Human herpesvirus 7

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Human herpesvirus 7
Classification and external resources
ICD-9 058.12
DiseasesDB 5863
MeSH D016199
Human herpesvirus 7
Virus classification
Group: Group I (dsDNA)
Order: Herpesvirales
Family: Herpesviridae
Subfamily: Betaherpesvirinae
Genus: Roseolovirus
Species

Human herpesvirus 7 (HHV-7)

Human herpesvirus 7 (HHV-7) is one of eight known members of the Herpesviridae family, also known as human herpes virus. HHV-7 is a member of Betaherpesviridae, a subfamily of the Herpesviridae that also includes HHV-6 and Cytomegalovirus (HHV-5 or HCMV).[1] HHV-7 often acts together with HHV-6, and the viruses together are sometimes referred to by their genus, Roseolovirus.[2] HHV-7 was first isolated in 1990 from CD4+ T cells taken from peripheral blood lymphocytes.[3]

Signs and symptoms[edit]

Both HHV-6B and HHV-7, as well as other viruses, can cause a skin condition in infants known as exanthema subitum, although HHV-7 causes the disease less frequently than HHV-6B.[4] HHV-7 infection also leads to or is associated with a number of other symptoms, including acute febrile respiratory disease, fever, rash, vomiting, diarrhea, low lymphocyte counts,[5] and febrile seizures,[6] though most often no symptoms present at all.[7]

There are indications that HHV-7 can contribute to the development of drug-induced hypersensitivity syndrome,[8] encephalopathy,[9] hemiconvulsion-hemiplegia-epilepsy syndrome,[10] hepatitis infection,[11] postinfectious myeloradiculoneuropathy,[12] pityriasis rosea,[13] and the reactivation of HHV-4, leading to "mononucleosis-like illness".[14]

Complications with HHV-7 infection has been shown to be a factor in a great variety of transplant types.[7]

Virology[edit]

Structure[edit]

A mature virus particle measures about 170 nanometres (1,700 Å) in diameter.[15]

The genome of HHV-7 is very similar to that of HHV-6, although it is about 10% smaller,[16] with a DNA genome of about 145,000 base pairs.[7] There are a number of key differences between the genome of HHV-7 and that of HHV-6, but the importance of them for viral DNA replication is not yet known.[7]

Cellular effects[edit]

HHV-7 resides mostly in CD4+ T cells,[17] albeit only in certain strains of them.[18] To enter CD4+ T cells, HHV-7, unlike HHV-6, uses CD4 and possibly some cell-surface glyoproteins to enter CD4+ T cells.[19] About a week after HHV-7 has infected a cell, it begins to downregulate CD4 transcription,[20] which interferes with HIV-1 infection[21] but may reactivate HHV-6 infection.[22] It is however unclear exactly what effect HHV-7 has on HIV infection.[7]

HHV-7 also has a number of other effects on cells. Among these include membrane leaking, the presence of lityic syncytia,[23] occasional apoptosis,[24] the supporting of latent infection,[25] and increases and decreases in levels of certain cytokines.[26]

Detection and treatment[edit]

In adults, the effects of HHV-7 separate from HHV-6 have not been well-researched.[27] One reason for this is because the detection of HHV-7 was at first difficult to do quickly, as the process for doing so involves a procedure that is difficult to do in commercial laboratories and because viral isolation and serological testing are long processes that do not lend themselves to finishing quickly. A process known as loop-mediated isothermal amplification (LAMP) has recently been developed to speed up detection of HHV-7, although a larger sample size of patients must be tested first to see if the test will still work across a broad range of subjects.[28] No reliable serological test has been developed yet for HHV-7 alone, but multiple are in the process of being developed.[7] The use of PCR assays to test for HHV-7 is also being explored.[7][29]

No treatment for HHV-7 infection exists, but no clinical situation where such treatment would be useful has yet been discovered.[7]

Epidemiological[edit]

Over 95% of adults have been infected and are immune to HHV-7,[30] and over three quarters of those were infected before the age of six.[31] Primary infection of HHV-7 among children generally occurs between the ages of 2 and 5, which means it occurs after primary infection of HHV-6.[32]

References[edit]

