The number of cases of Hepatitis C is down, but millions are chronically infected and may not know it, reports the September 2010 issue of The Harvard Health Letter.

Hepatitis C—sometimes shortened to “hep C”—is transmitted through blood. Before it was identified, it was spreading through blood transfusions, medical procedures such as kidney dialysis and organ transplantation, and needle sharing by intravenous drug users. The discovery of the virus meant that screening tests could be developed to find it. Diagnosis and treatment of the infection also became possible. Today, it is estimated that about 20,000 Americans are newly infected with hep C each year.

Hep C is not a conquered disease. Many infected people don’t realize they have the disease, because of a lack of symptoms, or that they can spread it to others. Hep C can lead to liver cirrhosis and liver cancer, and about 10,000 Americans die each year from it. There’s no vaccine, and the current treatments have bad side effects and aren’t effective in many cases.

Frequently, initial infection with the hep C virus doesn’t cause any notable symptoms. Some people (about 25%) may feel tired or feverish, lose their appetite, or have some pain in the upper right part of the abdomen, where the liver is located. Even when infection persists and becomes chronic, which happens about 80% of the time, hep C often doesn’t cause symptoms and can lurk undetected for decades. As a result, an infection is often discovered incidentally when a routine blood test shows a spike in certain liver-related enzymes.

The Harvard Health Letter notes that it isn’t clear why some people get cirrhosis while others live with chronic hep C infections that cause little, if any, harm to their livers. But several factors have been identified, including alcohol consumption, age, and race.

Read the full article: “The smoldering epidemic”