rinovirus

Rinovirus (often spelled rhinovirus) refers to a group of small, nonenveloped, positive-sense RNA viruses in the family Picornaviridae. They are the most common viral cause of the common cold in humans and are found worldwide. The genus includes three species: Rhinovirus A, Rhinovirus B, and Rhinovirus C, with many serotypes within A and B, and C also highly diverse.

Structure, genome, and replication: Rinoviruses are about 30 nanometers in diameter with an icosahedral capsid. They possess a single-stranded positive-sense RNA genome of about 7.2 kilobases encoding a single polyprotein processed into structural and nonstructural proteins (e.g., VP1-4). They replicate primarily in the upper respiratory tract at about 33 degrees Celsius and are acid-labile. The genome is highly variable, leading to extensive antigenic diversity and frequent reinfection.

Transmission and pathogenesis: Spread via respiratory droplets, direct contact, or fomites; infection often begins in the nasal mucosa leading to sneezing, sore throat, nasal congestion, and cough. Many serotypes bind to ICAM-1 as a receptor, with a minority using the LDL receptor. Symptoms are typically mild but can exacerbate asthma and chronic obstructive pulmonary disease in some individuals. Immunity is usually type-specific and short-lived, allowing reinfection with other serotypes.

Diagnosis, treatment, and prevention: Diagnosis is usually clinical; molecular assays are available in clinical labs. There are no approved vaccines or broadly effective antivirals due to diversity; treatment is supportive. Prevention focuses on hand hygiene, respiratory etiquette, and surface disinfection.