Human rhinovirus A (HRV‑A) is a non‑enveloped positive‑sense RNA virus belonging to the species Enterovirus alpharhino in the family Picornaviridae. As one of the three rhinovirus species, it is a major contributor to the common cold and can precipitate severe respiratory illnesses in vulnerable individuals.
Virology and clinical features
HRV‑A viruses have genomes of about 7.2–7.4 kb encoding a single polyprotein that is cleaved into structural and non‑structural proteins. The icosahedral capsid contains four structural proteins (VP1–VP4) and encloses the RNA genome. Like other rhinoviruses, HRV‑A is non‑enveloped and replicates optimally at around 33 °C, a temperature typical of the upper respiratory tract. Entry into host cells is mediated predominantly by the intercellular adhesion molecule 1 (ICAM‑1), though some HRV‑A types use the low‑density lipoprotein receptor. After binding, viral replication occurs in epithelial cells of the nasal passages and nasopharynx; progeny virions are shed in respiratory secretions and are transmitted via aerosols or contaminated surfaces. HRV‑A infection usually causes mild symptoms such as nasal congestion, sore throat and cough, but certain types are associated with more severe illness, wheezing and asthma exacerbations. Infants, the elderly and immunocompromised patients are more likely to develop bronchiolitis, pneumonia or sinusitis. There are no approved antivirals for rhinovirus infections, so treatment is supportive, focusing on symptom relief and management of complications. Prevention relies on hand hygiene, respiratory etiquette and avoiding close contact with infected individuals.
Clinical insights and epidemiology
HRV‑A and HRV‑C species viruses are more strongly associated with significant illness and wheezing than HRV‑B viruses. HRV‑A has been implicated in hospital and community outbreaks of bronchiolitis and pneumonia among infants and children and is frequently detected in exacerbations of chronic obstructive pulmonary disease and asthma. More than eighty genetically distinct HRV‑A types co‑circulate, and new types continue to be identified through sequencing studies. Seasonal peaks in HRV‑A activity are observed in autumn and spring, though the virus can be detected year‑round. Environmental studies reveal that HRV‑A is present in wastewater, illustrating its widespread circulation.
Human rhinovirus A is a common respiratory pathogen with a positive‑sense RNA genome and non‑enveloped icosahedral capsid. It replicates in the nasal mucosa at cooler temperatures and predominantly uses ICAM‑1 for cell entry. Although it typically produces mild cold‑like symptoms, HRV‑A can trigger severe respiratory disease and asthma exacerbations, particularly in susceptible populations. Continued surveillance and improvements in antiviral research are needed to mitigate its health impact.
Related Terms: Human Rhinovirus B, Human Rhinovirus C, Enterovirus D68, Echovirus 30, Human Parechovirus 1