In coming weeks, a new batch of freshman will set off for their first year of college. Awaiting them will be the stresses of class work, the anxiety of living away from home -- and the promise of new relationships.
But for a few unlucky students each year, the first semester also brings a cold, followed by fatigue that they just can't seem to shake.
Is it too many all-nighters cramming for exams? Too many parties? Not enough coffee?
For most, the answer is probably one of these. But for a few, the explanation may be mononucleosis.
What Is Mononucleosis?
Mononucleosis, also known as "mono" or the "kissing disease," is an infection often associated with teenagers, but it also occurs in children.
As can probably be guessed from its intimate moniker, locking lips with an infected person is the most notorious way to contract this disease -- a feature that makes it a natural scourge of college campuses.
However, children and young adults can also become infected by sharing food or drinks, or even simply through close contact with someone who is infected. For this reason, mononucleosis often spreads within families.
But what is the culprit behind this illness?
Most often this disease is caused by the Epstein-Barr virus, which infects white blood cells and causes a sore throat, swollen glands, fever and fatigue in teenagers. Once a person is infected with Epstein-Barr, the virus stays in their white blood cells for life.
Mono is not a rare disease, as 95 percent of people will get it during their lifetimes. By age of 5, about 50 percent of children in the United States have already been infected.
Unfortunately, since Epstein-Barr stays in a person's cells for life, anyone who has been infected in the past can pass the virus to someone else -- even if they have recovered from mono. Because of this, preventing infection is almost impossible.
In kids, mono is a very mild disease and is usually mistaken for the common cold. A second wave of Epstein-Barr infection strikes young adults between the ages of 18 and 24 who did not get the infection when they were younger.
This disease pops up frequently on college campuses, where one out of every 200 students gets mono each year.
When teenagers get mono, they get the more serious version of the disease. They may suffer from swollen glands, sore throat, fever and fatigue. Some teens will experience headaches, poor appetite, nausea, vomiting and abdominal pain.
Most of these symptoms go away within two or three weeks, but the accompanying fatigue can last for several months.
Though there is no treatment per se for mono, most people recover without any complications. Antibiotics, however, do not help treat mono and may make matters worse; some even cause an itchy skin rash if taken during an Epsein-Barr infection.
When the 'Kissing Disease' Gets Dangerous
Half of young adults who get mono develop an enlarged spleen, which can cause abdominal discomfort. Doctors can determine through a physical exam if your spleen has become enlarged. The spleen should return to normal size in four to six weeks and cause no long-term problems.
However, a patient with mono needs to be very careful if their spleen becomes enlarged. There is a danger of spleen rupture and internal bleeding if the spleen is injured while enlarged.
For this reason, teens diagnosed with mono must avoid contact sports -- or other activities that carry a risk of trauma -- for about six weeks. A ruptured spleen is a life-threatening emergency that usually requires surgery to remove the spleen and stop the bleeding.
Mono can also cause swelling of the tonsils. This is usually not a problem, but if the swelling is severe, it can obstruct airways to the extent that a person cannot breathe. This is a medical emergency that requires immediate treatment. Sufferers should call 911 or get to the nearest emergency room as soon as possible.
People with immune systems weakened by HIV infection or certain medications must also be aware that they have an increased risk for long-term complications from Epstein-Barr infection. In these people, Epstein-Barr can take advantage of the weak immune system to start growing out of control in white blood cells.
Rarely, Epstein-Barr can also cause lymphoma -- a cancer of white blood cells -- in people who have weakened immune systems.
Many studies have sought a link between chronic fatigue syndrome and Epstein-Barr, but no link has yet been established. Chronic fatigue syndrome may be caused by another, potentially unidentified infection.
Dr. Todd Wills is an assistant professor of infectious diseases and international medicine at the University of South Florida, and is the assistant clinical director of the university's signature interdisciplinary program in allergy, immunology and infectious disease.