"In patients with cirrhosis, we recommend complete abstinence. Even small amounts of drinking can accelerate disease progression," Lok says.

Prevention is also an important tool for preventing the spread of these infections. There are specific preventions people can take to protect others, such as avoiding sharing needles or household articles (such as razors and toothbrushes) that may be contaminated with blood, and practicing safe sex. There are vaccines for hepatitis A and B. As hepatitis C is spread only through blood-to-blood contact, health care workers, law enforcement personnel and others at risk for exposure are trained in the precautions they can take.

Here are the facts:

Hepatitis A: This liver infection is largely spread through contaminated food or water. It causes acute infection only, meaning there is a single transient episode of the disease. The virus is harbored in the stools of people who are infected and can move to other people's food via unwashed hands. Problems with municipal sewage systems can also release infected sewage into the water supply.

The older an infected person is, the more likely the acute attack will be severe. Mortality is between two and three percent if the patient's age is over 50, but mortality is nearly zero for younger people. People can have it and not know it because the symptoms aren't always severe.

• Hepatitis A symptoms: Fever, fatigue, loss of appetite, nausea, vomiting and jaundice.
• Diagnosis: Blood test
• People at risk: People traveling to underdeveloped countries; the military; those working in day care where there are a lot of incontinent babies in diapers
• How it spreads: Usually spread by eating food or drinking water that has been contaminated by the virus. The virus can be found in the stools of people who have hepatitis A, so poor hand-washing techniques by someone infected with the virus, or sewage spills into the community water system are common ways for the virus to spread.
• Prevention: For people at risk: vaccination. To minimize spread to food and water: good hand washing techniques among people with hepatitis A; enforcing sewage laws and keeping sewage treatment plants in good working condition
  
• Treatment: Most people improve on their own, over a few weeks or months. Hepatitis A does not progress to chronic infection and will not cause cirrhosis.

Hepatitis B: This liver infection is spread via bodily fluids such as blood, saliva or semen. Thus, pregnant mothers can transmit it to their infants. People engaged in unprotected sex and drug users who share needles are also at risk.

"Hepatitis B can be acute, but it can also progress to a chronic condition, meaning it lasts for longer than six months. Younger people who contract hepatitis B are more likely to progress to the chronic stage. Ninety percent of babies with acute hepatitis B progress to the chronic stage but only two to five percent of adults move from the acute to chronic stage," says Lok.

Because the disease frequently progresses to chronic infection, the CDC recommends that the hepatitis B vaccine be given to all babies at birth. For children and adolescents born before the implementation of universal vaccination, catch-up vaccination is recommended. Adults should consider the vaccine if they are at risk.

• Hepatitis B symptoms: During the acute stage: fever, fatigue, loss of appetite, nausea, vomiting and jaundice.
• Diagnosis: Blood test
• People at risk: Health care workers, some law enforcement personnel, drug users sharing needles, babies born to mothers already infected, someone having unprotected sex with a hepatitis B-positive partner, people from areas where hepatitis B is common, such as: eastern Europe, southeast Asia, some African countries.
• How it spreads: Direct contact with bodily fluids, such as blood, semen and saliva, for example, through unprotected sexual contact or sharing of needles during drug use. It can also be spread from an infected mother to a baby during childbirth.
• Prevention: For people at risk: vaccination. Avoid exposure to blood or bodily fluids. Do not share razors or toothbrushes. Use safe sex practices utilizing barrier contraception (condoms).
• Treatment: There is no cure at this time. Some people carry the virus but remain well. Two approved treatments are available for those with chronic hepatitis B but not all patients respond to these treatments, and long-term response is uncommon.

Hepatitis C: The virus for hepatitis C is largely spread via a blood-to-blood contact. People who have had a blood transfusion before 1990 (when effective blood screening tests were developed) are at risk, as well as anyone sharing needles.

"Unfortunately, despite very diligent work, we still haven't come up with a vaccine for hepatitis C. That's one reason why so much attention is paid to treating hepatitis C," says Lok.