biosecurity | Horse Racing Free Tips

New Strain Of Hendra Virus Discovered In Australia

Australian researchers have determined a new strain of Hendra virus was responsible for the unexplained death of a horse in 2015. Hendra virus has a mortality rate of nearly 80 percent in horses. It's also lethal to humans, with a 60 percent mortality rate. Since its discovery in 1994, Hendra virus has killed over 100 horses and four humans in Australia.

The new strain of Hendra virus had not been seen in routine equine biosecurity testing, but has been detected in grey-headed flying fox samples from 2013. The samples collected in Adelaide share 99 percent of their sequence identity with the virus infecting the 2015 horse sample.

Prior to this discovery, Hendra virus was only known to occur in areas where black flying foxes and spectacled flying foxes live. The research team has developed diagnostic lab techniques to identify the new strain. They expect the currently available Hendra virus vaccine will be effective against the newly discovered strain.

The research team, led by Dr. Peter Reid, suggests that unwell horses living in areas where flying foxes are present should be treated with the same precautions as horses that have had a positive Hendra diagnosis, even if their initial Hendra test comes back negative.

The scientists suggest that preventative measures to curtail the spread of Hendra virus be put in place, including vaccination, good hygiene, the use of personal protective equipment and putting biosecurity measures in place.

UK Gluck Center And VDL Preliminarily Identify Novel Rotavirus

Researchers at the University of Kentucky's Maxwell H. Gluck Equine Research Center and the Veterinary Diagnostic Laboratory have preliminarily identified a novel Rotavirus associated with diarrhea in very young foals.

This virus could not be detected using current diagnostic tests for equine Rotavirus A and appears to be different than the virus strain used in the currently available commercial vaccine.

Efforts are underway to better characterize the virus and determine its role in the current outbreak of diarrheal disease. Additional investigations are also underway at UK to identify other possible causes, and researchers are sending out an epidemiological survey to farms to better understand the outbreak.

Both the Gluck Center and the Veterinary Diagnostic Lab recommend strict biosecurity protocols as the best protection strategy at this time.

See the March 19 news release for more information on this issue here.

Six Tips To Prevent And Treat Equine Herpesvirus From Hagyard’s Dr. Nathan Slovis

Equine Herpesvirus (EHV-1) can cause respiratory disease, abortions and neurological disease. Transmission occurs via the respiratory system, with droplets of the virus being spread by mucus via snorting, coughing and human contact.

If you are in a high-risk area where there's a greater incidence of EHV-1 cases, the following tips may help ensure the horses in your care are protected from infection. These precautionary strategies come directly from Dr. Nathan Slovis, DACVIM, at Hagyard Equine Medical Institute. As an Internal Medicine Specialist and the Infectious Disease & Biosecurity Director, he has implemented the current Infectious Disease and Equine Emergency Response Programs at Hagyard.

Consider sharing these strategies with clients who have horses in high-risk areas.

Start monitoring your horse's temperature twice daily. Even if your horse has not been exposed, start recording their temperature now to understand what their normal baseline temperature is. A horse's temperature will usually spike prior to shedding significant amounts of the virus, and typically anything greater than 101.5°F should be considered a fever. If a fever is noted, you should isolate the horse to the best of your ability until a veterinarian can assess. It is recommended that any horse with a fever have both a whole blood sample and nasal swab submitted for PCR assessment for EHV-1 and EHV-4.
Limit exposure to any stressful situations that are not necessary. Examples include elective surgeries and other medical procedures. Minimizing stress will help protect the immune system so it can better fight off infection.
If your horse requires the use of corticosteroids, either systemically or intraarticularly, consult your veterinarian to see if it is feasible to stop administration. The continued use of corticosteroids can suppress the immune system and could hinder their ability to effectively fight off an infection.
Increase biosecurity measures since humans can inadvertently spread the infection on their hands, grooming equipment, etc. EHV-1 can survive on inanimate objects like halters, lead ropes, and tack, but is easy to kill on surfaces with disinfection. Therefore, these simple biosecurity measures can help stop the spread:

