India, July 14 -- More than 800 domestically acquired cases of cyclosporiasis have been confirmed across over 30 US states this year, prompting an ongoing investigation by health officials. While Cyclospora infections have been linked to contaminated fresh produce in past outbreaks, authorities have not yet identified the food responsible for the current surge.

So why has it been so difficult to pinpoint the source?

Experts say the answer lies in the parasite's long incubation period, the complexity of food supply chains and the challenges of tracing what people ate days or even weeks before they became ill.

Unlike many foodborne illnesses that appear within hours or a couple of days, Cyclospora infections often take much longer to dev...