Is it safe to eat sushi, the Japanese raw-fish specialty?

People with liver disorders and weakened immune systems should not eat raw or undercooked fish. The reason: Foods made with raw fish are more likely to contain parasites or bacteria than foods made from cooked fish.
 
Because freezing kills parasitic worms and their larvae, the FDA requires that fish served raw first be stored for seven days at a temperature of -4°F or for 15 hours at a temperature of -31°F in a blast chiller.  However, freezing does not kill bacteria and other micro-organisms. The only way to ensure that fish is safe to eat is to cook it thoroughly.
 
Source(s):
DrWeil.com "How Safe is Sushi?"