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Infectious Mononucleosis, or "mono" for short, is caused by the Epstein-Barr Virus. It is a viral infection with severe symptoms that can leave a person bed-ridden for weeks, even months. Epstein-Barr virus, frequently referred to as EBV, is a member of the herpes virus family and one of the most common human viruses. The virus 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 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. EBV also establishes a lifelong dormant infection in some cells of the body's immune system. A late event in a very few carriers of this virus is the emergence of Burkitt's lymphoma and nasopharyngeal carcinoma, two rare cancers that are not normally found in the United States. EBV appears to play an important role in these malignancies, but is probably not the sole cause of the disease. Most individuals exposed to people with infectious mononucleosis have previously been infected with EBV and are not at risk for infectious mononucleosis. In addition, transmission of EBV requires intimate contact with the saliva (found in the mouth) of an infected person. Transmission of this virus through the air or blood does not normally occur. The incubation period, or the time from infection to appearance of symptoms, ranges from 4 to 6 weeks. Persons with infectious mononucleosis may be able to spread the infection to others for a period of weeks. However, no special precautions or isolation procedures are recommended, since the virus is also found frequently in the saliva of healthy people. In fact, many healthy people can carry and spread the virus intermittently for life. These people are usually the primary reservoir for person-to-person transmission. For this reason, transmission of the virus is almost impossible to prevent.
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--------------------------------------------------------------------------------------------- Following is from the National Center for Infectious Diseases: www.cdc.gov/ncidod/diseases/ebv.htm --------------------------------------------------------------------------------------------- To see the Wikipedia entry on EBV, click: en.wikipedia.org/wiki/Epstein-Barr_Virus --------------------------------------------------------------------------------------------- From the American Cancer Society: Epstein-Barr Virus May Be Linked to Breast Cancer http://www.cancer.org Study Links Epstein-Barr Virus with Breast Cancer Article date: 1999/08/30 A report from French researchers suggests the Epstein-Barr virus (EBV) is present in a high number of breast cancers and is often associated with more aggressive tumors. In a study published in a recent issue of the Journal of the National Cancer Institute, researchers analyzed 100 biopsies from patients with early stage breast cancer along with 30 samples of healthy tissue taken from the area of the breast adjacent to the tumor. EBV was found in 51 of the 100 biopsies while only three of the 30 healthy samples contained the virus. "There was a statistically significant difference in the detection of EBV DNA between the malignant and healthy tissue, strongly suggesting that EBV is largely restricted to the tumor," said study co-author Irene Joab, PhD, of The French Institute of Health and Medical Research (INSERM) in Paris. Because the virus was more frequently associated with the most aggressive tumors, it may play some part in their development, according to the researchers. They observed that the EBV infection was associated with lymph node invasion, which suggests the infection may be related to the high potential of the tumor to spread. In recent years, studies have suggested the virus plays a role in the development of cancers including Hodgkin’s disease, B-cell lymphoma, and cancers of the nose and throat. EBV is a very common virus that infects nine out of 10 people worldwide. Most people infected with the virus have no symptoms. In an accompanying editorial, authors Ian Magrath, MD, and Kishor Bhatia, PhD, of the National Cancer Institute (NCI) wrote, "If EBV does prove to play a role in the development of breast cancer, there would be strong grounds for speeding up the development of an EBV vaccine." Debbie Saslow, PhD, director of breast and cervical cancer for the American Cancer Society (ACS), said the French study points to a need for more research into the nature of the link between breast cancer and EBV. "At this point, the study does not suggest any causal relationship between the virus and cancer," she said. Dr. Joab said research is already under way to find out if the virus is causing tumor growth. Research into EBV also could help with choosing treatment and predicting cancer outcomes, she said. The ACS estimates 175,000 women will be diagnosed with breast cancer this year in the US, and about 43,700 women will die of the disease.
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