CHICAGO (CBS) — It’s one of two COVID-19 clusters in the state.

Thirty-six students taking part in Lake Zurich’s High School summer sports camps. But the health department warns that number could be much higher.

CBS 2’s Vince Gerasole has been following the numbers and the investigation.

Hundreds of students attended those sports camps and we are still waiting for most of their tests to come in. The school district had screenings, temperature and social distancing plans in place. But what the Lake County Health Department suspects is a good number of these students were exposed away from school at parties and gatherings.

The numbers are considerable. At a mobile testing lab set up outside Lake Zurich High School last Sunday some 350 students, coaches and family members turned out.

But according to the Lake County Department of Public Health, as many as 400 students alone who attended various high school sports camps should be quarantining for 14 days and getting a COVID-19 Test.

“So it’s all students, regardless of what sport they are in,” said Hannah Goering of the Lake County Health Department.

What began with several students sent home with fevers or symptoms and the shut down of football, baseball and poms camp last Monday, escalated into the complete closure of all sports camps, including volleyball, cross country and girls basketball.  To date, 36 students have tested positive for COVID 19, and that doesn’t yet include results from last weekend’s testing.

“What we are finding in our investigation of this situation in lake Zurich is that many students attended various social gatherings leading up to the start of camp,” said Goering.

Health officials said that would include Fourth of July parties and celebrations where students and possibly their families let down their guard.

“It is likely if you have been to social gatherings and you are not keeping social distancing or wearing masks, then you have been in a situation where you have been exposed,” Goering said.

Lake County’s current positivity rate is 3.4%, which has dropped from over 20% in mid-May. But as the numbers stabilize for older patients, they are rising for those 30 and under.

“Our message to young people is please follow these precautions. Even if you are not vulnerable, you are not immune and someone you care about could get very ill from this illness,” Goering said.

According to the Lake County Health Department, a number of these students testing positive were asymptomatic, showing no signs at all but capable of spreading the virus.

A second mobile testing lab will again be set up this Sunday at the high school from 9:00 a.m. to 5:00 p.m.