Dengue virus found in donated blood

From Philadelphia, at a meeting of the American Society of Tropical Medicine and Hygiene

The virus that causes dengue fever has turned up in a dozen units of blood donated in Puerto Rico. The disturbing finding suggests that authorities might need to screen for the mosquito-borne virus in endemic areas, says epidemiologist Hamish Mohammed of the Centers for Disease Control and Prevention in San Juan, Puerto Rico.

Blood from donors in Puerto Rico also goes to other Caribbean islands and the United States. Blood donations are not currently screened for dengue virus, Mohammed says.

He and his colleagues tested more than 16,000 blood donations in Puerto Rico between September and December 2005, just after the peak of dengue season. They found 12 units that showed clear evidence of dengue-virus contamination.

People donating blood are asked pointedly about their health, but that may not be enough because “blood donors may present without any obvious illness,” Mohammed says. Initially, dengue cases are often mild or even asymptomatic. More-severe infections can cause high fever, chills, and severe back pain, hence the common name “break-bone fever.”

Susan Stramer of the American Red Cross in Gaithersburg, Md., says that health officials are collecting blood samples donated in Puerto Rico this year for testing later. As part of a larger study starting in 2008, the Red Cross and local officials plan to begin screening blood in Puerto Rico for dengue virus at the time it is donated.