Poliovirus:1. Classification:Poliovirus is an RNA non enveloped virus. It belongs to the family of Picorna viruses. The picorna virus family consists of two clinically important classes i.e. Enteroviruses and Rhinoviruses. Polio virus is included in enteroviruses alongside coxsackieviruses, echoviruses and hepatitis A virus. 2. Epidemiology:

3. Structure:Poliovirus is a non-enveloped single stranded RNA virus with an icosahedral nucleocapsid.Replicative cycle: The RNA that serves as the genome of the poliovirus is of positive polarity. This means it can serve as a functional messenger RNA to produce protein products within the host. After attaching to the receptors the virus is internalized and uncoating takes place. Uncoating means removal of capsid proteins; thereby exposing the viral RNA to the hosts cytoplasm. As mentioned this RNA is of positive polarity and is unusual in a way that it has a protein attached to the 5 end that serves as a primer. The transcription of RNA results in production of a very large polypeptide called as noncapsid viral protein 00. This protein in itself is nonfunctional and needs to be cleaved into small polypeptides and serves as a pre cursor for the smaller functional proteins. There is a protease encoded by the virus itself that serves the task of cleaving the polypeptide into small functional proteins. These proteins may be 1. Capsid proteins for the progeny virus.2. Non capsid proteins e.g. RNA polymerase that transcribes the genome for progeny viruses.After this, replication of the viral genome takes place. First the positive RNA strand from the parent is transcribed to form a complimentary negative RNA strand. This negative RNA strand serves as a template for the positive strands that will be assembled as the genomes of progeny viruses.

4. Mode of transmission5. Pathogenesis6. Clinical features7. Diagnosis8. Prevention and treatment