Health officials want almost 2,000 people in five states and the District of Columbia to get tested for hepatitis B after five people involved with a free two-day dental clinic in West Virginia contracted the disease.
The clinic was held in June 2009 at the Mission of Mercy Dental Clinic in Berkeley County, W.Va.
Three patients and two volunteers developed acute hepatitis B in November. Health officials said it's not certain they caught the disease at the clinic, but tests show four may have been infected by the same source.
Letters recommending testing for hepatitis B are being mailed to 1,137 patients and 826 volunteers at the clinic, according to the Berkeley County Health Department.
Most of the letters are going to West Virginians, but people from D.C., Virginia, Maryland, Pennsylvania and North Carolina also attended the event and are being told to get tested. Officials said the risk of widespread illness is low, but they are concerned some people may not know they are sick and could pass the disease to others.
"The problem comes if there has been unrecognized transmission and someone is chronically infected," said Danae Bixler, of the West Virginia Bureau of Public Health. "They need to know that."
About 90 percent of people who get hepatitis B recover, but 10 percent get a chronic form of the disease that can cause liver damage.