Transfusion-associated Chagas disease (American trypanosomiasis) in Mexico: implications for transfusion medicine in the United States.
BACKGROUND
Trypanosoma cruzi, the protozoan cause of Chagas disease, causes life-long infection and is easily transmitted by blood transfusion. Our goals were to determine the prevalence of Chagas disease among donors in five Mexican blood banks, to look for evidence of transmission of T. cruzi by transfusion, and to evaluate two serologic assays for Chagas disease.


METHODS
Blood samples from donors were tested initially with the Abbott Chagas EIA or the Meridian Chagas' IgG ELISA. Samples giving readings that were at least 50% of the cutoffs were run in a confirmatory radioimmune precipitation assay (RIPA), as were samples from recipients of blood products from RIPA-positive donors.


RESULTS
The overall prevalence of Chagas disease was 1/133 (55/7,296; 0.75%). In addition, 4 of 9 surviving recipients of blood products from T. cruzi-infected donors were in turn infected. Using the manufacturers' recommended cutoffs, the sensitivity and specificity of the Abbott test were 92.0% (23/25) and 99.8% (2,865/2,872) respectively, and the corresponding values for the Meridian assay were 70.0% (21/30) and 100.0% (4,369/4,369).


CONCLUSIONS
These findings indicate clearly that transfusion-associated transmission of T. cruzi is occurring in the study areas. Serologic testing of blood donors for Chagas disease should be performed there and in the rest of Mexico. The two screening assays evaluated may lack the accuracy necessary for blood donor testing when used as suggested by the manufacturers.
Kirchhoff
Louis V
LV
Department of Internal Medicine, University of Iowa, Department of Veterans Affairs Medical Center, Iowa City, Iowa 52242, USA. louis-kirchhoff@uiowa.edu
Paredes
Patricia
P
Lomelí-Guerrero
Abel
A
Paredes-Espinoza
Mario
M
Ron-Guerrero
Carlos S
CS
Delgado-Mejía
Manuel
M
Peña-Muñoz
José G
JG
D000328:Adult; D000818:Animals; D001803:Blood Transfusion / Q000706:statistics & numerical data*; D014355:Chagas Disease / Q000097:blood / Q000453:epidemiology / Q000635:transmission; D019353:Endemic Diseases / Q000706:statistics & numerical data; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D015995:Prevalence; D014349:Trypanosoma cruzi / Q000302:isolation & purification*; D014481:United States / Q000208:ethnology