HCV genotypes

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Hepatitis C virus (HCV) genotypes refer to the genetic variations that occurs in the hepatitis C virus. Hepatitis C is a contagious disease that primarily affects the liver, causing severe damage as the disease progresses.[1] It is caused by the Hepatitis C virus, a small, enveloped RNA virus. The transmission of hepatitis C is through the contact with the blood of the infected person, for example by sharing the needles or by using non-sterile medical equipment.[2] HCV is transmitted globally because of the high infection rate and is also associated with a high mortality rate.[3][4] The World Health Organisation indicates the 3.3% of the world population is infected by the HCV virus.[5] Statistical records show that there are about 13 million HCV affected persons in china, 3.5 million affected persons in the United States,[6] and about 10 million people are affected by HCV in Pakistan.[3] In all cases, the viral genotype of the HCV stays the same, occasionally mutations do occur making the treatment more complex by targeting the changes in the genotype.[7] Hepatitis C virus genotype is considered more common than the Hepatitis B virus infection contributing to more than a million cases annually[8] and is considered one of the major reason for liver transplantation in United States.[9] Some of the HCV genotypes may develop in people without symptoms leading to dangerous conditions like liver cirrhosis causing a permanent damage to liver and the unnoticed HCV conditions will affect brain, joints, blood vessels, bones, and kidneys.[10]

The complexity of the HCV genotypes made the treatment specific for the associated genotype. The treatment for the HCV genotype will also depends on the presence or absence of cirrhosis.[11] There are six major genotypes of hepatitis C virus which includes many subtypes.[12] The genotype can affect treatment of HCV infections.[3] Recent studies show that HCV genotypes consist of 7 genotypes and 67 subtypes.[13] All the genotypes and its subtypes affects the liver to the same extent of damage irrespective of the HCV genotype[7] Among the common six genotypes, genotype 1 is the most prevalent form in the United States of America,[14] covering around 70-90% of total infections. It is usually difficult to treat the people with HCV genotype 1.[citation needed] Genotype 2 and genotype 3 are less common contributing to around 10-20%.[14] Genotype 4 and 5 affects a large proportion of the population in undeveloped countries.[15] Genotype 4 is the most common type of infections in Middle east and Africa, around 80% of total infections.[16] About 15% of the people affected by HCV genotypes will get cured without medications, in which immune system plays a vital role in defeating the virus.[17] Until recently, there were no specific vaccines available for treating hepatitis C virus genotypes.[18] People traveling around different subcontinents where several HCV genotypes are common will have the possibility of resulting in mixed infection.[7]

Geographical distribution of HCV subtypes
HCV genotypes Subsets Geographical distribution[19]
Genotype 1 1a, 1b North America, Central Africa, Europe
Genotype 2 2a, 2b, 2c, 2d Western Africa
Genotype 3 3a, 3b, 3c, 3d, 3e, 3f Southeast Asia
Genotype 4 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j Central Africa
Genotype 5 5a South Africa and Asia
Genotype 6 6a Southeast Asia

Techniques[edit]

The Main techniques used to diagnose the HCV genotype are as follows:[16]

  • HCV ELISA (Enzyme-linked immunosorbent assay)
  • Quantitative HCV-RNA PCR (Hepatitis C virus-Ribonucleic acid Polymerase Chain reaction)
  • Recombinant immunoblot assay

References[edit]

  1. ^ Available at http://www.harvoni.com/education?gclid=CLfb7_vQvdICFY4kgQodKIoNYQ&gclsrc=aw.ds
  2. ^ Available at https://www.cdc.gov/hepatitis/hcv/
  3. ^ a b c Athar MA, Xu Y, Xie X, Xu Z, Ahmad V, Hayder Z, Hussain SS, Liao Y, Li Q (2015). "Rapid detection of HCV genotyping 1a, 1b, 2a, 3a, 3b and 6a in a single reaction using two-melting temperature codes by a real-time PCR-based assay". Journal of Virological Methods. 222: 85–90. doi:10.1016/j.jviromet.2015.05.013. PMID 26068393.
  4. ^ Teimourpour R, Tajani AS, Askari VR, Rostami S, Meshkat Z (2016). "Designing and Development of a DNA Vaccine Based On Structural Proteins of Hepatitis C Virus". Iranian Journal of Pathology. 11 (3): 222–230. PMC 5079455. PMID 27799971.
  5. ^ Lavanchy D (2009). "The global burden of hepatitis C". Liver International. 29 Suppl 1: 74–81. doi:10.1111/j.1478-3231.2008.01934.x. PMID 19207969.
  6. ^ Available at http://www.medicinenet.com/hepatitis_c/article.htm
  7. ^ a b c Treatment action group website. Available at http://www.treatmentactiongroup.org/hcv/factsheets/hcv-genotypes
  8. ^ Cooreman MP, Schoondermark-Van de Ven EM (1996). "Hepatitis C virus: biological and clinical consequences of genetic heterogeneity". Scandinavian Journal of Gastroenterology. Supplement. 218: 106–15. PMID 8865460.
  9. ^ Zein NN (2000). "Clinical significance of hepatitis C virus genotypes". Clinical Microbiology Reviews. 13 (2): 223–35. PMC 100152. PMID 10755999.
  10. ^ Website link for everyday life: http://www.everydayhealth.com/hs/hepatitis-c-living-well/dangers-untreated-hepatitis-c/
  11. ^ HEP website. Available at http://hepc.liverfoundation.org/treatment/the-basics-about-hepatitis-c-treatment/medication-regimens-according-to-genotype
  12. ^ http://www.hepatitiscentral.com/hepatitis-c/[full citation needed]
  13. ^ Smith DB, Bukh J, Kuiken C, Muerhoff AS, Rice CM, Stapleton JT, Simmonds P (2014). "Expanded classification of hepatitis C virus into 7 genotypes and 67 subtypes: updated criteria and genotype assignment web resource". Hepatology. 59 (1): 318–27. doi:10.1002/hep.26744. PMC 4063340. PMID 24115039.
  14. ^ a b http://hepatitis-c.emedtv.com/hepatitis-c/hepatitis-c-genotypes.html[full citation needed]
  15. ^ Messina JP, Humphreys I, Flaxman A, Brown A, Cooke GS, Pybus OG, Barnes E (2015). "Global distribution and prevalence of hepatitis C virus genotypes". Hepatology. 61 (1): 77–87. doi:10.1002/hep.27259. PMC 4303918. PMID 25069599.
  16. ^ a b Nouroz, Faisal; Shaheen, Sidra; Mujtaba, Ghulam; Noreen, Shumaila (2015). "An overview on hepatitis C virus genotypes and its control". Egyptian Journal of Medical Human Genetics. 16 (4): 291–8. doi:10.1016/j.ejmhg.2015.05.003.
  17. ^ Hepatitis central, available at http://www.hepatitiscentral.com/hepatitis-c/
  18. ^ Naderi M, Gholipour N, Zolfaghari MR, Moradi Binabaj M, Yegane Moghadam A, Motalleb G (2014). "Hepatitis C virus and vaccine development". International Journal of Molecular and Cellular Medicine. 3 (4): 207–15. PMC 4293608. PMID 25635247.
  19. ^ Yu CI, Chiang BL (2010). "A new insight into hepatitis C vaccine development". Journal of Biomedicine & Biotechnology. 2010: 548280. doi:10.1155/2010/548280. PMC 2896694. PMID 20625493.