DEAR DR. ROACH: I watched a show that described how a virus invades a cell and found it fascinating. What is the difference between a virus and a bacterial infection? -- G.D.

RSV is one of many viruses that cause upper respiratory infections, like the common cold with mild symptoms like stuffy nose, scratchy throat, and cough.

A sinus infection also involves sinus swelling but is caused by viruses (like colds and the flu), bacteria, or fungi. About 29 million people in the U.S. experience sinus infections yearly.

We may use terms like cold and the flu as if they are the same thing, but there are some key differences between them.

Getting infected with either of those mosquito-borne viruses is rare, but serious. Here are the common infections spread by the buzzing insect, and the differences between them: West Nile Virus ...

Here's what to know about the differences between the coronavirus, influenza and respiratory syncytial virus.