Human Rhinovirus C was first identified in 2006 as a previously unrecognized species of rhinovirus. It is a non‑enveloped positive‑sense RNA virus with a small icosahedral capsid that infects the human respiratory tract. The virus binds to cadherin‑related family member 3 (CDHR3) to enter airway epithelial cells, in contrast to rhinovirus A and B which use the immunoglobulin‑like receptor ICAM‑1. Human rhinovirus C replicates most efficiently at the cooler temperatures of the nasal passages and can cause significant illness with wheezing in susceptible individuals.
Virology and clinical significance
Human rhinovirus C genomes are approximately 7.2 kilobases long and encode a single polyprotein that is cleaved into structural and non‑structural proteins. The virus is more difficult to grow in culture than other rhinoviruses because it targets ciliated airway epithelial cells and has strict temperature requirements. Clinical presentations range from common colds to lower respiratory tract infections, especially in infants and young children. Human rhinovirus C has been linked to bronchiolitis, pneumonia and exacerbations of asthma. In experimental studies the virus uses CDHR3 to enter host cells, and polymorphisms in the CDHR3 gene (such as the rs6967330 Y529 variant) are associated with increased viral binding and severe disease. There is no licensed vaccine or antiviral therapy for rhinovirus C infection; management is supportive, and public health measures focus on hygiene and limiting exposure.
Notable cases and research highlights
After its discovery, human rhinovirus C quickly attracted attention because of its association with wheezing illnesses and asthma hospitalizations. Molecular surveillance has identified numerous genotypes circulating worldwide, with peaks in autumn and winter. Outbreaks in neonatal and pediatric wards have demonstrated the virus’s ability to cause severe bronchiolitis. Studies of patients with severe lower respiratory tract infections show that co‑infection with respiratory syncytial virus or influenza can worsen disease severity. Research on the CDHR3 receptor has revealed that a single‑amino‑acid change in the human receptor increases surface expression and susceptibility; this finding has provided insight into why some children develop more severe rhinovirus C disease. Human rhinovirus C is an important contributor to respiratory illness and wheezing exacerbations in infants and children. Its reliance on the CDHR3 receptor and its genetic diversity distinguish it from other rhinoviruses, and continued surveillance is necessary to understand its epidemiology and clinical impact. Related Terms: Human Rhinovirus A, Human Rhinovirus B, Enterovirus D68, Enterovirus A71, Human Parechovirus 3.