Blood banks put at risk by parasite

By Rong-Gong Lin II March 15, 2007 in print edition B-1 Note This article includes corrections to the original version. A little-known but potentially deadly parasite from Latin America has become one of the latest threats to the blood and organ supplies in the United States, especially in Los Angeles, where many donors have traveled to affected countries, health officials say. Last year, two heart transplant patients at different Los Angeles hospitals contracted the parasitic disease, called Chagas, causing health authorities to issue a national bulletin. Within months, both patients subsequently died, although not directly from Chagas, according to the U.S. Centers for Disease Control and Prevention. The parasite, which is generally passed to humans from a blood-sucking insect that looks like a striped cockroach, can feed over years on tissues of the heart and gastrointestinal tract. After decades, tissues can be eroded so much that the organs fail. Insect transmission of the parasite in the United States is rare, but public health and blood bank officials have been concerned about its increasing prevalence in the blood supply. In 1996, using an experimental test, the American Red Cross found that one in 9,850 blood donors in the L.A. area tested positive for the parasite, Trypanosoma cruzi. Two years later, it was one in every 3,400. By 2008, a more refined test detected the parasite in one in 6,800 donors. About 10% to 30% of infected people develop symptoms of chronic disease, experts say.