The Centers for Disease Control and Prevention released a report on Thursday about 22 participants, including three airmen, who fell sick in 2012 after participating in a “long-distance obstacle adventure race,” experiencing fever, vomiting and bloody diarrhea.

Twenty sought medical treatment and one was hospitalized.

CDC didn’t name the race, but apparently, the obstacles at the 2012 Las Vegas Tough Mudder included more than just high walls, an electric shock field and “Ladders to Hell.” Lurking in the waters and muck of a cattle ranch in Beatty, Nevada, was Campylobacter coli, a particularly nasty bacteria that can cause cramping, vomiting, dehydration, fever and abdominal pain for about a week.

An investigation found that some of the mud obstacles of the 10- to 12-mile course were contaminated with cow or pig poop — and racers who submerged their faces or slipped face first into mud or slurry inadvertently ingested some of the fecal matter containing Campylobacter coli.

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6317a2.htm?s_cid=mm6317a2_e