Picornaviruses

Definition

Picornaviruses are a family of small, non-enveloped viruses with single-stranded RNA genomes. They are important in virology because they include many well-known pathogens such as poliovirus and enteroviruses, which can cause significant diseases in humans and animals. Their classification is based on their genomic structure, transmission methods, and the diseases they cause.

5 Must Know Facts For Your Next Test

1. Picornaviruses are characterized by their small size (about 22-30 nanometers) and their stable, icosahedral structure.
2. They can be transmitted through the fecal-oral route, respiratory droplets, or direct contact with contaminated surfaces.
3. The family Picornaviridae is divided into several genera, including Enterovirus, Rhinovirus, and Hepatovirus.
4. Rhinoviruses, a subgroup of picornaviruses, are the most common cause of the common cold.
5. Picornaviruses can replicate quickly in host cells, leading to rapid onset of disease symptoms.

Review Questions

• What are the key characteristics that differentiate picornaviruses from other virus families?
  • Picornaviruses are small, non-enveloped viruses with single-stranded RNA genomes. Their compact size allows them to efficiently enter host cells, while their non-enveloped nature provides resistance to environmental conditions. Additionally, they have a unique replication strategy involving the direct translation of their RNA genome into viral proteins upon entering a host cell, which sets them apart from enveloped viruses.
• Discuss the significance of picornaviruses in public health and how their transmission routes impact control measures.
  • Picornaviruses pose significant public health challenges due to their widespread transmission routes, including fecal-oral contamination and respiratory droplets. This facilitates rapid outbreaks in crowded settings, such as schools or daycares. Control measures focus on promoting hygiene practices like handwashing and sanitation to prevent infection spread. Vaccination strategies for diseases caused by picornaviruses, such as poliomyelitis, have also been crucial in reducing incidence rates.
• Evaluate the role of picornaviruses in viral pathogenesis and their implications for vaccine development.
  • Picornaviruses play a critical role in viral pathogenesis due to their ability to rapidly replicate and cause disease through various mechanisms, including cytopathic effects on host cells and immune evasion strategies. Understanding these mechanisms is essential for vaccine development. For instance, the success of the oral polio vaccine demonstrates how targeting specific strains within the picornavirus family can lead to effective prevention strategies against potentially life-threatening diseases.

Related terms

Enterovirus: A genus of picornaviruses that includes several viruses responsible for common infections like hand, foot, and mouth disease.

Poliovirus: A member of the picornavirus family that causes poliomyelitis, a disease that can lead to paralysis.

Non-enveloped virus: A type of virus that lacks an outer lipid membrane, making it more resistant to environmental conditions.