NEW YORK 2-1-98 (Reuters) -- Health experts now view hepatitis C virus (HCV) infection as a major health threat worldwide, according to an article in this week's issue of The Lancet.

Already a major reason for liver transplants in adults in most countries, deaths due to liver complications from HCV infection are expected to triple over the next two decades in the United States -- eventually surpassing those caused by AIDS, according Dr. Adrian Di Bisceglie of St. Louis University School of Medicine in Missouri.

Experts estimate that as many as 1% to 2% of the populations of most developed countries are infected with HCV, while infection rates run even higher in parts of eastern Europe and Africa. "Egypt seems to have one of the highest prevalence rates of all, approaching 15% of the general population," he writes.

In the US, where HCV now causes 8,000 to 10,000 deaths a year, nearly 4 million people are infected with the virus, according to the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia.

In developed countries, the greatest risk of HCV infection was once thought to be contaminated blood transfusions. With the advent of new screening tests, however, it is now known that injection drug users also run a high risk, especially those who share needles.

Recent studies -- including a Swedish-Honduran investigation reported by Reuters -- suggest that HCV can be transmitted through sex. And according to Di Bisceglie, the CDC says individuals with multiple sexual partners are "clearly at greatest risk of having HCV."

Many people infected with HCV find out about it during a routine medical examination. Liver disease, including cirrhosis, may develop in about 20% of patients.

In terms of treatment, The Lancet article notes that long-term treatment (12 to 18 months) with an interferon drug may improve liver function and rid the virus from the blood in as many as 30% of HCV patients. But "definitive therapy for hepatitis C probably awaits the development" of new anti-viral drugs that act specifically against HCV, the author concludes.

SOURCE: The Lancet (1998;351:351-355)