Following intraperitoneal inoculation with A/WSN/1933 virus, a 7-fold and 15-fold depletion of B cells (CD19 positive populations) was observed at 5 days post-infection in the peritoneal cavity (Figure 2A, Figure S2A) and bone marrow (Figure 2B, Figure S2B), followed by partial recovery at 7 days and restoration to near-normal levels at 14 days post-infection in bone marrow. The gene discussed is CD19; the disease is infection.