The University of Houston has suspended voluntary workouts for all student-athletes after six symptomatic student-athletes in various sports tested positive for the coronavirus as the Houston area has seen a recent surge of positive tests.

In a statement Friday, the UH athletic department said it was suspending the activities "out of an abundance of caution." The school said the symptomatic student-athletes had been placed in isolation and contact tracing procedures have been initiated.

Houston did not test all athletes when they returned to campus, only those who showed symptoms of having the coronavirus, according to the Houston Chronicle. Any athlete having a temperature above 100.2 degrees, the current guideline set by the Centers for Disease Control and Prevention, was immediately put into isolation, evaluated by team doctors and quarantined until test results come back, according to the Chronicle.

Houston is the first school to suspend athletic activities after bringing student-athletes back to campus following a shutdown caused by the coronavirus pandemic. "As was contemplated prior to the return of student-athletes on June 1, UH Athletics is adapting its protocols to include repetitive COVID-19 testing as a component of any resumption of workouts on campus," the statement said. "During this pause in voluntary workouts, UH Athletics will continue its stringent cleaning and sanitization protocols in all facilities. UH Athletics will continue to partner with university officials, UH team physicians and local health professionals to determine best practices as it considers a return to workouts."

Harris County, Texas, where Houston is located, is currently at a "code orange" or Level 2 of a new color-coded "COVID-19 public health threat level system."

The system consists of four levels: Level 1 is a code red and considered a severe threat; Level 2 is a code orange and significant threat; Level 3 is a code yellow and moderate threat, and Level 4 is a code green and minimal threat.

Harris County Judge Lina Hidalgo said Thursday at a news conference that COVID-19 hospitalizations in Harris County were the highest they've ever been and are climbing.