Human Herpesvirus 5 (Cytomegalovirus)

Virus, Enveloped

VirusHerpesvirus 5 (Cytomegalovirus)
StructureEnveloped
GenomeDouble stranded DNA
FamilyHerpesviridae
Primary HostHumans
Disease(s) CausedMononucleosis-like illness in immunocompromised individuals
Symptomsfever, hepatitis, sore throat
Potential ComplicationsIn infants: hearing loss, vision loss, mental disability, seizures
Transmission ModeIn utero, contact with bodily fluids from an infected person
Sites of Community OutbreaksSchools, daycares

Importance of Human Herpesvirus 5 (Cytomegalovirus)

Human herpesvirus 5 (HHV-5), also known as Cytomegalovirus, is an enveloped member of the Herpesviridae family.

HHV-5 is highly prevalent, with anywhere from 40-100 percent of the adult population worldwide having been exposed at some point in their lifetime. In most cases, infection results in no clinical symptoms. HHV-5 is responsible for a small fraction of mononucleosis cases, with symptoms identical to those caused by the Epstein-Barr virus. In immunocompromised individuals, more severe symptoms can occur, such as encephalitis and mycocarditis.

HHV-5 poses a greater threat to newborns and infants. If a mother is first infected with HHV-5 during pregnancy, there is a chance that the virus will be passed to the fetus. As a result of this, about 20% of infected infants will have long-term complications such as vision loss, hearing loss, or mental disabilities. It is estimated that approximately 8,000 children in the United States are affected with a neurological complication of HHV-5 each year. It is thought that HHV-5 either directly disrupts chromosomes or influences the expression of developmental genes.

Importance of Disinfection: Survival of Human Herpesvirus 5 on Surfaces and Potential for Transmission via Fomites

HHV-5 is spread through close contact with infected bodily fluids. Contaminated surfaces can also serve as a transmission vector. A study found that in a group of 8 infants in an intensive care unit, 3 were infected with the same strain. Because the infants did not have any contact with each other, surfaces in the nursery were believed to have spread the virus.

As an enveloped virus, HHV-5 is highly susceptible to inactivation by environmental factors. HHV-5 has been found to remain viable on hands for 15 minutes. HHV-5 remained viable for 15 minutes when transferred from hands to plastic surfaces, and up to 5 minutes when transferred to metal, glass, and cloth. As with other enveloped viruses, a wide range of disinfectants are capable of inactivating HHV-5.

References

Cheeran, Maxim C.-J., James R. Lokensgard, and Mark R. Schleiss. “Neuropathogenesis of Congenital Cytomegalovirus Infection: Disease Mechanisms and Prospects for Intervention.” Clinical Microbiology Reviews22.1 (2009): 99–126. PMC. Web. 27 Jan. 2016.

"Transmission." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 06 Dec. 2010. Web. 19 Jan. 2016.

Spector, Stephen A. "Transmission of cytomegalovirus among infants in hospital documented by restriction-endonuclease-digestion analyses." The Lancet 321.8321 (1983): 378-381.

Stowell, Jennifer D. et al. “Cytomegalovirus Survival and Transferability and the Effectiveness of Common Hand-Washing Agents against Cytomegalovirus on Live Human Hands.” Applied and Environmental Microbiology 80.2 (2014): 455–461. PMC. Web. 19 Jan. 2016.

Taylor, Gregory H. "Cytomegalovirus." American family physician 67.3 (2003): 519-524.