This type of bacteria causes flu like symptoms. Certain viruses could also contaminate oysters, clams and mussels. These viruses may cause severe diarrhea in those who eat them. Cooking will kill these viruses as well. The reason oysters may be contaminated with viruses and bacteria are due to the method in which they eat.
Oysters are water filterers, as they obtain food through the water.
Unfortunately, they may also come in contact with contaminants in the water supply. If you eat the oyster raw, you also eat the live bacteria or virus they contain. Oysters are very nutritious, however, so go ahead and enjoy them cooked. They are low in fat and are one of the best food sources for zinc. You should not rely on this information as a substitute for personal medical attention, diagnosis or hands-on treatment.