The risk for Chagas’ disease in the Midwestern United States organ donor population is low Reports from Latin America (1–3) have shown that transplanted kidneys can transmit Chagas’ disease through the infectious causative agent Trypanoso- ma cruzi. A recent MMWR report described the transmission of T. cruzi infection by an organ donor in the United States to three recipients of solid organ transplants (4). The index case was a woman aged 37 years who had received cadaveric kidney and pancreas transplants on 5 March 2001 and returned to the hospital on 19 April for evaluation of a febrile illness. On 23 April, T. cruzi trypomastigotes were identified on a peripheral blood smear. Subsequently, two other persons who had received organs from the same donor – a woman aged 32 years who had received the liver and a woman aged 69 years who had received the other kidney – were found to be infected with T. cruzi. Cultures of blood from all three recipients Bryan CF, Tegtmeier GE, Rafik N, Markham LE, Murillo D, Nelson PW, Shield III CF, Warady BA, Aeder MI. The risk for Chagas’ disease in the Midwestern United States organ donor population is low. Clin Transplant 2004: 18 (Suppl. 12): 12–15. Ó Blackwell Munksgaard, 2004 Abstract: Purpose: Several recent publications have increased awareness that transplanted organs can transmit infectious diseases. In light of the recent report describing the transmission of Trypanosoma cruzi infection by an organ donor in the United States (MMWR 2002: 51: 210), we have tested archived serum samples from our Organ Procurement Organization’s (OPO’s) deceased organ donors and live donors from 23 October 1995 through 1 March 2002. Methods: A total of 1117 serum samples from 558 locally recovered de- ceased donors, 178 imported deceased donors, and 212 live donors were tested (several duplicates were included). Samples were screened for anti- bodies to T. cruzi, the protozoan parasite that causes Chagas’ disease, with a passive particle agglutination assay (Fujirebio, Inc., Tokyo, Japan). Indeterminate samples (those agglutinating both sensitized and control particles) were absorbed with control antigen and re-tested. Inconclusive samples (those not yielding clearly negative or positive results) were re- tested using the original test format, and if persistently inconclusive, were assayed by radio-immune precipitation (RIPA). Results: Of the 770 local OPO donors (deceased and live donor) and the 178 imported donors tested, 52 (5.5%) were indeterminate, but following absorption, all were negative. Forty-four samples (4.6%) were inconclusive and after re-testing 34 were negative while 10 remained inconclusive. Those 10 samples were found to be negative by RIPA. Conclusions: The risk of transmission of Chagas’ disease by organ trans- plantation in the Midwestern United States is low because during a 6.5 year period, none of our deceased or live donors tested positive for antibodies to T. cruzi. Although the passive particle agglutination test is simple to per- form, easy to interpret and rapid enough to be used in screening organ donors, because of the rate of false positive results, it should only be utilized when the donor population is at high risk for previous exposure to T. cruzi. Christopher F Bryan a , Gary E Tegtmeier b , Nour Rafik b , Lori E Markham a , Daniel Murillo c , Paul W Nelson d , Charles F Shield III e , Bradley A Warady f and Mark I Aeder g a Midwest Transplant Network, Westwood, KS; b Community Blood Center of Greater Kansas City, Kansas City, MO; c University of Kansas Hospital, Kansas City, KS; d Saint Luke’s Hospital, Kansas City, MO; e Via Christi- St. Francis Regional Medical Center, Wichita, KS; f Children’s Mercy Hospital, Kansas City, MO; and g Research Medical Center, Kansas City, MO, USA Key words: Chagas’ T. cruzi – Midwest – OPO – organ donors Corresponding author: CF Bryan, Midwest Transplant Network, 1900 West 47th Place, Suite 400, Westwood, KS 66205-1867, USA. Tel.: +1 (913) 262-1668; fax: +1 (913) 262-5130; e-mail: cbryan@mwtn.org Clin Transplant 2004: 18 (Suppl. 12): 12–15 Copyright Ó Blackwell Munksgaard 2004 12