Infectious Horse Disease Update from Equine Disease Communication Center

Veterinarian examining horse.
Veterinarian examining horse.

According to the Equine Disease Communication Center which works to protect horses and the horse industry from the threat of infectious diseases in North America, a number of infectious horse diseases continue to affect horses throughout the USA as summer weather continues.

Horse affected by infectious disease

Horse affected by infectious disease

Cases of West Nile virus, Equine Infectious Anemia, Equine Herpesvirus-1, and Eastern Equine Encephalitis continue to affect a number of horses throughout the USA as summer weather continues.

As of August 19, 2017, the Nevada Department of Agriculture has confirmed three horses tested positive for West Nile Virus (WNV) in western Nevada in the last two weeks. All three horses were not vaccinated.

In addition, the Kansas Department of Agriculture Division of Animal Health (KDA–DAH) confirmed a horse in Reno County has tested positive for West Nile virus (WNV). The horse was euthanized due to the severity of the illness.

This is the first reported equine case of WNV in Kansas in 2017. Horse owners are encouraged to vaccinate their horses to prevent the spread of WNV.  For more information go to:  http://www.agriculture.ks.gov/divisions-programs/division-of-animal-health

The Kansas Department of Agriculture Division of Animal Health (KDA–DAH) confirmed a horse in Finney County has tested positive for Equine Infectious Anemia (EIA). The facility is under quarantine and all the exposed horses were tested, with five additional positive EIA horses. Since the disease is not curable, the affected horses will be euthanized. The remaining horses at the facility will be observed and retested in 60 days.  For more info go to:  http://www.agriculture.ks.gov/divisions-programs/division-of-animal-health

The California Department of Food and Agriculture has confirmed two additional equine cases of West Nile Virus in an unvaccinated yearling Warmblood filly in San Joaquin County and a three year old Appaloosa gelding of unknown vaccination status in Glenn County which were displaying neurologic signs. The Warmblood filly was euthanized due to the severity of the disease and the Appaloosa gelding has been treated and is recovering.

For 2017, a total of seven(7) horses have been confirmed positive for WNV in California . For more information visit: https://www.cdfa.ca.gov/ahfss/animal_health/WNV_Info.html

The Kentucky Department of Agriculture has confirmed a diagnosis of West Nile Virus in two horses. On 8/13/2017 in Hart County an 8-year old Tennessee Walking Horse gelding was lethargic and had muzzle twitching, muscle fasciculations and rear limb ataxia.

The horse had no vaccination history and is reported to be improving. On 8/14/2017 in Russell County a 3-years old Thoroughbred had muscle fasciculations with mild ataxia which worsened over 24 hours. This horse had been vaccinated in 2015, thought to have been vaccinated in 2016 and received a single vaccination in the spring of 2017.  For more information go to:  http://www.kyagr.com/statevet/equine-infectious-diseases.html#WNV

On August 17th the Utah Department of Agriculture and Food confirmed West Nile Virus in an unvaccinated 9-year old Quarter Horse mare from Carbon County. The horse was ataxic with muscle faciculations and facial twitching at the onset of clinical signs on August 14th.

As of August 14th the horse has responded to treatment and is expected to recover. This is the second WNV case in Carbon County. For more information about WNV go to: https://aaep.org/sites/default/files/Documents/Outside%20Linked%20Documents/DiseaseFactsheet_WNV.pdf

On August 15, the Virginia Department of Agriculture and Consumer Services (VDACS) confirmed a diagnosis of Equine Herpesvirus-1 (EHV-1) on two horses from Culpeper County. A third horse on the quarantined farm developed a fever the evening of August 16 and tested positive for the neuropath genic strain of the Equine Herpes Virus -1.

The quarantine will be extended until September 6th. This third horse is under veterinary care and has no other symptoms. Because the farm is under quarantine, no additional horses have been exposed.

The Wisconsin Department of Agriculture, Trade, and Consumer Protection has confirmed its fourth case of equine EEE for 2017. The 10-year-old Quarter Horse gelding was from Jackson County. The vaccination status of this horse could not be determined. The horse had a high fever, showed neurologic signs, became non-ambulatory, and was euthanized. No quarantine was established.

The Wisconsin Department of Agriculture, Trade, and Consumer Protection has confirmed its fourth case of equine West Nile Virus for 2017. The nonvaccinated 13-year-old Belgian mare was from Jackson County. She showed neurologic signs, became nonambulatory, and was euthanized. No quarantine has been established.

The Michigan Department of Agriculture and Rural Development has received confirmation that two additional Michigan horses have tested positive for West Nile virus (WNV).  The two cases are as follows: a 10-year-old Belgian mare from Clinton County and a 21- year-old Quarter Horse mare from Wexford County.

Both horses developed a sudden onset of neurologic disease including being down/unable to get up and were subsequently euthanized due to the severity of the disease. Neither horse had been vaccinated against WNV.  This brings the total number of Michigan horses reported as having WNV in 2017 to seven, one each from the following counties: Clinton, Livingston, Jackson, Mecosta, Midland, Missaukee, and Wexford. No quarantines were issued.

Although not all cases of infectious horse diseases are reported to the EDCC, those reported give horse owners important information about equine diseases in their area. Horse owners are encouraged to monitor their individual state agricultural websites for local information regarding infectious horse diseases along with staying in touch with local veterinarians who follow important current information in their particular locality.

About the Author

Flossie Sellers

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As an animal lover since childhood, Flossie was delighted when Mark, the CEO and developer of EquiMed asked her to join his team of contributors.

She enrolled in My Horse University at Michigan State and completed a number of courses in everything related to horse health, nutrition, diseases and conditions, medications, hoof and dental care, barn safety, and first aid.

Staying up-to-date on the latest developments in horse care and equine health is now a habit, and she enjoys sharing a wealth of information with horse owners everywhere.

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