Mononucleosis, which is most also known as “mono,” is an infectious illness that is most common among teenagers and young adults—especially college students. Extreme fatigue is the most well-known symptom of this illness, and it often lasts for at least a month. In some cases, though, symptoms of mono can last for multiple months. Our AFC Urgent Care Cleveland team provides more helpful information on mono below, so keep reading! What Is Mono? Mono ...