hepatitis E

Hepatitis E 

Definition

The hepatitis E virus (HEV) is a common cause of hepatitis that is transmitted via the intestinal tract, and is not caused by the hepatitis A virus. Spread most often by contaminated drinking water, HEV infection occurs mainly in developing countries.

Description

Hepatitis E is also known as epidemic non-A, non-B hepatitis. Like hepatitis A, it is an acute and short-lived illness that can sometimes cause liver failure. HEV, discovered in 1987, is spread by the fecal-oral route. It is constantly present (endemic) in countries where human waste is allowed to get into drinking water without first being purified. Large outbreaks (epidemics) have occurred in Asian and South American countries where there is poor sanitation. In the United States and Canada no outbreaks have been reported, but persons traveling to an endemic region may return with HEV.

Causes and symptoms

There are at least two strains of HEV, one found in Asia and another in Mexico. The virus may start dividing in the gastrointestinal tract, but it grows mostly in the liver. After an incubation period (the time from when a person is first infected by a virus until the appearance of the earliest symptoms) of two to eight weeks, infected persons develop fever, may feel nauseous, lose their appetite, and often have discomfort or actual pain in the right upper part of the abdomen where the liver is located. Some develop yellowing of the skin and the whites of the eyes (jaundice). Most often the illness is mild and disappears within a few weeks with no lasting effects. Children younger than 14 years and persons over age 50 seldom have jaundice or show other clinical signs of hepatitis.

Hepatitis E never becomes a chronic (long-lasting) illness, but on rare occasions the acute illness damages and destroys so many liver cells that the liver can no longer function. This is called fulminant liver failure, and may cause death. Pregnant women are at much higher risk of dying from fulminant liver failure; this increased risk is not true of any other type of viral hepatitis. The great majority of patients who recover from acute infection do not continue to carry HEV and cannot pass on the infection to others.

Diagnosis

HEV can be found by microscopically examining a stool sample, but this is not a reliable test, as the virus often dies when stored for a short time. Like other hepatitis viruses, HEV stimulates the body's immune system to produce a substance called an antibody, which can swallow up and destroy the virus. Blood tests can determine elevated antibody levels, which indicate the presence of HEV virus in the body. Unfortunately, such antibody blood tests are not widely available.

Treatment

There is no way of effectively treating the symptoms of any acute hepatitis, including hepatitis E. During acute infection, a patient should take a balanced diet and rest in bed as needed.

Prognosis

In the United States hepatitis E is not a fatal illness, but elsewhere about 1-2% of those infected die of advanced liver failure. In pregnant women the death rate is as high as 20%. It is not clear whether having hepatitis E once guarantees against future HEV infection.

Prevention

Most attempts to use blood serum containing HEV antibody to prevent hepatitis in those exposed to HEV have failed. Hopefully, this approach can be made to work so that pregnant women living in endemic areas can be protected. No vaccine is available, though several are being tested. It also is possible that effective anti-viral drugs will be found. The best ways to prevent hepatitis E are to provide safe drinking water and take precautions to use sterilized water and beverages when traveling.

Key terms

Antibody — A substance made by the body's immune system in response to an invading virus, the antibodies then attack and destroy the virus.

Incubation period — The time from when a person is first infected by a virus until the appearance of the earliest symptoms.

Jaundice — Yellowing of the skin that occurs when pigments normally eliminated by the liver collect in high amounts in the blood.

Sanitation — The process of keeping drinking water, foods, or any anything else with which people come into contact free of microorganisms such as viruses.

Vaccine — A substance prepared from a weakened or killed virus which, when injected, stimulates the immune system to produce antibodies that can prevent infection by the natural virus.

Resources

Organizations

American Liver Foundation. 1425 Pompton Ave., Cedar Grove, NJ 07009. (800) 223-0179. http://www.liverfoundation.org.

Other

King, J. W. Bug Bytes. Louisiana State University Medical Center. 〈http://www.ccm.lsumc.edu/bugbytes〉.

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hepatitis /hep·a·ti·tis/ (hep″ah-ti´tis) pl. hepati´tides   Inflammation of the liver.

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hepatitis A  a self-limited viral disease of worldwide distribution, usually transmitted by oral ingestion of infected material but sometimes transmitted parenterally; most cases are clinically inapparent or have mild flu-like symptoms; any jaundice is mild.

anicteric hepatitis  viral hepatitis without jaundice.

hepatitis B  an acute viral disease transmitted primarily parenterally, but also orally, by intimate personal contact, and from mother to neonate. Prodromal symptoms of fever, malaise, anorexia, nausea, and vomiting decline with the onset of clinical jaundice, angioedema, urticarial skin lesions, and arthritis. After 3 to 4 months most patients recover completely, but some may become carriers or remain ill chronically.

hepatitis C  a viral disease caused by the hepatitis C virus, commonly occurring after transfusion or parenteral drug abuse; it frequently progresses to a chronic form that is usually asymptomatic but that may involve cirrhosis.

cholangiolitic hepatitis  cholestatic h. (1).

cholestatic hepatitis 

1. inflammation of the bile ducts of the liver associated with obstructive jaundice.

