A 40 yr old man who was seropositive for HIV experienced abdominal pain, fatigue and low-grade fever for 2 weeks A hest X-ray examination revealed lung inflitrates Gram and acid fast stains were negative A viral culture revealed the cause of his symptoms: a large, enveloped polyhedral virus with double stranded DNA what is the disease? Which virus caused it? Why was a viral culture done after the Gram and acid-fast stain results were obtained?