Human T-lymphotropic virus 2
Species of virus
Human T-lymphotropic virus 2 | |
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Specialty | Infectious diseases |
Symptoms | Mild cognitive Impairment, Mycosis fungoides |
Duration | Chronic, incurable |
Causes | HTLV-2 |
Risk factors | Unsafe sex, haemophiliacs |
Diagnostic method | Blood test |
Differential diagnosis | HIV/AIDS, Lymphoma, HTLV-1 |
Prevention | Practicing safe-sex, use of clean needles, screening blood transfusions, Avoiding breastfeeding. |
Medication | Antiretrovirals, chemotherapy |
Prognosis | 95% present with no symptoms, generally good |
Frequency | 15-20 million people worldwide |
Primate T-lymphotropic virus 2 | |
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Virus classification
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(unranked): | Virus |
Realm : | Riboviria |
Kingdom: | Pararnavirae |
Phylum: | Artverviricota |
Class: | Revtraviricetes |
Order: | Ortervirales |
Family: | Retroviridae |
Genus: | Deltaretrovirus |
Species: |
Primate T-lymphotropic virus 2
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A virus closely related to HTLV-I , human T-lymphotropic virus 2 ( HTLV-II ) shares approximately 70% genomic homology (structural similarity) with HTLV-I. It was discovered by Robert Gallo and colleagues. [1] [2]
HTLV-2 is prevalent among the indigenous populations in Africa and the Indian-American tribes in Central and South America as well as among drug users in Europe and North America [3] It can be passed down from mother to child through breastmilk and genetically as well from either parent.
HTLV-II entry in target cells is mediated by the glucose transporter GLUT1 . [4]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/f/f4/HTLV_Phylogeny.jpg/220px-HTLV_Phylogeny.jpg)
Virology
HTLV-1 and HTLV-2 share broad similarities in their overall genetic organization and expression pattern, but they differ substantially in their pathogenic properties. [3] The virus utilizes the GLUT-1 and NRP1 cellular receptors for their entry, although HTLV-1 , but not HTLV-2, is dependent on heparan sulfate proteoglycans . Cell-to-cell transmission is essential for virus replication and occurs through the formation of a virological synapse . [3] The family of Human T-lymphotropic virus (Figure 2) can be further categorized into four sub types. The figure also divides the retroviruses into exogenous and endogenous. Retroviruses can exist as two different forms: endogenous which consist of normal genetic components and exogenous which are horizontally transferred genetic components that are usually infectious agents that cause disease i.e. HIV . In (Figure 3) open reading frames (ORF) are shown which can if translated can predict which genes will be present and this can help to better understand human retroviruses . Of the four subtypes, HTLV-2 may be linked to Cutaneous T-cell lymphoma (CTCL). [5] In one study involving cultured lymphocytes from patients with mycosis fungoides (Figure 1), PCR amplification showed gene sequences of HTLV-II. This finding may suggest a possible correlation with HTLV-2 and CTCL. Further research and studies must be conducted to show a positive relationship. [1]
Transmission
Perinatal transmission and breastfeeding and through blood transfusion , sexual contact, and use of intravenous drugs. [3]
Epidemiology
HTLV-1 and HTLV-2 are both involved in actively spreading epidemics , affecting 15-20 million people worldwide. [4] In the United States , the overall prevalence is 22 per 100,000 population, with HTLV-2 more common than HTLV-1 . Data collection performed from 2000 to 2009 among US blood donors has shown a general decline since the 1990s. [6]
Symptoms
Human T- leukemia, type 2 (HTLV-2) generally causes no signs or symptoms . Although HTLV-2 has not been definitively linked with any specific health problems , scientists suspect that some affected people may later develop neurological problems such as: [7] [6]
- Sensory neuropathies (conditions that affect the nerves that provide feeling)
- Gait abnormalities
- Bladder dysfunction
- Mild cognitive impairment
- Motor abnormalities (loss of or limited muscle control or movement, or limited mobility)
- Erectile dysfunction
- Mycosis fungoides
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Neck_of_a_woman_suffering_from_mycosis_fungoides_of_the_skin_Wellcome_L0061976.jpg/220px-Neck_of_a_woman_suffering_from_mycosis_fungoides_of_the_skin_Wellcome_L0061976.jpg)
Although evidence is limited, there may also be a link between HTLV-2 and chronic lung infections (i.e. pneumonia and bronchitis ), asthma and dermatitis . [8]
Clinical significance
HTLV-II has not been clearly linked to any disease, but has been associated with several cases of myelopathy /tropical spastic paraparesis ( HAM/TSP )- like neurological disease and may cause chronic lung problems. [ citation needed ]
An impact on platelet count has been observed. [9]
