Knoxville (WVLT) - We often hear about small outbreaks of Mononucleosis on college campuses, because it's most often seen in teens and young adults.
Older adults usually don't get it, because we've already had it.
In fact, in the United States, 95 percent of people have been infected, and many didn't know it.
We're covering East Tennessee health with what else you probably don't know about mono, and how to protect your family.
Mononucleosis is commonly called the kissing disease because it can be spread through contact with saliva.
That's also one of the reasons it's easily spread on college campuses.
But infectious disease specialist Dr. mark Rasnake says you probably caught mono much earlier, from your mom, "It's not clear why some people avoid contracting it as children, most people would be exposed to it from their mother's saliva when they're very young children or infants and will acquire the infection that way."
When children get the virus, it often goes unnoticed because the symptoms are mild.
And adults usually don't get it, because they already have immunity.
Once you get over mono, your symptoms will go away for good, but you still carry the virus that caused it.
Dr. Rasnake says, "It's interesting in that the body typically has difficulty clearing the virus from the bloodstream, and actually infects the cells of the immune system. And the body has a hard time clearing the virus, so once you've had mono, the virus typically remains alive in your system for the rest of your life."
The most common symptoms of mono are a high fever, a severe sore throat, swollen glands and tonsils, and weakness and fatigue.
Symptoms usually start four to six weeks after you're exposed.
Dr. Rasnake says, "There is no treatment for mono, essentially it's rest during the period of severe illness -- fluids, bed rest, and allow the symptoms to pass."
If you have mono, you can avoid passing it to others by not kissing anyone, and not sharing things like glasses, silverware or toothbrushes.
In rare cases, mono can also cause the spleen to swell.
Pain in the upper left part of your stomach can also mean the spleen has burst.
But mono is almost never fatal.