Reports have surfaced that horse owners in Texas are becoming complacent and have backed off vaccinating their animals for West Nile virus (WNV), which has infected nearly 2,400 horses in the state since late 2002. Angela Pelzel, DVM, an epidemiologist with the Texas Animal Health Commission (TAHC), reported that she doesn’t believe that is the case–Texas horse owners have not grown complacent, are well aware of the threat of WNV, and are continuing to vaccinate.

The drive to encourage horse owners to vaccinate began when the killed-virus vaccine became available in 2001. Pelzel said, “West Nile virus was heading this way like a tidal wave–we were lucky we had the option of watching it come this way and had enough time to get our clients educated.

Before joining the TAHC, Pelzel spent time in private practice at Live Oak Equine Clinic in Liberty Hill, Texas (north of Austin). “We had 75-80% of our regular clients vaccinate their horses before the October 2002 outbreak,” she said. “That year I had 19 confirmed cases, and eight of those died or had to be euthanized.” In 2002, there were 1,699 equine WNV cases in Texas. She said the majority of victims were unvaccinated horses and that “many of those didn’t survive.”

In 2003 there were 695 equine cases in Texas. Pelzel said she treated only three horses infected with WNV, all unvaccinated animals. “Overall, response to the recommendations to vaccinate was very good. We only had a couple of stragglers who still hadn’t vaccinated last year,” she said. The decline in the number of cases probably was due to vaccination and natural immunity