Mononucleosis by Ray Sahelian, M.D.

Epstein-Barr virus, frequently referred to as EBV, occurs worldwide, and most people become infected with EBV sometime during their lives. In the United States, as many as 95% of adults between 35 and 40 years of age have been infected. Infants become susceptible to EBV as soon as maternal antibody protection (present at birth) disappears. Many children become infected with EBV, and these infections usually cause no symptoms or are indistinguishable from the other mild, brief illnesses of childhood. In the United States and in other developed countries, many persons are not infected with EBV in their childhood years. When infection with EBV occurs during adolescence or young adulthood, it causes infectious mononucleosis 35% to 50% of the time.

Symptoms of Mononucleosis

Symptoms of infectious mononucleosis are fever, sore throat, and swollen lymph glands. Sometimes, a swollen spleen or liver involvement may develop. Heart problems or involvement of the central nervous system occurs only rarely, and infectious mononucleosis is almost never fatal. There are no known associations between active EBV infection and problems during pregnancy, such as miscarriages or birth defects. Although the symptoms of infectious mononucleosis usually resolve in 1 or 2 months, EBV remains dormant or latent in a few cells in the throat and blood for the rest of the person's life. Periodically, the virus can reactivate and is commonly found in the saliva of infected persons. This reactivation usually occurs without symptoms of illness.

Mononucleosis and Sexual Transmission

Though mononucleosis is known as the "kissing disease," sexual intercourse may increase the odds of contracting the virus. A study found that of 510 college students who were initially free of EBV, nearly half became infected with the virus over the next three years, with sexually active students being at greater risk. Students who said they'd had intercourse during the study were more likely to become infected than those who reported no romantic relationships, as well as those whose relationships were limited to kissing and petting. The findings suggest that sexual intercourse itself makes EBV transmission more likely, according to the study authors, led by Dr. Dorothy H. Crawford of the University of Edinburgh. Most adults worldwide are infected with EBV, which, after first infecting a person, remains dormant in the body for life. Most of the time, the initial infection causes no apparent symptoms, especially when it's contracted in childhood. In developed countries, however, EBV infection often doesn't occur until adolescence or young adulthood, when it's more likely to cause symptomatic illness, mononucleosis -- a condition marked by fever, fatigue, sore throat and swollen lymph nodes. Sexually active teens and adults may be exposed to a larger dose of EBV through particularly "deep" kissing, or possibly through genital fluids, which can carry the virus. Clinical Infectious Diseases, August 1, 2006.

Diagnosis of mononucleosis
Common Blood Test Can Help Distinguish Between Mononucleosis and Tonsillitis
Measuring a patient's ratio of white blood cell types may help physicians to accurately distinguish between the similar conditions infectious mononucleosis and bacterial tonsillitis, potentially guiding treatment decisions. Acute tonsillitis (inflammation of the tonsils) and infectious mononucleosis (caused by the Epstein-Barr virus) are both common ear, nose and throat conditions with similar symptoms, according to background information in the article. These symptoms include sore throat, fever, painful swallowing, white plaque on the tonsils and redness of the throat and tonsils. The importance in differentiating patients with tonsillitis from those with glandular fever [ mononucleosis]  is the prevention of spontaneous rupture of the spleen and acute intra-abdominal hemorrhage, potential complications of mononucleosis,. Currently, distinguishing between them requires an expensive mononucleosis spot test. Dennis M. Wolf, B.Sc., DO-HNS, MRCS, and colleagues at St. George's Hospital, London, retrospectively analyzed laboratory tests from 120 patients with infectious mononucleosis and 100 patients with bacterial tonsillitis treated at their facility. All patients were given the spot test for mononucleosis and additional blood tests were performed to determine the number of lymphocytes (a particular type of white blood cell involved in the body's immune response) and overall white blood cell count. Total white blood cell count was significantly increased in the tonsillitis group compared with the mononucleosis group (16,560 cells per mcL vs. 11,400 cells per mcL), but the lymphocyte count was higher in the mononucleosis group (6,490 cells per mcL vs. 1,590 cells per mcL). The ratio of lymphocyte/white blood cell count ratio averaged.54 in the mononucleosis group and.10 in the tonsillitis group. Based on this data, the researchers determined that a ratio higher than.35 would have a sensitivity of 90 percent and a specificity of 100 percent for the detection of mononucleosis, meaning that an individual with a ratio this high would be correctly diagnosed with mononucleosis 90 percent of the time and an individual with a ratio of.35 or lower would be correctly diagnosed as not having mononucleosis 100 percent of the time. The specificity and sensitivity of this test seem to be better than the mononucleosis spot test itself.

Mononucleosis reactivation during pregnancy and leukemia in child
Reactivation during pregnancy of Epstein-Barr virus, which causes mononucleosis, may be associated with a proportion of childhood acute lymphoblastic leukemia cases.