  1. ^ "Other Herpesviruses: HHV-6, HHV-7, HHV-8, HSV-1 and -2, VZV". American Journal of Transplantation (Blackwell Munksgaard). 4 Suppl 10: 66–71. 2004. doi:10.1111/j.1600-6135.2004.00697.x. PMID 15504215. ; Widen, B. F.; Lowings, J. P.; Belak, S.; Banks, M. (August 1999). "Development of a PCR system for porcine cytomegalovirus detection and determination of the putative partial sequence of its DNA polymerase gene". Epidemiology and Infection (Cambridge University Press) 123 (1): 177–180. doi:10.1017/S0950268899002599. PMC 2810741. PMID 10487654. 
  2. ^ Ongrádi, JóZsef; Kövesdi, Valéria; Kováts, Enikő (2010). "Az emberi 7-es herpeszvírus". Orvosi Hetilap (in Hungarian) 151 (16): 645–51. doi:10.1556/OH.2010.28856. PMID 20353917. 
  3. ^ Frenkel, N; Schirmer, EC; Wyatt, LS; Katsafanas, G; Roffman, E; Danovich, RM; June, CH (1990). "Isolation of a new herpesvirus from human CD4+ T cells". Proceedings of the National Academy of Sciences of the United States of America 87 (2): 748–52. Bibcode:1990PNAS...87..748F. doi:10.1073/pnas.87.2.748. PMC 53343. PMID 2153965. 
  4. ^ Cohen, J. I.; Fahle, G.; Kemp, M. A.; Apakupakul, K.; Margolis, T. P. (2010). "Human Herpesvirus 6-A, 6-B and 7 in Vitreous Fluid Samples". Journal of Medical Virology 82 (6): 996–9. doi:10.1002/jmv.21751. PMC 2938775. PMID 20419813. 
  5. ^ Suga, S; Yoshikawa, T; Nagai, T; Asano, Y (1997). "Clinical features and virological findings in children with primary human herpesvirus 7 infection". Pediatrics 99 (3): E4. doi:10.1542/peds.99.3.e4. PMID 9099769. 
  6. ^ Clark, DA; Kidd, IM; Collingham, KE; Tarlow, M; Ayeni, T; Riordan, A; Griffiths, PD; Emery, VC; Pillay, D (1997). "Diagnosis of primary human herpesvirus 6 and 7 infections in febrile infants by polymerase chain reaction". Archives of Disease in Childhood 77 (1): 42–5. doi:10.1136/adc.77.1.42. PMC 1717251. PMID 9279150. 
  7. ^ a b c d e f g h Tremblay, Cecile (January 2, 2008). Hirsch, Martin S; McGovern, Barbara H, eds. "Human herpesvirus 7 infection". UpToDate. 
  8. ^ Hara, H; Kobayashi, M; Yokoyama, A; Tochigi, M; Matsunaga, A; Shimizu, H; Goshima, J; Suzuki, H (2005). "Drug-induced hypersensitivity syndrome due to carbamazepine associated with reactivation of human herpesvirus 7". Dermatology (Karger) 211 (2): 159–61. doi:10.1159/000086449. PMID 16088166. 
  9. ^ Van Den Berg, JS; Van Zeijl, JH; Rotteveel, JJ; Melchers, WJ; Gabreëls, FJ; Galama, JM (1999). "Neuroinvasion by human herpesvirus type 7 in a case of exanthem subitum with severe neurologic manifestations". Neurology 52 (5): 1077–9. doi:10.1212/wnl.52.5.1077. PMID 10102435. 
  10. ^ Kawada, J; Kimura, H; Yoshikawa, T; Ihira, M; Okumura, A; Morishima, T; Hayakawa, F (2004). "Hemiconvulsion-hemiplegia syndrome and primary human herpesvirus 7 infection". Brain & Development (Elsevier) 26 (6): 412–4. doi:10.1016/j.braindev.2003.12.003. PMID 15275707. 
  11. ^ Hashida, T; Komura, E; Yoshida, M; Otsuka, T; Hibi, S; Imashuku, S; Imashuku, S; Ishizaki, T et al. (1995). "Hepatitis in Association With Human Herpesvirus-7 Infection". Pediatrics 96 (4 Pt 1): 783–785. PMID 7567349. 
  12. ^ Mihara, T; Mutoh, T; Yoshikawa, T; Yano, S; Asano, Y; Yamamoto, H (2005). "Postinfectious myeloradiculoneuropathy with cranial nerve involvements associated with human herpesvirus 7 infection". Archives of Neurology 62 (11): 1755–7. doi:10.1001/archneur.62.11.1755. PMID 16286551. 
