Cyclospora Outbreak: Why Thousands Are Falling Ill Across the U.S.

A rapidly growing foodborne illness outbreak has expanded far beyond what federal health officials first believed, with thousands of Americans now either confirmed or under investigation for a parasitic infection that can cause weeks of debilitating gastrointestinal illness.

The Centers for Disease Control and Prevention says the outbreak has reached a level far exceeding recent years, with investigators now working across dozens of states to determine exactly what is making so many people sick.

The CDC announced Tuesday that 1,645 people have been confirmed to have cyclosporiasis after becoming infected in the United States since May 1, while more than 5,100 additional cases are under investigation.