The characteristics of hDPP4 transgenic mice subjected to aerosol MERS coronavirus infection via an animal nose-only exposure device

Hao, Xin-yan; Lv, Qi; Li, Feng-di; Xu, Yan-feng; Gao, Hong

We found that the progressions of virus replication and lung lesions in challenged mice were slower in the aerosol group than in the instillation group. Based on high viral loads in the lungs and brain of challenged mice, which was consistent with previous reports, 35 and acute renal failure in MERS patients, we carried out H&E staining to assess histopathological changes and immunohistochemical staining with a specific antibody to further characterize MERS-CoV expression in the lungs, brain, and kidneys. A relatively high viral load in the lower respiratory tract is associated with severe illness in viral respiratory diseases. 36, 37 At 3-5 days postinfection, mice in the intranasal group, which had high viral loads in the lungs and brain at 3-5 days, exhibited acute interstitial pneumonia and pathological brain changes. In the aerosol group, mice developed acute interstitial pneumonia at 3-9 days and pathological brain changes at 7-9 days, which were caused by high levels of virus RNA in the lungs at 3-9 days and in the brain at 7-9 days, respectively. Higher virus RNA levels in the instillation group might contribute to the more severe High level on days 3 and 5