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"What is the difference between mono and the flu?"

ZocdocAnswersWhat is the difference between mono and the flu?


Got a note from my son's school that there is a case of mono going around. My son is healthy right now, but how will I know if he gets it? How can you tell the difference between mono symptoms and just the flu or a cold?


The flu and mono are two clinical syndromes that are caused by different viruses, but each can cause some similar symptoms leading to confusion about the diagnosis. The flu is caused by the influenza virus. Typically influenza causes a rather abrupt onset of fever and muscle aches as the predominant symptoms. People with the flu also often complain about headache, joint aches, sore throat, chills and gastrointestinal disturbance, such as nausea or diarrhea. Flu is transmitted through the air or via contaminated surfaces. The illness is more severe than the run-of-the-mill common cold (caused by other viruses) but usually runs its course in 7-10 days. The flu can be confirmed with laboratory testing of nasal swabs. Mono (short for infectious mononucleosis) is caused by transmission of Epstein-Barr virus (EBV), a virus that over 90% of people in the U.S. will have been exposed to by adulthood. When children are first exposed to EBV, they may be completely asymptomatic or may develop symptoms very similar to those caused by the flu. When adolescents or adults are infected, they are typically more symptomatic, and complain predominantly of sore throat, fever and fatigue. Unlike the flu, mono does not get transmitted through the air, but rather through oral secretions (which is why it is commonly called the kissing disease). Mono can usually be diagnosed with blood tests by a physician, and is typically treated with supportive care. Telling the difference between flu and mono can be challenging, but a thorough physical exam and labs can usually lead to the diagnosis.

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