Figure 1.
Intranasal challenge with SARS-CoV-2 caused both pulmonary and enteric infections in rhesus monkeys. (A) Experimental design. Six rhesus monkeys were used for this experiment. Five animals were intranasally challenged with 1 mL of 107 PFU SARS-CoV-2, followed by clinical examinations, sampling, chest radiography, necropsy, and histopathologic analysis at the timepoints indicated. At 0 dpi, the animal MM-O/N-0 was necropsied as a control for both the intranasal and intragastric routes to reduce the number of animals. The animals MM-N-1, MM-N-4, MM-N-7, MM-N-14-1, and MM-N-14-2 were dissected on 1, 4, 7, 14, and 14 dpi, respectively. (B) Virus loads in tissue samples from the respiratory and digestive systems were measured by qRT-PCR. (C) Histopathology of respiratory tissues was analyzed after H&E staining after intranasal inoculation. (D) Histopathology of digestive tissues was analyzed after H&E staining after intranasal inoculation. (E) Cleaved caspase-3, as a marker for apoptosis, was evaluated by the IHC staining of digestive tissues. (F) The integrity of the digestive barrier was evaluated by AB-PAS staining after intranasal inoculation. (G) The marker for cell proliferation Ki67 was analyzed by the IHC staining of digestive tissues.