Symptoms may be reduced by drinking enough fluids, getting sufficient rest, and taking pain medications such as paracetamol (acetaminophen) and ibuprofen.Mononucleosis most commonly affects those between the ages of 15 to 24 years in the developed world. In the developing world, people are more often infected in early childhood when there are fewer symptoms. In those between 16 and 20 it is the cause of about 8% of sore throats. About 45 out of 100,000 people develop infectious mono each year in the United States. Nearly 95% of people have had an EBV infection by the time they are adults. The disease occurs equally at all times of the year. Mononucleosis was first described in the 1920s and is colloquially known as "the kissing disease". Signs and symptoms
The signs and symptoms of infectious mononucleosis vary with age. Children
Before puberty, the disease typically only produces flu-like symptoms, if any at all. When found, symptoms tend to be similar to those of common throat infections (mild pharyngitis, with or without tonsillitis). Adolescents and young adults
In adolescence and young adulthood, the disease presents with a characteristic triad:
Fever – usually lasting 14 days; often mild
Sore throat – usually severe for 3–5 days, before resolving in the next 7–10 days. Swollen glands –  mobile; usually located around the back of the neck (posterior cervical lymph nodes) and sometimes throughout the body.Another major symptom is feeling tired. Headaches are common, and abdominal pains with nausea or vomiting sometimes also occur. Symptoms most often disappear after about 2–4 weeks.
This may develop into systemic EBV-positive T cell lymphoma. Older adults
Infectious mononucleosis mainly affects younger adults. When older adults do catch the disease, they less often have characteristic signs and symptoms such as the sore throat and lymphadenopathy. Instead, they may primarily experience prolonged fever, fatigue, malaise and body pains. They are more likely to have liver enlargement and jaundice. People over 40 years of age are more likely to develop serious illness. (See Prognosis.) Incubation period
The exact length of time between infection and symptoms is unclear. A review of the literature made an estimate of 33–49 days. In adolescents and young adults, symptoms are thought to appear around 4–6 weeks after initial infection. Onset is often gradual, though it can be abrupt. The main symptoms may be preceded by 1–2 weeks of fatigue, feeling unwell and body aches. Cause
Epstein–Barr virus
About 90% of cases of infectious mononucleosis are caused by the Epstein–Barr virus, a member of the Herpesviridae family of DNA viruses. It is one of the most commonly found viruses throughout the world. Contrary to common belief, the Epstein–Barr virus is not highly contagious. It can only be contracted through direct contact with an infected persons saliva, such as through kissing or sharing toothbrushes. About 95% of the population has been exposed to this virus by the age of 40, but only 15–20% of teenagers and about 40% of exposed adults actually become infected. Cytomegalovirus
About 5% to 7% of cases of infectious mononucleosis is caused by human cytomegalovirus (CMV), another type of herpes virus.