Their finding followed an investigation into about three dozen cases of the liver infection that surfaced in 2003 and 2004 in nursing homes in Mississippi and North Carolina and an assisted living center in California.

Between 70,000 and 80,000 Americans contract hepatitis B each year, but most of them are young adults who have had unprotected sex with an infected person or shared dirty needles while injecting drugs.

The cases in the extended care facilities raised eyebrows because they occurred largely among elderly diabetics, according to a report published on Thursday by the Atlanta-based Centers for Disease Control and Prevention.

Investigators soon discovered that some of the equipment used to monitor blood sugar, including parts of fingersticks and glucometers, were being shared by patients in the homes, allowing for the possibility of cross-contamination.

Some nursing staff also were not wearing gloves or disinfecting their hands when administering the tests.

Since 1990, the CDC and the Food and Drug Administration have recommended that fingersticks, which draw a small trace of blood with a single prick, be restricted to a single use. The CDC also advises against sharing of glucometers.

Dr. Anthony Fiore, a CDC epidemiologist and one of the authors of the report, said he suspected other nursing homes across the nation were falling short of the federal guidelines, making them vulnerable to outbreaks of hepatitis B.

"These facilities looked perfectly nice and probably provided the same standard of care that many others provide," Fiore said. "I think it's a problem that could potentially exist elsewhere."

Fiore added that the three recent outbreaks were not identified or investigated in a timely manner, which complicated efforts to contain the spread of the virus, which is sometimes asymptomatic.

Those who do have symptoms of hepatitis B typically develop fatigue, fever, abdominal pain and jaundice. Most recover, although a small number go on to develop the chronic form of the disease.

Source: Diabetes In Control.com: CDC.