What is picornavirus replication?

Picornaviruses contain positive-sense, single-stranded RNA genomes and replicate in the cytoplasm of infected cells. As a result of the limited coding capacity of these viruses, cellular proteins are required by these intracellular parasites for both translation and genomic RNA replication.

Where is the initial replication site of picornavirus?

The ingested virus replicates in susceptible tissues of the pharynx or gut. Enteroviral replication can be observed in lymphoid tissue of the small intestine within 24-72 hours of ingestion of the virus.

What are the Classification of picornavirus?

Picornaviruses are classed under Baltimore’s viral classification system as group IV viruses, as they contain a single-stranded, positive-sense RNA genome. Their genome ranges between 6.7 and 10.1 (kilobases) in length.

What picornavirus means?

Definition of picornavirus : any of a family (Picornaviridae) of small single-stranded RNA viruses that include the causative agents of encephalomyocarditis, hepatitis A, polio, foot-and-mouth disease, and hand, foot and mouth disease — compare enterovirus, rhinovirus.

How does picornavirus modify the host translation system?

Importantly, picornaviruses subvert the host protein synthesis machinery by cleavage of canonical translation factors, inhibiting cellular translation and releasing ribosomes and associated proteins from their roles in cap-dependent translation.

What are salient features of the picornavirus family?

The picornaviruses are small (22 to 30 nm) nonenveloped, single-stranded RNA viruses with cubic symmetry. The virus capsid is composed of 60 protein subunits, each consisting of four poly-peptides VP1–VP4. Because they contain no essential lipids, they are ether resistant. They replicate in the cytoplasm.

How does picornavirus enter the host cell?

The virion first binds to a cellular receptor and enters the host cell in an endosome. The viral genome is released into the cytoplasm from early endosomes. The viral VPg protein is cleaved off the genomic RNA by a host protein called “unlinkase,” and the RNA associates with ribosomes.

What are the symptoms of picornavirus?

The most common symptom was rhinorrhea (in 81% of patients), followed by malaise (in 66%), nasal congestion (in 63%), and sore throat (in 49%). Cough or myalgia was present in <40% of the patients, and fever was present in only 4% of the patients. Approximately 53% of the patients tested positive for picornavirus.

Is picornavirus a genus?

The family Picornaviridae comprises five genera: Enterovirus, Hepatovirus and Rhinovirus, which infect humans: Apthovirus (foot-and-mouth disease virus), which infects cloven-hoofed animals and occasionally humans; and Cardiovirus, which infects rodents.

How does a picornavirus enter a host cell?

The infectious cycles of picornaviruses are initiated following viral attachment to specific cellular receptors. The RNA genome is then released from the virion capsid and enters the cytoplasm of the infected cell.

What effects does picornavirus have on host cells?

Effect of picornavirus infection on the host cell Host protein cleavage downregulates cellular translation while still allowing viral, cap-independent translation. Viral proteins direct the modification of host cell membranes to form replication complexes (shown as green orbs), the sites of viral RNA replication.