Virusoid

Virusoids are viruses whose packaging and discharge are dependent on the presence of a helper virus in the same infected cell. In contrast to the group of satellite viruses can independently of this second virus synthesize their genome and viral proteins. The virusoids encode traditionally not for their own packaging proteins, ie Proteins which form the viral envelope or capsid. The genome of the virusoids is associated with its own nucleoproteins. Sometimes satellite viruses are incorrectly referred to as virusoids.

The best known Virusoid is the hepatitis D virus in the genus Hepatovirus capable of forming infectious virions only in the simultaneous presence of the hepatitis B virus.