Dear Doc: Does raw sushi ever contain parasites? --Vanessa, Greenville, N.C. The short answer is yes. In the wild, human disease-causing parasites are more commonly found in saltwater fish than freshwater fish. Other aquatic animals such as snails, frogs, and snakes also contain parasites. Now, this fact does not stop me from hungering for my favorite sushi roll as I write this post. Sushi served in the U.S. very rarely contains any live parasites (notice I said live). All intended-to-eat raw seafood in the U.S. is flash frozen for a set time, killing potential human-disease causing parasites. Note to home-made sushi makers: non-commercial freezers do not freeze raw meats or seafood fast enough to ensure all parasites are killed. Also, seafood at a local grocery store is not frozen to the same standards as that of seafood used in sushi restaurants. For those who crave sushi while traveling outside the country, keep in mind that other countries may not follow similar U.S. food standards. --Dr. Sean Cook is a physician and outdoor enthusiast from Georgia.