus (Updated 09/29/2020)
Two (2) Case(s) Reported Y-T-D
Animal's Disposition: Two (2) Alive
Animal's West Nile Vaccination Status: Two (2) Not Vaccinated
Affected Counties: Madison (1), Washington (1)
2019 Kentucky's Equine West Nile Virus (Updated 10/15/2019)
Two (2) Case(s) Reported Y-T-D
Animal's Disposition: One (1) Alive - One (1) Died
Animal's West Nile Vaccination Status: Two (2) Not Vaccinated
Affected Counties: Boyle (1) and Powell (1)
2018 Kentucky's Equine West Nile Virus (Updated 11/14/2018)
Seventeen (17) Cases Reported Y-T-D
Animal's Disposition: Nine (9) Alive, Eight (8) Euthanized
Animal's West Nile Vaccination Status: Fourteen (14) Not Vaccinated, One (1) Current Vaccination Status
One (1) Partially Vaccinated and, One (1) Unknown – Pending a determination (perhaps partially vaccinated)
Affected Counties: Barren (1), Boyle (1), Carlisle (1), Fayette (1), Hardin (1), Harrison (1)
Jackson (1), Lewis (3), Logan (1), Magoffin (1), Mercer (1), Pendleton (1), Rockcastle (1), Todd (1), Woodford (1)
Breeds: American Saddlebred (1), KY Mountain Horse (1), Percheron (1), Pleasure Horse (1)
Quarter Horse (3), Standard Bred (2), Thoroughbred (2), TN Walking Horse (6)
Equine West Nile Virus (WNV) – Historical Data 2001 – 2017 Summary
744 Confirmed Equine West Nile Cases*
95.57% (711) Not Adequately Vaccinated**
3.49% (26) Reported by attending veterinarian to be ‘Current’ on Vaccination
0.94% (7) Vaccination history was unknown but believed to be unlikely
29.97% (223) Case* Mortality Rate
Available data does not provide us opportunity to define the number of vaccinated horses in Kentucky exposed to but not contracting WNV annually, it does provide evidence and supports a logical conclusion that timely vaccination against the virus is beneficial and a good defense in protecting horses against WNV. We encourage individuals to consult their veterinarians and determine if a previously vaccinated horse might benefit from administration of a booster. Factors to consider should include when was the previous vaccine administered (timing is a critical factor), prevalence of virus in the area, and the exposure risk.
*Confirmed by meeting Case Definition
**Not-vaccinated during 12mo period preceding onset or received only initial vaccination or did not receive booster
9.81% (73) Partially vaccinated (received only initial dose and/or did not receive booster)
0.94% (7) Vaccination status was unknown but believed unlikely
2017 Kentucky's Equine West Nile Virus (Updated 11/15/2017)
Sixteen (16) Cases Reported
Animal's Disposition: Twelve (12) survived, Four (4) euthanized
Animal's West Nile Vaccination Status: Thirteen (13) not vaccinated, Two (2) vaccinated, One (1) unknown
Affected Counties: Adair (2), Bourbon (1), Franklin (1), Garrard (1), Graves (1), Hardin (1), Hart (1), Johnson (1), Menifee (1), Metcalfe (1), Pulaski (1), Russell (3), Union (1)
2016 Kentucky's Equine West Nile Virus (Updated 11/11/2016)
Seven (7) Cases Reported
Animal's Disposition: Seven (7) survived, Zero (0) euthanized
Animal's West Nile Vaccination Status: Seven (7) not vaccinated
Affected Counties: Barren (1), Bourbon (1), Hardin (1), Hart (1), Logan (1), Powell (1), Union (1)
2015 Kentucky's Equine West Nile Virus (Updated 10/09/2015)
Eight (8) Cases Reported
Animal's Disposition: Eight (8) survived, Zero (0) euthanized
Animal's West Nile Vaccination Status: Seven (7) not vaccinated, One (1) vaccination unknown/pending
Affected Counties: Bourbon (1), Crittenden (1), Fayette (1), Jefferson (1) Montgomery (1), Nelson (2), Shelby (1)
The last reported cases of EEE affecting horses in Kentucky occured in 2013 (a 10yo, TWH, non-vaccinated gelding in Logan County and a second case occured in a 17yo QH mare in Carlisle County). Both horses had no known vaccination history and each animal expired. Prior to these cases, the most recent diagnosis was in 2008 (6mo Paint filly, non-vaccinated), and in 1995 (an 8yr female, Western Kentucky, non-vaccinated).
