A 22-year-old patient from Ghana without relevant co-morbidities was admitted twice with fever of unknown origin and reduced CD4 T-cell count. During the second hospital stay, after prolonged incubation of blood cultures and detection of vegetations on the mitral valve in a transesophageal echocardiogram, infectious endocarditis with Aggregatibacter aphrophilus was diagnosed. Treatment according to European guidelines resulted in resolution of the fever, dissolution of the mitral valve vegetations and recovery of CD4 T-cell count.