Hepatitis E
From Wikipedia, the free encyclopedia
| ICD-10 | B17.2 |
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| ICD-9 | 070.4 |
| DiseasesDB | 5794 |
| eMedicine | med/995 |
| Hepatitis E virus | ||||||||
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 Electron micrograph of hepatitis E viruses. |
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| Virus classification | ||||||||
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Hepatitis E is an acute viral hepatitis (liver inflammation) caused by infection with a virus called hepatitis E virus (HEV). Infection with this virus was first documented in 1955 during an outbreak in New Delhi, India. [1]
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[edit] Signs and symptoms
- Prolonged cholestasis has been described in up to 60 percent of patients. [2]
- Jaundice
- Malaise
- Anorexia
- Nausea
- Vomiting
- Abdominal pain
- Fever
- Hepatomegaly
- Other less common features include diarrhea, arthralgia, pruritus, and urticarial rash. Some patients have asymptomatic infection.
It is most common 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 to hepatitis A, but in pregnant women the disease is more often severe and is associated with a clinical syndrome called as 'fulminant hepatic failure'. Pregnant women, especially those in the third trimester, suffer an elevated mortality rate from the disease ~20%.
[edit] Virology
The viral particles are 27 to 34 nanometers in diameter, are non-enveloped and contain a single-strand of positive-sense RNA that is approximately 7300 basepairs in length. The virus particle was first visualised in 1983[3] but was only molecularly cloned in 1990.[4]
It was previously classified family Caliciviridae. However, its genome more closely resembles the rubella virus. It is now classified in a new virus family, named as Hepeviridae.
[edit] Epidemiology
[edit] Patterns
Hepatitis E is prevalent in most developing countries, and not uncommon 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 and monsoons because of their disruption of water supplies. Major outbreaks have occurred in New Delhi, India (30,000 cases in 1955-1956), Myanmar (20,000 cases in 1976-1977), Kashmir, India (52,000 cases in 1978), Kanpur, India (79,000 cases in 1991), and China (100,000 cases between 1986 and 1988).
[edit] Recent outbreaks
In 2004, there were two major outbreaks, both of them in sub-Saharan Africa. There was an outbreak in Chad in which, as of September 27 there were 1,442 reported cases and 46 deaths. In Sudan, 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, the Red 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 the health 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.
[edit] Prevention
Currently, the only viable method of prevention is improving sanitation, since no vaccine exists for the disease. Proper treatment and disposal of human waste, higher standards for public water supplies, improved personal hygiene procedures and sanitary food preparation are all important measures in preventing the spread of this disease. 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.
[edit] References
- ^ Gupta, DN, Smetana, HF. The histopathology of viral hepatitis as seen in the Delhi epidemic (1955-56). Indian J Med Res 1957; 45:101.
- ^ Chau TN, Lai ST, Tse C, Ng TK, Leung VK, Lim W, Ng MH (2006). "Epidemiology and clinical features of sporadic hepatitis E as compared with hepatitis A". Am J Gastroenterol 101 (2): 292–6.
- ^ Balayan MS, Andjaparidze AG, Savinskaya SS, et al. (1983). "Evidence for a virus in non-A, non-B hepatisis transmitted via the fecal-oral route". Intervirology 20: 23–31.
- ^ Reyes GR, Purdy MA, Kim JP, et al. (1990). "Isolation of a cDNA from the virus responsible for enterically transmitted non-A, non-B hepatitis". Science 247: 1335–39.
