Blood banks in the United States will soon be following in the footsteps of Latin American countries by screening donated blood for Chagas’ disease, a parasitic infection that can damage the heart and cause early death. In December 2006, the U.S. Food and Drug Administration approved the first test to detect infected blood from blood donors in this country. Within a year, the test may also be approved for screening donated organs, cells, and tissues in this country.

Also called American trypanosomiasis, Chagas’ disease is caused by the tropical parasite Trypanosoma cruzi (T. cruzi). The disease is spread by human contact with infected reduviid bugs, also called “kissing bugs”, or by blood transfusion, placental transfer, organ transplantation or accidental ingestion of parasitized reduviid bugs. A person can become infected when a reduviid bug bites them and defecates on or near the bite site. The T. cruzi parasites in the feces enter through the wound or nearby mucous membranes surrounding the eyes or mouth. From there, the parasite can spread to the circulatory system. During certain medical procedures (namely, blood transfusions and organ transplants), the infection can be transmitted from person to person. An infected donor puts the recipient at risk.

A Disease on the Move
The disease has been a major health problem in many Latin American countries, and blood banks in those countries are expected to routinely screen donated blood with the tests available there. Human infections occur primarily in rural areas where poor sanitation and housing allow excellent breeding places for the reduviid bugs. Once just a threat in South America, Chagas’ disease is now found in U.S. and European cities.

In Mexico, Central America, and South America, 16 to 20 million people are infected.

In the United States, more than 100,00 people are infected.

In the United States, Canada, and countries in Europe, more than a dozen transfusion- and transplant-associated cases have been reported.

Testing Protects Blood Supply
Screening donated blood in North America has become important because the number of Latin Americans who may be blood donors is increasing. In areas with a large population of Latin American immigrants, such as Los Angeles County and Miami, infections might be more common than current data show.

The newly approved Chagas’ screening test will help in two ways. First, the test will help keep infected blood out of the U.S. blood supply. Second, data from the tests will better reveal the extent of the disease in this country.

Sources
S1
US Food and Drug Administration. 13 Dec 2006. FDA approves first test to screen blood donors for Chagas’ disease (FDA News press release). Rockville, Md. On the Internet: http://www.fda.gov/bbs/topics/NEWS/2006/NEW01524.html. Accessed 18 Dec 2006.

S2
Ortho-Clinical Diagnostics receives FDA approval for first blood-screening test for Chagas’ disease (press release). 13 Dec 2006. Raritan, New Jersey: Ortho-Clinical Diagnostics. On the Internet: http://www.orthoclinical.com/pressReleases.aspx?id=132. Accessed 3 Jan 2007.

S3
Duncan R. 17 May 2005. The outlook for Chagas’ disease, Leishmania and bioterror agent testing of blood (presentation). US Department of Health and Human Services, Advisory Committee on Blood Safety and Availability. Available on the Internet: http://www.os.dhhs.gov/bloodsafety/presentations/Duncan.pdf. Accessed 3 Jan 2007.

S4
Maguire, JH. 24 Aug 2006. Chagas’ disease—can we stop the deaths? New England Journal of Medicine, 355; 8:760-1.

S5
Chagas’ disease after organ transplantation—Los Angeles, California 2006. 28 July 2006. MMWR 55(29); 798-800. US Centers for Disease Control and Prevention. Available on the Internet: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5529a3.htm. Accessed 3 Jan 2007.

S6
Questions and answers: Chagas’ disease and blood screening (fact sheet). Atlanta, Ga: US Centers for Disease Control and Prevention, National Center for Infectious Diseases, Division of Parasitic Diseases. On the Internet: http://www.cdc.gov/ncidod/dpd/parasites/chagasdisease. Last reviewed 13 Dec 2006. Accessed 29 Dec 2006.