VMC 211: General Veterinary Microbiology (1+1)

VIRIODS

• Viriods are nucleic acid entities of low molecular weight (1.1 – 1.3 x10⁵) having unique structure. They cause many important diseases of plants. Eg: potato spindle tuber and cucumber pale fruit diseases.
• Viriods are the smallest known agents of infectious disease. They do not have a protein coat and exist only as short infectious molecules of RNA.
• Some are single stranded covalently closed circular RNA molecules and some are single stranded linear RNA molecules. It is not known how they cause disease. They may cause host symptoms by interference with gene regulation in infected host cells.