2. hepatic inflammation and cholestasis resulting from reaction to drugs such as estrogens or chlorpromazines.

hepatitis D , delta hepatitis infection with hepatitis D virus, occurring either simultaneously with or as a superinfection in hepatitis B, whose severity it may increase.

hepatitis E  a type transmitted by the oral-fecal route, usually via contaminated water; chronic infection does not occur but acute infection may be fatal in pregnant women.

enterically transmitted non-A, non-B hepatitis  (ET-NANB) h. E.

hepatitis G  a post-transfusion disease caused by hepatitis G virus, ranging from asymptomatic infection to fulminant hepatitis.

infectious hepatitis  h. A.

infectious necrotic hepatitis  black disease.

lupoid hepatitis  chronic active hepatitis with autoimmune manifestations.

neonatal hepatitis  hepatitis of uncertain etiology occurring soon after birth and marked by prolonged persistent jaundice that may progress to cirrhosis.

non-A, non-B hepatitis  a syndrome of acute viral hepatitis occurring without the serologic markers of hepatitis A or B, including hepatitis C and hepatitis E.

posttransfusion hepatitis  viral hepatitis, now primarily hepatitis C, transmitted via transfusion of blood or blood products, especially multiple pooled donor products such as clotting factor concentrates.

serum hepatitis  h. B.

transfusion hepatitis  posttransfusion h.

viral hepatitis  h. A, h. B, h. C, h. D, and h. E.

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hepatitis E

n.

A self-limited, acute hepatitis caused by a calicivirus, having symptoms similar to those of hepatitis A and spread via contaminated drinking water and food. It is endemic in developing countries and has occurred in epidemics in regions of Asia, Africa, and Central America.

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hepatitis E (HE),

a self-limited type of hepatitis occurring primarily in Asia and Africa, acquired by ingestion of fecally contaminated water or food. Symptoms are similar to those of hepatitis A. Also called enterically transmitted non-A non-B hepatitis.

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hepatitis (hep´tī´tis),

n an inflammation of the liver.

hepatitis C (Hep C, non-A, non-B hepatitis),

n a type transmitted largely by blood transfusion or percutaneous inoculation, such as with in-travenous drug users sharing needles. The disease progresses to chronic hepatitis in up to 50% of the patients acutely infected.

hepatitis, chronic active,

n a hepatitis with chronic portal inflammation with regional necrosis and fibrosis, which may progress to nodular postnecrotic cirrhosis.

hepatitis, delta (Hep D),

n a particularly virulent form caused by the delta hepatitis virus in conjunction with the hepatitis B virus (HBV), which is spread by contaminated needles or by direct exposure to blood or other body fluids from infected individuals. It occurs primarily in persons who have been repeatedly exposed to the HBV either through frequent blood transfusions or intravenous drug use. It may also be spread during the birthing process.

hepatitis delta virus (HDV),

n the infectious agent that causes delta hepatitis, but only in the presence of the hepatitis B virus. The virus is usually superimposed on carriers of the hepatitis B surface antigen (HBsAg). It is also called the
delta agent.

hepatitis E (Hep E, epidemic non-A, non-B hepatitis),

n a self-limited type of hepatitis caused by the hepatitis E virus (HEV) that may occur after natural disasters because of fecal-contaminated water or food. There is currently no serologic test available.

hepatitis G,

n a viral infection of the stomach and intestines, transmitted via blood and coinfection with the hepatitis C virus. The duration of the incubation period and range of symptoms are unknown, and no vaccine is available.

hepatitis, homologous serum (homologous serum jaundice, serum hepatitis, syringe jaundice, type B hepatitis),

n a viral hepatitis clinically difficult to distinguish from epidemic infectious hepatitis. It is transmitted by human serum (that is, through parenteral injection, transfusions, lacerations). The incubation period is 40 to 90 days or longer. Principal manifestations are jaundice, gastrointestinal symptoms, anorexia, and malaise.

hepatitis, infectious (IH, type A hepatitis),

n a viral hepatitis that is frequently epidemic in nature and has an incubation period of 1 to 4 or even 7 weeks. It is usually transmitted by the virus in fecal matter but may be transmitted by human (transfusions, lacerations, needle punctures).

hepatitis, non-ABCDE,

n a viral infection of the stomach and intestines that is diagnosed by ruling out other forms of hepatitis. It may be transmitted orally, via injection, sexual contact, or fecal matter.

hepatitis, serum,

n See hepatitis, homologous serum.

hepatitis, viral,

n 1. hepatitis caused by one of three immunologically unrelated viruses: hepatitis A virus; hepatitis B virus; and non-A, non-B virus.
n 2. hepatitis caused by a viral infection, including that by Epstein-Barr virus and cytomegalovirus.

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hepatitis E

A hepatitis caused by a single-stranded RNA virus; it has been implicated in major epidemics where sanitation is poor, drinking water contaminated, and population malnourished