The Michigan Department of Community Health has confirmed that people who fell ill with gastrointestinal symptoms after participating in the 2013 Michigan Tough Mudder event between June 29-30 in Brooklyn, Mich. had norovirus.
Read back: Tough Mudder participants fall ill
The department says it has received more than 200 reports of the symptoms since July 1. Symptoms of norovirus infection include nausea, vomiting, diarrhea, and abdominal cramps.
In addition, people may experience a low-grade fever, chills, headache, muscle aches, and fatigue. In most people, the illness is self-limiting with symptoms lasting for one to two days.
According to MDCH, norovirus is transmitted through touching virus-contaminated surfaces and objects, eating or drinking contaminated food, or by direct person-to-person contact.
It is highly transmittable and hand sanitizers are not effective against the virus. Good personal hygiene, including frequent hand washing with warm, soapy water for 20 seconds is crucial to preventing the spread of the disease.