Health professionals say that two central Virginia residents displaying symptoms of the coronavirus have tested negative, but officials continue to investigate reports of one Northern Virginia patient who has exhibited similar symptoms.

The Virginia Department of Health said in a statement Sunday that the suspected case in Northern Virginia met “both the clinical and epidemiologic criteria for 2019-nCoV.” Test results for the suspected case in Northern Virginia are expected later this week. At this time, testing for 2019-nCoV is only available at the Centers for Disease Control and Prevention.

The respiratory outbreak—which has killed more than 50 people—was first detected in Wuhan, China. There have been at least five confirmed cases of this strand of the coronavirus in the U.S.

George Mason University said on Sunday that it is “aware of reports” that a student returning from China showed symptoms similar to those of the coronavirus. It’s not clear if the student is one of the cases that the Virginia Department of Health is investigating. The agency has not responded to a request comment.

Symptoms of the virus—which include fever, coughing, and trouble breathing—can appear within two to 14 days of exposure to the virus, health officials say.

Early patients reportedly had a connection to a seafood and animal market, but increasingly patients haven’t been exposed to animals, which suggests it is being spread person-to-person, according to the Virginia Department of Health.

George Mason University officials cautioned students and staff to practice good hygiene and take general precautions against spreading diseases.

This story originally appeared on WAMU. It has been updated to reflect new information ruling out two suspected cases of coronavirus in central Virginia.