More than 15,000 Americans die each year from illnesses related to hepatitis C, a number that has nearly doubled in the past decade.
That growing toll and an unusual combination of risk factors has prompted federal public health officials to propose that all Americans born between 1945 and 1965 get a one-time screening test for the virus.
According to the Centers for Disease Control and Prevention, as many as 2 million baby boomers are infected with hepatitis C, a contagious liver disease that ranges from a mild bout to a serious lifelong illness. The total number of infections in the U.S. is estimated at about 3.2 million.
Americans born during those years are thought to harbor as much as 75 percent of all adult HCV infections, but the CDC says as many as 1.5 million boomers carrying the virus don't know it.
So the CDC in mid-August set new guidelines urging all boomers to get the test just once. It's estimated that such testing could identify more than 800,000 additional people with the infection.
Baby boomers are at high risk for infection partly because of past behavior. In the 1970s and '80s, more than a few experimented with needle drugs.
There were tattoo parties. During the same period, health care settings exposed patients -- for surgery, dialysis and blood transfusions -- to higher risk. Widespread precautions, including testing of blood, didn't start until 1992.
Even shared razors, toothbrushes and manicure tools can spread the virus. And sexual transmission of the virus is possible, although rare, as is passing of the virus from mother to infant during birth.
Many people don't show any symptoms from the infections for as long as 30 years -- and up to a quarter of those infected are able to clear it from their bodies without any medicine.
But left untreated, hepatitis C can advance to attack the liver. It is the leading cause of liver cancer and liver transplants. The only way to be sure about infection is with a blood test, which is relatively inexpensive -- around $10 and up -- and usually covered by insurance.
It's important to note, however, that the recommended test only determines if a person is carrying the antibody for hepatitis C, not whether there's an active infection. With a positive test result, a person will need additional tests to confirm that the virus is actually present in the bloodstream.
It's also recommended that anyone identified with HCV infection have a prompt discussion with a doctor about alcohol use, since drinking alcohol is known to speed the progression of liver disease.
Studies have found that HCV can survive outside the body on surfaces at room temperature for at least 16 hours but no longer than four days.
The head of CDC's Division of Viral Hepatitis, Dr. John Ward, told reporters that several new therapies are capable of curing up to 75 percent of people treated for HCV, and even better drugs are in development.
"The earlier the treatment is provided, the more effective it can be at reducing risk for liver damage and liver cancer," Ward said.
Other treatments for the virus have proved effective only about a third of the time. There is no vaccine for hepatitis C, as there is for hepatitis A and B, although researchers are working to come up with one.