25 April 2007

Hepatitis B - Who gets it, What causes it?

Hepatitis B

What causes it?

HBV is transmitted from individual to individual through contact with infected bodily fluids, such as blood. Because chronic carriers of HBV are often unaware that they have the virus, they may transmit the disease to others unknowingly. Injecting illegal drugs with contaminated needles or having sex with an infected individual are common ways to become infected. Sharing and reusing diabetes blood testing supplies with any infected individual may also cause an individual to become infected. In addition, instruments such as those used for tattooing and body piercing can spread hepatitis if they are not properly sterilized between uses. A mother who is infected can transmit HBV to her baby during childbirth. However, it is not transmitted through breast-feeding.

Once HBV makes its way to the liver, it multiplies. Symptoms usually develop within one to 6 months. Exactly how liver cells are damaged or why some individuals acquire chronic infection or liver cancer is unknown.

Who has it?

Of all the serious transmittable diseases, hepatitis is the most common. Up to 100,000 new cases of hepatitis B are reported each year in the United States, and the Centers for Disease Control and Prevention (CDC) estimates that 1.25 million Americans are infected with chronic hepatitis B.

Hepatitis B affects individuals of both sexes and all ages, ethnic groups, and sexual orientations. About one-fifth of the world’s population will have hepatitis B at sometime in their lives. It is more common in males, with the highest occurrence between the ages of 20 and 49 years. Individuals with hemophilia may be slightly more at risk, if they use clotting factors that are made from human blood.

In the United States, the acute form of hepatitis has been declining due to the availability of an effective vaccine and the aggressive promotion of vaccination among children and teenagers. Changes in high-risk behavior may also contribute to the decrease. In 1990, approximately 21,000 Americans were believed to have acute hepatitis B. By 2002, that number had dropped to approximately 8,000.

Chronic hepatitis B affects an estimated 1.25 million Americans and about 400 million chronic carriers are believed to exist in the world population. As the number of acute cases goes down, the number of chronic carriers of hepatitis B is also expected to decline. However, increases in occurrence have been observed among the major risk groups: individuals with compromised immune systems, sexually active individuals, and injectable drug users.

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