Viral hepatitis

Source: Wikipedia, the free encyclopedia.
Viral hepatitis
chronic hepatitis B infections (a type of viral hepatitis), and represent accumulations of viral antigen in the endoplasmic reticulum. H&E stain.
SpecialtyInfectious diseases, gastroenterology Edit this on Wikidata

Viral hepatitis is

viral infection.[1][2] It may present in acute form as a recent infection with relatively rapid onset, or in chronic form, typically progressing from a long-lasting asymptomatic condition up to a decompensated hepatic disease and hepatocellular carcinoma (HCC).[3]

The most common causes of viral hepatitis are the five unrelated hepatotropic viruses

herpes simplex virus.[4]

Mode of transmission

Viral hepatitis is either transmitted through contaminated food or water (A, E) or via blood and body fluids (B, C). The viruses transmitted through water and food are mostly self-limited, resulting in acute illness with full resolution. The blood borne viruses (B, C) can cause both acute and chronic liver disease and can be transmitted from mother to child during birth, through contact with body fluids during sex, unsafe injections and through unscreened blood transfusions.[5]

The most common types of hepatitis can be prevented or treated.[6] Hepatitis A and hepatitis B can be prevented by vaccination. Effective treatments for hepatitis C are available but costly.[6]

In 2013, about 1.5 million people died from viral hepatitis, most commonly due to hepatitis B and C.[6] East Asia, in particular Mongolia, is the region most affected.[6]

Hepatitis viruses

The most common cause of hepatitis is viral. Although the effects of various viruses are all classified under the disease hepatitis, these viruses are not all related.[citation needed]

Hepatitis viruses
Hepatitis A virus (HAV) Hepatitis B virus (HBV) Hepatitis C virus (HCV) Hepatitis D virus (HDV) Hepatitis E virus (HEV)
Viral species
Hepatovirus A
 Hepatitis B virus Hepacivirus C
Hepatitis delta virus
Orthohepevirus A
Viral family
Picornaviridae
 		Hepadnaviridae Flaviviridae Incertae sedis Hepeviridae
Genome
(+)ssRNA
dsDNA-RT
(+)ssRNA
(−)ssRNA
(+)ssRNA
Antigens HBsAg, HBeAg Core antigen Delta antigen
Transmission
Enteral
Parenteral
 Parenteral Parenteral Enteral
Incubation period 20–40 days 45–160 days 15–150 days 30–60 days 15–60 days
Severity/Chronicity[7] Mild; acute Occasionally severe; 5–10% chronic Subclinical; 70% chronic Exacerbates symptoms of HBV; chronic with HBV Mild in normal patients; severe in pregnant women; acute
Vaccine 2 injections; at least 20 years of protection[8] 3 injections; lifetime protection None available None available, but not considered necessary; Hep B vaccine provides protection[9] Investigational (approved in China)

Viral hepatitis types

Hepatitis A

Main article: Hepatitis A

Hepatitis A or

relapsing symptoms from six months to a year following initial diagnosis.[11]

Hepatitis A[12]
Marker Detection Time Description Significance
Faecal HAV 2–4 weeks or 28 days – Early detection
Ig M anti HAV 4–12 weeks Enzyme immunoassay for antibodies During acute Illness
Ig G anti HAV 5 weeks–persistent Enzyme immunoassay for antibodies Old infection or reinfection

Hepatitis B

Main article: Hepatitis B

Hepatitis B is caused by the hepatitis B virus, a

Needle-exchange programmes have been created in many countries as a form of prevention.[citation needed
]

Patients with chronic hepatitis B have antibodies against the virus, but not enough to clear the infected

alpha-interferon, pegylated interferon, adefovir, entecavir, telbivudine, lamivudine, tenofovir disoproxil and tenofovir alafenamide with a 65% rate of sustained response.[citation needed
]

