Strongyloides stercoralis infection increases the likelihood to detect Trypanosoma cruzi DNA in peripheral blood in Chagas disease patients.

OBJECTIVES: In a previous study performed by our group, Strongyloides stercoralis infection in patients with Chagas disease was associated with higher proportion of Trypanosoma cruzi DNA detection in peripheral blood. The aim of the study was to confirm this association in a larger cohort of patients. METHODS: Cross-sectional study of all patients with Chagas disease diagnosed from 2005 to 2015 during blood donation at the Catalan Blood Bank. Demographic data and T. cruzi RT-PCR were collected. S. stercoralis infection diagnosis was based on a serological test. RESULTS: Two hundred and two blood donors were included. T. cruzi RT-PCR was positive in 72 (35.6%) patients, and S. stercoralis serology was positive in 22 (10.9%) patients. Patients with positive S. stercoralis serology had higher proportion of positive T. cruzi RT-PCR than those with negative serology (54.5% vs. 33.3%, P = 0.050), and the difference increased when taking a serological index cut-off of 2.5, which increases the specificity of the test to detect a confirmed strongyloidiasis (60% vs. 33%, P = 0.017). CONCLUSIONS: Patients with Chagas disease with positive S. stercoralis serology had higher proportion of positive T. cruzi RT-PCR in peripheral blood than those with negative serology, which reflects the potential immunomodulatory effects of S. stercoralis in T. cruzi co-infected patients.