Vector control has led to a drastic decrease in the prevalence of acquired Chagas disease in Latin America, thus redirecting attention to congenital Chagas disease. We report results of a longitudinal study of 359 pregnant women in Yacuiba in southern Bolivia, of whom 147 (40.9%) were infected with Trypanosoma cruzi, to evaluate the relationship between the patency period of the parasitemia and the risk of congenital infection. Maternal infection was assessed by using T. cruzi-specific serologic tests, and parasitemia in mothers and newborns was diagnosed by using microscopic examination of blood in heparinized microhematocrit tubes. Parasitemia was present in 28.6% of the infected women. Its prevalence increased during the third trimester, then decreased at delivery. The likelihood of congenital infection was significantly correlated with the parasite density in the mother's blood. The risk of transmission increased during the third trimester of pregnancy and could explain premature births or low-weight newborns for infected mothers.
Background: Complement C4 gene copy number variation plays an important role as a determinant of genetic susceptibility to common diseases, such as systemic lupus erythematosus, schizophrenia, rheumatoid arthritis, and infectious diseases. This study aimed to develop an assay for the quantification of copy number variations in the C4 locus. Methods: the assay was based on a gene ratio analysis copy enumeration (GRACE) PCR combined with high resolution melting (HRM) PCR. The test was optimized using samples of a known genotype and validated with 72 DNA samples from healthy blood donors. Results: to validate the assay, standard curves were generated by plotting the C4/RP1 ratio values against copy number variation (CNV) for each gene, using genomic DNA with known C4 CNV. The range of copy numbers in control individuals was comparable to distributions observed in previous studies of European descent. Conclusions: the method herein described significantly simplifies C4 CNV diagnosis to validate the assay.
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