Hepatitis A overview: Difference between revisions
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==Overview== | ==Overview== | ||
[[image:8153_thumb.jpg|left|200px|thumb|Transmission electron micrograph (TEM) of hepatitis virions]] | [[image:8153_thumb.jpg|left|200px|thumb|Transmission electron micrograph (TEM) of hepatitis virions]] | ||
'''Hepatitis A''' (formerly known as ''infectious hepatitis'') is an [[Acute (medical)|acute]] [[infectious disease]] of the [[liver]] | '''Hepatitis A''' (formerly known as ''infectious [[hepatitis]]'' and epidemical virus) is an [[Acute (medical)|acute]] [[infectious disease]] of the [[liver]] caused by the hepatitis A virus (Hep A),<ref name=Sherris>{{cite book | author = Ryan KJ, Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th | pages = 541–4 | publisher = McGraw Hill | year = 2004 | isbn = 0838585299 }}</ref> an RNA virus, usually spread the fecal-oral route; transmitted person-to-person by ingestion of contaminated food or water or through direct contact with an infectious person. Tens of millions of individuals worldwide are estimated to | ||
become infected with Hep A each year.<ref name="pmid16775039">{{cite journal | |||
| doi=10.1093/epirev/mxj012 | |||
| author=Wasley A, Fiore A, Bell BP | |||
| title=Hepatitis A in the era of vaccination | |||
| journal=Epidemiol Rev | |||
| volume=28 | |||
| pages=101–11 | |||
| year=2006 | |||
| pmid=16775039 | |||
}}</ref> The time between infection and the appearance of the symptoms (the [[incubation period]]) is between two and six weeks and the average incubation period is 28 days.<ref name="pmid16271543">{{cite journal | |||
| author=Connor BA | |||
| title=Hepatitis A vaccine in the last-minute traveler | |||
| journal=Am. J. Med. | |||
| volume=118 |issue=Suppl 10A | |||
| pages=58S–62S | |||
| year=2005 | |||
| pmid=16271543 | |||
| doi=10.1016/j.amjmed.2005.07.018 | |||
| url=http://linkinghub.elsevier.com/retrieve/pii/S0002-9343(05)00611-X | |||
}}</ref> | |||
In [[developing country|developing countries]], and in regions with poor hygiene standards, the [[incidence (epidemiology)|incidence]] of infection with this virus is high<ref name="pmid16271541">{{cite journal | |||
| author = Steffen R | |||
| title = Changing travel-related global epidemiology of hepatitis A | |||
| journal = Am. J. Med. | |||
| volume = 118 |issue=Suppl 10A | |||
| pages = 46S–49S | |||
| year = 2005 | |||
| month = October | |||
| pmid = 16271541 | |||
| doi = 10.1016/j.amjmed.2005.07.016 | |||
| url = http://linkinghub.elsevier.com/retrieve/pii/S0002-9343(05)00609-1 | |||
| accessdate = 2008-12-20 | |||
| issue = 10 | |||
}}</ref> and the illness is usually contracted in early childhood. As incomes rise and access to clean water increases, the incidence of HAV decreases.<ref name="pmid15831565">{{cite journal | |||
| doi=10.1093/ije/dyi062 | |||
| author=Jacobsen KH, Koopman JS | |||
| title=The effects of socioeconomic development on worldwide hepatitis A virus seroprevalence patterns | |||
| journal=Int J Epidemiol | |||
| volume=34 | |||
| issue=3 | |||
| pages=600–9 | |||
| year=2005 | |||
| pmid=15831565 | |||
}}</ref> Hepatitis A infection causes no clinical signs and symptoms in over 90% of infected children and since the infection confers lifelong immunity, the disease is of no special significance to those infected early in life. In Europe, the United States and other industrialized countries, on the other hand, the infection is contracted primarily by [[susceptible]] young adults, most of whom are infected with the virus during trips to countries with a high incidence of the disease<ref name="pmid16271543"/> or through contact with infectious persons. | |||
HAV infection produces a self-limited disease that does not result in chronic infection or chronic liver disease. However, 10–15% of patients might experience a relapse of symptoms during the 6 months after acute illness. Acute liver failure from Hepatitis A is rare (overall case-fatality rate: 0.5%). The risk for symptomatic infection is directly related to age, with >80% of adults having symptoms compatible with acute viral hepatitis and the majority of children having either asymptomatic or unrecognized infection.<ref name="pmid10683554">{{cite journal |doi=10.1016/S0264-410X(99)00470-3 |author=Ciocca M. |title=Clinical course and consequences of hepatitis A infection |journal=Vaccine |volume=18 |pages=71–4 |year=2000 |pmid=10683554}}</ref> Antibody produced in response to HAV infection persists for life and confers protection against reinfection. The disease can be prevented by [[vaccination]], and [[hepatitis A vaccine]] has been proven effective in controlling outbreaks worldwide.<ref name="pmid16271543"/> | |||
