The number of measles cases, which usually causes a rash, exceeded 550 in South Carolina by Friday, as cases spread out of Spartanburg County for the first time. (iStock / Getty Images Plus)
COLUMBIA — More than 550 people have been sickened with measles in three Upstate counties, the state health department said Friday.
The number of cases exploded in the beginning of the new year, with 148 reported in the past week. Since Jan. 7, the case count has more than doubled, according to the health department…