PETERSBURG, Va. (WRIC) — The Virginia Department of Health is warning of a measles outbreak following the arrival of evacuees from Afghanistan. The CDC is also changing its guidance on how to care for individuals who recently evacuated.

In a letter to clinicians, the director of Crater District Health Departments, Dr. Alton Hart Jr., says VDH is aware of several confirmed cases of measles cases in evacuees.

“The CDC has determined that we need to consider all recent Afghan evacuees as exposed to measles,” the letter states.

Evacuees who are still staying at bases like, Fort Lee and Fort Pickett, are to quarantine there for 21 days as they get immunizations. Some evacuees have already been placed with family or hosts within the community.

Related coverage: Five measles cases linked to Afghan evacuation flights; no risk to those with MMR vaccine

Health leaders say the exposure is impacting local EMS agencies and hospitals.

Initial symptoms for measles are fever, cough, runny nose and watery eyes. Three to five days after initial symptoms, a rash will start and spread over the entire body.

As of Monday, the CDC says they’ve been notified of 16 confirmed measles cases and four cases of mumps among Afghan nationals and U.S. citizens who recently arrived from Afghanistan.

All patients who have been confirmed with measles have been isolated and their contacts have been quarantined.

The agency is urging public health officials to continue to look for people with symptoms, isolate those with symptoms and contact their local and state health departments of any suspected cases.

Vigilance should be particularly enhanced at bases that are housing evacuees including Fort Pickett and Fort Lee.

Last week, the health department said the vast majority of Virginians are already immunized against the measles but say it’s important to be up to date on all your shots.