NBME Microbiology Practice Test

Parvovirus B19 can cause a transient cessation of red blood cell production in bone marrow, leading to an aplastic crisis in patients with sickle cell disease. In sickle cell, red cell turnover is already high, so when the virus infects erythroid precursors (via the P antigen), it halts erythropoiesis for a short period. The result is a sudden drop in hemoglobin with an inappropriately low reticulocyte count, while white cells and platelets remain typically normal. Clinically, this presents as marked anemia and fatigue after a recent viral-like illness. Diagnosis is supported by evidence of Parvovirus B19 infection and reticulocytopenia, and treatment is supportive care, often with red blood cell transfusion if needed. This is the specific complication Parvovirus B19 causes in sickle cell disease.