Reciting the Hepatitis ABCs

The term hepatitis simply means inflammation of the liver. But when you're talking about hepatitis C, you're talking about viral hepatitis, and hep C isn't the only form of hepatitis caused by a virus.

So far, five different viruses have been found that cause hepatitis, and they're named with letters: Hepatitis Avirus causes hepatitis A; hepatitis B virus causes hepatitis B; hepatitis C virus causes hepatitis C; and hepatitis E virus causes hepatitis E. Hepatitis D virus is a special case, because it can't infect you unless you also have hepatitis B virus.

The different types of viral hepatitis have similar features but also important differences. Depending on the hepatitis virus, the disease may be temporary — an acute form, which lasts less than a year. With hepatitis B or C, though, infection can become chronic and last for decades, or life, unless you undergo successful treatment against the virus.

Hepatitis A virus

Hepatitis A (also called infectious hepatitis) was identified in 1973. Hepatitis A spreads through food or water that has been contaminated with infected feces. You can get hepatitis A from:

• Not washing your hands after exposure to feces: Examples include not washing your hands after using the bathroom or changing a diaper.

• Eating contaminated food: This situation can occur with uncooked food and food prepared by someone who didn't wash his hands after using the toilet.

• Drinking contaminated water: Dealing with contaminated water could be a problem when traveling.

• Sexual contact with someone who's infected: Practice safer sex and especially take care if you have anal or oral–anal sex.

Hepatitis A causes an acute infection. In the United States, 200,000 cases of hepatitis A are reported yearly, and a third of all people have already been exposed to hepatitis A virus at some point in their lives but may not have known it. If you've been exposed to hepatitis A in the past or gotten a vaccine, you'll be immune, or protected from future hepatitis A infection.

Hepatitis B virus

The hepatitis B virus (serum hepatitis) was found in 1963 and spreads through contact with infected body fluids (including saliva, vaginal fluid, and semen) and blood. You can get hepatitis B from

• Injection drug use

• Unprotected sex

• Transmission from mother to child during birth

• The razor or toothbrush of an infected person

• Occupational exposure of healthcare workers or emergency personnel to infected blood or body fluids

Hepatitis B can cause an acute or chronic infection, but chronic infection occurs in only approximately 5 percent of cases. A hepatitis B vaccine protects against hepatitis B (and hepatitis D).

Hepatitis C virus

The hepatitis C virus was discovered in 1989. For decades before that, it was called "non-A non-B" hepatitis because researchers knew that it wasn't caused by the other known hepatitis viruses at the time. Hep C is transmitted through blood, and 75 to 85 percent of people infected will have a chronic infection, which puts them at risk for cirrhosis, liver cancer, and liver failure over many decades of infection. No vaccine is available for hepatitis C, so prevention is the key to avoiding infection.

Hep C infection can last a lifetime, so you need to take good care of yourself physically, emotionally, and financially. Medical research is ongoing to develop more effective drugs with fewer side effects. Currently, combination therapy with two drugs — pegylated interferon and ribavirin — is the best treatment, but it doesn't work for everyone.

Hepatitis D virus

Hepatitis D was discovered in 1977 and is an incomplete virus thatcan't infect you on its own; it has to tag along with hepatitis B virus. When it does, it can produce more-severe hepatitis B disease. Transmission of hepatitis D is the same as for hepatitis B. Vaccination against hepatitis B prevents hepatitis D infection, too.

Hepatitis E virus

The hepatitis E virus was discovered in 1983 as another hepatitis virus that's transmitted through contamination of water with feces. Outbreaks of hepatitis E occur primarily in developing countries in Africa, Asia, and Central America due to unsanitary water supplies. Hepatitis E is rare in Canada, the United States, and other developed countries.

Hepatitis E is an acute infection. For some as-yet-unexplained reason, pregnant women appear to be at risk of a more severe disease when infected with hepatitis E.

Other hepatitis viruses

Researchers believe that most people with viral hepatitis have one of the hepatitis viruses from A to E. But scientists are always on the lookout for new viruses that can cause disease. The viruses called hepatitis G virus (HGV), TTV (transfusion transmitted virus), and sentinel viruses (SEN) have all been discovered in the blood of people with hepatitis. But it's not absolutely clear that these viruses actually cause hepatitis. Hepatitis F is a name for a virus that's no longer thought to cause hepatitis.