Update – Belle Alert – Sick Horses

December 14, 2007


As COW reported on March 26th, a strain of Equine Herpes Virus (EHV-1) was found to be present in California, a potential COW-tastrophe here in horse-loving Woodside. The good news is that according to the U.C. Davis Center for Equine Health, there were additional cases of EHV-1 in California during the year, but no new cases have been reported since June.

The virus is prevalent in the United States, however, and remains a possible health threat to horses. A barn at the famous Churchill Downs racetrack in Kentucky was quarantined for two weeks because of a horse that came down with the neurologic strain of Equine Herpes Virus, and the virus was also detected in North Dakota in recent weeks.

There are several strains of the virus – the older forms that causes a pneumonia-like respiratory illness in horses or induce abortion of foals in mares, and the newer strain known as the neuropathogenic form of EHV-1. This newer strain is increasingly common, and can cause paralyzation and other neurological symptoms. All forms of EHV-1 have the potential to cause death in horses, though most horses recover. While there are vaccines for some forms of EHV-1, there is currently no approved vaccine for the neuropathogenic strain of virus.

The Center for Equine Health’s report that there haven’t been any reported cases in California since June is good news, but horse-owning COWs still should be aware of the symptoms of EHV-1. Riders who bring their horses to horse shows, competitions, and other large congregations of horses should take special notice – an article on The Horse.com states that the greatest risk for infection comes from groups of horses from different sources or stables that are housed with many other horses. Horses of all breeds, ages, and vaccination status can be affected, though older horses are at more risk.

The symptoms of EHV-1 include a fever of 102ºF or higher. In some cases this is the only symptom. Other symptoms include nasal discharge and cough, or reddish mucous membranes, usually in combination with a fever. Horses with the neuropathogenic strain of the virus can become uncoordinated and weak, have trouble standing (especially the back legs), or have difficulty with urinating or defecating. Extreme lethargy and coma-like symptoms can follow in the next few days. As always, if you suspect your horse is ill, see a vet immediately.

EVH-1 can be spread by an asymptomatic horse, so good cleanliness practices and disinfection are always a good idea, both for this disease and any other that can affect horses. See our earlier article or the Davis Center for Equine Health’s website for tips on keeping your horses and barns virus-free.

Also in horse (and human!) health news, the California Department of Public Health has a website about the West Nile Virus, which can affect not only humans and birds, but dogs, cats, and horses, too! According to the CDPH, 28 horses in 14 California counties have been infected so far this year, with 14 having to be put down. During the same period, 376 people in California have tested positive for the virus, with 16 deaths.

While luckily none of the human or horse cases have occurred in San Mateo County, according to the CDPH, the virus has been detected in our County. The virus is a mosquito-borne illness, so this time of year is relatively safe, but as always, you should educate and protect yourself and your animals.

Most people who get West Nile have no symptoms at all, and twenty percent of people get flu-like symptoms. A very small percentage of people will be severely affected and can possibly die from the disease. The elderly are more at risk of developing more severe symptoms. There is no specific treatment for West Nile Virus, so the best plan is prevention – avoid being bitten by mosquitoes. Wearing clothes that cover your arms and legs, not going out at dawn and dusk when mosquitoes are most active, not letting standing water pool on your property, and using effective mosquito repellants are all good methods of prevention. On the plus side, once you’ve had West Nile, it is thought that you are immune for life.

Good news for our pets and animal companions: there is an effective vaccine for West Nile Virus available for horses (along with vaccines for other mosquito-related diseases, such as western equine encephalitis) so speak with your vet about protecting your herd. Dogs and cats are also susceptible to infection from West Nile, but according to the CDPH, are highly resistant to the disease and rarely become ill.

Stay healthy, COWs! While the risk to you and your horses are low from both EHV-1 and West Nile, taking smart precautions will help keep all of us happy in the hay!

For more information, please check out the following websites:

U.C. Davis Center for Equine Health

Report on the Neuropathogenic Form of EHV-1

The California Department of Public Health West Nile Virus Website

California Department of Food and Agriculture Equine West Nile Page

2 Comments on “Update – Belle Alert – Sick Horses

  1. Jumps

    Greatful for these reports and the website information. Keep Woodside healthy!

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