This page is devoted to all things equestrian. Please check back regularly
for new information postings. News articles, information and opinion for
and from the equestrian community and other resources will be posted
as soon as available and will be updated regularly.
Although this information has been posted before, West Nile virus
poses a serious threat to the equine community in Ventura County.
Please read the information thoroughly and consult your veterinarian
for the most contemporary information, or call the Bureau for
additional resources
RESURGENCE OF WEST NILE VIRUS IN CALIFORNIA POSES
RISK TO HORSES
Horse owners urged to pursue vaccinations
SACRAMENTO - The return of West Nile virus to California this year
is renewing calls for horse owners to make sure their animals are
vaccinated. Last year, 540 horses in the state were known to have
contracted the disease, with 229 deaths. Of the known cases, 356
of the horses were not vaccinated and 145 more were vaccinated incompletely. "Outbreaks of West Nile virus this year may be even
worse than last year," said California State Veterinarian Dr. Richard
Breitmeyer. "Horse owners should contact their veterinarians as soon
as possible to ensure vaccination status is current. If people get the
necessary shots for their horses now, horses will have the protection
they need against the deadly disease." Signs of West Nile virus include
stumbling, staggering, wobbling, weakness, muscle twitching and inability
to stand. Horses contract the disease from carrier mosquitoes and are not
contagious to other horses or people. Not every horse exposed to the
virus will die. CDFA is collaborating with state, federal and local agencies
to detect and respond to the disease in California. CDFA is distributing
a video public service announcement about West Nile virus and has
taken a public education program directly to the equine community
over the last several years, including tips on mosquito control. For more information, click on www.cdfa.ca.gov or call the Equine West Nile Virus Information Line at 1-800-268-7378. Questions may be e-mailed to
CDFA at WNVirus@cdfa.ca.gov
WEST NILE ENCEPHALITIS IN HORSES
Horse owners urged to pursue vaccinations
BACKGROUND
West Nile virus, a mosquito-borne virus, was detected for the first time
in the United States in August 1999. The virus can cause encephalitis,
which is characterized by inflammation of the brain and spinal cord.
The first outbreak of West Nile encephalitis in the United States occurred
in the New York City metropolitan area, where 62 people were diagnosed
with the disease. Seven of those people died. The infection also was
diagnosed initially in several breeds of horses, a variety of zoo birds,
and various native bird species, especially crows.
In October 1999, a total of 25 horses, all from Long Island, NY, had confirmed signs of West Nile encephalitis¹, of which nine died or were euthanized. Since then, positive detections in horses have been made in most states throughout the United States. Horses may be exposed to West Nile virus
and not show signs, but of those that are infected and become ill almost
one-third die or are euthanized. With the continuing health threat of West Nile virus to horses, ongoing research to learn more about the disease and develop effective prevention and control measures, such as vaccines, becomes even more important. To date, there has been one verified
case of West Nile Encephalitis seen in a non-vaccinated horse in
Ventura County.
TRANSMISSION OF WEST NILE VIRUS
Infected birds serve as the reservoir host of the West Nile virus. These birds develop a high level viremia-a large number of virus particles
in their circulatory system. Mosquitoes become infected after taking
a blood meal from an infected bird. They in turn infect horses by
biting them.
The incubation period- the time between exposure to the virus and appearance of the first signs of disease – is estimated to be between 3
and 15 days. Humans and horses are known as “dead-end” or “terminal” hosts. These hosts have so few virus particles in their bloodstream that
a mosquito cannot accumulate enough of the virus while taking a blood
meal to subsequently transmit the infection.
No evidence suggests that horses can transmit West Nile virus to other
horses, birds, or humans. Infact, evidence exists that the virus can be
found in the horse's bloodstream for only a few days during the entire
course of the infection. Despite this fact, one should use caution when handling blood, spinal fluid, or nervous tissue from suspect animals,
since these may contain the virus.
In current peer-reviewed journals, West Nile encephalitis in horses
is more commonly referred to as West Nile encephalomyelitis, which
is an inflammation of the brain and spinal cord.
SIGNS OF WEST NILE ENCEPHALITIS
The West Nile virus can affect the central nervous system and cause encephalitis. Horses with severe clinical signs can die as a result of the infection or are euthanized due to secondary complications. Current data indicates that the mortality rate in clinically affected horses is 30 percent
and even higher in recumbent horses. Clinical signs may include one
or more of the following: weakness (hind-end, front-end, or both, characterized by falling to their knees or difficulty in remaining standing), ataxia (incoordination), muscle twitching or tremors, altered mental state (somnolent or aggressive, circling or stall-walking), hypersensitivity to
touch or sound, cataplexy or narcolepsy, seizures, blindness, cranial
nerve deficits (facial paralysis, tongue weakness, difficulty swallowing),
recumbency, and fever.
