FDA Still Hunting Source of Cyclospora Outbreak That Has Sickened More Than 1,400

An earlier lab result pointing to contaminated lettuce turned out to be a false positive, complicating the investigation

U.S. health officials say more than 1,400 people have been infected in an outbreak of cyclosporiasis, a parasitic illness, even as investigators continue searching for its source after an earlier test result proved to be a false positive, according to Al Jazeera and CBS News.

U.S. officials had said evidence pointed to lettuce grown in Mexico as the likely source of contamination, a conclusion Mexico's Health Ministry has disputed, according to Al Jazeera. The dispute leaves the outbreak's origin unresolved even as the case count climbs.

Dr. David Acheson, a food safety expert with more than 40 years of experience who previously served as an FDA medical officer, told CBS News that the false positive complicates the investigation, since it removes a lead investigators had been pursuing without offering a confirmed replacement. Cyclospora is a microscopic parasite that causes intestinal illness and is typically spread through contaminated food or water, with fresh produce a common vector in past U.S. outbreaks.

Health and Human Services Secretary Robert F. Kennedy Jr. said the outbreak is "under control," according to CBS News, even as the FDA works to pin down its origin.

— Compiled from reporting by Al Jazeera and CBS News.