Rhinovirus

Virus, Non-Enveloped

VirusRhinovirus
StructureNon-enveloped
FamilyPicornaviridae
Host(s)Humans
Disease(s) CausedCommon cold
SymptomsRunny nose, sore throat, nasal congestion, cough, headache
Potential ComplicationsSecondary bacterial infections (sinusitis, ear infection, etc)
Transmission Mode

Inhalation of aerosols, contact with contaminated fomites

Sites of Community OutbreaksSchools, hospitals, daycare centers, nursing homes
Importance of the Rhinoviruses

Rhinoviruses are the causative agents of approximately half of all human common colds, with almost officially recognized 100 serotypes (9). The incubation period generally ranges from 1 to 2 days (4), followed by rhinitis (runny nose), nasal congestion, sore throat, cough, and less frequently headaches for symptomatic individuals.

Common cold outbreaks occur worldwide and throughout the year, although in the northern hemisphere most cases are reported from September through April. They tend to occur in locations where persons are in close proximity to one another, such as schools and nursing home facilities (5, 6), with high mortality rates often reported for the latter.

The Importance of Disinfection: Survival of Rhinoviruses on Surfaces and Transmission Potential via Fomites

Unlike the human coronaviruses, which cause approximately 25% of colds (9), rhinoviruses are non-enveloped in structure and grouped phylogenetically with the Picornaviridae family which includes fecal-oral pathogens such as hepatitis A virus. Rhinoviruses do not remain active on surfaces for the extended periods characterized by hepatitis A. However, Rhinovirus 14 has demonstrated viability for >25 hours following inoculation onto hard, nonporous surfaces (stainless steel disks) in the presence of both nasal discharge and tryptose-phosphate broth, with high humidity and low temperature conditions most conducive to viral survival (7).

Coughing and sneezing are hallmark symptoms of the common cold, and the forced projection of nasal fluids (which may contain ~7-log10 of infectious viruses per ml) results in the deposition of infectious viruses on surrounding fomites. Transfer of viruses to the hands occurs by touching these fomites, and self-inoculation has been reported when rhinoviruses were moved from fomites to the nose (mucous membranes) and eyes (1, 2). The disinfection of environmental surfaces therefore becomes of increased importance for the reduction of rhinovirus transmission. Rhinoviruses on stainless steel disks treated for 10 minutes with either a 0.1% o-phenylphenol plus 79% ethanol solution, or bleach (800 ppm free chlorine) were reduced to undetectable levels as detected following attempted transfer to human hands; in contrast, surfaces treated with quaternary ammonium compound and phenolic formulations failed to prevent the transmission of infectious rhinoviruses to the hands (8).

Antimicrobial hand formulations and sanitizers have also been evaluated for efficacy in effort to reduce the transmission of viruses from hands to surfaces and to lower the risk of self-inoculation. Diluted iodine-based (1.0%) solutions in an ethyl alcohol or water base proved most effective for the inactivation of rhinovirus 29 when applied immediately following viral inoculation, with residual activity also observed for up to an hour, while ethyl and benzyl alcohol mixtures proved relatively ineffective (3). Ethanol-based hand sanitizers supplemented with organic acids also proved more efficacious for the elimination of rhinovirus 39 from the hands relative to use of water alone and the combination of water plus soap (10). However, the highly controlled conditions of research studies are not reflective of actual use conditions in natural settings, where people tend towards highly variable behaviors including the volume(s) of antimicrobials applied and the time spent washing/treating the hands.

References
  1. Gwaltney, J. and J. Hendley. 1982. Transmission of experimental rhinovirus infection by contaminated surfaces. American Journal of Epidemiology. 116: 828-833.
  2. Hendley, J., R. Wenzel, and J. Gwaltney. 1973. Transmission of rhinovirus colds by self-inoculation. The New England Journal of Medicine. 288: 1361-1364.
  3. Hendley, J., L. Mika, and J. Gwaltney. 1978. Evaluation of virucidal compounds for inactivation of rhinovirus on hands. Antimicrobial Agents and Chemotherapy. 14: 690-694.
  4. Lessler, J. et al. 2009. Incubation periods of acute respiratory viral infections: a systematic review. The Lancet Infectious Diseases. 9: 291-300.
  5. Longtin, J. et al. 2010. Rhinovirus outbreaks in long-tern care facilities, Ontario, Canada. Emerging Infectious Diseases. 16: 1463-1465.
  6. Louie, J. et al. 2005. Rhinovirus outbreak in a long term care facility for elderly persons associated with unusually high mortality. Clinical Infectious Diseases. 41: 262-265.
  7. Sattar, S. et al. 1987. Survival of human rhinovirus type 14 dried onto nonporous inanimate surfaces: effect of relative humidity and suspending medium. Canadian Journal of Microbiology. 33: 802-806.
  8. Sattar, S. et al. 1993. Chemical disinfection to interrupt transfer of rhinovirus type 14 from environmental surfaces to hands. Applied and Environmental Microbiology. 59: 1579-1585.
  9. Strauss, J.H. and E.G. Strauss. Viruses and Human Disease. Elsevier Academic Press, Burlington, MA. 2008.
  10. Turner, R., J. Fuls, and N. Rodgers. 2010. Effectiveness of hand sanitizers with and without organic acids for removal of rhinovirus from hands. Antimicrobial Agents and Chemotherapy. 54: 1363-1364.