SURVEILLANCE: The Departments of Agriculture and Public Health have included EEE in our arbovirus surveillance. Mosquitoes being screened for West Nile Virus are also tested for Eastern Equine Encephalitis virus. In addition, equine suspected of having contracted an encephalitic condition are being tested for West Nile and when warranted the sample is forwarded to the National Veterinary Services Laboratory for EEE screening.
Equine West Nile Virus – Historical Data 2001 – 2017 Summary
744 Confirmed Equine West Nile Cases
95.69% (712) Not Adequately Vaccinated*
29.97% (223) Case Mortality Rate**
*Not-vaccinated during 12mo period preceding onset or received only initial vaccination (no booster)
**Confirmed by Case Definition
Annual Reports of Equine West Nile Cases
- 2001 West Nile 8 Confirmed Equine West Nile Cases 0% Vaccinated
75% (6) Mortality Rate of Affected Equine - 2002 West Nile 513 Confirmed Equine West Nile Cases / 97% (496) Not Vaccinated within previous 12 months
27% (137) Mortality Rate of Affected Equine - 2003 West Nile 102 Confirmed Equine West Nile Cases 94% (96) Not Vaccinated within previous 12 months
34% (35) Mortality Rate of Affected Equine - 2004 West Nile 8 Confirmed Equine West Nile Cases 100% (8) Not Vaccinated within previous 12 months
50% (4) Mortality Rate of Affected Equine - 2005 West Nile 9 Confirmed Equine West Nile Cases 100% (9) Not Vaccinated within previous 12 months
33% (3) Mortality Rate of Affected Equine - 2006 West Nile 18 Confirmed Equine West Nile Cases 100% (18) Not Vaccinated within previous 12 months
44% (8) Mortality Rate of Affected Equine - 2007 West Nile 6 Confirmed Equine West Nile Cases 100% (6) Not Vaccinated within previous 12 months
33% (2) Mortality Rate of Affected Equine - 2008 Equine Cases 5 Equine West Nile 80% (4) Not Vaccianated within Previous 12 months 20% (1) Vaccination Status Unknown
0% Mortality
1 EEE Confirmed - Not Vaccinated* - Deceased *Vaccinated EEE ~72hrs prior to onset - 2009 Equine West Nile Cases 8 Confirmed Equine West Nile Cases 87.5% (7) Not Vaccinated within previous 12 months 12.5% (1) Vaccination Status Unknown
12.5% Mortality Rate of Affected Equine - 2010 Equine WNV 6 Confirmed Equine West Nile Cases 100% (6) Not Vaccinated within previous 12 months
50% (3) Mortality Rate of Affected Equine - 2011 Equine WNV Map 1Confirmed Equine West Nile Case 100% (1) Not Vaccinated within previous 12 months 0.0% Mortality Rate of Affected Equine
- 2012 West Nile Virus 13 Confirmed Equine West Nile Cases 9 Not Vaccinated, 3 Partially Vaccinated, 1 Reportedly Vaccinated 54% Mortality Rate of Affected Equine
- 2013 Equine West Nile and EEE Map 12 Confirmed Equine West Nile Cases 100% (12) Not Vaccinated within previous 12 months
83% (10) Mortality Rate of Affected Equine Note: 2 EEE , Not Vacc, Both Expired - 2014 Equine West Nile 4 Confirmed Equine West Nile Cases 75% (3) Not Vaccinated within previous 12 months (1 Unknown Status)
75% (4) Mortality Rate of Affected Equine - 2015 Equine West Nile Cases 8 Equine Confirmed West Nile Cases 87.5% (7) Not Vacc and (1) not thought to be vacc w/in prev 12mon
100% (8) Reported as surviving - 2016 Equine West Nile Cases 7 Equine Confirmed West Nile Cases 100% (7) Not Vacc and
100% (7) Reported as surviving.
Affected Counties: Barren (1), Bourbon (1), Hardin (1), Hart (1), Logan (1), Powell (1), Union (1) - 2017 Equine West Nile Cases 16 Equine Confirmed West Nile Cases
81% (13) Not vaccinated, Two (2) vaccinated, One (1) unknown
75% (12) survived
Affected Counties: Adair (2), Bourbon (1), Franklin (1), Garrard (1), Graves (1), Hardin (1), Hart (1), Johnson (1), Menifee (1), Metcalfe (1), Pulaski (1), Russell (3), Union (1)