Equine Herpes Virus


Equine Herpes Virus is often times a mild disease in horses and is caused by EHV-1.  When this virus infects a horse, there is a time that the horse is often shedding the virus in nasal secretions with or without clinical signs.  If the horse gets a high viral load in the blood, then there is an increased chance that this horse will become neurological.  We say these horses have Equine Herpesvirus Myeloencephalopathy (EHM). Often times these horses are still shedding virus into the environment.  Non-neuropathic EHV-1 strain and Neuropathic EHV-1 strain classifications are somewhat confusing as both strains can lead to neurologic involvement.

This disease has broken out in 5 racetracks around the US.  There are also cases of showing up of horses that have been to rodeo type events here in Arizona as well as training facilities in Wyoming to name a few.

It is recommended that if your horse is showing signs of disease not to take it to an event and work with your veterinarian when it come to vaccinations for your equine companion.  Also think twice before sharing tack, buckets or grooming supplies as these can spread the virus.

Below is the press release for Turf Paradise Racetrack and further down is some more detailed information on EHM with thanks to the Equine Disease website.


NEWS RELEASE DATE: February 14, 2018

MEDIA CONTACT: Sharma Torrens, 602-542-3191, storrens@azda.gov

Quarantine in Place to Contain Equine Herpes Virus

Arizona Department of Agriculture (AZDA) Director Mark Killian ordered the quarantine of a barn at Turf Paradise Racetrack today in response to the reported case of a neurotropic form of Equine Herpes Virus – 1 (EHV-1) in one horse housed at the track.

Investigations are underway to identify any other horses that may have been exposed to EHV-1. The AZDA State Veterinarian and the Arizona Department of Gaming Division of Racing are working with officials at Turf Paradise to quarantine and monitor any other potentially exposed horses. Track management is also requiring strict biosecurity measures be practiced by all horse-owners and other personnel during this quarantine period.

Equine Herpes Virus -1 is highly contagious among horses but poses no threat to humans. The symptoms in horses may include a fever, nasal discharge, wobbly gait, hind-end weakness, dribbling of urine and diminished tail tone. The virus is easily spread by airborne transmission, horse-to-horse contact and by contact with nasal secretions on equipment, tack, feed and other surfaces. Caretakers can spread the virus to horses if their hands, clothing, shoes or vehicles are contaminated.

State Veterinarian, Dr. Peter Mundschenk, encourages Arizona horse-owners to contact their veterinarian for medical questions and to contact the State Veterinarian’s Office (602-542-4293) for quarantine questions and reminds Arizona veterinarians to report any horses exhibiting neurological signs to the State Veterinarian immediately.

Equine Herpesvirus Myeloencephalopathy

Disease Type: This disease is caused by the EHV1 virus which is common in the horse population. In extremely rare cases, EHV4 can develop into EHM.

Transmission: EHV1 is spread from horse to horse through contact with nasal discharge or spread as aerosol droplets. Horses can also contract the virus by coming into contact with contaminated surfaces such as stalls, water, feed, tack, and transport vehicles. Humans can spread the virus from horse to horse by contaminated hands and clothing.

Frequency: Although EHV1 and EHV4 are a relatively common cause of a mild respiratory disease, EHM, the neurologic form caused by either EHV1 or EHV4, is not common.

Incubation period: Ranges from 2 to 10 days. Horses can shed the virus during the incubation period.

Carrier status: Infected horses are carriers and can shed the virus even when showing no clinical signs.

Latency: EHV is a viral disease that most horses have been infected with at some point in their life. It is unknown why this virus produces the neurological form in some horses. Horses that have had EHV1 may be carriers and the virus may be latent and reoccur under periods of stress such as transport or a new activity.

Severity: EHM is life threatening.

Clinical signs:

FeverThis virus typically causes a biphasic (two phase) fever. The horse will have fever on day 1 or 2 and again on day 6 or 7. Neurological signs may not present until the second fever. Some horses may not develop a fever.

  • Nasal discharge
  • Depression
  • Incoordination
  • Hind limb weakness
  • Loss of tail tone
  • Loss of bladder toneurine dribbling or inability to urinate
  • Dog sitting position
  • Leaning against a fence or wall to maintain balance
  • Recumbencyinability to rise

Diagnosis: The diagnosis is made by having a veterinarian collect nasal swabs and whole blood collected from the horse. Horses with neurologic signs which test positive for EHV1 are considered positive for EHM.

Treatment: There is no cure for EHM. Supportive care is administered including the use of nonsteroidal antiinflammatory drugs (NSAIDS) such as phenylbutazone (Bute) or flunixin meglumine (Banamine) to reduce fever, inflammation, and pain. Corticosteroids have been used but there is no evidence of benefit. Antiviral drugs such as acyclovir and valacyclovir have been used but their value in horses with EHV infection is unknown.

Prognosis: Prognosis for horses who test positive for EHV and then develop neurologic signs of EHM is often poor with fatality as high as 30%. In rare cases, horses with neurologic signs can recover from the infection but may retain neurologic deficits.

Prevention: Currently, there is no USDA licensed EHV1 vaccine which is proven to protect against the neurological disease associated with EHV1. The best method of protection is always to maintain current EHV vaccinations on all horses on your property and to follow correct biosecurity protocol when bringing new horses onto your premises, when travelling, or during any activity where horses may come together.

Biosecurity: EHV1, and rarely EHV4, has the potential to cause EHM so biosecurity measures appropriate for EHV1 should be taken. EHV1 is spread via aerosol particles from nasal discharge or from contaminated surfaces including people, clothing, feed and water, implements, and stalls; isolation of affected or exposed horses is critical to preventing spread of the virus. Proper biosecurity measures include extensive cleaning and disinfection of surfaces and equipment that come in contact with affected horses. Individuals treating or coming into contact with infected horses need to follow appropriate disinfection protocols when handling multiple horses (Go To: http://equinediseasecc.org/biosecurity.aspx ).




