Mononucleosis, also known as mono, is a disease caused by either the Epstein-Barr virus or the cytomegalovirus. Usually, it is spread though saliva and mucus, but it can be transmitted in other ways. Symptoms of mononucleosis can include fever, swollen lymph nodes, extreme exhaustion, sore throat, and other symptoms. The symptoms usually get better in one or two months without any treatment, and most people can return to work or school after three to four weeks.
Mononucleosis (mono) is an illness caused by a virus, which can result in fever, swollen lymph glands, and a sore throat.
Mononucleosis is most common in people 10 to 35 years old, with its peak incidence in those 15 to 17 years old. Only 50 people out of 100,000 in the general population get mononucleosis, but it strikes as many as 2 out of 1,000 people in their teens and twenties, especially those in high school, college, and the military.
Two viruses can cause mononucleosis: the Epstein-Barr virus (EBV) and cytomegalovirus (CMV). Both viruses are in the herpes family, whose other members include viruses responsible for cold sores and chickenpox. EBV causes mononucleosis in 85 percent of cases. When EBV is the cause, it is also referred to as infectious mononucleosis. When CMV causes it, it is also referred to as mononucleosis syndrome, or CMV mononucleosis.
(Click Mononucleosis Causes for more information on this topic.)