What Is a Viral Infection?
Viruses are much smaller than bacteria or fungi and cannot be seen with a light microscope. A virus generally lives inside of another cell, such as a human cell, and releases its DNA and RNA (its own genetic code) in the process of replicating or multiplying itself. A virus can affect the host cell’s functioning and perhaps even kill the cell it has infected. Most viral infections are transmitted from one person to another. Well-known examples include viruses such as rhinoviruses (the common cold), flu viruses (influenza), rubella and rubeola (measles), herpes, human papillomavirus (which causes genital warts), viruses which cause liver inflammation (hepatitis), and HIV. In the past, when diagnosing a viral infection, doctors would screen for the development of antibodies in a patient’s blood (serologic diagnosis) against the virus. Unfortunately, serologic diagnoses are often not useful, since a patient may be well into the infection or recovered from it by the time the antibody test
