I once heard a tattoo defined as "a permanent reminder of a temporary feeling."

Some years ago, those who went under the needle often lived to regret it, but now tattoos -- or body art, as they are more popularly called -- are fairly common. Statistics vary as to how many people have become walking art galleries, but in 2003, a Harris poll found that 16 percent of all adults have at least one tattoo. The highest incidence was among 25- to 29-year-olds, at 36 percent.

No doubt those numbers today are higher yet; unfortunately, this also means that ever more people are unaware of the chief health risk posed by acquiring body art: becoming infected with the hepatitis B and/or hepatitis C viruses.

These two strains of hepatitis are blood-borne viruses transmitted through blood-to-blood contact. Both strains can result in severe liver damage.

The viruses can be transmitted by both the ink and the needle used to inject the ink below the skin.

According to a study presented in mid-October at a conference of the American College of Gastroenterology, college students are mostly unaware of the dangers of acquiring hepatitis when they get tattoos or engage in other high-risk behaviors --ñ intravenous drug use, sniffing cocaine, body piercing and sharing body jewelry. The researchers also were surprised at how infrequently primary care providers ask young adults about these behaviors.

Just what are the risks of contracting hepatitis B and hepatitis C from the tattooing process?

It's difficult to tell exactly, said Dr. Tarek Hassanein, medical director of liver transplantation and chief of clinical hepatology at UCSD.

"That's because many of our patients have multiple risk factors in addition to tattoos --ñ IV drug use, intranasal straw use, blood transfusions before 1992," he said. (Tests were developed after 1992 to test for hepatitis in donated blood.)

If a tattoo is a must, there are several things to know, but the bottom line is that customers are at the mercy of the tattoo artist and his or her equipment.

Ask artists if they are using sterile needles and not re-using ink, Hassanein advised, adding "there is no fool-proof way of knowing whether the ink is unused."

One Web site that has extensive explanations of considerations when choosing a tattoo artist and questions regarding safety factors is http://tattoo.about.com/cs/beginners/a/blchecklist.htm.

According to the Centers for Disease Control and Prevention Web site, the agency is currently conducting a large study to evaluate tattooing as a potential risk for acquiring hepatitis B and hepatitis C infections.

Blow-dry those lice

On the horizon: The LouseBuster, a machine that uses hot, dry air to kill head lice. Developed at the University of Utah, the prototype looks like a small vacuum cleaner and is more effective than the chemical shampoos for which consumers spend $160 million a year. A single, 30-minute treatment will do the job, researchers say.

A cautionary note: A hair dryer cannot substitute for the LouseBuster. The hair dryer is actually too hot, and the LouseBuster produces twice the air flow and has a special piece that helps expose the hair roots.

According to epidemiologists, six million to 12 million Americans are infested with head lice annually, and children miss 12 million to 24 million school days because of the condition, known as pediculosis.

- E'Louise Ondash of Vista is a registered nurse. Contact her at elo3@cox.net.