What Kind of Threat Is Hepatitis E?
When it comes to infectious diseases affecting the liver, there seems to be no shortage of possibilities. Joining the ranks of Hepatitis A, B, C and D, Hepatitis E (HEV) has been the culprit of several cases of acute hepatitis across the globe. Caused only by infection with the Hepatitis E virus, HEV has only been recognized as a distinct human disease since 1980.
Although the symptoms may be similar, the genetics of each hepatitis virus are unique, with differing modes of transmission, infection course and treatment per disease. However, most experts agree that infection with one or more types of hepatitis viruses simultaneously carries a worse prognosis. Especially when laden with chronic Hepatitis C, infection with another hepatitis virus typically leads to an increased potential for liver damage.
Similar to how Hepatitis A is contracted, HEV is transmitted via the fecal-oral route. Primarily a waterborne disease, most Hepatitis E outbreaks have been associated with consumption of contaminated water or food supplies. Drinking water contaminated with fecal matter and ingestion of raw or uncooked shellfish have been implicated in cases of HEV in endemic areas. Since the virus is shed in feces, HEV could potentially be transmitted when infected animals meet poor sanitation practices. There is no evidence that Hepatitis E is transmitted through sexual contact, from needles or blood transfusions.
Where Is Hepatitis E?
The highest rates of Hepatitis E infection occur in regions where low standards of sanitation promote the transmission of the virus. Epidemics of Hepatitis E have been reported in the following locations where fecal contamination of drinking water is common:
- Central Asia
- South-East Asia
- North Africa
- West Africa
In addition to the natives, travelers visiting the above locations are susceptible to this infection. Epidemics normally happen after water supplies are contaminated with sewage following monsoons or local flooding. Infected individuals in the United States have usually returned from travel to an area where the virus is more common. Although primarily affecting regions with poor sanitation, sporadic cases of Hepatitis E have been reported elsewhere, and serological surveys suggest a global distribution of strains of HEV.
Symptoms and Disease Course
As a viral infection targeting the liver, symptoms of Hepatitis E are similar to other types of hepatitis:
- Abdominal Pain
- Loss of Appetite
- Nausea and Vomiting
- Dark Urine
In general, Hepatitis E is a self-limiting viral infection. As such, HEV is typically limited to an acute course. Although HEV infection is typically mild, one to two percent of those infected develop a sudden and severe form of liver disease known as fulminant hepatitis. Occurring more frequently in pregnancy, fulminant hepatitis is associated with a mortality rate of 20 percent among pregnant women in their third trimester.
Some additional facts about the Hepatitis E virus include:
- Once exposed to Hepatitis E, the infection takes hold within one to two months.
- Infected persons are presumed contagious for up to two weeks after symptoms appear.
- There have been no cases of chronic Hepatitis E reported.
- Symptomatic HEV infection is most common in young adults aged 15 to 40 years.
- Although HEV infection is frequent in children, it is mostly asymptomatic and goes undiagnosed.
Treatment and Prevention
Once infected with HEV, the only treatment is rest and increased fluid intake – similar to how you would recuperate from the flu. Since Hepatitis E is a viral disease, antibiotics are of no value in the treatment of this infection. Unlike Hepatitis A and B, there is no immune globulin to protect or recover from HEV.
Since no specific therapy is capable of altering the course of acute Hepatitis E infection, prevention is the most effective approach against the disease. As almost all HEV infections are spread by the fecal-oral route, good personal hygiene, high quality standards for public water supplies and proper disposal of sanitary waste can prevent most Hepatitis E infections.
For travelers to highly endemic areas, the usual elementary food hygiene precautions are recommended. These include:
- Avoid drinking water and/or ice of unknown purity.
- Do not eat uncooked shellfish, or fruits or vegetables not peeled or prepared by the traveler.
At present, no commercially available vaccines exist for the prevention of Hepatitis E. However, several studies for the development of an effective vaccine against Hepatitis E are in progress.
Of Most Concern
While Hepatitis E infection does not pose a major health threat, it can be dangerous for pregnant women and those already infected with another hepatitis virus.
- Pregnancy – When infected with HEV, pregnant women in their third trimester are most susceptible to developing fulminant hepatitis, a potentially fatal condition.
- Co-Infection – Belgian researchers presented an overview of co-infection with multiple hepatitis viruses in the December 2006 issue of European Journal of Gastroenterology and Hepatology. The authors wrote, “Co-infection with other hepatitis viruses modifies the viral profile in serum and leads to more liver damage and more rapid progression during the course of Hepatitis C virus infection.” Although not specific to HEV, the combined effects of co-infection with more than one hepatitis virus are attributable to an enhanced immune response. This immune response is responsible for a majority of the liver damage associated with viral hepatitis.
Nobody wishes to fall ill and be bedridden with an illness such as Hepatitis E. However, any serious risks from this illness are confined to the special populations of pregnant women and those already infected with a hepatitis virus. Until a vaccine is available to prevent HEV, any members of these special populations should pay keen attention to food hygiene, especially if traveling to a country where Hepatitis E is endemic.
http://english. chosun.com, New Hepatitis E Virus Flares Up in Korea, Digital Chosun, June 2007.
www.cdc.gov, Hepatitis E: Fact Sheet, US Department of Health and Human Services, 2007.
www.hivandhepatitis.com, Impact of Coinfection with more than one Hepatitis Virus, Liz Highleyman, hivandhepatitis.com, 2007.
www.emedicine.com, Hepatitis E, Jonathan M. Schwartz, MD, WebMD, 2007.
www.sciencedaily.com, Hepatitis E Takes a Piggyback, ScienceDaily LLC, May 2007.
www.thirdworldtraveler.com, Hepatitis E, Third World Traveler, 2007.
www.webmd.com, Hepatitis E Vaccine Shows Promise, Miranda Hitti, WebMD Inc., 2007.
www.who.int, Hepatitis E, World Health Organization, 2007.
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