Prolonged Primary Cytomegalovirus Infection in an Immunocompetent Adult Successfully Treated With Valganciclovir.

Cytomegalovirus (CMV) infection in immunocompetent adults is generally asymptomatic or causes a mild, self-limited illness, but it may occasionally present as CMV mononucleosis with prolonged fever. We report a case of primary CMV infection in an immunocompetent adult presenting with prolonged fever and subsequent clinical improvement following antiviral therapy. A 26-year-old woman presented with a three-week history of intermittent fever reaching 39°C. Laboratory findings revealed atypical lymphocytes and elevated liver enzymes. Serological findings were consistent with primary CMV infection. Despite supportive care, the fever and liver dysfunction persisted, and CMV antigenemia was subsequently found to be positive. Valganciclovir was initiated, and the patient became afebrile within five days, followed by improvement in the laboratory abnormalities. This case highlights that primary CMV infection in immunocompetent adults can cause prolonged fever lasting more than five weeks. In selected patients with persistent symptoms and evidence of ongoing viral activity, antiviral therapy may warrant consideration.