At least 43 people have tested positive for coronavirus after attending a large house party in Michigan, health officials said Monday.
The majority of the cases are among people between the ages of 15 and 25 years who went to or came in contact with someone who went to a house party between July 2 and 3 in the area of Saline, about 10 miles south of Ann Arbor, the Washtenaw County Health Department said in a statement.
Another 66 people, not including family members who live with the 44 who are infected, have been exposed to the virus. These include employees and customers of retail stores, restaurants, canoe liveries, clubs, camps, athletic team members and employees and residents of a retirement community.
People in other counties and one other state have also been exposed because people who were infected had traveled, according to the Washtenaw County Health Department.
"Anyone who attended the initial event or knows they were exposed should self-quarantine and monitor themselves for symptoms for 14 days," the department's statement said.
Younger people in their 20s, 30s, and 40s are playing a large role in the surge of coronavirus cases across the country, according to health officials. The increases are due in part to more testing, but also fueled by large gatherings.
“This is a very clear example of how quickly this virus spreads and how many people can be impacted in a very short amount of time,” said Jimena Loveluck, the Health Officer with Washtenaw County Health Department. “We need people of all ages, including young people, to take COVID-19 seriously and follow public health guidelines and instructions.
"That means avoiding large gatherings without physical distancing or face coverings," Loveluck warned. "It also means cooperating with the Health Department to complete case investigation and contact tracing."
Saline Mayor Brian D. Marl said residents "have the opportunity to work together and with our local health department to contain this as quickly as possible. We know what we need to do, and we can certainly do it.”
“None of us wants to be the reason someone in our community or county becomes seriously ill or dies,” he said.
This article was originally published on NBCNews.com.