There are many different types of hepatitis. The most common types, identified alphabetically as A, B, and C are all viruses that can cause liver damage.
Hepatitis A is spread through contaminated food and water. There is a safe and effective preventative vaccine for hepatitis A. If you have not been vaccinated and are traveling outside of the US, you should see your physician.
Hepatitis B also has a safe preventative vaccination. It is spread through infected blood, sex, and shared needles. An infected mother can also infect her newborn child. Unfortunately, hepatitis B patients are also at risk for developing a companion type virus, hep D. Hep D is only found in people who already have type B which worsens the symptoms of the original virus.
Hepatitis C is the most common type of viral hepatitis. Typically spread through contaminated blood products and needles. There is no vaccine, but there are several antiviral treatments that are showing great promise in actually curing patients with hep C.
It is estimated that as many as 5 million are infected and as many as 75% of those are unaware that they carry the virus. Testing is simple, so you should speak to your doctor.