Infection: Hepatitis A

Definition
Description
Demographics
Causes and Symptoms
Diagnosis
Treatment
Prognosis
Prevention
The Future
For more information

Definition

Hepatitis A is an infectious disease of the liver caused by the HAV virus. The disease is usually transmitted by food or water contaminated by human wastes containing the virus or by close human contact. As far as is known, only humans and some primates can get hepatitis A; it is not carried by other animals.

Description

Hepatitis A is an inflammation of the liver caused by the HAV virus. It differs from hepatitis B and hepatitis C in that it does not cause long-term liver damage. Even though people can take several weeks or months to recover completely from hepatitis A, they have lifelong immunity afterward. Complications from hepatitis A are rare and usually limited to people with chronic liver disease or who have received a liver transplant.

Hepatitis A varies in severity. Children and younger adults may have no symptoms at all, although they can still spread the disease. In general, adults are more likely to have noticeable symptoms than children or teenagers. The symptoms begin between two and six weeks after the person has been infected with HAV. The most common symptom is loss of energy and overall tiredness. Some people develop a mild flu-like illness with diarrhea, low-grade fever, nausea, vomiting, and muscle cramps. People with more severe symptoms may have pain in the abdomen in the area of the liver (below the rib cage on the right side of the body); they may notice that their urine has turned dark brown or that they have jaundice—yellowing of the skin and the whites of the eyes. Some have itchy skin.

Most people feel better within four to six weeks after the symptoms begin, although about 15 percent of patients may take up to nine months to completely regain their energy and feel normal again.

Demographics

Hepatitis A is much more common in Africa, Asia, and South America than in the United States. The rates of hepatitis A in North America have been steadily dropping since the 1980s. In 1988 the Centers for Disease Control and Prevention (CDC) reported 32,000 cases in the United States; in 2003, 7,653 cases were reported. In developing countries, children below the age of two account for most new cases of hepatitis A; in the United States, the age group most often affected is children between the ages of five and fourteen.

Males and females are equally likely to get hepatitis A, as are people from all races and ethnic groups in the United States.

Some groups of adults are at increased risk of hepatitis A:

• People who travel to parts of the world with high rates of the disease and poor sanitation
• Male homosexuals
• People who use illicit drugs, whether injected or taken by mouth

• Medical researchers and laboratory workers who may be exposed to HAV
• Child care workers
• Homeless people

Causes and Symptoms

Hepatitis A is caused by a virus that is transmitted by close personal contact with an infected person, by needle sharing, and by eating food or drinking water contaminated by fecal matter. After the virus enters the body, it multiplies in the cells of the liver, causing inflammation of the liver and a general response from the immune system that leads to most of the symptoms of the illness.

The HAV virus is shed from the liver into the bile (a digestive fluid secreted by the liver) and then into the person's stools between fifteen and forty-five days before symptoms appear. That means that people can spread the virus through their feces before they know that they are sick. In the United States, hepatitis A is most commonly spread by food handlers who do not wash their hands properly after using the bathroom; by childcare workers who do not wash their hands after changing a baby's diaper; by anal sex; and by eating raw shellfish harvested from sewage-polluted waters. In very rare cases the virus can be transmitted through blood transfusions.

Hepatitis E

Hepatitis E is an infection of the liver caused by the hepatitis E virus, or HEV, first identified during an outbreak in New Delhi, India, in 1955, when 30,000 cases were reported following river flooding that carried raw sewage into the city's water supply. At first the disease was thought to be hepatitis A, but was later identified as a new virus. In 1990 its genetic material was analyzed and the virus was named hepatitis E.

Hepatitis E is most common in countries with tropical climates, particularly in southeastern Asia, Africa, India, and Central America. Unlike hepatitis A, which seems to affect only humans, hepatitis E has been found in deer, pigs, rats, and other animals, and can be spread by uncooked meat or shellfish. Mortality rates are generally low (around 2 percent) with hepatitis E; however, pregnant women are at high risk of liver failure from the disease. In India as many as 20 percent of pregnant women infected with hepatitis E die of liver failure.

Hepatitis E is rare in the United States, affecting primarily people who travel to countries where it is common. The disease is self-limited and is usually treated with fluid replacement; antibiotics are not effective in treating viruses. The best treatment is prevention—travelers in countries with tropical climates should avoid drinking water that has not been tested for purity and eating uncooked shellfish or raw, unpeeled fruits or vegetables.

In addition to fatigue, the most common symptoms of hepatitis A include:

• Low-grade fever (101°F [38.3°C])
• Nausea, vomiting, and diarrhea
• Loss of appetite and weight loss
• Swelling of the liver and pain in the area of the abdomen over the liver

• Tea- or coffee-colored urine
• Jaundice
• Generalized sensation of itching
• Pale or clay-colored stools
• Muscle pains

Diagnosis

The doctor may suspect that a patient has hepatitis A during a physical examination by feeling the area over the liver for signs of swelling and pain; and checking the skin and eyes for signs of jaundice. A definite diagnosis is provided by a blood test for certain antibodies to the HAV virus. The doctor will also have the sample of blood checked for abnormally high levels of chemicals produced in the liver.

