Health officials in Iowa and Nebraska said they linked the illnesses in their states to packaged salad mix -- containing iceberg and romaine lettuce, carrots and red cabbage -- but federal health officials said they were not ready to say if the sickness in the other states were linked to the same salad ingredients.
The parasite is spread when people eat food or water that has come into contact with infected feces.
People get Cyclospora infections from some fresh fruit and vegetables that probably came into direct contact with an infected person or contaminated water. Fruit and vegetables grown or packed outside of the United States may have a higher risk of having Cyclospora on them, health officials said.
Previous epidemics of cyclosporiasis have been traced to contaminated lettuce, basil and raspberries grown in Guatemala, Mexico and the United States.
The Cyclospora parasite cannot survive freezing therefore is it not common on cold-weather crops, such as spinach, broccoli, cabbage, or greens harvested in the winter.
In addition, the parasite cannot survive heated water at about 60 degrees or cooking so wash produce with warm water.
Wash hands with soap and water before washing produce and after handling produce to minimize the risk of cross-contamination.
People should always wash hands after going to the bathroom, changing a diaper, or before touching food. Use plenty of soap and warm water, and get a good soap lather and rub hands together to loosen and wash away germs.