NID1 and viral infectious disease: A study of BmDV infection in silkworms with mosaic midguts showing susceptibility ( + Nid-1/ + Nid-1) and nonsusceptibility (Nid-1/ + Nid-1) genotypes demonstrated that columnar cells were degraded by virus infection only in the longitudinal half of the midgut, and surprisingly the larvae did not die36.