Clinical meaning
Infectious mononucleosis (commonly called 'mono' or the 'kissing disease') is an acute viral infection caused primarily by the Epstein-Barr virus (EBV), a member of the herpesvirus family (Human Herpesvirus 4). EBV is one of the most common human viruses, infecting approximately 95% of the world's adult population. The virus is transmitted through intimate contact with oropharyngeal secretions, most commonly through saliva (kissing, sharing utensils, drinking containers, or toothbrushes). After entering the oropharynx, EBV initially infects and replicates within the epithelial cells of the pharynx and salivary glands. The virus then crosses into the underlying lymphoid tissue and specifically targets B lymphocytes by binding to the CD21 receptor (complement receptor 2) on the B cell surface. Once inside the B lymphocyte, EBV can follow one of two pathways: lytic infection (active viral replication that kills the host cell and releases new viral particles) or latent infection (the viral genome integrates into the B cell DNA and persists indefinitely without active replication). During the acute phase of mononucleosis, EBV-infected B lymphocytes proliferate rapidly and circulate throughout the lymphoreticular system, including the lymph...