Hepatitis, Infectious

Hepatitis (heh-puh-TIE-tis) is an inflammation of the liver ^* . It can have several different causes, most commonly viral infection.

What Is Infectious Hepatitis?

The liver plays many important roles in the body. It filters out toxins ^* and other harmful substances from the blood, stores vitamins and nutrients, regulates cholesterol ^* production, and helps in the production of many other substances the body needs to function normally. Long-term drug or alcohol abuse, exposure to harmful chemicals or other toxins, various infections, trauma ^* , and certain medications all can damage the liver and lead to hepatitis. Viruses usually cause infectious hepatitis, although other organisms, such as bacteria or parasites, sometimes can be the culprit as well.

Several different viruses can bring about acute ^* hepatitis, including at least five known hepatitis viruses (A through E). Among these viruses, hepatitis B (HBV) and C (HCV) cause the most serious disease. Most of the time, people recover fully from viral hepatitis. But in some people HBV and HCV cause chronic ^* hepatitis, in which the infection remains in the body and the liver does not recover completely from the inflammation. Chronic hepatitis eventually can lead to severe liver damage, liver cancer, and sometimes cirrhosis ^* of the liver. Other viral infections, such as infectious mononucleosis ^* or "mono," which usually is caused by the Epstein-Barr (EP-steen BAR) virus, can produce short-lived, mild hepatitis.

Types of Viral Hepatitis

Hepatitis A

Among the five major types, hepatitis A virus (HAV) causes the most common and least serious form of hepatitis. It typically spreads through eating food or drinking water contaminated with feces ^* from someone who is infected. Parts of the world with poor sanitation are at greatest risk for outbreaks of the disease. In the United States, cases of HAV infection sometimes arise when food handlers fail to practice good hygiene, such as regularly washing their hands. HAV also can be transmitted during unprotected sexual intercourse.

Hepatitis B

HBV infection can lead to chronic hepatitis in up to 10 percent of infected adults and older children, in up to 30 percent of infected children younger than 6 years old, and in up to 90 percent of infants who contract the virus from their infected mothers at birth. It is a more serious form of hepatitis because it can cause long-term or permanent liver inflammation and scarring, liver cancer, and liver failure.

HBV can pass easily from person to person through direct contact with infected blood and other body fluids, including semen ^* , vaginal ^* fluids, and sometimes saliva. It most often is spread through unprotected sexual intercourse, injection of drugs with contaminated needles, blood transfusions ^* , kidney ^* dialysis ^* , organ transplants, or from a mother to her child during birth. HBV also can be transmitted if improperly sterilized equipment is used during body piercing, tattooing, or circumcision ^* . Health care workers are advised to take precautions to avoid accidental sticks from needles used in the care of patients, because patients might be infected with the virus.

Hepatitis C

Like HBV, HCV can spread through direct contact with infected body fluids, especially blood. HCV most often is transmitted through the sharing of needles by injection drug users. In the United States, up to 90 percent of cases occur this way. Patients receiving long-term dialysis for kidney failure are also at relatively higher risk of HCV infection. The infection can result in long-lasting complications. About 80 percent of those who contract HCV may develop chronic hepatitis, which can put them at risk for other forms of serious liver disease. HCV infection is the most common reason for liver transplants in the United States.

Hepatitis D

Hepatitis D virus (HDV) infection is found only in those who also have been infected with HBV. HDV is passed from person to person in the same way as HBV. Co-infection can transform a mild HBV infection or an infection that has no symptoms at all into a more serious, rapidly progressing disease. HDV usually spreads through contact with infected blood, most often from injection drug use with contaminated needles.

Hepatitis E

Like HAV, hepatitis E virus (HEV) is transmitted through drinking water contaminated with infected feces. HEV infection occurs most often in underdeveloped countries with poor sanitation.

How Common Is Viral Hepatitis?

