Cytoplasmic Polyhedral Virus Infecting the Silkworm

Open Access
Publisher Website
Google Scholar
Abstract
1. The mid-gut polyhedrosis attacking silkworm shows similar symptoms to the flacherie-disease, especially in the change appearing in alimentary canal. The mid-gut, especially the middle and posterior portions, exhibits a distinctly whitish colour. 2. Numerous polyhedral bodies are produced in the cylindrical cells of the mid-gut epithelium, but never in the goblet or interstial cells. The polyhedra are produced only in the cytoplasm, the nucleus is entirely free from polyhedra or virus-like particles. 3. The polyhedra are almost identical in shape to those produced in the nucleus. 4. On sections the polyhedra show numerous holes or protuberances which are of about the same size as the spherical particles which appear by treatment with dilute alkali. The polyhedra develop from clusters of spherical particles included in a proteinous matrix which seem to be virus particles. 5. There are two types of the polyhedral virus infecting the silkworm, rod-shaped one and spherical one. The former usually invades the nucleus of the epidermis and some other tissues, while the latter seems to invade specifically the cytoplasm of the cylindrical cells of the mid-gut epithelium.