The virino is a hypothetical infectious particle once theorized to be the cause of scrapie and other degenerative diseases of the central nervous system. It was thought to consist of nucleic acids within a protective coat of host cell proteins. The hypothesis was never widely accepted, and the causative agents responsible for these diseases are now widely accepted to be prions.
Origin of the concept
The virino was described partially to protect the central dogma of molecular biology, which was threatened by the existence of a series of degenerative neurological TSE diseases including kuru, CJD, scrapie in sheep, and BSE in cattle. The central dogma states that nucleic acids act as information carriers, and DNA and RNA make proteins. Proteins alone cannot make DNA. However, studies searching for the transmission agent of scrapie and other TSEs failed to culture bacteria, and tests attacking nucleic acids strands have little effect on the infectivity of TSE solutions.