From the article (emphasis mine):
All five patients returned from a trip to Egypt in late February where officials say they contracted the virus. They didn’t show symptoms immediately and so they went about their business as usual for a few days, officials said.
The presumptive positive cases are all considered actionable, officials say. This means the patients’ tests were conducted and confirmed as coronavirus by a local lab but officials are waiting for the Centers for Disease Control and Prevention lab in Atlanta to confirm the test results.
Officials are working to determine who else was on the trip with the five patients.
As of now, 17 members of the Rice University community are under self-quarantine and 10 people who came in direct contact with the patient from Fort Bend County are also under self-quarantine.