Central Spain has a high density of both breeding and sport horses and is a popular international competition area. | Photo Credit: Lbpetersen/Wikimedia Commons

“The central area of Spain is an area with a high density of horse populations (both breeding and sport horses) and also the area where the majority of competitions are held,” said Fátima Cruz-Lopez, PhD, DVM, of the Complutense University Veterinary School, in Madrid. “Furthermore, it’s a frequent stop for horses traveling to northern Europe. So it was a good area for comparing the seroprevalence of EVA in breeding and sport horses.”

Blood samples from 155 breeding horses at 16 stud farms and 105 sport horses at 12 riding clubs revealed a 21% positive rate in breeding horses compared to 6.7% in sport horses, she said. That doesn’t mean these horses have active infection, but rather that they have been exposed to the virus at some point in their lives and have developed antibodies against it.

“We weren’t surprised by our results,” Cruz-Lopez said. “Our study showed that it’s quite common to find antibodies against EVA in our breeding horses, but the experience in our laboratory tells us that it is not so common to find carrier stallions or even outbreaks of the disease