Hundreds of horses at a major show jumping event in Florida have been quarantined as a precaution after state agricultural officials reported an outbreak of a high contagious equine herpes virus.Agriculture Commissioner Adam Putnam said Thursday that state officials, horse owners and veterinarians are taking strict precautions to contain the spread of the virus also known as EHV-1.
Quarantine of hundreds of horses
More horses from the HITS Ocala show grounds have been confirmed positive for "wild strain" of equine herpesvirus leading to quarantine of hundreds of horses.
The outbreak of Equine Herpes Virus centered on the famous "HITS" show in Ocala is growing as the number of horses that have tested positive has jumped from one to six. The first horse from the HITS Ocala show grounds that was confirmed positive for EHV-1 neurologic disease on February 22, 2013 is responding well to aggressive treatment.
Equine herpesvirus is not transmittable to humans, but can result in neurological disease, respiratory disease, abortion and neonatal death in horses. Equine Herpes Virus, or EHV-1, is not a sexually transmitted virus. It's spread through respiratory secretions and via contaminated feed buckets, food, grooming tools and other equine equipment.
The affected horses in Ocala have the so-called "wild" strain according to authorities The seventh horse diagnosed in the Wellington, Fla. area has not had direct or indirect contact with any of the horses at the Ocala show.
Other areas where horses were exposed to the virus while at the Ocala show are also under quarantine.
The United States Equestrian Federation said in a news release that established "protocols" for such competitions are important and are in place to safeguard horses brought in from different locations.
In Utah, the state State Veterinarian has issued several quarantines in Cache County following the confirmation of four cases of EHV-1, along with one other suspected case. According to a news release Wednesday, two of the five horses were euthanized. The cases in Florida and Utah do not appear to be linked.
The Large Animal Medicine Service at the University of Florida provides the following information for horse owners concerned about EHV and EHM:
How does EHV cause EHM?
EHV can cause inflammation of the blood vessels surrounding the brain and spinal cord. The neurologic signs (EHM) result from that inflammation and small blood clots that affect the neural tissue. During an outbreak of EHM, usually only 10% of infected horses develop neurologic signs. At this time, we still don’t fully understand why some horses get EHM and others don’t, but it is likely a combination of factors specific to that individual horse and to the virus infecting it.
What does “wild type” strain of EHV-1 mean?
There are two strains of EHV-1, known as D752 and N752. D752 is more frequently associated with EHM, and is therefore sometimes called the “neurotropic strain” while N752 is called the “wild type” strain, implying that it is the “normal” variant. This is misleading, however, as either strain can cause neurologic disease. D752 is more likely to cause neurologic disease, but the same control methods are indicated for either strain.
What are the signs of EHM?
Clinical signs typically begin with a fever, usually 1-3 days after infection although it can be up to 10 days. Neurologic signs usually appear around 7 days post-infection, and progress rapidly over 24 to 48 hours. Signs may include incoordination, weakness, loss of tail tone, urine dribbling, head tilt, and inability to rise.
How is EHV spread?
Herpesvirus is primarily spread by direct horse to horse contact via the respiratory tract. It is unknown how far the virus can spread in the air surrounding an infected horse. Virus can also be spread by contaminated hands, clothing, buckets, tack, grooming equipment, and trailers. The virus can live for about 7 days in the environment, but it is easily killed by most disinfectants.
How is EHM diagnosed?
Horses with a fever and neurologic signs should be tested by your veterinarian. Currently recommended testing consists of a nasal swab and blood collection to detect virus by PCR (polymerase chain reaction) which detects the DNA of the virus. Doing both nasal swab and blood testing increases the likelihood of making a correct diagnosis. Any horse that dies or is euthanized due to neurologic disease should also be submitted for a necropsy examination.
Who decides how an outbreak is managed?
EHM is a reportable disease. That means that when a veterinarian confirms that a horse is positive for EHV and showing neurologic signs, the state animal health officials are notified. The state veterinarians are specially trained to deal with animal disease prevention, surveillance, and control programs. They determine the necessity for quarantine or restricted movement of animals.
Is there a treatment for EHM?
Treatment is primarily supportive. This includes anti-inflammatory drugs. Intravenous fluids may be necessary if the horse is having trouble drinking. Nursing care is also extremely important if the horse is unable to rise. Antibiotics are not effective against EHV, but can be used if there is a secondary bacterial infection. Antiviral drugs such as valacyclovir may prevent infection in exposed horses.
My horse is vaccinated, so he is safe, right?
Unfortunately, no. While there are several vaccines available that provide protection against respiratory disease and abortion, none are labeled for protection against the neurologic form.