  13. ^ Chuh, A; Chan, H; Zawar, V (2004). "Pityriasis rosea--evidence for and against an infectious aetiology". Epidemiology and Infection 132 (3): 381–390. doi:10.1017/S0950268804002304. PMC 2870116. PMID 15188706. 
  14. ^ Chiu, H-H; Lee, C-Y; Lee, P-I; Lin, K-H; Huang, L-M (1998). "Mononucleosis syndrome and coincidental human herpesvirus-7 and Epstein-Barr virus infection". Archives of Disease in Childhood (BMJ Group) 78 (5): 479–480. doi:10.1136/adc.78.5.479. PMC 1717555. PMID 9659100. 
  15. ^ Klussmann, J. P.; Krueger, E.; Sloots, T.; Berneman, Z.; Arnold, G.; Krueger, G. R. F. (1997). "Ultrastructural study of human herpesvirus-7 replication in tissue culture". Virchows Archiv (SpringerLink) 430 (5): 417–426. doi:10.1007/s004280050051. PMID 9174632. 
  16. ^ Nicholas, John (September 1996). "Determination and analysis of the complete nucleotide sequence of human herpesvirus 7" (PDF). Journal of Virology 70 (9): 5975–5989. PMC 190618. PMID 8709220. 
  17. ^ Katsafanas, GC; Schirmer, EC; Wyatt, LS; Frenkel, N (1996). "In vitro activation of human herpesviruses 6 and 7 from latency" (PDF). Proceedings of the National Academy of Sciences of the United States of America 93 (18): 9788–92. Bibcode:1996PNAS...93.9788K. doi:10.1073/pnas.93.18.9788. PMC 38507. PMID 8790409. 
  18. ^ Berneman, ZN; Ablashi, DV; Li, G; Eger-Fletcher, M; Reitz Jr, MS; Hung, CL; Brus, I; Komaroff, AL; Gallo, RC (1992). "Human herpesvirus 7 is a T-lymphotropic virus and is related to, but significantly different from, human herpesvirus 6 and human cytomegalovirus". Proceedings of the National Academy of Sciences of the United States of America 89 (21): 10552–10556. Bibcode:1992PNAS...8910552B. doi:10.1073/pnas.89.21.10552. PMC 50377. PMID 1332051. ; Mirandola, P; Secchiero, P; Pierpaoli, S; Visani, G; Zamai, L; Vitale, M; Capitani, S; Zauli, G (2000). "Infection of CD34(+) hematopoietic progenitor cells by human herpesvirus 7 (HHV-7)". Blood 96 (1): 126–131. PMID 10891440. ; Yasukawa, M; Inoue, Y; Ohminami, H; Sada, E; Miyake, K; Tohyama, T; Shimada, T; Fujita, S (1997). "Human herpesvirus 7 infection of lymphoid and myeloid cell lines transduced with an adenovirus vector containing the CD4 gene". Journal of Virology 71 (2): 1708–1712. PMC 191236. PMID 8995705. 
  19. ^ Secchiero, P; Sun, D; De Vico, AL; Crowley, RW; Reitz Jr, MS; Zauli, G; Lusso, P; Gallo, RC (1997). "Role of the extracellular domain of human herpesvirus 7 glycoprotein B in virus binding to cell surface heparan sulfate proteoglycans". Journal of Cirology 71 (6): 4571–80. PMC 191679. PMID 9151851. 
  20. ^ Hall, CB (1997). "Human Herpesviruses at Sixes, Sevens, and More (editorial)". Annals of Internal Medicine (American College of Physicians) 127 (6): 481–3. doi:10.1059/0003-4819-127-6-199709150-00010 (inactive 2014-03-22). PMID 9313006. 
  21. ^ Lusso, P; Secchiero, P; Crowley, RW; Garzino-Demo, A; Berneman, ZN; Gallo, RC (1994). "CD4 is a critical component of the receptor for human herpesvirus 7: interference with human immunodeficiency virus". Proceedings of the National Academy of Sciences of the United States of America 91 (9): 3872–6. Bibcode:1994PNAS...91.3872L. doi:10.1073/pnas.91.9.3872. PMC 43684. PMID 7909607. 
  22. ^ Tanaka-Taya, K; Kondo, T; Nakagawa, N; Inagi, R; Miyoshi, H; Sunagawa, T; Okada, S; Yamanishi, K (2000). "Reactivation of human herpesvirus 6 by infection of human herpesvirus 7". Journal of Medical Virology (Wiley InterScience) 60 (3): 284–9. doi:10.1002/(SICI)1096-9071(200003)60:3<284::AID-JMV6>3.0.CO;2-8. PMID 10630960. 
