Aplastic crisis is usually associated with infection by which type of pathogen?

Aplastic crisis is usually associated with infection by which type of pathogen?

• A. Bacterial infection
• B. Viral infection
• C. Parasitic infection
• D. Fungal infection

Answer: (B)

Aplastic crisis occurs when an infection transiently shuts down production of red blood cells by directly targeting erythroid precursors in the bone marrow. The classic trigger is Parvovirus B19, a virus that infects erythroid progenitors via the P antigen and temporarily halts erythropoiesis. In people with already high red-cell turnover—such as those with sickle cell disease or thalassemia—this leads to a rapid and marked drop in hemoglobin because new red cells cannot be produced, while white blood cells and platelets are relatively spared. A hallmark is a severe reticulocytopenia, reflecting the pause in red-cell production. Other types of pathogens can cause illness, but they do not produce the isolated, transient erythroid suppression seen in an aplastic crisis. Bacterial infections, parasites, or fungi typically do not cause this selective shutdown of the erythroid lineage to the same extent.

Aplastic crisis occurs when an infection transiently shuts down production of red blood cells by directly targeting erythroid precursors in the bone marrow. The classic trigger is Parvovirus B19, a virus that infects erythroid progenitors via the P antigen and temporarily halts erythropoiesis. In people with already high red-cell turnover—such as those with sickle cell disease or thalassemia—this leads to a rapid and marked drop in hemoglobin because new red cells cannot be produced, while white blood cells and platelets are relatively spared. A hallmark is a severe reticulocytopenia, reflecting the pause in red-cell production.

Other types of pathogens can cause illness, but they do not produce the isolated, transient erythroid suppression seen in an aplastic crisis. Bacterial infections, parasites, or fungi typically do not cause this selective shutdown of the erythroid lineage to the same extent.