Treatment

There is no specific drug treatment for hepatitis A, as antibiotics cannot be used to treat virus infections. Most people can care for themselves at home by making sure they get plenty of fluids and adequate nutrition. People whose appetite has been affected may benefit from eating small snacks throughout the day rather than three main meals and eating soft and easily digested foods. Patients with mild vomiting may be prescribed antiemetics (drugs to control nausea). Those with severe vomiting may need to be hospitalized in order to receive intravenous fluids.

Patients with hepatitis A should avoid drinking alcohol or taking acetaminophen (Tylenol), which make it harder for the liver to recover from inflammation. Patients should also tell their doctor about any other over-the-counter or prescription drugs they are taking, because the drugs may need to be stopped temporarily or have the dosages changed.

Prognosis

Most people recover fully from hepatitis A within a few weeks or months. Between 3 and 20 percent have relapses (temporary recurrences of symptoms) for as long as six to nine months after infection.

About 1 percent of patients develop liver failure following HAV infection, mostly those over sixty or those with chronic liver disease. In these cases liver transplantation may be necessary for the patient's survival. There are about 100 deaths from hepatitis A reported each year in the United States.

Prevention

Hepatitis A can be prevented by a vaccine called Havrix that is given before exposure to the HAV virus. The vaccine is given in two shots, the second given between six and eighteen months after the first. It confers immunity against hepatitis A for at least twenty years. Those who should receive the vaccine include people in the military and those who travel abroad frequently; men who have sex with other men; people who use intravenous drugs; people with hemophilia who must receive human blood products; and people who have chronic hepatitis B or C infection.

People who have been exposed to the HAV virus and children under the age of two should not be given Havrix, but they can be given another type of drug to protect them against HAV.

WORDS TO KNOW

Antiemetic: A type of drug given to control nausea and vomiting.

Bile: A yellow-green fluid secreted by the liver that aids in the digestion of fats.

Hepatitis: The medical term for inflammation of the liver. It can be caused by toxic substances or alcohol as well as infections.

Jaundice: A yellowish discoloration of the skin and whites of the eyes caused by increased levels of bile pigments from the liver in the patient's blood.

Everyone can reduce their risk of hepatitis A by observing the following precautions:

• Practice good personal hygiene; wash hands frequently, especially after using the toilet or changing a child's diaper.
• When traveling, drink only bottled water, avoid raw or under-cooked meat or shellfish, and avoid eating fresh fruits or vegetables unless you have washed and peeled them yourself.
• Avoid sharing drinking glasses and eating utensils. If someone in the family has hepatitis A, wash their glasses and utensils separately in hot, soapy water.
• Avoid sexual contact with anyone who has hepatitis A.

The Future

The rates of hepatitis A in the United States and other developed countries are likely to continue to drop, given the availability of an effective vaccine against the disease. Hepatitis A is, however, likely to continue to be a major health problem in developing countries, and travelers will need to protect themselves against it for the foreseeable future.

SEE ALSO Alcoholism; Hemophilia; Hepatitis B; Hepatitis C

For more information

BOOKS

Centers for Disease Control and Prevention (CDC). “Surveillance for Acute Viral Hepatitis—United States, 2006.” Morbidity and Mortality Weekly Report, 57 (March 21, 2008): 1–24. Available online at http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5702a1.htm (accessed July 26, 2008).

National Institute of Allergy and Infectious Diseases (NIAID). “The Story of the Hepatitis E Vaccine.” NIAID Discovery News, Spring 2007. Available online at http://www3.niaid.nih.gov/healthscience/healthtopics/HepatitisE/storyHepatitisEVaccine.htm (accessed July 26, 2008).

WEBSITES

American Academy of Family Physicians (AAFP). Hepatitis A. Available online at http://www.familydoctor.org/online/famdocen/home/common/infections/hepatitis/897.html (updated October 2007; accessed July 25, 2008).

American Liver Foundation. Hepatitis A. Available online at http://www.liverfoundation.org/education/info/hepatitisa/ (updated November 27, 2007; accessed July 26, 2008).

Mayo Clinic. Hepatitis A. Available online at http://www.mayoclinic.com/health/hepatitis-a/DS00397 (updated September 7, 2007; accessed July 26, 2008).

National Institute of Allergy and Infectious Diseases (NIAID). Hepatitis A. Available online at http://www3.niaid.nih.gov/healthscience/healthtopics/HepatitisA/default.htm (updated December 10, 2007; accessed July 26, 2008).