Hepatitis C

Main article: Hepatitis C

Hepatitis C (originally "non-A non-B hepatitis") is caused by hepatitis C virus (HCV), an RNA virus of the family Flaviviridae. HCV can be transmitted through contact with blood (including through sexual contact if the two parties' blood is mixed) and can also cross the placenta. Hepatitis C usually leads to chronic hepatitis, culminating in cirrhosis in some people. It usually remains asymptomatic for decades. Patients with hepatitis C are susceptible to severe hepatitis if they contract either hepatitis A or B, so all persons with hepatitis C should be immunized against hepatitis A and hepatitis B if they are not already immune, and avoid alcohol. HCV can lead to the development of hepatocellular carcinoma, however, only a minority of HCV-infected individuals develop cancer (1–4% annually), suggesting a complex interplay between viral gene expression and host and environmental factors to promote carcinogenesis. The risk is increased two-fold with active HBV coinfection and a 21% increase in mortality compared to those with latent HBV and HCV.[13] HCV viral levels can be reduced to undetectable levels by a combination of interferon and the antiviral drug ribavirin. The genotype of the virus is the primary determinant of the rate of response to this treatment regimen, with genotype 1 being the most resistant.[citation needed]

Hepatitis C is the most common chronic

bloodborne infection in the United States, and the leading cause of liver tranplants.[14]

Hepatitis C[15]
Marker Detection Time Description Significance Note
HCV-RNA 1–3 weeks or 21 days PCR Demonstrates presence or absence of virus Results may be intermittent during course of infection. Negative result is not indicative of absence.
anti-HCV 5–6 weeks Enzyme Immunoassay for antibodies Demonstrates past or present infection High false positive in those with autoimmune disorders and populations with low virus prevalence.
ALT 5–6 weeks – Peak in ALT coincides with peak in anti-HCV Fluctuating ALT levels is an indication of active liver disease.

Hepatitis D

Main article: Hepatitis D

Hepatitis D is caused by the hepatitis D virus (HDV), or hepatitis delta virus; it belongs to the genus Deltavirus. HDV is similar to a

satellite virus as it can only propagate in the presence of the hepatitis B virus, depending on the helper function of HBV for its replication and expression. It has no independent life cycle, but can survive and replicate as long as HBV infection persists in the host body. It can only cause infection when encapsulated by hepatitis B virus surface antigens. The vaccine for hepatitis B protects against hepatitis D virus because of the latter's dependence on the presence of hepatitis B virus for it to replicate.[9][16]

Hepatitis E

Main article: Hepatitis E

Hepatitis E is caused by the Hepatitis E virus (HEV), from the family Hepeviridae. It produces symptoms similar to hepatitis A, although it can take a fulminant course in some patients, particularly pregnant women (mortality rate about 20%); chronic infections may occur in immune-compromised patients. It is more prevalent in the Indian subcontinent. The virus is feco-orally transmitted and is usually self-limited.[citation needed]

Hepatitis F virus

Main article:
Hepatitis F

Hepatitis F virus (HFV) is a hypothetical virus linked to certain cases of hepatitis. Several hepatitis F virus candidates emerged in the 1990s, but none of these reports have been substantiated.[citation needed]

GB virus C

Main article: GB virus C

The GB virus C is a virus that is probably spread by blood and sexual contact.[17] It was initially identified as Hepatitis G virus.[18] There is very little evidence that this virus causes hepatitis, as it does not appear to replicate primarily in the liver.[19] It is now classified as GB virus C.[20]

2022 hepatitis of unknown origin

Main article: 2022 hepatitis of unknown origin in children

In 2022, several hundred cases of acute hepatitis of probable infectious origin were reported worldwide.

adenovirus is suspected.[23][24]

Relationship between hepatitis C virus and liver cancer

Hepatitis C virus (HCV) can cause acute and chronic infections that are a major cause of hepatocellular carcinoma (HCC), advanced hepatic fibrosis and cirrhosis.[citation needed]

