Subtypes of HIV

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Human immunodeficiency virus
Phylogenetic Tree of the SIV and HIV viruses.
Phylogenetic Tree of the SIV and HIV viruses.
Virus classification
Group: Group VI (ssRNA-RT)
Family: Retroviridae
Genus: Lentivirus
Species
  • Human immunodeficiency virus 1
  • Human immunodeficiency virus 2
International Statistical Classification of Diseases and Related Health Problems Codes
Classification and external resources
ICD-10 B20-B24
ICD-9 042-044

One of the obstacles to treatment of the Human Immunodeficiency Virus is its high genetic variability.[1] These subtypes are sometimes more virulent or are resistant to different medications.

Contents

[edit] Major Subtypes

[edit] HIV 1

HIV 1 includes the most common strains of the virus, and it is further subdivided into three groups called M, N, and O.

Group M

This is the most common type of HIV, with more than 90% of HIV cases being HIV-1 group M. It is subdivided further into clades that are also given a letter. This is further complicated due to changes in the virus during the course of infection, and many cases are given a "circulating recombinant form" or CRF which is given two letters. CRF A/C, for example, is a combination of subtypes A and C.

  • Subtype A is common in West Africa.[2]
  • Subtype B is the dominant form in Europe, the Americas, Japan, Thailand, and Australia. [3]
  • Subtype C is the dominant form in Southern and Eastern Africa, India, and Nepal.[3]
  • Subtype D is generally only seen in Eastern and central Africa.[3]
  • (Subtype E) has never been purified, and is always seen combined with subtype A as CRF A/E.[3]
  • Subtype F has been found in central Africa, South America and Eastern Europe. [4]
  • Subtype G (and the CRF A/G) have been found in Africa and central Europe.[4]
  • Subtype H is limited to central Africa.[4]
  • (Subtype I) was originally used to describe a strain that is now accounted for as a combination of other subtypes.[citation needed]
  • Subtype J is limited to Central America[4]
  • Subtype K is limited to the Democratic Republic of Congo and Cameroon. [4]

These subtypes are sometimes further split into groups such as A1 or F2.[citation needed] This is not thought to be a complete or final list, and further types will likely be found.[5]

HIV-1 subtype prevalence in 2002
HIV-1 subtype prevalence in 2002
Group N

This group, discovered in 1998[citation needed], has only been seen in Cameroon and is extremely rare.[citation needed]

Group O

This strain is not usually seen outside of West-central Africa and is very rare. It caused some concern because it could not be detected by standard test kits, though more advanced HIV tests will detect it and group N.[6]

[edit] HIV 2

Like Group N and Group O, HIV-2 has not been widely seen outside of Africa. The first case in the United States was in 1987[7]. Many test kits for HIV-1 will also detect HIV-2[8].

[edit] References

  1. ^ Robertson DL, Hahn BH, Sharp PM (March 1995). "Recombination in AIDS viruses". J. Mol. Evol. 40 (3): 249–59. PMID 7723052. 
  2. ^ Bobkov AF, Kazennova EV, Selimova LM, et al (October 2004). "Temporal trends in the HIV-1 epidemic in Russia: predominance of subtype A". J. Med. Virol. 74 (2): 191–6. doi:10.1002/jmv.20177. PMID 15332265. 
  3. ^ a b c d Goudsmit, Jaap. Viral Sex; The Nature of AIDS. Oxford University Press. New York, New York, 1997. Pg. 51-58. Retrieved May 25, 2008.
  4. ^ a b c d e [1] Introduction to HIV types, groups and subtypes. March 3, 2008. Retrieved May 25, 2008.
  5. ^ HIV types, subtypes, groups & strains
  6. ^ http://www.abbottmolecular.com/PDF/E0608633_RealTimeHIV_rev.pdf
  7. ^ HIV-2
  8. ^ CBER - Donor Screening Assays for Infectious Agents and HIV Diagnostic Assays

[edit] External links