Most people catch the kissing disease as children and never notice
Nearly 95 percent of adults have been infected with the Epstein-Barr virus, the usual cause of glandular fever. Catch it as a small child and you may barely feel it. Catch it as a teenager or young adult and it can bring weeks of fever, a raw throat, swollen glands and exhaustion.
Infectious mononucleosis, known as mono or glandular fever, is usually triggered by Epstein-Barr virus, also called human herpesvirus 4. A handful of other viruses and the parasite Toxoplasma gondii can produce the same illness. It spreads mainly through saliva, which earned it the nickname the kissing disease, but shared glasses, toothbrushes, coughs and sneezes can pass it on, and more rarely blood or semen. People can be infectious for weeks before they feel ill. It was first described in the 1920s and shows no seasonal pattern.
Age shapes the experience. Before puberty the infection often causes nothing worse than a mild sore throat. In the developed world it strikes most often between 15 and 24, and among 16 to 20-year-olds it accounts for roughly 8 percent of sore throats. The classic trio is a fever lasting around two weeks, a throat that is very sore for three to five days, and swollen glands at the back of the neck. Tiredness is a major feature: symptoms usually fade within two to four weeks, but fatigue persists beyond a month in an estimated 28 percent of cases, and most people are back to normal within two to three months. Over-40s are more likely to become seriously ill, often with prolonged fever and liver involvement rather than the typical throat.
Some signs are distinctive. About half of patients develop tiny reddish-purple spots on the roof of the mouth. Almost everyone given the antibiotics amoxicillin or ampicillin develops an itchy rash, though that does not mean a lasting penicillin allergy. The spleen commonly enlarges in the second and third weeks, and in fewer than one percent of cases it ruptures.
Diagnosis rests on symptoms, confirmed by antibody blood tests; the quick monospot test is not recommended because it is inaccurate. There is no vaccine yet, although research continues, and in healthy people the illness generally resolves without specific treatment. About 45 in every 100,000 Americans develop it each year.
Source: Infectious mononucleosis