<br clear="left"/> | <br clear="left"/> | ||
==References== | ==References== | ||
{{reflist|2}} | {{reflist|2}} | ||
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[[Category:Picornaviruses]] | [[Category:Picornaviruses]] | ||
[[Category:Viral diseases]] | [[Category:Viral diseases]] | ||
[[Category:Infectious disease]] | |||
[[Category:Disease]] | |||
Revision as of 16:06, 7 March 2012
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Hepatitis A |
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Hepatitis A overview On the Web |
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American Roentgen Ray Society Images of Hepatitis A overview |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Hepatitis A (formerly known as infectious hepatitis and epidemical virus) is an acute infectious disease of the liver caused by the hepatitis A virus (Hep A),[1] an RNA virus, usually spread the fecal-oral route; transmitted person-to-person by ingestion of contaminated food or water or through direct contact with an infectious person. Tens of millions of individuals worldwide are estimated to become infected with Hep A each year.[2] The time between infection and the appearance of the symptoms (the incubation period) is between two and six weeks and the average incubation period is 28 days.[3]
In developing countries, and in regions with poor hygiene standards, the incidence of infection with this virus is high[4] and the illness is usually contracted in early childhood. As incomes rise and access to clean water increases, the incidence of HAV decreases.[5] Hepatitis A infection causes no clinical signs and symptoms in over 90% of infected children and since the infection confers lifelong immunity, the disease is of no special significance to those infected early in life. In Europe, the United States and other industrialized countries, on the other hand, the infection is contracted primarily by susceptible young adults, most of whom are infected with the virus during trips to countries with a high incidence of the disease[3] or through contact with infectious persons.
HAV infection produces a self-limited disease that does not result in chronic infection or chronic liver disease. However, 10–15% of patients might experience a relapse of symptoms during the 6 months after acute illness. Acute liver failure from Hepatitis A is rare (overall case-fatality rate: 0.5%). The risk for symptomatic infection is directly related to age, with >80% of adults having symptoms compatible with acute viral hepatitis and the majority of children having either asymptomatic or unrecognized infection.[6] Antibody produced in response to HAV infection persists for life and confers protection against reinfection. The disease can be prevented by vaccination, and hepatitis A vaccine has been proven effective in controlling outbreaks worldwide.[3]
References
- ↑ Ryan KJ, Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. pp. 541–4. ISBN 0838585299.
- ↑ Wasley A, Fiore A, Bell BP (2006). "Hepatitis A in the era of vaccination". Epidemiol Rev. 28: 101–11. doi:10.1093/epirev/mxj012. PMID 16775039.
- ↑ 3.0 3.1 3.2 Connor BA (2005). "Hepatitis A vaccine in the last-minute traveler". Am. J. Med. 118 (Suppl 10A): 58S–62S. doi:10.1016/j.amjmed.2005.07.018. PMID 16271543.
- ↑ Steffen R (2005). "Changing travel-related global epidemiology of hepatitis A". Am. J. Med. 118 (10): 46S–49S. doi:10.1016/j.amjmed.2005.07.016. PMID 16271541. Retrieved 2008-12-20. Unknown parameter
|month=ignored (help) - ↑ Jacobsen KH, Koopman JS (2005). "The effects of socioeconomic development on worldwide hepatitis A virus seroprevalence patterns". Int J Epidemiol. 34 (3): 600–9. doi:10.1093/ije/dyi062. PMID 15831565.
- ↑ Ciocca M. (2000). "Clinical course and consequences of hepatitis A infection". Vaccine. 18: 71–4. doi:10.1016/S0264-410X(99)00470-3. PMID 10683554.