In the 1980s, HTLV-2 was identified in a patient with an unidentified T cell lymphoproliferative disease that was described as having characteristics similar to the B cell disorder , hairy cell leukemia . [10] HTLV-2 was identified in a second patient with a T cell lymphoproliferative disease; this patient later developed hairy cell leukemia , but HTLV-2 was not found in the hairy cell clones. [11] The cause of hairy cell leukemia is not known, but it is no longer believed to be related to viral infections . [ citation needed ]
Treatment
There are few treatments [12] including chemotherapy and antiretrovirals that can slow the viral load but no cure or definitive treatment exists for HTLV-2. [8]
Diagnosis
Human T- leukemia, type 2 (HTLV-2) is usually diagnosed based on blood tests that detect to the virus. However, HTLV-2 is often never suspected or diagnosed since most people never develop any signs or symptoms of the infection . Diagnosis may occur during for blood donation , testing performed due to an infection , or a work-up for an HTLV-2-associated medical problems. [8]
Prevention
Due to there being no cure for HTLV II the prevention is focused on early detection and preventing the spread of HTLV-2 to others. blood donors, promoting safe sex and discouraging needle sharing can decrease the number of new infections. Mother-to-child transmission can be reduced by screening pregnant women so infected mothers can avoid breastfeeding . [8]
Prognosis
The long-term outlook for most people infected with HTLV-2 is good. Infection with HTLV-2 is lifelong , but 95% of affected people have no signs or symptoms of the condition . Although, HTLV-2-related health problems tend to be significantly milder than those associated with HTLV1 . [8]
References
- 1 2 Geskin, Larisa J.; Pomerantz, Rebecca G.; Mirvish, Ezra D. (2011-02-01). "Infectious agents in cutaneous T-cell lymphoma" . Journal of the American Academy of Dermatology . 64 (2): 423–431. doi : 10.1016/j.jaad.2009.11.692 . ISSN 0190-9622 . PMC 3954537 . PMID 20692726 .
- ↑ "Robert gallo discovers htlv2 and 1" . Retrieved 23 February 2019 .
- 1 2 3 4 Ciminale, Vincenzo; Rende, Francesca; Bertazzoni, Umberto; Romanelli, Maria G. (2014-07-29). "HTLV-1 and HTLV-2: highly similar viruses with distinct oncogenic properties" . Frontiers in Microbiology . 5 : 398. doi : 10.3389/fmicb.2014.00398 . ISSN 1664-302X . PMC 4114287 . PMID 25120538 .
- ↑ Manel N, Kim FJ, Kinet S, Taylor N, Sitbon M, Battini JL (November 2003). "The ubiquitous glucose transporter GLUT-1 is a receptor for HTLV" . Cell . 115 (4): 449–59. doi : 10.1016/S0092-8674(03)00881-X . PMID 14622599 .
- 1 2 "Journal of the American Academy of Dermatology" . www.jaad.org . Retrieved 2019-02-22 .
- 1 2 "Human T-Cell Lymphotropic Viruses (HTLV)" . Medscape . Retrieved 22 February 2019 .
- ↑ "HTLV Type I and Type II" . NORD (National Organization for Rare Disorders) . Retrieved 2019-02-22 .
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"Human T-cell leukemia virus type 2"
. US Department of Health and Human Services | Genetic and Rare Diseases Information Center (GARD) – an NCATS Program
. Retrieved
2019-02-22
.
This article incorporates text from this source, which is in the public domain .
- ↑ Bartman MT, Kaidarova Z, Hirschkorn D, et al. (November 2008). "Long-term increases in lymphocytes and platelets in human T-lymphotropic virus type II infection" . Blood . 112 (10): 3995–4002. doi : 10.1182/blood-2008-05-155960 . PMC 2581993 . PMID 18755983 .
- ↑ Kalyanaraman VS, Sarngadharan MG, Robert-Guroff M, Miyoshi I, Golde D, Gallo RC (November 1982). "A new subtype of human T-cell leukemia virus (HTLV-II) associated with a T-cell variant of hairy cell leukemia". Science . 218 (4572): 571–3. Bibcode : 1982Sci...218..571K . doi : 10.1126/science.6981847 . PMID 6981847 .
- ↑ Rosenblatt JD, Giorgi JV, Golde DW, et al. (February 1988). "Integrated human T-cell leukemia virus II genome in CD8 + T cells from a patient with "atypical" hairy cell leukemia: evidence for distinct T and B cell lymphoproliferative disorders" . Blood . 71 (2): 363–9. doi : 10.1182/blood.V71.2.363.363 . PMID 2827811 . Retrieved 10 July 2020 .
- ↑ Gotuzzo, Eduardo; Vanham, Guido; Vandamme, Anne-Mieke; Dooren, Sonia Van; González, Elsa; Verdonck, Kristien (2007-04-01). "Human T-lymphotropic virus 1: recent knowledge about an ancient infection" . The Lancet Infectious Diseases . 7 (4): 266–281. doi : 10.1016/S1473-3099(07)70081-6 . ISSN 1473-3099 . PMID 17376384 .
External links
- " Human T-lymphotropic virus 2 " . NCBI Taxonomy Browser . 11909.
- International Retrovirology Association
- Human+T-lymphotropic+virus+2 at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
Arthropod
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Mammal
-borne |
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Authority control
: National
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