HCC is a major cause of death in patients with chronic HCV infection. Regarding the pathogenesis of HCC associated with HCV, that virus may play direct or indirect roles.[25]

A major risk for the development of HCC is persistent infection with HCV, and the highest risk for HCC development is associated with co-infection of HBV with HDV, HCV or HIV.[26]

Risk factors that can lead to the development of HCC in those with chronic HCV include synchronous liver diseases, viral genotype, diabetes mellitus, and obesity. Lifestyle factors such as liver steatosis, smoking, and alcohol use can accelerate progression to HCC and liver decompensation in patients with HCV.[3]

The purpose of HCV treatment is to eliminate the infection, reduce the transmission to other people and decrease the risk of HCC development.[3]

Other viruses

The virus first known to cause hepatitis was the

yellow fever virus, a mosquito-borne flavivirus
. Other viruses than can cause hepatitis include:

Additionally, a casual role between the virus

alanine transferases without other known cause.[35]

References

  1. ^ "National Library of Medicine » Medical Subject Headings »Virus Diseases (C02) » Hepatitis, Viral, Human (C02.440) » Scope Note".
  2. ^ "Hepatitis | MedlinePlus". Retrieved 2017-06-23.
  3. ^
    PMID 22164334
    .
  4. PMID 32148514
    .
  5. ^ "Hepatitis B". World Health Organization. Retrieved 5 October 2021."Hepatitis C". World Health Organization. Retrieved 5 October 2021.
  6. ^
    PMID 27394647
    .
  7. ^ Kuo, Infectious Causes of Jaundice, ATSU School of Osteopathic Medicine Arizona, June 2012
  8. ^ "Hepatitis a Q&As for Health Professionals | CDC". 9 April 2021.
  9. ^
    ISBN 978-0-12-375147-8
    .
  10. ^ "CDC Hepatitis A FAQ". Retrieved 2008-03-03.
  11. ^ "CDC Hepatitis A Fact Sheet". Retrieved 2008-03-03.
  12. ^ "AccessMedicine – Internal Medicine Clinical Resource". accessmedicine.mhmedical.com.
  13. PMID 28893941
    .
  14. ^ "Hepatitis C, The Disease, Epidemiology, Treatment, Eradication Part 3: United States Epidemiology". Forbes. Retrieved 2023-05-26.
  15. ^ "WHO | Hepatitis C". Who.int. 2010-12-08. Retrieved 2012-08-26.
  16. ^ "U.S. National Library of Medicine "Delta Agent (hepatitis D)"".
  17. PMID 8940225
    .
  18. S2CID 12931655
    .
  19. PMID 9500722
    .
  20. ^ "00.026. Flaviviridae". ICTVdB Index of Viruses. Archived from the original on 2008-05-11. Retrieved 2008-08-09.
  21. ^ "Joint ECDC-WHO Regional Office for Europe Hepatitis of Unknown Origin in Children Surveillance Bulletin". cdn.ecdc.europa.eu. Archived from the original on 14 May 2022. Retrieved 14 May 2022.
  22. ^ "Multi-Country – Acute, severe hepatitis of unknown origin in children". www.who.int. Archived from the original on 24 April 2022. Retrieved 24 April 2022.
  23. ^ Adenovirus probable cause of mysterious child hepatitis. BBC News, 25 April 2022. Retrieved 25 April 2022.
  24. ^ "Investigation into acute hepatitis of unknown aetiology in children in England: case update". UK Health Security Agency. 23 May 2023.
  25. PMID 20300384
    .
  26. PMID 28893941
    .
  27. PMID 2164704
    .
  28. PMID 14767982
    .
  29. PMID 9606764
    .
  30. PMID 21322282
    .
  31. S2CID 38640928
    .
  32. PMID 8092915
    .
  33. PMID 21279280
    .
  34. PMID 21951624
    .
  35. S2CID 22339362
    .

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Viral_hepatitis&oldid=1218226958"