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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.


September 28, 2018
West Nile Virus
Tuscarawas, Wayne, Holmes Counties, OH
Confirmed Case(s): No Quarantine
Source: Ohio Department of Agriculture

The Ohio State Department of Agriculture confirmed 7 new cases of West Nile Virus (WNV) in September 2018. On September 18th12-year-old Standardbred gelding from Tuscarawas County had weak posterior limbs. The veterinarian described the symptoms as mild. The horse was not vaccinated against WNV. The horse is alive and recovering as of September 25th. On September 18tha 7-year-old Pony mare from Tuscarawas County wouldn’t move and had weak front limbs. Facial paralysis, a low-grade fever, malaise, lack of appetite, and mild ataxia were found during the veterinarian’s examination. The horse was not vaccinated against WNV. The horse is alive and recovering as of September 25th. On September 18tha 3-year-old Standardbred gelding from Wayne County was uncoordinated and had a low-grade fever. The horse was not vaccinated against WNV. The horse is alive and recovering as of September 26th. On September 19tha 7-year-old Standardbred gelding from Tuscarawas County was lame, stiff and had weak hind limbs. The unvaccinated horse is alive and responding to veterinary treatment recovering as of September 26th.On September 19than adult Belgian mare from Holmes County was off balance and had weak rear legs. On September 20th the horse was down and unable to rise. In spite of treatment, the owner opted to euthanize the horse on September 20th. The horse was not vaccinated against WNV. On September 19than adult Standardbred gelding from Wayne County had an unsteady gait. The horse was treated by a veterinarian, is alive and is recovering as of September 26th. The thirty-eighth positive horse was a 2-year-old Morgan mare from Holmes County. The horse was not vaccinated against WNV.  As of September 28ththe clinical outcome is not known. Serum samples collected and submitted to NVSL (seven cases) and Cornell University (one case), were all reported positive for WNV exposure by IgM capture ELISA titer of 1:400. As of September 27, Ohio has had 38 confirmed cases of WNV.

September 28, 2018
West Nile Virus
Muskegon County, MI
Confirmed Case(s): No Quarantine
Source: Michigan Department of Agriculture and Rural Development

The Michigan Department of Agriculture and Rural Development confirmed a second case of West Nile virus (WNV) for 2018. An unvaccinated 15-year-old Standardbred mare from Muskegon County, began to experience severe incoordination in the hindlimb on September 13, 2018. The horse was euthanized. No quarantines were issued.

September 27, 2018
Equine Infectious Anemia
Multiple Counties, CO
Information Only
Source: Colorado Department of Agriculture

The Colorado State Veterinarian’s Office at CDA has continued to work to trace and test horses involved in the EIA Incident in the State of Colorado. As of 09/27/2018: ·There is only one confirmed positive horse in Colorado (index case); ·The index premises in Weld County is under a quarantine order; two associated premises are under hold orders. The 124 exposed horses under quarantine on the index premises tested negative for EIA on 09/10/2018. They will be re-tested on or after 10/19/2018 (sixty days after last exposure to the positive horse). 138 exposed horses have been located in Colorado (out of approximately 152 we expect to be in the state). ·61 premises are under hold orders in 24 Colorado counties: Adams, Arapahoe, Archuleta, Boulder, Costilla, Crowley, Delta, Douglas, Eagle, Elbert, El Paso, Fremont, Gilpin, Gunnison, Huerfano, Jefferson, Larimer, Mesa, Moffat, Montrose, Morgan, Phillips, Sedgwick, and Weld. ·Five premises have been released from hold after the 60-day re-tests were completed for all exposed horse(s) on those premises and found to be negative. ·72 exposed horses have been positively identified in 12 other states (out of approximately 83 we expect to be out-of-state): Arizona, Idaho, Kentucky, Louisiana, Maine, Missouri, Nebraska, Nevada, Oklahoma, Tennessee, Texas, and Wyoming. Re-testing of Exposed Horses under Hold Orders: Many of the exposed horses will be eligible for their final 60-day EIA re-test over the next three weeks. We have informed owners of exposed horses to work with their veterinarians to get the re-testing done after the date stated on their Hold Orders. The date varies depending on the last date that their horse was exposed to the EIA-positive horse. At this time only the exposed horses need to be tested, not all of the horses on the premises under the Hold Order. Once we receive the negative 60-day EIA re-test results, CDA will release the Hold Order as quickly as possible so please notify our office with the results. If you have any questions, please call the State Veterinarian’s Office at 303-869-9130 or email animalhealth@state.co.us.

