Hundreds of Tough Mudder racers infected by rugged, nasty bacterium

Enlarge / Competitors take part in "Tough Mudder" at the Glen Helen Raceway in San Bernardino, California, United States on April 2, 2023. (credit: Getty | Tayfun CoÅkun)

Hundreds of people who participated in a recent Tough Mudder event—a very muddy obstacle course race—held in Sonoma, California, have fallen ill with pustular rashes, lesions, fever, flu-like symptoms, nerve pain, and other symptoms, local health officials and media outlets report.

The cases could be caused by various infectious agents, including Staphylococcus bacteria, but the leading culprit is the relatively obscure Aeromonas bacteria—specifically A. hydrophila, according to the Sonoma County health department. In a statewide alert this week, the California Department of Public Health said it is considering it an Aeromonas outbreak, noting that multiple wound cultures have yielded the hardy bacterium.

A spokesperson for the Sonoma County health department told the Los Angeles Times on Thursday that, based on calls and emails the department had received, health officials estimate that the outbreak involves around 300 cases. Tough Mudder participants, meanwhile, have tallied as many as 489 cases in online forums.