a–d, Three Malayan pangolins positive for pangolin-CoV (b–d, original amplification × 100) in comparison with a virus-negative Malayan pangolin (a). Red blood cells are seen in the bronchioles of two infected pangolins (b, d). Mononuclear cell infiltration is seen in the bronchiole wall of one infected pangolin (c). Severe congestion is seen in the alveolar tissue (in close proximity to the bronchiole) of one pangolin (d). The respiratory epithelium in the bronchioles is intact.