September 27, 2018
West Nile Virus
Woodford County, KY
Confirmed Case(s): No Quarantine
Source: Kentucky Department of Agriculture

On Thursday, September 27, 2018, the Kentucky Office of the State Veterinarian confirmed a case of West Nile Virus (WNV) in Woodford County. The 5 year-old mare began showing clinical signs on September 18, 2018 including muscle fasciculation, hypermetria, profuse sweating throughout body, hyperexcitability, and progressive ataxia in all 4 limbs. The mare was euthanized. Vaccination was reported as being current with annual vaccination, the most recent one being in January 2018. For more information about West Nile go to: https://aaep.org/sites/default/files/Documents/Outside%20Linked%20Documents/DiseaseFactsheet_WNV.pdf

September 27, 2018
West Nile Virus
Woodward County, OK
Confirmed Case(s): No Quarantine
Source: Oklahoma Department of Agriculture, Food and Forestry

The Oklahoma Department of Agriculture, Food and Forestry confirmed the third West Nile Virus (WNV) case  positive horse in Oklahoma for 2018. An unvaccinated 2-year old Quarter Horse stallion located in Woodward County had moderate neurologic signs.  A quarantine was not issued.  For more information visit:http://www.ag.ok.gov

September 26, 2018
West Nile Virus
Clinton and Wapello Counties, IA
Confirmed Case(s): No Quarantine
Source: Iowa State Veterinarian

The Iowa State Veterinarian confirmed 2 new cases of West Nile Virus. On September 20, 2018 a 18-year old Belgian gelding in Clinton county had facial and chest muscle fasiculations, stiffness in the legs, muscle weakness in the hind limbs, ataxia and mild fever. The horse first developed posterior paresis on September 22nd and progressed to being recumbent the next day.  The horse was treated symptomatically, examined the following day and the owner elected to humanely euthanize on September 24th.  This mare was not vaccinated for WNV this year and had no previous history of WNV vaccination. A 3 year old Quarter Horse mare in Wapello county was examined on September 23, 2018.  The horse first developed posterior paresis on September 22nd and progressed to being recumbent the next day.  The horse was treated symptomatically, examined the following day and the owner elected to humanely euthanize on September 24th.  This mare was not vaccinated for WNV this year and had no previous history of WNV vaccination.

September 25, 2018
Equine Herpes Viruses
Loudon County, VA
Information Only
Source: Virginia Department of Agriculture, Office of Veterinary Services

On September 24, 2018 the Virginia Department of Agriculture, Office of Veterinary Services placed a small private farm in Loudoun County under quarantine for Equine Herpes Myelonencephalopathy (EHM). A hold order had been placed on the farm on September 21 after the Virginia State Veterinarian learned that a horse originating from the farm had tested positive for EHM and was quarantined in Maryland.  No other horses have been on or off the Virginia farm in the last month. There was no exposure to horses outside of the farm. Temperatures are being monitored twice a day for the duration of the quarantine. Any horse that displays fever or clinical signs compatible with EHM will be reported to the State Veterinarian and will be tested.

September 24, 2018
Eastern Equine Encephalitis
Oneida 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 has confirmed its second case of Eastern Equine Encephalitis (EEE) for 2018 in Oneida County. The affected horse was a 15-year-old Belgian/Paint cross gelding from Oneida County tested positive with IgM Capture ELISA. He was incompletely vaccinated, having had his first ever EEE vaccine this spring without a booster. The gelding began showing neurologic signs on September 13, 2018, became recumbent and was euthanized on September 14th.

September 24, 2018
West Nile Virus
Poweshiek County, IA
Confirmed Case(s): No Quarantine
Source: Iowa State Veterinarian's Office

The Iowa State Veterinarian’s Office confirmed a case of equine West Nile virus (WNV) in Poweshiek County. An unvaccinated two-year-old Standardbred gelding showed an onset of clinical signs on September 17th, 2018 including ataxia and dragging one hind-leg. The horse was treated symptomatically and is recovering. WNV was confirmed at the Iowa State University Veterinary Diagnostic Laboratory.

September 24, 2018
Equine Infectious Anemia
Colorado, United States
Information Only
Source: Colorado State Veterinarian’s Office

The Colorado State Veterinarian’s Office at CDA has continued to work to trace horses involved in the EIA Incident in the State of Colorado. As of 09/24/2018: Only one horse has been confirmed positive horse in Colorado (index case). The index premises in Weld County is under a quarantine order; two associated premises are under hold orders. The 124 exposed horses under quarantine on the index premises tested negative for EIA last week; they will be re-tested on or after 10/19/2018 (sixty days after last exposure to the positive horse). 128 exposed horses have been located in Colorado. 54 premises are now under hold orders in 20 Colorado counties: Adams, Arapahoe, Boulder, Crowley, Delta, Douglas, Eagle, Elbert, El Paso, Fremont, Gilpin, Gunnison, Huerfano, Jefferson, Larimer, Mesa, Moffat, Montrose, Phillips, and Weld. 64 exposed horses have been positively identified in 10 other states: Arizona, Kentucky, Louisiana, Maine, Missouri, Nebraska, Nevada, Oklahoma, Texas, and Wyoming. Last week, two exposed horses that were re-tested on their final 60-day test were negative and those two Colorado premises were released from their Hold Order. Re-testing of Exposed Horses under Hold Orders: Some of the exposed horses will be eligible for their final 60-day EIA re-test over the next four weeks. CDA has informed owners and their veterinarians about the testing of exposed horses which can begin on the date stated on their Hold Orders. The date varies depending on the last date that the horse was exposed to the EIA-positive horse. At this time only the exposed horses need to be tested, not all of the horses on the premises under the Hold Order.