Cord Blood Sample Screening for Evidence of Maternal Chagas Disease

To the Editor: The article by Edwards et al. (1) contained several errors regarding testing, results, and interpretation of results. The authors incorrectly described the testing performed for the cord blood samples. The American Red Cross (ARC) National Testing Laboratory (NTL) (identified as the “American Red Cross National Donor Testing Laboratory” in the article) has never performed indirect hemagglutination assay testing, a method not licensed by the Food and Drug Administration (FDA) for detection of antibodies to Trypanosoma cruzi. In fact, the laboratory used a combination of testing algorithms during 2007–2014, the period of the study, involving 2 different FDA-licensed screening tests and a combination of research and licensed supplemental tests. Each algorithm had varying positive predictive values, ranging from <10% to >50%. The laboratory Given the paucity of literature data regarding malaria prevalence in internationally adopted children, testing by PCR, microscopy, or both, followed by treatment of infected children, would be preferable to the empiric treatment, considering the costs and possible adverse effects of antimarial drugs. Moreover, the preferable screening strategy is not apparent. We did not observe any discrepancy between microscopy and PCR results; however, a higher sensitivity by PCR has been reported (4,5). In contrast, some experts prefer testing by microscopy examination because PCR techniques are not sufficiently standardized or validated to be used for routine clinical diagnosis (2). In our dataset, malaria prevalence was substantially higher than that previously reported (4). This finding may be due to the particular situation of these children and to orphanage conditions (i.e., lack of mosquito nets). Moreover, it should be noted that, to date, 3 countries— DRC, Nigeria, and India—account for 40% of all estimated malaria cases in the world (6). Also, a high prevalence of asymptomatic malaria in DRC has been reported, in ≈15% of children (7,8). Our results should be interpreted with caution, given the small dataset, but they should alert pediatricians regarding the importance of assessing malaria risk in children who have been adopted internationally. The degree of malaria endemicity in the child’s area of origin may be considered in the decision to screen asymptomatic children adopted in non–malaria-endemic countries. In particular, children who come from areas of high malaria endemicity, such as DRC, deserve a careful screening, even in the absence of any sign or symptom.