What is the most important way to prevent a foodborne illness from viruses?

Nina has the flu and a high fever. her immune system is exhibiting the line of defense. this defense is part of immunity.

According to the article, when our sleep/wake cycle breaks down, we are at an increased risk for all but which select one: a. respiratory illnesses b. dementia c. diabetes d. heart disease

Can someone give me one specific health problem, and explain it. !