Which body system is primarily affected by mononucleosis?

Mononucleosis, commonly known as "mono," is primarily associated with the lymphatic system. This illness is caused by the Epstein-Barr virus (EBV), which is a member of the herpesvirus family. The lymphatic system is crucial for immune response as it helps in the production and circulation of lymphocytes, which are white blood cells that fight infection.

In the case of mononucleosis, the virus targets B lymphocytes, leading to their proliferation and the symptoms commonly associated with the disease, such as fatigue, fever, sore throat, and swollen lymph nodes. The swollen lymph nodes and the enlarged spleen that are often seen in patients with mono are direct effects of the lymphatic system's response to the infection. This clear association illustrates why the lymphatic system is the primary body system impacted by mononucleosis, highlighting its role in mediating immune responses to viral infections.