Wash or sanitize your hands between interacting with each horse.
Take care when filling water buckets and feed tubs – neither the hose nor the feed scoop should have contact with the bucket or tub.
Minimize the use of shared equipment, disinfecting tack (bits, bridles, etc.) between horses. Items like water buckets and feed tubs should not be shared.
There are a multitude of safe and effective disinfectants available. A few I recommend are a 1:4 ratio of bleach to water, or accelerated hydrogen peroxide-based disinfectants (like Rescue™) since they are safe for both human and animal use.

Keep your horse up to date with their EHV vaccine schedule. If you horse has not been vaccinated against EHV three months prior to travelling into an area that has a high incidence of EHV, then I would recommend vaccinating your horse. If you are in a high-risk area, consult your veterinarian about the use of vaccines that have a high antigenic load for herpes virus so you can get a robust immune response. Remember, there is no vaccine on the market that can prevent the neurological form of EHV-1. The goal of vaccinating is to reduce the severity of clinical signs and reduce shedding of the EHV-1 virus if a horse does get sick.
Some inactivated vaccines with the highest number of antigens for virus neutralization include Calvenza®, Pneumabort-K® and Prodigy®. Other vaccines like Rhinomune® are a modified live vaccine, and also have a high virus neutralization response.

If your horse is exposed or gets sick, contact your veterinarian to see what course of action they recommend. As mentioned, diagnosis requires the detection of the virus from either whole blood or nasal swab samples via PCR testing. If you are in a barn with a horse that has EHV-1, the use of the antiviral drug valacyclovir may decrease virus shedding and may help your horse from acquiring the infection. Veterinarians have also discussed the use of lysine to theoretically reduce viral replication. Horses can be administered safely 12 grams orally once daily in their feed. This has not been proven to prevent neurological forms of EHV-1.

In the neurologic form of EHV-1, the virus interacts with the blood vessels that supply the spinal cord. This inflammation in the blood vessels can cause a stroke-like event (blood clot), resulting in decreased blood flow to that portion of the spinal cord. To potentially prevent this from happening, veterinarians may prescribe anticoagulants like aspirin and/or heparin to prevent this from happening if your horse becomes clinical.

To learn more about Equine Herpesvirus, Dr. Slovis recommends referring to the American Association of Equine Practitioners (AAEP) website for accurate information and resources.

Report: 18 Horses Ill As EHV-1 Sweeps Through Canadian Riding Stable

Staff at Venturing Hills Equestrian, a riding stable in Luskville, Quebec, Canada, have been working around the clock to try to save the farm's horses, which have been affected by the neurologic form of the equine herpes virus (EHV).

There are multiple strains of the equine herpes virus, including EHV-1, which can cause respiratory disease, abortion, neonatal death or neurological disease. Some horses exposed to the virus will develop neurologic signs. There is no cure for the neurological symptoms associated with EHV-1.

On Feb. 3, a healthy 5-year-old horse that lived at the farm began stumbling when he walked. His symptoms worsened and he was euthanized later that day. Samples the attending veterinarian had taken were positive for EHV-1. The second horse that died from EHV-1 was a 20-year-old horse on Valentine's Day. Both horses had been vaccinated for EHV.

Currently, 18 horses are sick, two are dead and five remain healthy. To try to keep the remaining horses disease free, staff has completely quarantined the healthy horses from the ill horses by building stalls on the property. They have also instituted biosecurity measures like limiting the people who see the infected horses, wearing hazmat suits and steaming hay nets to kill the virus.

Owner Rae Becke believes a new horse that arrived at the facility on January 15 brought the virus with him from Toronto. She later learned that three horses at the horse's former facility had died from the virus on Jan. 29. Becke was never informed of the situation, so the new horse was turned out with Venturing Hills' equine residents.