It is important not to presume that horses with clinical signs of encephalitis have West Nile encephalitis. A definitive diagnosis requires ruling out other important diseases with similar neurological signs. Rabies, botulism, equine protozoal myeloencephalitis (EPM), and Eastern (EEE), Western (WEE), and Venezuelan (VEE) equine encephalitis are examples
of other diseases with neurological signs that may be confused with West Nile encephalitis. A positive diagnosis of West Nile encephalitis can be
made only by examining blood from an infected horse. Determining the actual number of horses exposed to the West Nile virus is difficult as some horses exposed to the virus may not show any clinical signs or perhaps
may exhibit only vague signs of the disease.
Even when clinically ill horses recover from West Nile encephalitis,
up to 40% of them may have residual effects, such as gait abnormalities
and a change in their usual temperament or behavior. These effects may
be significant and affect the owner's use or enjoyment of the horse. Keep
the veterinarian involved in reassessing the horse's neurological condition beyond the apparent resolution of the initial signs. This continued veterinary involvement is very important since some of these effects may impact a person's safety when handling these horses and impact the future use
and management of affected horses.
TREATMENT FOR WEST NILE ENCEPHALITIS
In August 2003, an antiserum was conditionally licensed for use in horses
to aid in the control of signs and progression of disease with West Nile virus. Consult with your veterinarian for Recommendations for current treatment methods. Interferon as well as hyper-immune plasma is also now available. Affected horses should be treated based on the presenting signs and focused on reducing the severity of the disease. Weakened and impaired animals should be protected from injuring themselves. Fluid and nutritional supportive therapy also may be required, either by intravenous methods or by stomach tube.
WEST NILE VIRUS VACCINE INFORMATION
A conditionally licensed (killed virus) vaccine for horses became available in 2001 and in February 2003 a full license was granted by the USDA. The first time the horse receives the vaccine, it is very important that a series of two doses be given about 3 to 6 weeks apart. It appears that horses will not develop high, presumably protective, antibody levels until they receive the “booster or second vaccination in the series. In addition, the second dose should be given at least 4 weeks before mosquitoes are likely to bite and infect them. This vaccine requires an annual booster. In December 2003, a different type of vaccine was approved. This recombinant DNA vaccine also requires an initial 2-injection series with a recommended yearly booster. With either vaccine, depending upon the time of year the horse is vaccinated and the regional presence of the disease, veterinarians might recommend boosters be given twice yearly. Horses vaccinated against Eastern, Western, and/or Venezuelan equine encephalitis will not be protected against West Nile virus.
Owners should keep records of all vaccinations or treatments which may affect international shipment of horses. Owners are advised to contact the U.S. Department of Agriculture or their state Department of Agriculture for current regulations involving interstate and inter- national travel of horses.
PREVENTION AND CONTROL
Horse owners can reduce the likelihood of exposure to mosquitoes by implementing the following pest management practices:
- Keep horses stabled during peak periods of mosquito activity (dusk and dawn).
- Fans may reduce the ability of mosquitoes to feed on horses.
- Avoid turning on lights inside the stable during the evening and overnight. Mosquitoes are attracted to incandescent bulbs. Fluorescent lights neither attract nor repel mosquitoes.
- Place incandescent bulbs about 50 yards from the stable to attract mosquitoes away from the horses. Black lights are of little value as attractants for mosquitoes.
- Prohibit pigeons and other birds from roosting and living in or near the stables.
- Carefully examine your property and eliminate locations that could serve as breeding grounds for mosquitoes. Shallow stagnant or standing water, used tires, clogged roof gutters, and manure storage pits are ideal places for mosquitoes to breed.
- Clean water troughs once a week and pay attention to puddles that form around and under the troughs. Consider using stone or landscaping to reduce or eliminate hoof- prints, where mosquitoes might breed.
- Topical preparations containing mosquito repellents are available for horses. Read the label before using the product, and follow all instructions.
- Stable premises can be fogged in the evening to reduce the number of mosquitoes.
- Do not allow water to stagnate in bird baths, wading pools, wheelbarrows, ornamental pools, water gardens, and swimming pools and their covers.
SUMMARY
Research is in progress to learn more about West Nile encephalitis. Horse
owners should stay informed of information and resources concerning this
disease, especially if it is detected in their area. For more information on the
most current recommendations regarding prevention and treatment, consult
reliable sources, such as your veterinarian, and Web sites, such as the ones
noted in this report.
The West Nile virus represents a real health threat to horses because they
appear more susceptible to the disease than other livestock or companion
animals. The killed virus vaccine seems highly efficacious when administered
properly, but it has not protected 100 percent of all horses studied. West Nile
virus will be a threat to horses as long as a virus reservoir remains in the bird
population, as is the case with Easter, Western, and Venezuelan equine
encephalitis.
