Vaccinated Against WNV and EEE or Infected? Vets Can Tell

Researchers determined that vaccination does not result in a false positive diagnosis of acute disease.
Share
Favorite
Close

No account yet? Register

ADVERTISEMENT

Inoculating a horse against a disease causes his immune system to mount a response that on certain blood tests can look like natural infection. So, this begs the question: When dealing with a potentially deadly mosquito-borne disease, such as Eastern equine encephalomyelitis (EEE) or West Nile virus (WNV), how do you tell the difference between a horse that’s been vaccinated and one that’s truly infected?

“This is a common question to the technical services veterinarians at the vaccine companies and to veterinarians,” explained Frank Andrews, DVM, Dipl. ACVIM, LVMA Equine Committee Professor of Equine Medicine and director of the Equine Health Studies Program at Louisiana State University (LSU), in Baton Rouge. “For example, the veterinarian goes out to vaccinate a horse, and it comes down with the disease or becomes ataxic (incoordinated). Then they test the horse and it is positive. So, did the vaccine cause the positive titer or was it true disease?”

To get a better understanding, Andrews and colleagues at LSU and Boehringer-Ingelheim Vetmedica (BI), looked at a killed-antigen vaccine (BI’s Vetera Gold) designed to protect against EEE/WNV. Both viruses are endemic in the United States and can cause ataxia and acute death, especially in the case of EEE, with infections occurring only seven to 14 days or four to 10 days, respectively, after exposure to the virus.

Andrews was interested in two antibodies produced by specialized white blood cells called lymphocytes, immunoglobulins IgG and IgM

Create a free account with TheHorse.com to view this content.

TheHorse.com is home to thousands of free articles about horse health care. In order to access some of our exclusive free content, you must be signed into TheHorse.com.

Start your free account today!

Already have an account?
and continue reading.

Share

Written by:

Stephanie L. Church, Editorial Director, grew up riding and caring for her family’s horses in Central Virginia and received a B.A. in journalism and equestrian studies from Averett University. She joined The Horse in 1999 and has led the editorial team since 2010. A 4-H and Pony Club graduate, she enjoys dressage, eventing, and trail riding with her former graded-stakes-winning Thoroughbred gelding, It Happened Again (“Happy”). Stephanie and Happy are based in Lexington, Kentucky.

Related Articles

Stay on top of the most recent Horse Health news with

FREE weekly newsletters from TheHorse.com

Sponsored Content

Weekly Poll

sponsored by:

Where do you primarily feed your horse?
305 votes · 305 answers

Readers’ Most Popular

Sign In

Don’t have an account? Register for a FREE account here.

Need to update your account?

You need to be logged in to fill out this form

Create a free account with TheHorse.com!