Cytomegalovirus (CMV) Infection

Cytomegalovirus is a double-stranded DNA virus in the Herpesviridae family. After infection, it remains latent in host cells and can reactivate when immune surveillance is weakened. In an immunocompetent person, CMV is often asymptomatic. Primary infection may instead produce a mononucleosis-like illness with fever, fatigue, lymphadenopathy, and atypical lymphocytes. These findings do not by themselves distinguish CMV from Epstein–Barr virus infection. The clinical priority changes sharply with the host’s immune status. In a person receiving a transplant, chemotherapy, high-dose immunosuppression, or living with advanced HIV infection, viral replication can injure specific organs: - Retinitis: painless floaters, blurred vision, scotomata, or loss of visual acuity - Colitis: persistent diarrhoea, abdominal pain, fever, weight loss, or blood in the stool - Pneumonitis: progressive dry cough, dyspnoea, hypoxaemia, and diffuse pulmonary infiltrates - Encephalitis: confusion, altered behaviour, seizures, or focal neurological changes A new symptom in an immunocompromised patient should therefore be interpreted as a possible end-organ complication, not simply as another viral syndrome. Congenital CMV develops when CMV crosses the placenta during pregnancy. A newborn may have petechiae or purpura, jaundice, hepatosplenomegaly,...