Variable levels of thrombocytopenia and platelet dysfunction during infection with highly pathogenic arenaviruses. (A) Platelet counts expressed in giga cells/L. The base level is calculated as the mean of all values from 3 mock-infected animals and the value at the day of challenge of 53 animals. The rest of the legend is as previously described. (B) Platelet function evaluated through platelet aggregation normalized by platelet count. Platelet aggregation was measured in response to 3 classical platelet agonists: ADP, RISTO, and COL. Tests were performed at the day of euthanasia and raw values were normalized by the platelet count on the corresponding time point. Bars and error bars represent the mean and SEM of each condition, individual values appear as circles. Asterisks indicate a statistically significant difference with the base level according to a 2-tailed Mann-Whitney test (∗P < .05; ∗∗P < .01; ∗∗∗P < .005). (C) Number and relative frequency of colonies from each myeloid lineage obtained after a 10-day culture of CD34⁺ hematopoietic cells from vaccinated and unvaccinated animals challenged with LASV Josiah animals. Bone marrow specimens from 3 animals in each condition were used and cultures were carried out in triplicates. Dots correspond to the mean of technical triplicates, bars to the mean of 3 animals and error bars to their standard error of the mean. Asterisks indicate a statistically significant difference with the base level according to a Welch t test (∗P < .05; ∗∗P < .01).