1. Infectious Mononucleosis (Mono) Slideshow Pictures
2. Infectious Mononucleosis Medical Pictures Image Collection
3. Take the Quiz - Is it Contagious?

Medical Author:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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In this Article

• Infectious mononucleosis (mono) facts
• What is infectious mononucleosis?
• What is the cause of mono?
• What are risk factors for mono?
• How is mono transmitted or spread?
• What are the symptoms of mono?
• What are the signs of mono?
• How is mono diagnosed?
• What is the usual course and treatment of mono?
• What are the complications of mono?
• How can mono be prevented?
• Conclusion
• Infectious Mononucleosis (Mono) - Slideshow
• Pictures of Infectious Mononucleosis - Image Collection
• Take the Quiz - Is it Contagious?
• Patient Comments: Infectious Mononucleosis (Mono) - Symptoms
• Patient Comments: Infectious Mononucleosis (Mono) - Treatments
• Infectious Mononucleosis Index

The EBV that causes mono is found throughout the world. By the time most people reach adulthood, an antibody against EBV can be detected in their blood. In the U.S., up to 95% of adults 35-40 years of age have antibodies directed against EBV. This means that most people, sometime in their lives, have been infected with EBV. The body's immune system produces antibodies to attack and help destroy invading viruses and bacteria. These specific antibodies can be detected in the blood of people who have been infected.

When infection occurs in childhood, the virus most often produces no symptoms. It is estimated that only about 10% of children who become infected with EBV develop the illness. Likewise, probably because of immunity from prior infection, adults typically do not develop the illness. Most cases of infectious mononucleosis occur in the 15-24 age group.

While there are other illnesses falling under the broad classification of mononucleosis that can cause similar symptoms (cytomegalovirus [CMV] infection is one example) and an increase in blood lymphocytes, the form caused by the EBV is by far the most common.

The EBV can infect any person. As previously discussed, the majority of people have become infected with the virus by the time that they reach adulthood, and the majority of these infections produce no symptoms or are not recognized as mono. Mono is most often diagnosed in adolescents and young adults, with a peak incidence at 15-17 years of age. However, it can also be seen in children. Generally, the illness is less severe in young children and may mimic the symptoms of other common childhood illnesses, which may explain why it is less commonly diagnosed or recognized in this younger age group.

Infectious mononucleosis symptoms and signs