A stallion, several mares, and a foal have tested positive for equine viral arteritis (EVA) at two French Lusitano farms in a new outbreak of a disease not seen in France since 2007, according to a European equine pathology surveillance network. The mares suffered fertility issues, including abortion, and the foal died.

"To our knowledge, several problems of reproduction were reported in the breeding center where the foal died: embryonic reabsorption, low fertility, and infertility," said Christel Marcillaud Pitel, director of the Réseau d’Epidémio-Surveillance en Pathologie Equine in Caen, France. "There was only one case of an abortion causing an expulsed fetus, and the fetus was born alive but very weak, and it died within 48 hours."

The outbreak occurred in two neighboring farms in southeast France near Marseille and Montpellier. The outbreak appears to be limited to a Lusitano breeding program in the area, Marcillaud Pitel said. The affected stallion’s semen was not shipped for artificial insemination because he only provides live cover, she added.

Analyses revealed that both farms were affected by the same strain of the virus, but the origin of the outbreak is unknown