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Disease Outbreak Alerts

Updates on current disease outbreaks are listed here as they occur and will include the date listed, disease name, location and current status. Specific premises will not be named but the general location by town, county and state will be listed. When locations, events or horses are at risk they will be listed. Updates will be posted as they are received.


August 25, 2017
Eastern Equine Encephalitis
Jasper and Charleston Counties, SC
Confirmed Case(s): No Quarantine
Source: South Carolina State Veterinarian

The South Carolina State Veterinarian’s office has received laboratory confirmations of 2 positive EEE cases this week. One was 4 year old Tennessee Walking Horse mare in Jasper County that was vaccinated last fall. The second positive EEE case was a 3.5 year old Quarter Horse gelding with unknown vaccination status diagnosed in Charleston County.  Both horses were euthanized. 

August 25, 2017
West Nile Virus
Riverside County, CA
Confirmed Case(s): No Quarantine
Source: California Department of Food and Agriculture

On August 24, 2017, the California Department of Food and Agriculture has confirmed an additional equine cases of West Nile Virus. A 3 year old Quarter Horse stallion in Riverside County, California displaying neurologic signs was confirmed positive for the virus. The stallion was euthanized due to the severity of the disease. For 2017, a total of nine(9) horses have been confirmed positive for WNV in California . For more information visit:https://www.cdfa.ca.gov/ahfss/animal_health/WNV_Info.html

August 25, 2017
West Nile Virus
Carbon County, UT
Confirmed Case(s): No Quarantine
Source: Utah Department of Agriculture and Food

The Utah Department of Agriculture and Food received confirmation of WNV in a 1-year-old pony mare from Carbon County. This is the fourth case of WNV for Utah in 2017.

August 25, 2017
Equine Herpes Viruses
King William County, VA
Confirmed case(s): Official Quarantine
Source: Virginia Department of Agriculture and Consumer Services

The Virginia Department of Agriculture and Consumer Services’ (VDACS) has confirmed a diagnosis of Equine Herpesvirus Myeloencephalopathy (EHV-1) on a second farm in Virginia. On August 15 VDACS announced an unrelated finding of EHV-1 on a farm in Culpeper County. That farm continues to be under quarantine. This new case originated from a small private pleasure horse farm in King William County. Out of the 4 horses that showed clinical signs compatible with Equine Herpesvirus Myeloencephalopathy (EHM), 2 horses tested positive and both of them were euthanized. This farm is under quarantine and all exposed horses are being monitored twice daily for fever (temperature over 101.50oF) and other clinical signs. No horses have been on or off the premises for 1 year. There are no horses near this farm that have been exposed, and there is no association between this farm and any of the horses or people at the first quarantined farm, including equine professionals. 

August 25, 2017
West Nile Virus
Dodge County, WI
Confirmed Case(s): No Quarantine
Source: Wisconsin Department of Agriculture, Trade, and Consumer Protection

The Wisconsin Department of Agriculture, Trade, and Consumer Protection received confirmation of its fifth equine West Nile Virus case for 2017.  An unvaccinated 5-year-old Quarter Horse gelding from Dodge County was examined and sampled 8/17 after exhibiting a sudden onset of ataxia, mainly in the front quarters.  The horse was treated and is improving.

August 23, 2017
West Nile Virus
Plumas County, CA
Confirmed Case(s): No Quarantine
Source: California Department of Food and Agriculture

On August 22, 2017, the California Department of Food and Agriculture confirmed an additional equine case of West Nile Virus in an unvaccinated 2.5-year-old Paint gelding in Plumas County, California displaying neurologic signs was confirmed positive for WNV. The gelding is alive and recovering. For 2017, a total of eight(8) horses have been confirmed positive for WNV in California. For more information visit: https://www.cdfa.ca.gov/ahfss/animal_health/WNV_Info.html

August 23, 2017
West Nile Virus
Morgan County, MO
Confirmed Case(s): No Quarantine
Source: University of Missouri Veterinary Health Center

The University of Missouri Veterinary Health Center has confirmed a case of WNV. The 7-year-old mare from Morgan County showed acute onset of clinical signs on August 2nd which included non-weight bearing left hind lameness and recumbency (inability to stand) and was euthanized. The mare had been vaccinated in March of 2017.

August 22, 2017
Eastern Equine Encephalitis
Richland County, SC
Confirmed Case(s): No Quarantine
Source: South Carolina State Veterinarian

The South Carolina State Veterinarian’s office has received laboratory confirmation of a positive Eastern Equine Encephalitis case from Richland County. The 3 year old TB gelding of unknown vaccination status was euthanized. This is the third case of EEE confirmed in SC in 2017.

August 22, 2017
West Nile Virus
Bonner County, ID
Confirmed Case(s): No Quarantine
Source: Idaho State Department of Agriculture

The Idaho State Department of Agriculture has confirmed a case of West Nile Virus in Bonner County. The 6 year old HQ horse gelding of unknown vaccination status was recumbent (unable to stand) with hind limb paralysis. This is the second WNV positive diagnosed in Idaho in 2017.

August 22, 2017
West Nile Virus
Bruce and Simcoe Counties, ON
Confirmed Case(s): No Quarantine
Source: Ontario Ministry of Agriculture, Food and Rural Affairs

On August 21, the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) was notified of two positive test results for West Nile Virus (WNV); one from a 10-year-old gelding in Simcoe County and the other from a 25-year-old mare in Bruce County. The Simcoe County gelding was euthanized after developing severe neurological signs and seizures. The mare developed severe neurological deficits in all four limbs as well as facial hyperaesthesia and is recovering under veterinary medical supervision.