Mononucleosis, or glandular fever, is a highly contagious disease. Called "the kissing disease," it can be transmitted through casual contact. It is caused by the Epstein-Barr virus or, in a minority of cases, cytomegalovirus, both of which are transmitted in saliva, and the latter of which can be passed in sexual intercourse. Transmission is most likely in the period between infection and the appearance of symptoms. though some studies suggest it remains contagious for as long as a year. Treatment is usually focused on the symptoms of the disease, which with rest generally clears up within about two weeks. Mononucleosis presents with flu-like symptoms, as well as fatigue and lethargy. In older patients, it often involves body pain, jaundice, and liver enlargement.
Mononucleosis is most serious in people older than 40. That’s because Epstein-Barr virus is one of the most commonly found viruses among humans, with almost everyone hosting the virus. Because the virus is so common, 90 percent of adults have developed an immunity, and so infectious mononucleosis is more common almost exclusive to people under teens and young adults.
Because of the ubiquity of Epstein-Barr virus, the transmission of glandular fever is almost impossible to prevent. However, recent research into how it virus is able to get everywhere and escape detection by the immune system may be able help doctors develop a vaccine to stop it once and for all. The virus is able to conceal the proteins that the immune system looks for in order to eliminate the virus. With these proteins silenced, the virus becomes invisible to the immune cells. A vaccine for Epstein Barr—which would fight not only mono, but a number of other diseases, including some types of cancer—would have to make these proteins visible.
One thing that makes Epstein Barr relatively intractable is that it doesn’t die with the cell it infects. Instead, when the host cell undergoes apoptosis—a process of cell death infected cells go through to prevent the spread of the infectious agent—the virus can see it coming, and exhibit what researchers call an emergency replication process, allowing the infection to remain.