Hepatitis B is caused by a virus that infects the liver, causing disease that can lead to a deadly cancer.  The World Health Organization calls hepatitis B a serious global public health problem.  Many people who have it, even in the United States, are completely unaware they are infected.  VOA's Carol Pearson has more.

The World Health Organization estimates that two billion people worldwide are infected with hepatitis B -- far more than the 40 million people living with HIV/AIDS.  Of those who are infected with hepatitis B, more than 300 million have a chronic or lifelong infection that puts them at risk of developing cancer or cirrhosis of the liver. High rates of hepatitis B can be found in much of the developing world. But western countries, including the United States, are also affected.

Anthony Chiu is a software developer in San Francisco, California. "And I had a really bad stomachache again.  So this time it was so bad, I had to go to the emergency room. So they gave me some medicine and they did some scans afterward and that's how I found out."

Chiu had a cancerous tumor half the size of his liver, but it had not spread, and the tumor was successfully removed.  His cancer was a result of having chronic hepatitis B.

San Francisco and other cities in the U.S. with large numbers of Asian immigrants have high rates of hepatitis B and liver cancer.  Many people do not know they have chronic hepatitis B.

Dr. Samuel So is trying to change that.  He is the director of the Asian Liver Center at Stanford University. "We call hepatitis B a silent killer because usually those who are infected feel perfectly healthy," he says.

Hepatitis B can be easily detected through a blood test.  A simple vaccine can provide lifelong protection. Dr. So says, with hepatitis B, it is important to have an early diagnosis. If someone does test positive, treatment is available. "There are now treatments as simple as taking a pill a day that could reduce the risk of developing liver cancer and liver disease."

Hepatitis B can be spread by contact with contaminated needles and through sex.

Mothers can pass it to their babies during childbirth. That is how Chiu contracted the disease.  Seven years after his surgery, he is still cancer free. "So far, so good. No recurrence at all.  I want to keep it that way."

In the United States, as in other countries, there is no screening program for immigrants and no funding for an adult vaccination program.  The Hepatitis Foundation International is an organization dedicated to the eradication of this disease.  The Foundation says hepatitis B is already a global epidemic, despite the fact that a relatively cheap and effective vaccine is available.