The US horse who came down with a fever before the FEI Endurance World Championships at Pisa in Italy last month tested negative for EHV-1 (equine herpesvirus).
The entire US team was withdrawn from the event before arrival at the venue at San Rossore. Analysis of blood samples suggested a viral infection and withdrawal of the entire team was based on all the horses being considered contacts.
The team’s five horses had travelled and been stabled together over the previous two weeks, leading to the decision by the US team to withdraw from the event. The horse had developed a fever on Thursday, May 20, and the US team immediately put in place additional biosecurity measures to prevent any possible transmission of disease.
At its most recent meeting, the FEI Veterinary Epidemiology Working Group said that there had been no reported cases of EHV-1 linked to FEI events since May 19. Within the last month, small numbers of EHV-1 neurological disease have been reported in Italy, the UK and USA, but the ongoing outbreak in the UK has no links to the Spanish outbreak. Cases of EHV-1 respiratory disease that were recently reported in Italy were not linked to FEI events.
It is unclear whether the EHV-1 cases at Ornago in Italy are related to the Spanish outbreak, the working group reported.
Positive EHV-1 tests were reported in two horses among a group of US horses arriving in Liège in Belgium bound for a dressage event in Compiegne (France). They tested positive several days after arrival but did not show any clinical signs of infection. The horses, which had no links to either the Spanish outbreak or Ornago, did not go to Compiegne, and were isolated and were to be re-tested.
Research and data collection
The working group is looking to obtain data from events held since April 12, 2021 to determine the prevalence of EHV in sport horses, with the aim of comparing events where pre-arrival EHV-1 testing was mandatory and events where there were no testing requirements.
A research application to the FEI Veterinary Committee for an EHV-1 project to collect data from National Federations is being prepared.
Other EHV research projects will be discussed at the forthcoming International Horse Sports Confederation (IHSC) and OIE Technical Committee meeting.