Although many West Nile virus infections in horses last only a short time and
result in no illness or mild signs with a complete recovery, the disease can be
deadly. Thus, horse owners should take precautions to minimize exposure to
mosquitoes and should monitor their animals for encephalitic signs. They
should quickly contact their veterinarian to examine and test any horse that is
showing any signs suggestive of this disease.
UNDERSTANDING EQUINE INSURANCE
Developed by the American Association of Equine Practitioners
Provided by Humphrey, Giacopuzzi and Associates
Equine Hospital, 4774 Donlon Rd., Somis, CA
Telephone: 805-386-4291 / Fax 805-386-4298
Understanding Horse Insurance Responsibilities
Whether a horse is purchased for personal or business reasons, ownership
represents a significant investment of time, money, resources and
responsibility. While no one likes to think about the potential for tragedy,
horses seem to be prone to illness, accidents and injury. Should some peril
befall your horse, nothing may ease the emotional burden, but wise planning
can help reduce the economic impacts.
Many reputable insurance companies offer policies to help protect owners
from financial loss should a horse fall ill, become incapacitated or die.
Because individual policies vary so much from company to company and
circumstance to circumstance, it is beyond the scope of this brochure to
explain how to find the right coverage to meet your needs. What’s important
to note is that each policy has its own terms, conditions and requirements
which may necessitate action from you, your veterinarian and insurance company.
Types of Coverage
Common types of coverage available for horses include but are not limited to:
- Mortality – paid if the horse dies, most often applied for
- Loss of Use – paid if horse is permanently incapacitated for its intended use or purpose
- Major Medical – like health insurance, offsets costs of catastrophic veterinary care
- Surgical – policies which cover only specific procedures such as colic surgery
- Breeding Infertility – covers stallions and mares for reproductive failure
- Specified Perils – includes any number of things such as lightning, fire or transportation
Major Medical / Surgical policies can be added with mortality policy for a
nominal premium and coverage up to $7,500.00.
Know Your Policy
Insurance policies are legal contracts between the underwriter (the company)
and the insured (horse owner). To better safeguard yourself and your horse:
- Read the contract thoroughly before you sign it.
- Ask the insurance representative to explain any words, phrases or provisions you do not understand completely.
- Know your responsibilities. What is required should your horse fall ill, become injured or die?
- Understand any specific guidelines for emergency situations. A crisis is not the time to be trying to interpret your policy’s fine print.
- If euthanasia is recommended, know what steps must be taken in order for a claim to be valid.
- Make a list of questions to ask your insurance agent or company.
- Define your needs.
- Comparison shop. Besides cost, buyers should look at the longevity and reputation of both the agency and the insurance carrier.
Health Certificates
Most equine insurers require a current health certificate signed by a
veterinarian before a policy will be issued for a horse. Remember, this is a
legal document. You should not ask nor expect your equine practitioner to
make claims about a horse he or she has not verified through a thorough
physical examination.
A veterinarian cannot simply “take the client’s word for it,” or complete the
requested information based on prior knowledge of the horse. The certificate
requires the determination of the animal’s health be made on the day of the
examination.
Your veterinarian will be compensated for the exam and any tests that may
be required to accurately and adequately complete the insurance forms.
The exact requirements of the exam may depend upon the type of coverage
being applied for. A breeding infertility policy would require a different type of
exam than a simple mortality policy, for example.
Determining Roles
A veterinarian cannot attest to the insurability of a horse. Your veterinarian can only respond to questions of which he or she has direct knowledge, reporting the medical facts to the best of his or her ability. He or she will be asked to positively identify the horse for which the application is being made. However, your equine practitioner has no role in determining the insurable value of a horse. That is a matter for the insurance underwriter and the owner to establish.
Regardless of the circumstances, never ask or expect your veterinarian to report a claim to the insurance company. This is your responsibility as the owner. The veterinarian may be asked to supply necessary medical documentation.
Do not expect your equine veterinarian to be an insurance expert. If you have questions regarding your policy, ask your insurance agent rather than your veterinarian.
If there is something that your insurance company requires, make sure your veterinarian receives the request in writing.
If a question or dispute should arise regarding a claim, it is a matter for you and your insurance company to resolve. It is not the responsibility of your veterinarian.
Euthanasia
Euthanasia is the intentional destruction of a horse for humane reasons. For an insurance claim to be valid, many companies require advance notification and prior permission – except under the most extreme conditions. In some cases, the insurance company may wish to seek a second opinion before a horse is euthanized.
The American Association of Equine Practitioners has established guidelines that state the justification for euthanasia should be based solely on medical, not economic considerations, regardless of the age, sex or potential value of a horse. Four criteria are given to help make this determination:
- Is the condition chronic and incurable?
- Has the immediate condition a hopeless prognosis for life?
- Is the horse a hazard to himself or his handlers?
- Will the horse require continuous medication for the relief of pain for the remainder of his life?
