In Nonendemic Areas, Is Microscopy Better than Polymerase Chain Reaction for Diagnosis of Congenital Chagas Disease?

[Q1][Q2]To the Editor—We read with interest the review [Q3]article by Rosenblat published in Clinical Infectious Diseases [1]. The author states that “the standard method for diagnosis of American trypanosomiasis during the acute phase of infection is microscopy of thick and thin blood or buffy coat” [1, p 1107[Q4]]. In Spain, immigration has increased continuously in recent years, and we started testing pregnant Bolivian women 2 years ago. Thus far, 71 of these women have received a diagnosis of Chagas Disease [2]. In one case of vertical transmission, the diagnosis in the newborn could only be made with use of polymerase chain reaction (PCR). In the largest cohort of Latin-American pregnant women to date in Europe, follow-up was performed with PCR alone [3]. The appropriate diagnosis of American trypanosomiasis by microscopy requires expert eyes. [Q5]In countries where Trypanosoma cruzi is endemic, the superiority of PCR over microscopy has been demonstrated (reports from Argentina [4], Bolivia [5], and Paraguay [6]). PCR assays for T. cruzi now have enough sensitivity and specificity to be considered the standard method for diagnosis in areas where T. cruzi is not endemic and where there are less experienced microbiologists.