A 40 year old Caucasian patient presents with difficulty in speaking and walking for 3 days, in a background of fever and fatigue for 1 week.

He has been HIV-positive for 7 years. Close questioning reveals poor compliance with HAART.

There is no contact history with tuberculosis nor a travel history to South America. He keeps a cat as a pet.

He is allergic to sulfa-drugs. A CD4 count is performed and is found to be 100 cells/microL.