MONONUCLEOSIS

formally infectious mononucleosis, or glandular fever common infection in humans, believed to be caused by the Epstein-Barr (EB) virus. The disease occurs predominantly in persons from 10 to 35 years old, but it is known to appear at any age. Infection of young children usually causes little or no illness, although it does confer immunity. Infectious mononucleosis is transmitted primarily by oral contact with exchange of saliva, hence its popular name, the kissing disease. The incubation period is thought to be about 30 to 40 days. The most common symptoms are malaise and sore throat. Enlargement of the lymph nodes in all parts of the body is frequent; those in the neck are most often affected. Fever is usual. In some cases the only signs of the disease are fever and generalized discomfort; in these cases, the diagnosis is made by study of the blood. The throat is often red; a membrane, white to dark gray in colour and resembling that of diphtheria, may be present; ulceration of the pharynx occurs occasionally. There is a petechial rash on the soft palate in many cases. In about two-thirds of patients, the spleen is enlarged; death has occurred in rare cases from rupture of this organ. A rash consisting of multiple small hemorrhages or resembling that of measles or scarlet fever sometimes appears. Pneumonia is present in about 2 percent of the cases. Involvement of the liver, as shown by chemical tests, is almost universally present; severe disease of the liver with jaundice is rare. Encephalitis, meningitis, or peripheral neuritis occurs uncommonly; death has followed the encephalitis. The heart is rarely affected. Swelling of the upper eyelids is a common finding. In rare cases the urine may contain blood. Infectious mononucleosis usually lasts for about 7 to 14 days. In some instances it may persist for several weeks, especially when the liver or nervous system is affected. Relapse occurs uncommonly, and second attacks are probably very rare. There is no specific therapy. Antibiotics are of value only for the secondary bacterial infections of the throat that occur in some cases.