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EDCC Disease Update

The Equine Disease Communication Center (EDCC) offers alerts about equine diseases that have been confirmed by reliable sources. The following information is from the EDCC. The following reports are in chronological order from most recent to oldest from previous reports.

Fourth 2016 WNV Case in Kentucky

The EDCC released on September 23 that the Kentucky State Veterinarian’s office had reported Kentucky’s fourth case of West Nile virus (WNV) for the state this year. This case was located in Hart County. The unvaccinated 4-year-old Standardbred mare presented with moderate rear limb ataxia, muscle fasciculation and lip paresis on September 15. As of September 23, the mare is reported as much improved with a prognosis of full recovery. Click the following link to view the Kentucky Department of Agriculture’s current summary (includes geographic reference map):

WNV in California

On September 22, 2016, a 10-year-old Quarter Horse gelding in Shasta County, California, was displaying neurologic signs and was confirmed positive for West Nile virus. The vaccination status of this horse is unknown. The gelding is recovering. For 2016, a total of nineteen (19) horses have been confirmed positive for WNV in California. Seven of the 19 confirmed horses died or were euthanized. The California Department of Food and Agriculture (CDFA) continually monitors and investigates equine neurologic cases for the presence of WNV in California. CDFA urges horse owners to consult with their veterinarians concerning a WNV vaccination program to ensure maximum protection of their horses. For more information visit:

WNV in Minnesota

The Minnesota Veterinary Medical Association has reported the 16th case of WNV in the state this year. The unvaccinated Quarter Horse gelding, located in Morrison County, was first observed showing clinical signs on September 8 and is still alive, although unable to stand without assistance.

WNV in Kentucky

Results of diagnostic testing received from the University of Kentucky’s Veterinary Diagnostic Laboratory confirmed on September 22 that the state's third equine West Nile virus case of the year. The unvaccinated 3-year-old Standardbred mare presented with acute lethargy, general weakness and ataxia, and mild muscle fasciculation in neck and chest area on September 18 and was hospitalized on September 20. The horse continues to receive supportive care at the hospital and is reported to be in a stable condition. For more information go to

WNV in West Virginia

The West Virginia Department of Agriculture has reported a case of West Nile virus confirmed on September 20. The 6-year-old Quarter Horse mare,located in Mineral County, showed severe, acute neurologic symptoms, but is still alive. Vaccination status is unknown.

Potomac Horse Fever in West Virginia

The West Virginia Department of Agriculture confirmed a case of Potomac Horse Fever on September 20 in Hampshire County. The 6-year-old Quarter Horse gelding was febrile, lethargic and passing loose stool. Vaccination status is unknown; the horse was alive at time of reporting.

First 2016 WNV Case in Arizona

A horse in Cochise County, Arizona, has tested positive for West Nile virus, marking the first detection of the disease in Arizona for the 2016 season. The affected horse is a 4-year-old Quarter Horse gelding with no history of vaccination for WNV. The horse exhibited advancing medical signs and was euthanized.

EEE Deaths in Two Michigan Counties

As of September 20, the Michigan Department of Agriculture and Rural Development (MDARD) had identified two cases of Eastern equine encephalitis (EEE). On September 15, 2016, the MDARD was notified that a 4-month-old Standardbred filly in Clare County tested positive for EEE. The filly had developed a sudden fever, was staggering and eventually unable to rise. The filly was not vaccinated against EEE and died. On September 16, Michigan's second case of EEE was identified in a 12-year-old Quarter Horse mare in Menominee County. The horse had a fever, was not eating or drinking, and was leaning against walls. The unvaccinated mare later died. For more information visit

20th 2016 EEE Case in Florida

On September 19, a new EEE case was confirmed in Sumter County, Florida. The 11-year-old Quarter Horse mare was last vaccinated for EEE in late Summer 2015 per the owner and had no recent travel history. Clinical signs began on August, 13 and the horse was euthanized for humane reasons later the same day. This is the first confirmed EEE case in Sumter County and case 20 in Florida for 2016.

WNV in Multiple Washington State Counties

The Washington State Department of Agriculture has documented nine confirmed cases of West Nile Vvrus so far in September. None of the horses were vaccinated. Reported cases were: a 7-year-old Quarter Horse mare in Stevens County was confirmed positive on September 1; prognosis is good. A cross-bred gelding in Spokane County was confirmed positive on September 3; prognosis is good. A 12-month-old Quarter Horse cross filly in Stevens County was confirmed positive on September 4 and died. A 2-year-old Arabian colt in Grant County was confirmed positive on September 6; prognosis is good. A 17-year-old gelding in Kittitas County was confirmed positive on September 7; prognosis is good. A 13-year-old Paint gelding in Franklin County was confirmed positive on September 12; euthanized. A 6-year-old Quarter Horse mare in Pend Oreille County was confirmed positive on September 11; prognosis is fair. A 23-year-old Arab cross mare in Okanogan County was confirmed positive on September 11 and was euthanized. A 5-year-old Arab cross mare in Spokane County was confirmed positive on September 13; prognosis is good.

EEE in Wisconsin

An unvaccinated, 12-year-old, Quarter Horse mare seen on September 7 in Vilas County, Wisconsin, was fourth confirmed equine case of EEE in the state in 2016. The mare was febrile, unable to rise and unresponsive with various neurologic sign,s including extensor rigidity, struggling, nystagmus, intermittent tonic-clonic activity and frequent tooth grinding. The attending veterinarian humanely euthanized the mare.

Strangles in Florida

On September 19, one premise in Hillsborough County, Florida, was placed under quarantine for strangles. A horse began showing respiratory signs on September 7 after being imported from a Louisiana Kill Facility and was isolated. A respiratory panel taken returned positive for strangles and EHV-4. That horse is the only equine on the premises, and no animals have left the facility since clinical signs began. This is the second strangles case in Hillsborough County and case 20 for Florida in 2016.

WNV in Ohio

Testing on samples taken from a 7-year-old Standardbred in Tuscarawas County, Ohio, confirmed the positive WNV diagnosis to the Ohio Department of Agriculture on September 12. The horse’s veterinarian first examined the animal on August 29. The animal was euthanized after exhibiting significant clinical signs, including shaking, agitation and thrashing. The horse had not been vaccinated. For more information go to

About EDCC

The Equine Disease Communication Center works to protect horses and the horse industry from the threat of infectious diseases in North America. The communication system is designed to seek and report real time information about disease outbreaks similar to how the Centers for Disease Control and Prevention (CDC) alerts the human population about diseases in people.

The goal of the EDCC is to alert the horse industry about disease outbreak information to help mitigate and prevent the spread of disease. Ultimately frequent and accurate information about diseases outbreaks improves horse welfare and helps to prevent negative economic impact that can result from decreased horse use due to a fear of spreading infection. As part of the National Equine Health Plan the EDCC will serve as part of the communication to help educate and promote research about endemic and foreign disease.

Working in cooperation with state animal health officials and the United State Department of Agriculture, the EDCC seeks information about current disease outbreaks from news media, social media, official state reports and veterinary practitioners. Once information is confirmed, it is immediately posted on this website and messages sent to all states and horse organizations by email. Daily updates are posted until each outbreak is contained or deemed no longer a threat.

The EDCC is made possible by generous donations from organizations and horse owners. Please visit our sponsors that have generously supported this program for the benefit of the health and welfare of horses. To learn how you can help go to SUPPORT.



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