They are spread from one place to another and you can't even see it with your own two eyes. We are talking about bacteria.
"There is no such thing as a safe bacteria. It all depends on the dosage and your resistance," says Biologist, Gary McCallister.
Especially with cold and flu season here, it is very important to protect yourself from germs, but it isn't just a common cold or flu that we need to worry about. There is actually a long list of viruses and illnesses that you should be aware of.
"If someone is infected with a virus and they don't wash their hands, you may [wash your hands], but you can still become contaminated," says Nurse, Karen Milbank.
There's all sorts of things you can get contaminated with. Take Hepatitis A for example. This can make you extremely sick.
Milbank says some of the symptoms of Hepatitis A are the following: stomach upset, g.i. problems, yellowing of the skin and eyes, and liver problems.
All of this from just coming in contact with a bathroom's doorknob,
but this isn't the only virus that is easily passed from unwashed hands.
Milbank says other viruses that are commonly spread are ecoli, staph and salmonella.
While you can't control the germs that are already living on surfaces like a doorknob, you can stop them from finding a new home on your body. The first thing to do is always wash your hands. It's recommended to wash your hands with warm water and soap for fifteen to twenty seconds. Then instead of using your clean hands to open the door, use a towel.
Still with all of this bacteria floating around, experts say there is no reason to panic.
McCallister explains, "We have lived for thousands of years in less clean conditions that we have right now and we survived and thrived."