Most People Have No Symptoms From EBV but Some Can Get Cancer

Have you ever been told not to share a drink with someone? A spoon? A toothbrush? I remember being told if I shared a drink, I might get mono. But what is mono, is it really so bad, what causes it, and what can we do about it?

To start, mono is not the real name. The disease is properly termed infectious mononucleosis. The term mononucleosis was first used in the 1920s to describe how some white blood cells, called lymphocytes, grow and have a central nucleus that resembles a different type of cell, a monocyte. Infectious mononucleosis has a few different causes, but 90% of cases are from a single virus; the Epstein-Barr virus (EBV). EBV is part of the herpes family of viruses. This category includes those that cause chickenpox/shingles and genital herpes, but each are its own separate type and can’t change into another.

EBV and infectious mononucleosis are very common. Per the NIH, 90% of people can expect to get EBV at some point in their lives. Most of the time we are infected as children and have few or no symptoms. It turns out those cootie shots weren’t working after all. The most common symptoms are very generic: fatigue, fever, sore throat, and swollen lymph nodes. These usually resolve within a few weeks. For some people, however, infectious mononucleosis will persist or lead to complications. These include a rash, liver enlargement, and spleen enlargement. Further issues may develop. The liver and spleen may have problems, including a ruptured spleen if the patient engages in intense physical activities. Additionally, EBV is one of the few viruses that can lead to the development of cancer. Even without severe complications, some cases of mono can last for several weeks.

So what is the Epstein-Barr virus, and how does it cause problems? EBV is, as the name implies, a virus. These are “organisms at the edge of life” and need to infect host cells to replicate. EBV infects two types of cells, the epithelial cells that line the throat and B lymphocytes, a type of defensive white blood cell. When you are first infected, EBV is in a lytic phase. Lytic is from the Greek for “loosen,” and this stage is where EBV replicates rapidly and causes most of its symptoms. DNA inside the virus is open to being replicated and does so by the thousands and millions. EBV is sneaky, though, because not all of the virus particles do this. Instead, some of these particles bend their DNA into a circle inside of B cells. These B cells don’t “know” they’re infected and go about their business as usual. This is the latent stage. Latent EBV doesn’t reproduce on its own instead, it is copied when a cell splits. Latent EBV presents no symptoms and may even be integrated into our own DNA. Some will die with B cells during normal activity, but we can never be rid of EBV once we catch it. EBV occasionally reactivates and becomes lytic again. Scientists aren’t certain exactly why this happens but think it may be in response to a different infection, where the B cells are called into action. This can increase a person’s risk of developing nasopharyngeal cancer, certain lymphomas, or stomach cancers. Non-cancerous symptoms are caused by swollen, poorly performing B cells and infected cells that line the throat called epithelial cells. 

So what can we do about infectious mononucleosis and EBV in general? Most of the time, we don’t need to do much. Most cases resolve on their own between 2-6 weeks as the body fights and EBV converts into the latent phase. During this time, treating symptoms at home can help: drink fluids, rest, and take over-the-counter medicine for pain and fever – acetaminophen is commonly used. Rest is very important, even if you don’t feel too fatigued. B cells are produced in the spleen, which can get swollen during infection. High-intensity activity, like sports, can cause it to rupture (not good). For rare or difficult symptoms, your doctor may prescribe corticosteroids or antivirals. Antibiotics do not work, as EBV is not a bacteria. With potentially serious symptoms and EBV staying in your systems lifelong, prevention would be ideal, but is currently impractical due to the lack of a vaccine. There are also no medicines available to rid your body of EBV.  

EBV is spread through saliva and other body fluids, so you can get it from sharing a straw, kissing, or getting an organ transplant. There is no approved vaccine against EBV yet, but we are hoping one may be available in the future. Look out for a clinical trial for EBV vaccines to help quench the kissing disease.

References:

U.S. Department of Health & Human Services/Centers for Disease Control and Prevention (September 28, 2020). About Epstein-Barr Virus  https://www.cdc.gov/epstein-barr/about-ebv.html

Luzuriaga K, Sullivan JL. Infectious mononucleosis [published correction appears in N Engl J Med. 2010;363(15):1486]. N Engl J Med. 2010;362(21):1993-2000 https://www.researchgate.net/publication/44632890_Infectious_Mononucleosis

Odumade, O. A., Hogquist, K. A., & Balfour Jr, H. H. (2011). Progress and problems in understanding and managing primary Epstein-Barr virus infections. Clinical microbiology reviews, 24(1), 193-209. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3021204/ 

Rybicki, E. (1990). The classification of organisms at the edge of life or problems with virus systematics. South African Journal of Science, 86(4), 182. https://journals.co.za/doi/pdf/10.10520/AJA00382353_6229