Fig. 2. Longitudinal tracking of clinical signs, viral replication, hematological changes, and radiological changes.

(A and B) Clinical signs in each monkey. Monkeys were examined daily for changes in body weight and rectal temperature over the observation period after the initial infection, followed by virus rechallenge. The changes in weight are expressed as body weight loss prior to primary infection. (C, D, and E) Detection of viral RNA in nasal, throat, and anal swabs. The SARS-CoV-2 RNA was detected by qRT–PCR in the swabs from seven monkeys at the indicated time points. (F) Hematological changes, including WBC, LYMP, and NEUT counts in the peripheral blood, were monitored. (G) Chest X-rays of animals at 0, 7, 28, and 33 dpi (5 dpr) were examined and the representative images of M4 and M6 are shown (red circles, areas of interstitial infiltration and exudative lesion; red arrows, obscured diaphragmatic surface; blue circles and arrows, areas that have recovered from pneumonia). Four monkeys (M3 to M6) were rechallenged at 28 dpi (dotted line and shaded areas), and the results of the initial infection and rechallenge were compared in bar graphs. The bars represent the average of four rechallenged animals at the indicated time points. The viral RNA in nasal, throat, and anal swabs of rechallenged animals were significantly lower than those of the initial infection, while significant hematological changes were observed between the primary and second challenges (unpaired t-test, dpi vs. dpr, *P < 0.05; **P < 0.01; ***P < 0.001; ^#P < 0.05 0 dpi vs. 7 dpi).