Hepatitis B Virus
Acute HBV is the greatest cause of viral hepatitis throughout the world. World Health Organization figures released in 1992 indicate that as many as 350 million people worldwide carry the highly infectious HBV. Because of its severity and often lengthy duration, coupled with the lack of any effective treatment, 40% of those carriers—possibly as many as two million per year—will eventually die from resultant liver cancer or cirrhosis. HBV-related liver cancer deaths are second only to tobacco-related deaths worldwide. Infected children who survive into adulthood may suffer for years from the damage caused to the liver. In the United States alone, as many as 300,000 people become infected with HBV every year, medical costs amount to more than $1 million per day, and the death rate over the last 15 or so years has more than doubled in the U.S.A. and Canada.
If serology tests detect the presence of HBV six months or more from time of initial diagnosis, the virus is then termed "chronic." Chronic persistent hepatitis may develop following a severe episode of acute HBV. Within a year or two, however, this type usually runs its course and the patient recovers without serious liver damage. Chronic active hepatitis also may follow a severe attack of acute HBV infection, or it may simply develop almost unnoticed. Unlike persistent hepatitis, the chronic active type usually continues until fatal liver damage occurs. In long-term studies of 17 patients with chronic active hepatitis, 70% developed cirrhosis of the liver within two to five years. Fortunately, this type of hepatitis is rarely seen in children. Several modes of treatment—including the use of steroids—have been relatively unsuccessful, and treatment with corticosteroids, while appearing at first to have some positive benefit, actually cause additional liver damage.
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