The number of suspected cyclosporiasis cases in the United States has risen to more than 18,000, with more than 6,700 lab-confirmed cases since May 1.

Health officials are continuing to investigate as cases of cyclosporiasis spread across the U.S. But what exactly goes into investigating an foodborne outbreak?

Cases of cyclosporiasis have topped 18,000 in 45 states, according to data updated Wednesday from the CDC.