In addition, co-expression of ACE2 and TMPRSS2 was detected in more than 50% of Wolfring’s gland cells in the cat eyelid and epicardial cells in the cat heart (Fig. 2b and Supplementary Data 2), suggesting the possibility that such tissue could act as a putative portal for the initial infection and transmission of SARS-CoV-2. Here, TMPRSS2 is linked to infection.