Herpesviruses

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Herpesviruses are a family of DNA viruses, with the eight herpesviruses having very high prevalence rates in humans being known as human herpesviruses.[1] Once someone is infected with a herpesvirus, the infection is life-long; many herpesviruses have treatments that can suppress any symptoms but there is no cure.[2] While generally, immunocompetent hosts are able to keep the virus in a latent state and remain asymptomatic, human herpesviruses can cause symptoms if they reactivate. They can also increase the risk of autoimmune disease and cancer.[1][3]

Types[edit | edit source]

Viruses in the herpesvirus family that can infect humans include:

Alphaherpesviruses[edit | edit source]

Betaherpesviruses[edit | edit source]

Gammaherpesviruses[edit | edit source]

More than 90% of adults have been infected with at least one herpesvirus.

See also
Epstein-Barr virus, Human herpesvirus 6, Human herpesvirus 7.

Latency[edit | edit source]

After the initial infection, herpesvirus usually remain latent for life (they are not curable), and may be reactivated later.[6]

Reactivation[edit | edit source]

Classical triggers for herpesvirus reactivation: Fever, Microbial co-inrfection, UV-light, Stress, Tissue injury, Hyperthermia, Hormonal imbalance, Allogeneic stimulation, Cytokines, Cell differentiation, Toxic stimuli Novel triggers for reactivation: Nanoparticles, Respirable fibres, Helminth co-infection, ? The classic and novel triggers may have common or different pathways.
Triggers of Herpesvirus Reactivation. Source: Stoeger and Adler (2019). Front. Microbiol. 9:3207.[7]

Reactivation of herpesviruses do not usually cause disease,[7] although some may cause disease,[4] for example:

  • reactivation of latent varicella-zoster virus may cause shingles (varicella zoster), typically in adults, with the virus typically being caught in childhood and resulting in chickenpox before becoming latent, and
  • CMV pneumonia may be caused by CMV reactivation, which is most likely in immunosuppressed people, especially bone marrow transplant recipients and people with HIV.[4]
  • HSV-1 has been implicated in Alzheimer's, although this does not mean it is the only cause.[8]

Several of the herpesviruses have transactivating potential, that is, they can cause the increased rate of gene expression of other viruses.[6]

Chronic fatigue syndrome[edit | edit source]

It is unclear whether herpesviruses associated with Chronic fatigue syndrome play an etiological role or are "bystanders" – opportunistic reactivations under a state of immune dysregulation. In the 1984 Incline Village chronic fatigue syndrome outbreak, Gary Holmes found that patients with what his team hypothesized was chronic Epstein-Barr had elevated antibody titers to Epstein-Barr virus, cytomegalovirus, herpes simplex and measles viruses than age-matched controls.[9] However, the study cohort was defined as patients who had experienced excessive fatigue between January 1 and September 15. 

A prospective study of 250 primary care patients revealed a higher prevalence of chronic fatigue syndrome after infectious mononucleosis (glandular fever) when compared to an ordinary upper respiratory tract infection.[10] Anti-early antigen titers to Epstein-Barr virus were elevated in CFS patients and associated with worse symptoms.[11]

Notable studies related to Herpesviruses and ME/CFS[edit | edit source]

  • 2019, "Novel" Triggers of Herpesvirus Reactivation and Their Potential Health Relevance[7] - (Full text)
opinion article

"In this review, we provide evidence from animal and human studies of the Epstein-Barr virus as a prototype, supporting the notion that herpesviruses dUTPases are a family of proteins with unique immunoregulatory functions that can alter the inflammatory microenvironment and thus exacerbate the immune pathology of herpesvirus-related diseases including myalgic encephalomyelitis/chronic fatigue syndrome, autoimmune diseases, and cancer...[we] approached the possibility that two or more herpesviruses may act synergistically and that virus-encoded proteins, rather than the viruses themselves, may act as drivers of or contribute to the pathophysiological alterations observed in a subset of patients with ME/CFS."[12]

See also[edit | edit source]

Learn more[edit | edit source]

References[edit | edit source]

