The dangers posed by bacteria and viruses occur in different ways. Since bacteria have their own metabolism, waste products cause and can trigger diseases in the human body. The process is different for viruses. Viruses invade a cell and inject their genetic information into the cell. The cell loses its original function and is forced to produce more viruses. This process can destroy all cells and weaken the body's defense mechanisms for a while. If the human immune system does nothing about this, the proliferation of both bacteria and viruses will continue unchecked.