Blood donated at the Blood Alliance and other blood centers across the United States is now being tested for Trypanosoma cruzi, a parasite that causes a chronic illness called Chagas disease.

What is Chagas Disease?

Chagas disease develops after infection with the T. cruzi parasite, as a result of a bite by an infected reduvid bug. These insects are rare in the U.S., but are more commonly found in Latin American countries. Once infected, the person develops “antibodies” that indicate they have been infected. The parasite stays in the body for years, without symptoms, but ultimately can cause damage to the heart muscle or intestinal walls. As we become a more diverse country, donations from those who were born in or resided in other countries may unknowingly pass along the infection to recipients of their blood.

How is it diagnosed?

By screening donations with a test for antibodies to the T. cruzi parasite, another potential transfusion transmitted disease can be prevented. Blood banks in states where immigration from Mexico, Central and South American is most common have begun using the test since early in 2007. The map below indicates sites where potentially infected donors have been identified.

What if my blood donation tests positive?

As with all blood screening tests, a positive result does not automatically mean that you are infected with T. cruzi. An additional confirmatory test is performed to make sure the positive test is due to this specific parasite. There are other infections that can lead to a positive screening test- including malaria and leishmania – diseases seen in those traveling outside the US. Occasionally, tests can be positive in otherwise healthy individuals for poorly understood reasons. Blood from donors with positive tests will not be used for transfusion. A safe blood supply is essential for the peace of mind of the patients we serve.

Below is a map showing the latest confirmed positive cases by ZIP code.

Continental U.S. Map: RIPA Positives (updated 5/10/07)