HOLLAND, Mich. (WZZM) - The Michigan Department of Community Health has identified the illness that closed down Margarita's Restaurant and caused at least 200 to become sick.

Test samples show norovirus was present at Margarita's Mexican restaurant. The virus causes nausea, vomiting, diarrhea, cramping, and low-grade fever. Health officials say it is very contagious and spread easily from person to person. The virus is found in the stool and vomit of infected people. People can become infected by consuming contaminated foods or beverages, by touching contaminated surfaces or objects and then touching their mouths, or by having direct contact with another person who is infected and then touching their mouths.

Norovirus can be prevented with frequent hand washing using soap, water, and friction for 20 seconds. Hand washing is especially important before eating, after using the restroom, and after sneezing or coughing. Alcohol based hand sanitizers do not work against Norovirus. Those with symptoms of Norovirus should not prepare food for others while they are sick, and should not prepare food for three days after symptoms end.

There is no treatment or vaccine for Norovirus. By drinking fluids, such as juice or water, people can reduce their chance of becoming dehydrated.

More information about norovirus is available at www.miOttawa.org/health.

Approximately 200 people reported symptoms to the department since Thursday. The health department is no longer taking reports of illness related to this outbreak. The overwhelming public response was critical, however to the investigation.