The risk for Chagas' disease in the Midwestern United States organ donor population is low

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.

A total of 1117 serum samples from 558 locally recovered deceased donors, 178 imported deceased donors, and 212 live donors were tested (several duplicates were included). Samples were screened for antibodies 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).

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.

The risk of transmission of Chagas' disease by organ transplantation 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 perform, 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.