On January 28, the Bureau of Animal Health and Welfare received notification of laboratory confirmation of EHV-1 (neuropathogenic form) infection in horses being boarded at a private stable in DuPage County, Illinois. In addition, several other locations have reported outbreaks of EHV-1.
A sick horse
Equine Herpes Virus can cause respiratory disease, abortion in mares, neonatal foal death, and/or neurologic disease. The virus can spread through the air, contaminated equipment, clothing and hands making biosecurity measures a priority to prevent spreading the disease.
The stable has been placed under quarantine by state animal health officials. The source of the exposure is unknown.
At the time of notification, eight horses were affected with two being subsequently euthanized. The Bureau has provided requested information to the stable operator and practicing veterinarians.
In an Update, it was reported that no new cases of EHV-1 infection have been reported since the initial report on 1/28/16. Horses at the affected premises continue to be monitored and have been free of clinical signs of disease for over one week. The quarantine of the premises remains in effect.
In addition to the cases of EHV-1 in Illinois, Equine Herpes virus cases have been confirmed in a number of horses at Sunland Park, New Mexico. The number of horses diagnosed positive for the EHV-1 to-date is 70. The number of horses that have been released from isolation is 15. Currently there are still 15 exposed barns.
The surrounding facilities have not had any positive cases and have been released from quarantine after 21 days with no movement on or off premises. The list of facilities within the quarantine perimeter include Sunland Park Racetrack, Frontera Training Center, Jovi, and Lazy S. Both Frontera and Sunland Park remain under quarantine.
Equine Herpes Virus (EHV-1) impacts horses and can cause respiratory disease, abortion in mares, neonatal foal death, and/or neurologic disease. The virus can spread through the air, contaminated equipment, clothing and hands.
According to the University of Kentucky Equine Research Center, the virusâs ability to reside as a silent and persistent infection in horses provides for continual transmission. It is vital that good biosecurity measures be implemented on exposed premises.
Horse owners need to be mindful that most horses are exposed to one or more strains of EHV at a very young age. Periods of high stress or additional exposure may cause an animal to exhibit clinical signs of disease.
Occasionally, the disease is exhibited as a serious neurologic disease. Owners should consult with their veterinarian when deciding whether or not to attend an equine event as anytime horses are commingled there is the opportunity for exposure.
The United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) states, the incubation period of EHV-1 is 1-10 days; typically signs are seen within 1-3 days post exposure.
Viral shedding occurs for 7-10 days, but can occur up to 28 days from the onset of signs.
The neurologic signs include ataxia, urinary bladder atony and reduced tail tone. In severe cases, horses will be unable to stand; these cases have a very poor prognosis. Foals are rarely affected with the neurologic form of EHV-1, and no sex predilection is seen. Treatment is supportive and tailored to the specific case.
Once a horse is infected, it should be quarantined. USDA recommends isolating and monitoring of all exposed horses for at least 7 days. During the isolation period, it is recommended to discontinue or reduce any strenuous training or exercise for exposed horses.
All exposed horses should have rectal temperatures taken twice daily (8-12 hours apart) and recorded in a log for at least 7 days after the date of potential exposure. Horses whose rectal temperature registers higher than 101.5 degrees Fahrenheit are considered to be febrile. All horses on the premises should also be monitored for neurologic signs (ataxia, posterior incoordination, weakness, recumbency with inability to rise, circling, head pressing, head tilt, bladder atony) during the home quarantine period.
Central nervous system signs, such as posterior incoordination, weakness, recumbency with inability to rise, and bladder atony are most common in EHM affected horses.
More info:
http://www.aaep.org/info/horse-health?pubsearch=Search+Publication+Archives&pubcat=Equine+Herpesvirus+%28EHV%29
http://www2.ca.uky.edu/gluck/biblioehv1.asp
http://www.aphis.usda.gov/vs/nahss/equine/ehv/ehv_ehm_recommendations_051611.pdf