A typical case of measles begins with mild to moderate fever, cough, runny nose, red eyes and sore throat.
Two or three days after symptoms begin, tiny white spots (Koplik's spots) may appear inside the mouth.
Three to five days after the start of symptoms, a red or reddish-brown rash appears.
For more information about measles, visit www.cdc.gov/measles/index.html.
Between 1995 and 2013, only nine measles cases were reported in Tennessee. This year, five already have been reported.
2014: 5 (to date)
Source: Tennessee Department of Health
Tennessee health officials are investigating five measles cases that have broken out over the last month - the highest count the state has seen in nearly 20 years.
One victim of the highly contagious disease visited Chattanooga on May 7 and was likely contagious during the visit, Chattanooga-Hamilton County Health Department officials said.
The local case is the first the county has seen since 2002, said Margaret Zylstra, epidemiology manager at the department.
The nation is seeing its highest number of measles cases this year in nearly two decades, the U.S. Centers for Disease Control and Prevention reports.
State officials say the Tennessee measles cases likely started with a single adult traveler who was exposed to the disease while visiting a foreign country that officials declined to name.
The four other patients - all adults - are known to have been in close contact with that first patient since late April, said Dr. Tim Jones, the Tennessee state epidemiologist.
Some of those who came down with measles had been vaccinated against the illness, Jones said.
The health department has alerted all Tennessee medical providers and is trying to trace the infected people's steps and let anyone they contacted know they might be susceptible to the illness, Zylstra said.
The measles virus can stay airborne or live on surfaces for up to two hours, and those infected can transmit the virus for about five days before their first symptom - typically a rash - appears.
No additional measles cases have been identified in Hamilton County, Zylstra said.
But it may take several weeks to be sure no more pop up, since its incubation period is a week to 18 days, officials said.
Jones said the department has to go overboard to try to contain the disease, which quickly can get out of control.
Since 1995, the state has seen only nine cases of measles, Jones said. The most recent year was 2011, when three cases were reported.
Between Jan. 1 and May 9, 187 cases were reported in the U.S., the highest number reported for this period since 1996.
Jones said the five patients who contracted the disease are "all doing well."
For some, though, measles can have severe complications or even be deadly; the CDC estimates measles caused 164,000 deaths worldwide as recently as 2008.
State officials urged vaccination as the best prevention, and especially those considering international travel.
Outbreaks have been reported in parts of Asia and several European countries, where an increasing number of people have rejected vaccines, Jones said.
The U.S. also has seen a growing trend of parents refusing to vaccinate their children.
Some children's doctors, including Chattanooga pediatrician Dr. Nita Shumaker, have taken a hard line on the issue.
Shumaker's practice, Galen North Pediatrics, no longer accepts children whose parents refuse to vaccinate them. Shumaker said the rule protects patients in the waiting room - especially babies and children receiving immune-suppressing treatments such as chemotherapy.
"These are parents who ... have never seen measles, or never seen a child die from the measles," Shumaker said. "Study after study shows that these vaccines are not only safe, but one of the most important things you can do for your child's health."
Contact staff writer Kate Harrison at email@example.com or 423-757-6673.