Chagas disease

Almost 100 years ago, the Brazilian physician Carlos Chagas discovered the parasite Trypanosoma cruzi, which causes Chagas' disease. Today, it infects as many as 18 million people worldwide. Once established in the body the infection is lifelong, and several thousand South and Central Americans die annually of heart and digestive problems caused by the parasite. Up to 20 percent of infected people never exhibit symptoms. Over the years, Chagas' disease has often been transmitted by transfusion in South America. Prior to the availability of a test, and since, there has been no treatment for Chagas' disease. Earlier, gentian violet was added directly to units of blood prior to transfusing them. More recently, testing for Chagas' disease has become routine in much of South America. While the infection remains rare outside of South and Central America, it has come to be considered a threat to the blood supply because of global travel and migration, especially from South America to North America. To date, there have been only seven cases of transfusion-transmitted Chagas' disease reported in North America (two of them in Canada), but it is estimated that several million people from countries where Chagas' disease is present now reside in the United States, and 100,000 or more may be infected with T. cruzi (Kirchoff et al.., 1987). In several investigational studies of US blood donors with confirmed sensitive tests, so far there has been only a handful of cases of blood donors with confirmed positive tests, but not all have been tracked to donors from countries where Chagas' disease is endemic. As a precaution, the American Association of Blood Banks' guidelines prohibit blood donation from anyone who has had Chagas' disease. Laboratory and screening tests are now under development. It is expected that, when approved, such testing will be implemented routinely on all donations.

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