Mononucleosis is an infectious disease that is associated with fever, fatigue, and swollen lymph glands.
Mononucleosis is caused by the Epstein-Barr virus (EBV). Found mainly in saliva and mucus, EBV is passed from person to person by intimate behavior, such as kissing.
Many people get EBV during their lifetime. Factors that increase the likelihood that EBV will develop into mononucleosis include:
One episode of mononucleosis usually produces permanent immunity.
Signs of mononucleosis usually begin 4-7 weeks after you were exposed to the virus. The initial symptoms may be a sense of general weakness that lasts about 1 week. This is followed by symptoms that may include:
You will be asked about your symptoms and medical history. A physical exam will be done.
Your bodily fluids may be tested. This can be done with blood tests.
There is no treatment to cure mononucleosis or to shorten the length of the illness. It usually lasts 4-6 weeks, although the fatigue may last longer.
During the first few weeks after diagnosis, you should avoid contact sports and lifting anything heavy. Inflammation of the spleen from mononucleosis puts you at high risk of splenic rupture. This can require surgery. In rare cases, it can be fatal.
It is important to get plenty of rest. Other supportive care may involve:
Most people contract the EBV virus sometime during their lives. Prevention is geared toward decreasing the likelihood that EBV will develop into mononucleosis. This can be done by:
Centers for Disease Control and Prevention
National Institute of Allergy and Infectious Diseases
About Kids Health—The Hospital for Sick Children
The College of Family Physicians of Canada
Balfour HH Jr, Hokanson KM, et al. A virologic pilot study of valacyclovir in infectious mononucleosis. J Clin Virol. 2007;39:16-21.
Ebell MH, Call M, et al. Does this patient have infectious mononucleosis?: The rational clinical examination systematic review. JAMA. 2016 Apr 12;315(14):1502-1509.
Epstein-Barr virus-associated mononucleosis. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T114945/Epstein-Barr-virus-associated-infectious-mononucleosis. Updated June 1, 2016. Accessed September 28, 2016.
Luzuriaga K, Sullivan JL. Infectious mononucleosis. N Engl J Med. 2010 May 27;362(21):1993-2000.
Mononucleosis. Academy of Family Physicians Family Doctor website. Available at: http://familydoctor.org/familydoctor/en/diseases-conditions/mononucleosis.html. Updated March 2014. Accessed June 9, 2015.
Last reviewed June 2016 by Marcie Sidman, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.