The Food and Drug Administration reports 436 cases of cyclospora have been confirmed by labs in an outbreak linked to McDonald's salads. ( File photo )

The Food and Drug Administration continues to investigate infections caused by the parasite Cyclospora thought to have been transferred by McDonald’s salad, and the number of cases is still growing.

The FDA on Aug. 9 released another update on the outbreak. In the week since the last update on Aug. 2, the number of illnesses rose from 395 to 436 in 15 states.

The investigation centers on McDonald’s restaurants and a romaine-carrot blend supplied by a Fresh Express processing plant in Streamwood, Ill.

The FDA, Centers for Disease Control and Prevention, local and state health agencies and Fresh Express are aiding in the investigation.

“The investigation is ongoing and the FDA is currently reviewing distribution and supplier information for romaine and carrots,” according to the FDA update.

The last onset date was July 20, according to the FDA. It can be up to two weeks before someone exhibits symptoms associated with the parasite.