Which virus is an important cause of pneumonia in immunocompromised patients?

• A. Hepatitis C virus
• B. Human papillomavirus
• C. Dengue virus
• D. Cytomegalovirus

Answer: (D)

In immunocompromised patients, latent viruses that stay quiet in healthy individuals can reactivate and cause serious lung infections, with cytomegalovirus being a classic culprit of pneumonitis. CMV is a herpesvirus that reactivates when cell-mediated immunity is blunted (such as after organ transplantation, in advanced HIV, or during high-dose immunosuppressive therapy). Pneumonia from CMV often presents with fever, cough, and shortness of breath, and shows diffuse interstitial infiltrates on imaging. Diagnosis is typically via CMV DNA or antigen testing in blood or respiratory specimens, or tissue showing characteristic owl’s-eye inclusions. Treatment uses antivirals like ganciclovir or valganciclovir.

The other viruses listed are not the typical drivers of pneumonia in this setting: hepatitis C mainly damages the liver, human papillomavirus causes warts or cancer with no frequent pneumonia association, and dengue causes acute febrile illness rather than opportunistic pneumonia.