A group of entomopathogenic viruses that infect arthropods. According to the International Committee on Taxonomy of Viruses (ICTV), CPVs are classified under the family Reoviridae and genus Cypovirus. Cytoplasmic polyhedrosis viruses have a very wide host range, affecting mainly lepidopterous insects. Cytoplasmic polyhedrosis has been recognised as one of the most important diseases of the silkworm, inflicting substantial economic losses to the sericulture industry in Japan.