Pneumonia caused by cytomegalovirus. most humans are exposed to cytomegalovirus. healthy individuals do not develop signs and symptoms of infection. patients with weakened immune system (e.g., aids patients, cancer patients who are being treated with chemotherapy, and patients who have received bone marrow or solid organ transplants) develop signs and symptoms of infection. they include cough, shortness of breath, fatigue, malaise, fever, muscle and joint pain, and excessive sweating.