Some of the foreign-born workers who prepared the basil products have tested positive for Cyclospora.

ECONOMIST: A bug with social aspirations

However, unlike some other foodborne parasites, cyclospora doesn't become infectious until days or weeks after it's passed in a bowel movement.

CNN: Cyclospora infection

However, since 1995, lettuce, fresh basil and imported raspberries have been implicated in cyclospora outbreaks in the United States and Canada.

CNN: Cyclospora infection

So the first thought of the disease detectives at the health department working on the latest Cyclospora outbreak was imported vegetables.

ECONOMIST: A bug with social aspirations

For example, only 20 years ago Listeria, E. coli O157:H7, Campylobacter and Cyclospora, all of which have caused recent outbreaks, were not known to cause foodborne illness.

ECONOMIST: Food poisoning

Before 1996, sporadic cases of cyclospora infection turned up only in people who traveled in developing countries and in those with HIV or another condition causing immune-system compromise.

CNN: Cyclospora infection

No one knows exactly how cyclospora is transmitted.

CNN: Cyclospora infection