Presence of a circulating inhibitor of coagulation in the plasma of LASV Josiah animals. (A) Plasma from LASV Josiah-infected animals at 8 or 11 DPI was mixed 50:50 with a pool of 3 mock-infected animals. The aPTT of the test plasma, the control plasma, and the mixed plasma were measure to calculate the Rosner index as follows: RI = (aPTT of mix – aPTT of control)/aPTT of test. Squares represent the samples for which the aPTT of the test plasma was within a 95% confidence interval of the mean of mocks and circles the samples with a prolonged aPTT. Red bars represent the mean of each time point. Dashed lines highlight the scores of 10 and 15, between which the result is evocative of an inhibitor of coagulation but inconclusive and above which the test is considered positive with certainty. (B) dRVVT of LASV Josiah-infected animals at 8 or 11 DPI. Legend is as previously, except for the dashed line that indicates the score of 1.5, which is the threshold of positivity for lupus anticoagulant.