NASHVILLE, Tenn. — The Tennessee Department of Health is now reporting a fifth confirmed case of measles in the state that's linked to four other cases in East Tennessee.

A fourth case was reported the day before. 

April 18, 2019: 1st measles case diagnosed in East Tennessee

READ MORE: Two more measles cases confirmed in East TN

The first case of measles was reported back in April, and the man reportedly traveled to Mississippi through Alabama. The TDH identified two specific locations in Clinton and Chattanooga where people may have been exposed to measles.

►READ MORE: If you were at these East Tennessee gas stations, you may have been exposed to measles

The Knox County Health Dept. said that first patient is a man who is not from Knox County, but who spends time here. We also know that he traveled in Mississippi from April 9-11 while he was contagious, then stopped at two locations in Alabama as he was traveling home on April 11.

Doctors said last week these may not be the last measles cases we hear about in East Tennessee, and given the continued spread since then-- they've been correct.

"We may not have seen the end of this current outbreak yet," Dr. Mark Rasnake said.

Rasnake specializes in infectious diseases at UT Medical Center.

"It could be several weeks before we know this outbreak is ended," Rasnake said. "If we don't see any more cases after today, it would still be a few more weeks before we know for sure that it's over."

Rasnake says that's because of the virus' incubation period--the time between when it enters your body and when you start seeing symptoms.

"The flu virus only has a incubation period of a couple days from the time you're exposed to the time you get sick," Rasnake said. "Measles kind of falls in the middle of the spectrum, and then there are some viruses, like hepatitis viruses, where it may be a month or more from exposure before you know you're sick."

While this outbreak investigation is currently centered in East Tennessee, TDH said all Tennesseans should be aware of measles and its symptoms. 

RELATED: Here's what everyone needs to understand about the measles virus

Symptoms include runny nose, body aches, watery eyes and white spots in the mouth. Several days after these symptoms start, a red, spotty rash typically begins on the face and spreads over the body.

Symptoms may develop any time in the 21 days following exposure to the illness. Nearly one in three measles patients will develop ear infections, diarrhea or pneumonia. Measles can be fatal in approximately one to two out of every 1,000 cases.

All Tennesseans are urged to ensure they are up-to date on MMR vaccine, which is extremely effective in preventing infection. 

RELATED: Born before 1989? You may need another dose of the measles vaccine

"The vast majority of people in East Tennessee have nothing to worry about from measles, because we've been vaccinated and we're immune," Rasnake said.

He says you can check the Kindergarten Immunization Compliance Assessment online for your child's school.

"One of the first things I did when measles was reported in the community was check my kid's school vaccine database that the state publishes," Rasnake said. "And over 95 percent of the kids in my kid's school were protected against measles, and that's really good news."

He says if you're not vaccinated, you need to do that soon.

"I am worried about individuals who may not have immunity, I think those folks have a legitimate concern," Rasnake said.

The measles virus is highly contagious and can stay airborne or live on surfaces for up to two hours. People recently infected with measles may not have any symptoms of illness, but can transmit the virus for about five days before the typical measles rash appears.

TDH said anyone who believes they or a loved one has measles symptoms should stay home and contact a health care provider to make arrangements to visit a health care facility before going to a health care center to prevent further exposure of others to the illness.

RELATED: East Tennessee Children's Hospital uses air filters, pressure to limit airborne illnesses like the Measles

TDH is providing information about measles and how to prevent it online. This page includes the number of measles cases in the state this year, which will be updated daily by 3 p.m. Central time if additional cases are confirmed.

People with questions about how to protect themselves against measles should call a health care provider, the local health department or a hotline established to provide answers to questions from the public about measles. The hotline number is 865-549-5343; calls to the hotline will be answered from 7 a.m. – 3:30 p.m. Central time/8 a.m. – 4:30 p.m. Eastern time.

For more information about measles, visit the CDC website.