TMPRSS2 and infection: Larval enterocytes expressed not only ace, but also ace2 and tmprss2, the human ortholog of which activates the coronavirus spike protein, thereby stimulating infection, and expresses in the human digestive system (Fagerberg et al., 2014; Hoffmann et al., 2020; Millet and Whittaker, 2015; Walls et al., 2020).