Cases of EHV-1 Confirmed in Wisconsin, Single Location

Chicago Equestrian release

West Bend, WI – May 14, 2016 – On May 10th, 2016, a 17-year-old Appendix QH gelding at Seoul Creek Farm,  50 stall hunter/jumper stable in West Bend, Wisconsin, developed acute, severe neurologic signs. He was evaluated and treated immediately. Diagnostic samples were taken and the horse was placed in isolation. The horse deteriorated rapidly and was euthanized early May 12th. Diagnostic testing confirmed a diagnosis of Equine Herpes Myeloencephalopathy (EHM) caused by Equine Herpesvirus, EHV-1, the non-neuropathogenic strain.

After testing every horse on the Seoul Creek Farm property, it was determined that an additional 11 horses have either tested positive on nasal swab, blood test or both. These additional horses have been isolated. None of these horses have had a fever, nasal discharge and none are exhibiting neurologic signs. All horses have tested positive for the wild-type strain (non-neuropathogenic) strain which fortunately has a very low chance of producing neurologic disease (less than 10%).

The 3 horses that had a fever on May 12th still have some additional testing – results are pending.

All horses testing positive or those with fevers have been isolated. The extent of infection is now known and all horses’ temperatures will be monitored twice daily. The state veterinarian has visited the farm, issued a written quarantine and has reviewed the isolation protocol. The state veterinarian deemed it to be excellent and the farm’s veterinarian, Wisconsin Equine Clinic & Hospital, will evaluate all horses on an ongoing basis.

The farm is working closely with the state veterinarian and Wisconsin Equine Clinic & Hospital to address further biosecurity protocols. They are still limiting human traffic at the barn until further notice.

Barn owner Courtney Hayden-Fromm, has demonstrated exemplary efforts in her quarantine and containment procedures. The facility is large enough to provide proper isolation for infected horses and immediate veterinary attention was provided to the entire barn. Biosecurity measures are being followed to the letter and communication is being provided to owners, veterinarians and the state Department of Agriculture.

All the horses at Seoul Creek had been vaccinated prior to the outbreak.

Please direct questions or concerns to the Wisconsin Equine Clinic & Hospital; they are doing an exceptional job of directing the barn management during this challenging time and helping to educate clients and the public regarding the outbreak. Updates can be found on the Old Seoul Equestrian Facebook page and will be shared on Chicago Equestrian’s Facebook page and on Wisconsin Equine’s Facebook as well.

About EHV-1

EHV-1 is a viral disease that has 3 different presentations:

1) Respiratory disease – this is very common in young horses and typically presents as fever, nasal discharge, lymph node swelling and cough. The signs are short lived and horses recover quickly.

2) Abortion in mares – infected mares can abort – typically in mid to late gestation

3) Neurologic disease – this is a much more rare presentation. Approx. 10% of infected horses progress to neurologic disease but the outcome is often euthanasia.

Transmission of the virus occurs via respiratory secretions and aborted fetal membranes. Also indirect transmission can occur via objects such as buckets, tack and humans who have contacted multiple horses.

Diagnosis of EHV-1 is based on clinical signs and PCR testing on both nasal swabs and whole blood.

Treatment of EHV-1 is directed at managing the fever and any spinal cord inflammation that manifests as neurologic signs. Common medications used include NSAID’s, steroids and DMSO. Antiviral medications may decrease the risk of neurologic disease but are very expensive.

Management of an outbreak lies in the prompt identification and isolation of new cases. Infected horses may demonstrate a fever 5-10 days after infection and show signs of neurologic disease in 7-14 days. An infected horse could shed the virus for up to 28 days prompting strict farm quarantine.

Vaccination in the face of an outbreak is controversial. There are currently no vaccines that prevent the neurologic form of the disease. Vaccination may decrease the shedding of the virus via the respiratory tract.

More Information

The DATCP is providing information resources and situational updates on its website at datcp.wi.gov/animals/animal_diseases and on social media at facebook.com/widatcp, and twitter.com/widatcp.

Information can also be found on the Equine Disease Communication Center at www.equinediseasecc.org/outbreaks.aspx.

Get Answers to your Questions from Wisconsin Equine Clinic & Hospital at 262-569-1550. Updates can be found on their website at www.wisconsinequineclinic.com and on Facebook.

http://www.vetmed.ucdavis.edu/ceh/resources/ehv1/index.cfm

https://www.aphis.usda.gov/publications/animal_health/2011/bro_keep_horses_healthy.pdf

http://content.govdelivery.com/bulletins/gd/WIDATCP-14913a5