Equine Influenza

Equine Influenza in Arizona is a monitored disease.  This means at the Department of Agriculture we take reports of outbreaks to understand the spread of this disease and pockets throughout the state, yet as an agency do not quarantine the facility.  This does not mean that a farm owner or manager cannot impose a self quarantine on the facility so new animals are not infected.

What causes equine influenza? 

Equine influenza A2 virus (EIV) causes flu in horses.  In the literature you may see the  A2 EIV is also called subtype H3N8 (which, to scientists, relates it to the H3 flu viruses in other animals).

How does my horse get the disease?

Horses often get the flu much like humans do from other humans by coming in contact with an infected horse or from nasal secretions from an infected horse.  This often happens during times of stress such as at shows or other events where groups horses commingle.  These horses then may bring it home to and spread it through the facility. Young horses (ages 1 to 5) with limited natural immunity, unvaccinated horses, and those that come into frequent contact with large numbers of horses have the highest infection risk.

What can I do to protect my horse?

 It is recommended that you work with your veterinarian to determine the risk of your horse due to activities and tailor a vaccination program to protect your equine friend.

Download this free fact sheet to learn how to protect your horse from influenza, a highly contagious respiratory disease.

Download link available at the Source url. https://thehorse.com/156815/equine-influenza-protect-your-horse/





Rabies alert

This is a great time to remind everyone to have their animals vaccinated for Rabies.  This should include livestock like horses.


The following is a news release from Arizona Department of Health Services.  If you see any wild animals acting out of the normal contact Arizona Game and Fish.


NEWS RELEASE For Immediate Release | Dec. 13, 2017

Media Contact | Nicole Capone

Mobile | 480.980.2940

Gray Fox Rabies Activity Has Quadrupled in Several Arizona Counties This Year

Public Urged to Take Precautions to Prevent Rabies Infections

PHOENIX – Rabies activity in Arizona’s gray fox populations has quadrupled in the last year according to data released by the Arizona Department of Health Services. As of a report today, there are 24 rabid foxes in 2017, compared with 6 rabid foxes reported statewide in 2016. Six of these cases were confirmed in the past two months.

An outbreak of fox rabies is occurring in the east-central part of Arizona near recreational hiking trails and camping areas in Maricopa and Pinal Counties, which includes the Superstition Mountains Wilderness Area. Several foxes have been seen alongside trailheads and there is evidence that the outbreak may be spreading to more urban areas posing additional risk to people and their pets living in residential communities. So far in 2017, rabid foxes have been identified in Cochise, Navajo, Pima, and Santa Cruz Counties and now recently in Gila, Maricopa, and Pinal Counties.

“It is very important for people to take precautions such as keeping their pets on a leash and vaccinated against rabies, which is a very serious disease that can be fatal,” said Dr. Cara Christ, director of the Arizona Department of Health Services. “People can still walk, hike, or camp in these areas, but should

be aware that rabid animals have been identified. It is important to make sure you and your pets are not

interacting with wild animals. When at home, pets should be supervised or kept in a fenced yard.”

Rabies is a virus spread by the bite of or contact with saliva of an infected animal. Rabies causes severe damage to the central nervous system and usually leads to death once symptoms appear. Human exposures to rabid animals are usually rare, but domestic animals, such as cats and dogs often come into contact with wild animals.

In Arizona, bats, skunks, and foxes are the main animal sources of rabies. The first sign of rabies is

usually a change in the animal’s behavior. Animals may act more aggressive or more tame than usual, be out during the day, stagger, tremble, or seem weak. Rabid animals may appear agitated and excited or paralyzed and frightened. Sometimes, rabid animals do not show any signs of illness before death from rabies.

ADHS advises that people do not touch, or feed wild or unfamiliar animals, even if they do not appear sick or aggressive. Any wild animal exhibiting erratic or aggressive behavior should be reported to local animal control officials or the Arizona Game and Fish Department at 602-942-3000. If you or your pet is bitten or has contact with a wild animal, seek immediate medical or veterinary attention and contact your county public health department.

For more information on rabies, go online to www.azhealth.gov/rabies.

Dangers of Raw Milk

The consumption of raw milk over the last few years has increased due to the feeling that it has many benefits from good bacteria over pasteurized milk and milk products.  Pasteurization while not changing the milk does kill bad  bacteria like Tuberculosis,  Brucellosis and Listeria which will make people sick.

Stay safe and feel free to share.

Dr. Mundschenk



Texas raw milk Brucella contamination hits 7 states

By Coral Beach

Food Safety News

September 15, 2017



Although it is against federal law to sell unpasteurized milk across state lines, the CDC and state health departments are investigating illnesses in at least seven states in relation to Brucella bacteria found in raw milk from a Texas dairy.

 One woman in Texas has been in the hospital for weeks with a lab-confirmed case of brucellosis. A sample from her matches antibiotic-resistant Brucella bacteria found in raw milk from K-Bar dairy in Paradise, TX, according to Texas officials and the federal Centers for Disease Control and Prevention.

 “It’s very important for people who drank raw milk from this dairy to seek treatment to prevent infection with Brucella RB51,” said Dr. William Bower who is leading the CDC’s brucellosis investigation group.

 “Even if people don’t have any symptoms now, they can develop a chronic infection that can impact their health for years to come.”

 Full text: http://tinyurl.com/yath4gfk