Robin Roberts' treatment for myelodysplastic syndrome is - by her account - going well, though she did hit a speedbump lat week. On leave from "Good Morning America" following a bone marrow transplant in early September, she told followers on a Facebook post Sunday that she had been hospitalized last week for a viral infection. Blaming the week stay on a "latent virus, many of us have, was not responding to medication, and was pulling down my numbers," she said the virus was currently "under control," and that she left the hospital Friday. Roberts, who is undergoing treatment for a blood disorder related to earlier treatments for breast cancer, said, "Our immune systems usually take care of a virus like this...but mine is only 59 days old." Doctors and nurses, she said, "assured me the majority of BMT patients have to be re-admitted to the hospital for various reasons. I decided to look at my brief stay as a 'tune up'...and then I would be back on the road to recovery. By the grace of God, I am!" Her sister and donor, Sally-Ann, interviewed Roberts for a piece that will air on "GMA" Tuesday..