  1. ↑ 1.0 1.1 White, Douglas W.; Beard, R. Suzanne; Barton, Erik S. (January 2012). "Immune Modulation During Latent Herpesvirus Infection". Immunological reviews. 245 (1): 189–208. doi:10.1111/j.1600-065X.2011.01074.x. ISSN 0105-2896. PMC 3243940. PMID 22168421.
  2. ↑ Dong, Haisi; Wang, Zeyu; Zhao, Daqing; Leng, Xiangyang; Zhao, Yicheng (September 1, 2021). "Antiviral strategies targeting herpesviruses". Journal of Virus Eradication. 7 (3): 100047. doi:10.1016/j.jve.2021.100047. ISSN 2055-6640. PMC 8187247. PMID 34141443.
  3. ↑ "Viruses that can lead to cancer". cancer.org. Retrieved August 20, 2020.
  4. ↑ 4.0 4.1 4.2 Template:Cite boom
  5. ↑ Davison, Andrew J. (2007). "1 Overview of classification". In Arvin, Ann; Campadelli-Fiume, Gabriella; Mocarski, Edward; Moore, Patrick S.; Roizman, Bernard; Whitley, Richard; Yamanishi, Koichi (eds.). Overview of classification. Cambridge: Cambridge University Press. ISBN 978-0-521-82714-0. PMID 21348096.
  6. ↑ 6.0 6.1 De Bolle, Leen; Naesens, Lieve (January 2005), "Update on Human Herpesvirus 6 Biology, Clinical Features, and Therapy", Clin Microbiol Rev, 8 (1): 217–245, doi:10.1128/CMR.18.1.217-245.200
  7. ↑ 7.0 7.1 7.2 Stoeger, Tobias; Adler, Heiko (2019). ""Novel" Triggers of Herpesvirus Reactivation and Their Potential Health Relevance". Frontiers in Microbiology. 9. doi:10.3389/fmicb.2018.03207. ISSN 1664-302X. PMC 6330347. PMID 30666238.
  8. ↑ Experts Say There’s a Herpes-Alzheimer’s Link, Time, March 10, 2016
  9. ↑ Homes, Gary P (May 1, 1987). "A Cluster of Patients With a Chronic Mononucleosis-like Syndrome Is Epstein-Barr Virus the Cause?". Journal of the American Medical Association. 257: 2297–2302.
  10. ↑ White, P.D.; Thomas, J.M.; Amess, J.; Crawford, D.H.; Grover, S.A.; Kangro, H.O.; Clare, A.W. (December 1998). "Incidence, risk and prognosis of acute and chronic fatigue syndromes and psychiatric disorders after glandular fever". The British Journal of Psychiatry: The Journal of Mental Science. 173: 475–481. ISSN 0007-1250. PMID 9926075.
  11. ↑ Schmaling, K.B.; Jones, J.F. (January 1996). "MMPI profiles of patients with chronic fatigue syndrome". Journal of Psychosomatic Research. 40 (1): 67–74. ISSN 0022-3999. PMID 8730646.
  12. ↑ Williams, Marshall V.; Cox, Brandon; Ariza, Maria Eugenia (2017), "Herpesviruses dUTPases: A New Family of Pathogen-Associated Molecular Pattern (PAMP) Proteins with Implications for Human Disease", Pathogens, 6 (1): 2, doi:10.3390/pathogens6010002

cytomegalovirus (CMV) - A common herpesvirus found in humans. Like other herpesviruses, it is a life-long infection that remains in a latent state inside the human body, until it is 'reactivated' by appropriate conditions. CMV infects between 60% to 70% of adults in industrialized countries and close to 100% in emerging countries. Much is unknown about this virus, although it has been found in salivary glands and myeloid blood cells such as monocytes. It has also been linked to the development of certain cancers. Congenital CMV is a leading infectious cause of deafness, learning disabilities, and intellectual disability. A common treatment for CMV is valganciclovir, commonly known as Valcyte.

etiology The cause of origin, especially of a disease.

antibodies Antibody/immunoglobulin refers to any of a large number of specific proteins produced by B cells that act against an antigen in an immune response.

somatic symptom disorder A psychiatric term to describe an alleged condition whereby a person's thoughts somehow cause physical symptoms. The actual existence of such a condition is highly controversial, due to a lack of scientific evidence. It is related to other psychiatric terms, such as "psychosomatic", "neurasthenia", and "hysteria". Older terms include "somatization", "somatoform disorder", and "conversion disorder". Such terms refer to a scientifically-unsupported theory that claims that a wide range of physical symptoms can be created by the human mind, a theory which has been criticized as "mind over matter" parapsychology, a pseudoscience.

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