Congenital Trypanosoma cruzi infection is a highly pathogenic and underreported condition. Early recognition is essential for effective treatment. Umbilical chord blood from newborns (n = 302) to infected mothers was analyzed with microhematocrit, hemoculture, and PCR methods. Each subject was then followed serologically. In calibrated suspensions of T. cruzi in blood, the sensitivity of PCR was 27-fold higher than hemoculture. However, this advantage was not reflected during routine testing of samples from maternities, partly because of the uneven distribution of few parasites in small samples. Levels of detection of congenital infection were 2.9% (8/272) for microhematocrit, 6.3% (18/287) for hemoculture, 6.4% (15/235) for PCR, and 8.9% (27/302) for cumulated results. Evaluation against the standard of delayed serology indicates that the regular application of PCR, hemoculture, and microhematocrit to blood samples allows the rapid detection of about 90% of the congenitally infected newborns, in samples that can be obtained before the mother and child leave the maternity ward.

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We evaluated the polymerase chain reaction (PCR) for the diagnosis of endemic American Tegumentary Leishmaniasis in Salta, Argentina. Diverse Leishmania species, coexistence of mycotic and varicose ulcers, and high endemicity T. cruzi, represent diagnostic challenges in the region. We performed a simplified PCR using sensitive, generic primers on samples obtained by a non-invasive method. We tested different culture types and clinical specimens with other microorganisms that induce leishmaniasis-like lesions. The PCR had a sensitivity and specificity of 100%. Forty-five patients with presumptive leishmaniasis were compared to the PCR, smears, and the Montenegro skin test (MST). In the same population, the PCR had an increased sensitivity, detecting 25 of 45 cases compared with 16 of 45 for smears and had a higher sensitivity in detecting mucocutaneous lesions. Diagnosis by PCR was supported by clinical presentation, positive MST results, compatible epidemiology, and in some cases histopathologic results or isolation of parasites by culture. These findings indicate the convenience of incorporating this PCR into diagnostic strategies for detecting leishmaniasis in northern Argentina.

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