Human herpesvirus 7
|Human herpesvirus 7|
|Classification and external resources|
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). HHV-7 often acts together with HHV-6, and the viruses together are sometimes referred to by their genus, Roseolovirus. HHV-7 was first isolated in 1990 from CD4+ T cells taken from peripheral blood lymphocytes.
Signs and symptoms
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. 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, and febrile seizures, though most often no symptoms present at all.
There are indications that HHV-7 can contribute to the development of drug-induced hypersensitivity syndrome, encephalopathy, hemiconvulsion-hemiplegia-epilepsy syndrome, hepatitis infection, postinfectious myeloradiculoneuropathy, pityriasis rosea, and the reactivation of HHV-4, leading to "mononucleosis-like illness".
Complications with HHV-7 infection has been shown to be a factor in a great variety of transplant types.
A mature virus particle measures about 170 nanometres (1,700 Å) in diameter.
The genome of HHV-7 is very similar to that of HHV-6, although it is about 10% smaller, with a DNA genome of about 145,000 base pairs. 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.
HHV-7 resides mostly in CD4+ T cells, albeit only in certain strains of them. To enter CD4+ T cells, HHV-7, unlike HHV-6, uses CD4 and possibly some cell-surface glyoproteins to enter CD4+ T cells. About a week after HHV-7 has infected a cell, it begins to downregulate CD4 transcription, which interferes with HIV-1 infection but may reactivate HHV-6 infection. It is however unclear exactly what effect HHV-7 has on HIV infection.
HHV-7 also has a number of other effects on cells. Among these include membrane leaking, the presence of lityic syncytia, occasional apoptosis, the supporting of latent infection, and increases and decreases in levels of certain cytokines.
Detection and treatment
In adults, the effects of HHV-7 separate from HHV-6 have not been well-researched. 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. No reliable serological test has been developed yet for HHV-7 alone, but multiple are in the process of being developed. The use of PCR assays to test for HHV-7 is also being explored.
No treatment for HHV-7 infection exists, but no clinical situation where such treatment would be useful has yet been discovered.
Over 95% of adults have been infected and are immune to HHV-7, and over three quarters of those were infected before the age of six. 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.
- "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.
- 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.
- 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.
- 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.
- 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.
- 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.
- Tremblay, Cecile (January 2, 2008). Hirsch, Martin S; McGovern, Barbara H, eds. "Human herpesvirus 7 infection". UpToDate.
- 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.
- 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. PMID 10102435.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- "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.
- 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.
- 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.
- 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.
- 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.
- 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.
- Caselli, E; Di Luca, D (2007). "Molecular Biology and Clinical Associations of Roseoloviruses Human Herpesvirus 6 and Human Herpesvirus 7". New Microbiologica 30 (3): 173–187. PMID 17802896.
- Dewhurst, S (2004). "Human Herpesvirus Type 6 and Human Herpesvirus Type 7 Infections of the Central Nervous System". Herpes: the Journal of the IHMF. 11 Suppl 2: 105A–111A. PMID 15319097.
- Kempf, W (2002). "Human Herpesvirus 7 in Dermatology: What Role Does It Play?". American Journal of Clinical Dermatology 3 (5): 309–315. PMID 12069636.
- De Araujo, T; Berman, B; Weinstein, A (2002). "Human Herpesviruses 6 and 7". Dermatologic Clinics 20 (2): 301–306. doi:10.1016/S0733-8635(01)00008-0. PMID 12120443.
- Jackson, MA; Sommerauer, JF (2002). "Human Herpesviruses 6 and 7". The Pediatric Infectious Disease Journal 21 (6): 565–566. doi:10.1097/00006454-200206000-00016. PMID 12182383.
- Clark, DA (2002). "Human Herpesvirus 6 and Human Herpesvirus 7: Emerging Pathogens in Transplant Patients". International Journal of Hematology. 76 Suppl 2: 246–252. PMID 12430932.