- Hepatitis E
Taxobox | color=violet
name = "Hepatitis E virus"
image_caption = TEMmicrograph of hepatitis E virions.
virus_group = iv
familia = "Unassigned"
genus = "Hepevirus "
species = "Hepatitis E virus"DiseaseDisorder infobox
Name = PAGENAME
Caption =
ICD10 = ICD10|B|17|2|b|15
ICD9 = ICD9|070.4
DiseasesDB = 5794
MedlinePlus =
eMedicineSubj = med
eMedicineTopic = 995Hepatitis E is a viral
hepatitis (liver inflammation) caused byinfection with avirus called hepatitis E virus (HEV). Infection with this virus was first documented in1955 during an outbreak inNew Delhi , India. [cite journal |author=Gupta DN, Smetana HF |title=The histopathology of viral hepatitis as seen in the Delhi epidemic (1955-56) |journal=Indian J. Med. Res. |volume=45 |issue=Suppl. |pages=101–13 |year=1957 |pmid=13438544 |doi=]Virology
The viral particles are 27 to 34
nanometer s in diameter, are non-enveloped and contain a single-strand of positive-senseRNA that is approximately 7300 bases in length. The virus particle was first visualised in 1983 [cite journal |author=Balayan MS, Andjaparidze AG, Savinskaya SS, "et al" |title=Evidence for a virus in non-A, non-B hepatitis transmitted via the fecal-oral route |journal=Intervirology |volume=20 |issue=1 |pages=23–31 |year=1983 |pmid=6409836 |doi=] but was only molecularly cloned in 1990. [cite journal |author=Reyes GR, Purdy MA, Kim JP, "et al" |title=Isolation of a cDNA from the virus responsible for enterically transmitted non-A, non-B hepatitis |journal=Science |volume=247 |issue=4948 |pages=1335–9 |year=1990 |pmid=2107574 |doi=10.1126/science.2107574]It was previously classified family
Caliciviridae . However, itsgenome more closely resembles the rubella virus. It is now classified as the only member of the genusHepevirus , and that genus has not yet been assigned to a family.cite web |url=http://www.ncbi.nlm.nih.gov/ICTVdb/Ictv/fs_hepev.htm |title=00.084.0.01. Hepevirus 00.084. Unassigned - ICTVdB Index of Viruses |format= |work= |accessdate=2008-06-15]Epidemiology
The incidence of hepatitis E is highest in adults between the ages of 15 and 40. Though children often contract this infection as well, they less frequently become symptomatic. Mortality rates are generally low, for Hepatitis E is a “self-limiting” disease, in that it usually goes away by itself and the patient recovers. However, during the duration of the
infection (usually several weeks), the disease severely impairs a person’s ability to work, care for family members, and obtain food. Hepatitis E occasionally develops into an acute severe liver disease, and is fatal in about 2% of all cases. Clinically, it is comparable tohepatitis A , but in pregnant women the disease is more often severe and is associated with a clinical syndrome calledfulminant hepatic failure . Pregnant women, especially those in the third trimester, suffer an elevatedmortality rate from the disease ~20%.Patterns
Hepatitis E is prevalent in most
developing countries , and common in any country with a hot climate. It is widespread in Southeast Asia, northern and central Africa, India, and Central America. It is spread mainly through fecal contamination of water supplies or food; person-to-person transmission is uncommon. Outbreaks of epidemic Hepatitis E most commonly occur after heavy rainfalls andmonsoons because of their disruption of water supplies. Major outbreaks have occurred inNew Delhi ,India (30,000 cases in1955 -1956 ),Burma (20,000 cases in1976 -1977 ),Kashmir ,India (52,000 cases in1978 ),Kanpur ,India (79,000 cases in1991 ), andChina (100,000 cases between1986 and1988 ).Animals as a reservoir
Domestic animals have been reported as a reservoir for the hepatitis E virus, with some surveys showing infection rates exceeding 95% among domestic pigs. [cite journal |author=Satou K, Nishiura H |title=Transmission dynamics of hepatitis E among swine: potential impact upon human infection |journal=BMC Vet. Res. |volume=3 |issue= |pages=9 |year=2007 |pmid=17493260 |doi=10.1186/1746-6148-3-9 |url=http://www.biomedcentral.com/1746-6148/3/9] Transmission after consumption of
wild boar meat and uncooked deer meat has been reported as well. [cite journal |author=Li TC, Chijiwa K, Sera N, "et al" |title=Hepatitis E virus transmission from wild boar meat |journal=Emerging Infect. Dis. |volume=11 |issue=12 |pages=1958–60 |year=2005 |pmid=16485490 |url=http://www.cdc.gov/ncidod/EID/vol11no12/05-1041.htm] The rate of transmission to humans by this route and the public health importance of this are however still unclear. Rats also carry the virus. [ [http://www.ratbehavior.org/WildRatDisease.htm RatBehavior.org] ]Recent outbreaks
In
2004 , there were two major outbreaks, both of them in sub-Sahara nAfrica . There was an outbreak inChad in which, as of September 27 there were 1,442 reported cases and 46 deaths. InSudan , which has been troubled with conflict recently (see,Darfur conflict ), they are also suffering from a severe Hepatitis E epidemic. As of September 28, there were 6,861 cases and 87 deaths, mainly in the West Darfur Region.UNICEF ,Doctors Without Borders , theRed Cross , and other international health organizations are currently working to increase the availability of soap, dig new wells, and chlorinate water supplies and reserves. However, the existing resources are still not enough, and more personnel and funds are severely needed in the region to assure thehealth and welfare of the people. Increasingly, hepatitis E is being seen in developed nations with reports of cases in the UK, US and Japan. The disease is thought to be a zoonosis in that animals are thought to be the source. Both deer and pigs have been implicated.Prevention
Improving
sanitation is the most important measure, which consists of proper treatment and disposal of human waste, higher standards for public water supplies, improved personal hygiene procedures and sanitary food preparation. Thus, prevention strategies of this disease are similar to those of many others that plague developing nations, and they require large-scale international financing of water supply and water treatment projects.A vaccine based on recombinant viral proteins has been developed and recently tested in a high-risk population (military personnel of a developing country). [cite journal |author=Shrestha MP, Scott RM, Joshi DM, "et al" |title=Safety and efficacy of a recombinant hepatitis E vaccine |journal=N. Engl. J. Med. |volume=356 |issue=9 |pages=895–903 |year=2007 |pmid=17329696 |doi=10.1056/NEJMoa061847] The vaccine appeared to be effective and safe, but further studies are needed to assess the long-term protection and the cost-effectiveness of hepatitis E vaccination.References
External links
* [http://patric.vbi.vt.edu/organism/overview.php?organismId=7 Hepatitis E Virus] (from [http://patric.vbi.vt.edu/ PATRIC] the PathoSystems Resource Integration Center, a [http://www3.niaid.nih.gov/ NIAID] Bioinformatics Resource Center)
* [http://www.who.int/mediacentre/factsheets/fs280/en/ WHO hepatitis E factsheet]
* [http://www.hephelp.net/hepatitis-e/ Hepatitis E Help - General Information about Hepatitis E]
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