Infectious hepatitis is common all over the world. Each year HAV infects up to 1.4 million people worldwide, including about 250,000 Americans. Most cases in the United States are seen in children less than 10 years of age. According to the U.S. Centers for Disease Control and Prevention (CDC), at least 80,000 people in the United States are infected with HBV each year, and about 5,000 die from the disease annually. Africa and parts of South America and Asia, especially the Middle East, all have high rates of HAV and HBV infection. The World Health Organization (WHO) estimates that there are 170 million people infected with HCV around the globe, with 3 million to 4 million new cases appearing annually. About 4 million people in the United States have HCV, with about 25,000 new cases diagnosed each year.

What Are the Signs and Symptoms of Hepatitis?

Common symptoms of all forms of acute infectious hepatitis include extreme tiredness, loss of appetite, fever, headache, muscle and joint aches, nausea, vomiting, diarrhea, jaundice ^* , and stomach pain. Bowel movements may look pale in color, and urine may become dark, so that it looks like tea. Children infected with HAV frequently have few or no signs of illness, and people with HCV infection often show no symptoms or have only mild symptoms like those of the flu until the disease has caused serious liver damage.

How Do Doctors Make the Diagnosis?

Hepatitis is diagnosed by blood tests, which can show that the liver is inflamed and indicate how well it is working. Blood tests can also reveal which type of hepatitis virus is causing the disease. When a person is very ill from hepatitis or remains sick for a long time, a biopsy ^* of the liver may be done to determine whether the liver is becoming damaged or scarred.

What Is the Treatment for Hepatitis?

Treatment for viral hepatitis depends on its cause and how sick the patient is.

Hepatitis A and E

People with HAV and HEV infection usually recover completely without needing hospitalization. They can take care of themselves at home by making sure they get enough rest and drink plenty of fluids. Doctors advise avoiding alcohol and drugs, because these substances can stress an already inflamed liver.

Hepatitis B and C

Most of the time, HBV and HCV infection can be monitored with blood tests that look for liver inflammation and measure liver function. In severe cases of viral hepatitis, hospitalization may be necessary, especially when the liver is damaged and stops working well. Medications, including alpha-interferon (AL-fa in-ter-FEER-on) injections, may be given to help the body's immune system fight chronic hepatitis B, C, and D. It is recommended that people who have chronic infectious hepatitis live a healthy lifestyle by avoiding alcohol, getting enough sleep, exercising regularly, and eating a nutritious diet. These measures reduce stress on the liver and can prevent or slow the progression of long-term liver disease.

What to Expect

People typically recover completely from HAV or HEV infection within about 2 months, but sometimes it takes longer. Those infected with HBV or HCV usually recover within 6 months. Cases of chronic viral hepatitis can last for decades or even a lifetime. HBV and HCV can lead to scarring of the liver, liver cancer, liver failure, and sometimes death. A liver transplant may be required in cases that progress to liver failure.

How Can Hepatitis Be Prevented?

A vaccine ^* exists for HAV, but it is not used routinely in the United States, except in areas where the number of cases is consistently high, as seen in several western states. The vaccine is recommended for certain laboratory workers, anyone who has more than one sexual partner or who engages in other high-risk types of behavior, or people traveling to underdeveloped areas of the world with poor sanitation. People who come into contact with HAV can be treated with immune globulin ^* , which is more than 85 percent effective in preventing HAV infection if treatment begins within 2 weeks after exposure to the virus. The best way to prevent HAV and HEV is to practice good hygiene, such as frequent hand washing. Avoiding areas of poor sanitation and unwashed or uncooked food, particularly while traveling, can limit the risk of infection as well.

Today, infants in the United States typically are vaccinated against HBV by age 2 years. Infants born to mothers with HBV infection generally are given immediate injections of HBV immune globulin and receive their first dose of the HBV vaccine within 12 hours of birth. It is recommended that all teens and adults who are at high risk of exposure to infected body fluids, such as health care workers, receive the HBV vaccine. Since HDV infects only those who already have HBV, vaccination against HBV can prevent HDV as well. Using latex condoms for all forms of sexual intercourse also can help protect against HBV. Avoiding intravenous drug use and sharing of razors, toothbrushes, or needles, even for tattoos or body piercing, can help prevent both HBV and HCV. Since 1992 blood banks in the United States have screened donated blood for HBV and HCV. Currently, there is no vaccine for HCV.