Participants of an 8.1-mile mud race held near Nice, France, on June 20, have reported symptoms including diarrhea, vomiting, stomach cramps, and fever, according to Agence Regionale de Sante (ARS). As of June 26, of the sold-out event’s 8,400 participants, more than 1,000 have complained of illness.
Race organizers for the Mud Day first issued a statement on June 22. “[We] have immediately decided to make every effort to determine what could be causing stomach upset some competitors complain,” the Mud Day said on its website.
The cause of the widespread sickness remains unclear, though one participant said that the racecourse shared space with the local equestrian center.