A viral infection transmitted through saliva, mononucleosis is usually quite minor. That’s because the Epstein-Barr virus responsible for it is quite common, meaning most people have developed a resistance for it. Indeed, the disease is common in older teenagers, in part because the prevalence and easy transmissibility (including in saliva) of the virus means almost all 15- to 17-year-olds are exposed to it sooner or later.
Epstein-Barr is actually one of the most common viruses infecting humans; 95 percent of people are infected at some point before the age of 40, though only in some cases does it develop into mononucleosis, usually younger people who have no immune response yet. Symptoms include swollen lymph nodes and tonsils, fatigue, headache and sore throat, and general malaise, with some people developing hepatitis or enlargement of the spleen.
The primary way the virus is transmitted is through saliva, either by sharing food dishes, utensils, and cups or by more direct means. The only way to stop the spread of the virus is by avoiding transmission; there is no vaccine. There’s no real treatment either, except rest and plenty of fluids. Medical care is usually focused on the secondary infections such as strep and tonsillitis. These are treated as usual with antibiotics; penicillin cannot be given to people with mononucleosis, otherwise patients will develop a rash, so other types of antibiotics that aren’t related to penicillin are used instead. To treat the swelling and inflammation, corticosteroids such as prednisone are used. Over-the-counter pain relievers and gargling with salt water serve to treat the symptoms of the disease.
Although people who get mononucleosis—as well as most people who don’t—develop an immune response to the Epstein-Barr virus, it can cause illness in later life as well. The virus is associated with some types of cancer, and recently scientists have found that reactivation of Epstein-Barr is linked to heart disease. This reactivation is often a sign of stress, and in fact this is believed to be a major part of the connection between stress and susceptibility to heart disease. When the virus reactivates as a result of the host experiencing stress, it causes inflammation, which in turn leads to cardiac malfunction.