How do viruses enter the body?
Viruses enter the human body in different ways, as do bacteria-via airborne droplets from respiratory infections or in the food we eat, for example. Viruses can be passed from hand to mouth or introduced directly into the bloodstream by an infected transfusion or a dirty needle associated with drug abuse. They can also be spread by sexual contact. Once introduced, each virus has its own affinity, or tropism, for a specific body part. For example, viruses that cause the common cold affect the nose, sinuses, and respiratory tract. The agent that causes viral gastroenteritis goes to the gastrointestinal tract.
