Counting Medals? Count Mosquitoes, too!

A lot of people are counting medals this week. Will Germany dominate? Are you rooting for Isabel or Anky? Was Australia robbed of the Eventing Gold it deserved?

Take a minute today to look up from the Olympics your television or your monitor and check with your local or state health department. What are the West Nile Virus (WNV) and Eastern Equine Encephalitis (EEE) risks in your area?

Today we have the first announcement of EEE in the state of Wisconsin, and the fifth case of EEE in Marion County, the area around uber-horsey Ocala, Florida. Seventy-two horses have been diagnosed with EEE in Florida so far this year.

Two horses in Orange County, California tested positive for EEE. West Nile Virus was recently found in mosquitoes tested in Vermont.

And it doesn't end there. Just a few of the alerts on hand include WNV in Oak Park, Illinois; Greenwich, Connecticut; Salinas, California, and Minnehaha, South Dakota.

EEE recently showed up in Craven County, North Carolina and Carroll County, Tennessee.

Vermont is having one of the worst mosquito seasons on record. Just how many mosquitoes are out there? It sounds like Vermonters have a lot of time on their hands. One researcher set out to determine just how many mosquitoes inhabit an acre of land...they're still counting.

Keep these three facts in mind: 1) Both diseases are carried by mosquitoes; 2) Both diseases can also be transferred by mosquitoes to humans; and 3) Both diseases are highly preventable with a simple vaccination program.

California Reports First Confirmed Case of West Nile Virus in Horses for 2008

The first positive equine case of West Nile Virus (WNV) in California in 2008 has been reported in Riverside County, southeast of Los Angeles. The affected horse, a 15-year-old Quarter horse gelding, died of WNV disease complications, according to the California Department of Food and Agriculture today.

WNV is a mosquito–borne virus that was first detected in the United States in 1999 in the New York City area. It may cause a wide range of clinical illnesses from mild, "flu-like" symptoms to encephalitis (inflammation of the brain) that may be fatal to both humans and horses. While horses are susceptible to WNV, many horses infected with the disease will not develop any illness and will recover uneventfully. Currently, there is no specific treatment for WNV.

California became the focus for West Nile Virus in 2004 with 540 confirmed clinical equine cases. Over 40 percent of clinically affected horses died or were euthanized. However, in 2006 and 2007 there was a significant decrease in confirmed equine cases with 58 and 28 cases, respectively.

Signs of West Nile Virus in horses include stumbling, staggering, loss of coordination, muscle twitching, circling, and inability to stand. Birds serve as the primary reservoir for harboring the disease. Mosquitoes transmit the disease to humans and horses after feeding on infected birds. Once infected, horses do not spread the disease to other humans or horses.

The California Department of Food and Agriculture is urging horse owners to consult their veterinarian to ensure each horse is current on West Nile Virus vaccinations. It is also important to practice mosquito control methods to aid in reducing mosquito-breeding sites.

For more information on West Nile Virus in horses, visit http://www.cdfa.ca.gov/ahfss/ah/wnv_info.htm.

Horse with Lighter Coat Colors Are More at Risk for West Nile Virus

"Have you heard?"

An announcement received today from the Merial corporation is putting horse owners on notice that West Nile virus (WNV) is a risk for all horses in infected areas, but that owners of light-colored horses should be particularly concerned.

The reason? A recently published study shows that light-colored horses have a greater chance of dying from West Nile virus (WNV). (Reference: Epp T, Waldner C, West K, Townsend H. Factors associated with West Nile virus disease fatalities in horses. Canadian Veterinary Journal 2007;48:1137-1145.)

Researchers at the University of Saskatchewan evaluated 133 clinical cases of WNV in the southern portion of the province. Of the total cases, 43.8 percent died. Light horses such as palominos, buckskins, grays, whites or duns were four times more likely to die than dark or multicolored horses.

“The study did not explore specific reasons for increased fatality risk for light-colored horses,” says Frank Hurtig, DVM, MBA, Director, Veterinary Services for Merial Ltd. “However, vaccinating for WNV can help protect all horses.”

WNV is transmitted from mosquitoes to horses. If infected, a horse may exhibit signs such as fever, depression, muscle tremors, weakness, lack of coordination and paralysis. (See Canadian study.) About one out of every three equine WNV cases dies.

The American Association of Equine Practitioners (AAEP) recently revised its core vaccination guidelines to include WNV. Every horse in the United States could be exposed at some point during the year, but spring and summer is an especially important time to protect against WNV. The disease shows no geographic borders and has been identified in all areas of the country. (See: Guidelines for Vaccination of Horses: West Nile Virus. American Association of Equine Practitioners. Available at: http://www.aaep.org/wnv.htm.) Plus, more temperate climates may experience longer mosquito seasons, potentially exposing horses to WNV for a longer period.

Blogger's note: this information was provided by Merial; the company is the manufacturer of Recombitek vaccine for West Nile virus. ®RECOMBITEK is a registered trademark of Merial Limited. Duluth, Georgia.

Fun photo courtesy of our friends at Equitana 2009, coming up in March 14-19 in Essen, Germany: see you there!

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West Nile Virus: Still A Threat

With all the reports and quarantines for Equine Herpes Virus (EHV) this winter, it's easy to forget about West Nile Virus (WNV) and the threat it poses to horses. As the sun climbs higher in the sky, the mosquito season draws closer, and some cases have already been reported this year.

The first case of equine West Nile in 2007 was reported in Sonoma County, Calif., in February - much earlier than recent years - and at least six counties in California have already reported West Nile virus activity. Unseasonably warm winter weather, which has been experienced in many parts of the country, may lead to an increased threat of West Nile virus, which is considered endemic in all areas of the country and poses a major health threat to humans, horses and other animals.

"Because it isn't headline news anymore and because it's been around for several years, many horse owners believe West Nile virus is no longer a threat to their horses," says Tom Lenz, DVM, Vice President of Professional Services at Fort Dodge Animal Health, which manufactures the WNV vaccine West Nile-Innovator(R). "This is not true. More than 1,000 horses were diagnosed with the disease last year, with some states reporting more than 50 cases. It is still a serious equine health issue and all horses should be vaccinated."

West Nile Virus had its day on the front page, that's for sure. This year it's EHV and bird flu. And next year? Stay tuned; this blog may come in handy!