MEMPHIS, Tenn.-Shelby County is home to more measles cases than the rest of the U.S. combined after an outbreak that began last week.
Six cases so far have been confirmed in the county. That's 60 percent of all U.S. cases this year, according to the Shelby County Health Department.
Measles had been considered eradicated in the U.S. 16 years ago, but the anti-vaccination movement of recent years has led to new outbreaks.
The Tennessee Health Department initially confirmed two cases of measles late last week. That number rose to six earlier this week. But those people could have been exposed to the virus as far back as April 5, according to health officials.
"It is very possible that we will have additional cases," Department spokeswoman Shelley Walker said.
The highly contagious virus often leads to mild illness, but one in four leads to hospitalization and roughly one in 1,000 cases results in death.
Health officials have not named those sickened in Shelby County but have said they are all expected to recover.
Officials so far have not determined the initial source of the outbreak, but they have identified 14 sites where people could have been exposed along with the times when exposure was likely to occur. Officials are asking any unvaccinated person who visited one of the sites during the specified times to stay home for 21 days and watch for measles symptoms - a fever, runny nose, cough and red eyes that progresses to a rash spreading from the head down the body.
More than 90 percent of Shelby County's school-age children are vaccinated, but that still leaves about 10 percent who are not.
Collierville pediatrician Wayland Hayes said his office has been fielding a lot of calls from parents worried about the outbreak.
"This wouldn't be an issue at all if there weren't people who thought it was a good idea not to be vaccinated," he said.