Hepatitis viruses overview
Hepatitis is major cause of morbidity and mortality worldwide, particularly in the developing world. The major causes of infective hepatitis are hepatitis viruses A, B, C, D or E. In the acute phase, there are no clinical features that can reliably differentiate between these viruses. Infection may be asymptomatic or can present as jaundice, fevers, abdominal pain, fatigue or vomiting. An acute hepatitis infection can last days to months, but can also cause fulminant liver failure.
Some hepatitis virus infections become chronic, leading to cirrhosis and the development of hepatocellular carcinoma. The difficulty in finding and treating these patients is that chronic infection is often asymptomatic until these endpoints develop. Co-infection with different hepatitis viruses or with HIV tends to worsen the prognosis. Treatment decisions and regimes are complex and are beyond the scope of this summary. National hepatitis guidelines are currently in development.
World Hepatitis Day took place on 28th July 2014 to raise awareness of the disease and so in this article a table summarising the key features of hepatitis virus infections is presented in Table 1.
Table 1. Key features of hepatitis viruses [1, 2]
Hepatitis virus |
A |
B |
C |
D |
E |
|
Prevalence/incidence worldwide
|
1.4 million per year Epidemics
|
240 million with chronic hepatitis B (5-10% prevalence in Sub-Saharan Africa) |
130-150 million |
15 million |
20 million per year Epidemics |
|
Transmission
|
Faecal-oral via food/water |
Parenteral via body fluids |
Parenteral via blood, vertical transmission |
Parenteral via blood and sexual contact |
Faecal-oral via water, undercooked meat of an infected animal, blood transfusion |
|
Incubation
|
14-28 days |
30-180 days
|
2 weeks- 6 months |
3-7 weeks when infected simultaneously with hepatitis B. Shorter if superinfection of hepatitis D on chronic hepatitis B
|
3-8 weeks |
|
Duration of infection
|
Acute Self-limiting
|
Acute or chronic Spontaneous clearance is rare in perinatal/childhood infection, but 95% when infected in adulthood |
Acute or chronic Spontaneous clearance in 15-45% |
Acute or chronic Self-limiting in 95% when simultaneous infection with hepatitis B Chronic in 80% when superinfection on chronic hepatitis B |
Acute Self-limiting May become chronic in immunosuppressed |
|
Other disease features
|
Higher morbidity with age 90% infected before 10 years old in developing countries |
Assess for fibrosis |
Assess for fibrosis |
Requires co-infection with hepatitis B |
Higher morbidity if pregnant or co-existing liver disease Zoonotic reservoir |
|
When to test |
Acute hepatitic illness Epidemic |
Acute hepatitic illness Evidence of chronic liver disease High risk groups*/post exposure Pregnancy |
Acute hepatitic illness Evidence of chronic liver disease High risk groups/post exposure |
HBsAg positive patients Chronic hepatitis B with symptomatic/severe illness |
Acute hepatitic illness Epidemic |
|
Diagnostic tests |
HAV IgM and IgG or RT-PCR |
HBsAg in all Persistence > 6 months indicates chronic infection IgM to HBcAg in acute infection HBeAg denotes high infectivity |
Anti-HCV antibodies NAT to confirm current vs. past infection Genotyping if positive
|
Anti-HDV antibodies RT-PCR |
HEV IgM and IgG RT-PCR |
|
Prognosis |
Rarely fatal |
15-25% mortality from cirrhosis or hepatocellular carcinoma in chronic infection obtained in childhood |
15-30% develop cirrhosis within 20 years of infection Cure rates with treatment vary from 50-90% |
10 times higher mortality than hepatitis B alone Cirrhosis takes 5-10 years to develop |
20% mortality if pregnant |
|
Treatment
|
Supportive treatment |
Acute hepatitis B: Supportive treatment Chronic hepatitis B: IFN or antiviral nucleoside antagonists e.g. tenofovir, entecavir |
IFN and RBV and/or newer antivirals Choice depends on availability and genotype
|
No effective treatment Some help with IFN-α Liver transplant if fulminant |
Supportive treatment RBV if fulminant or chronic |
|
Prevention |
Water hygiene Sanitation |
Screening high risk groups, barrier contraception, blood donor screening, safe disposal/sterilization of sharps |
Screening high risk groups, blood donor screening, safe disposal/sterilization of sharps |
As for hepatitis B |
Water hygiene Sanitation Safe food preparation |
|
Vaccine availability
|
Yes Can be effective when given up to 2 weeks post exposure |
Yes Childhood vaccination programme recommended |
No |
No, but hepatitis B vaccine effective |
Yes, but not available globally |
*High risk groups include men who have sex with men, sexual partners of known infected individuals, individuals with multiple sexual partners, intravenous drug users, unscreened blood transfusion recipients, children of known infected mothers, high prevalence areas.
Glossary
HAV Hepatitis A virus
HBcAg Hepatitis B core antigen
HBeAg Hepatitis B envelope antigen
HBsAg Hepatitis B surface antigen
HBV Hepatitis B virus
HCV Hepatitis C virus
HDV Hepatitis D virus
HEV Hepatitis E virus
IFN Interferon
NAT Nucleic acid test
RBV Ribavarin
RT-PCR Reverse transcriptase polymerase chain reaction
References
Rizzetto M. Hepatitis D: thirty years after. J Hepatol. 2009 May;50(5):1043-50. http://www.ncbi.nlm.nih.gov/pubmed/19285743
- World Health Organization. Health topics: Hepatitis http://www.who.int/topics/hepatitis/en