  23. ^ Secchiero, P; Berneman, ZN; Gallo, RC; Lusso, P (1994). "Biological and molecular characteristics of human herpesvirus 7: in vitro growth optimization and development of a syncytia inhibition test". Virology 202 (1): 506–12. doi:10.1006/viro.1994.1371. PMID 8009865. ; Frenkel, N; Schirmer, EC; Wyatt, LS; Katsafanas, G; Roffman, E; Danovich, RM; June, CH (1990). "Isolation of a new herpesvirus from human CD4+ T cells". Proceedings of the National Academy of Sciences of the United States of America 87 (2): 748–52. Bibcode:1990PNAS...87..748F. doi:10.1073/pnas.87.2.748. PMC 53343. PMID 2153965. 
  24. ^ Secchiero, P; Flamand, L; Gibellini, D; Falcieri, E; Robuffo, I; Capitani, S; Gallo, RC; Zauli, G (1997). "Human Herpesvirus 7 induces CD4(+) T-cell death by two distinct mechanisms: necrotic lysis in productively infected cells and apoptosis in uninfected or nonproductively infected cells". Blood 90 (11): 4502–12. PMID 9373261. 
  25. ^ Menegazzi, P; Galvan, M; Rotola, A; Ravaioli, T; Gonelli, A; Cassai, E; Di Luca, D (1999). "Temporal mapping of transcripts in human herpesvirus-7". Journal of General Virology 80 (10): 2705–12. PMID 10573164. 
  26. ^ Atedzoe, BN; Menezes, J; D'Addario, M; Xu, J; Ongradi, J; Ahmad, A (1999). "Modulatory effects of human herpes virus-7 on cytokine synthesis and cell proliferation in human peripheral blood mononuclear cell cultures". Journal of Leukocyte Biology 66 (5): 822–8. PMID 10577515. ; Atedzoe, BN; Ahmad, A; Menezes, J (1997). "Enhancement of natural killer cell cytotoxicity by the human herpesvirus-7 via IL-15 induction". Journal of Immunology 159 (10): 4966–72. PMID 9366423. 
  27. ^ "Other Herpesviruses: HHV-6, HHV-7, HHV-8, HSV-1 and -2, VZV". American Journal of Transplantation (Blackwell Munksgaard). 4 Suppl 10: 66–71. 2004. doi:10.1111/j.1600-6135.2004.00697.x. PMID 15504215. 
  28. ^ Yoshikawa, Tetsushi; Ihira, Masaru; Akimoto, Shiho; Usui, Chie; Miyake, Fumi; Suga, Sadao; Enomoto, Yoshihiko; Suzuki, Ryota et al. (March 2004). "Detection of Human Herpesvirus 7 DNA by Loop-Mediated Isothermal Amplification". Journal of Clinical Microbiology 42 (3): 1348–1352. doi:10.1128/JCM.42.3.1348-1352.2004. PMC 356854. PMID 15004116. 
  29. ^ Clark, D. A; Kidd, I M.; Collingham, K. E; Tarlow, M.; Ayeni, T.; Riordan, A.; Griffiths, P. D; Emery, V. C; Pillay, D. (1997). "Diagnosis of primary human herpesvirus 6 and 7 infections in febrile infants by polymerase chain reaction". Archives of Disease in Childhood 77 (1): 42–45. doi:10.1136/adc.77.1.42. PMC 1717251. PMID 9279150. 
  30. ^ Clark, DA; Freeland, ML; MacKie, LK; Jarrett, RF; Onions, DE (1993). "Prevalence of antibody to human herpesvirus 7 by age". The Journal of Infectious Diseases (University of Chicago Press) 168 (1): 251–2. doi:10.1093/infdis/168.1.251. PMID 8390545. 
  31. ^ Cermelli, C; Fabio, G; Montorsi, M; Sabbatini, AM; Portolani, M (1996). "Prevalence of antibodies to human herpesviruses 6 and 7 in early infancy and age at primary infection". New Microbiologica 19 (1): 1–8. PMID 8673847. 
  32. ^ Yoshikawa, T (2003). "Human Herpesvirus-6 and -7 Infections in Transplantation". Pediatric Transplantation 7 (1): 11–17. doi:10.1034/j.1399-3046.2003.02094.x. PMID 12581322. 

Further reading[edit]