Browsing by Autor "Edward Valencia Ayala"

Filter results by typing the first few letters
Now showing 1 - 3 of 3
  • Thumbnail Image
    Item type: Item ,
    IgG Subclasses and Congenital Transmission of Chagas Disease
    (American Society of Tropical Medicine and Hygiene, 2021) Cristian Roca; Edith S. Málaga-Machaca; Manuela Verástegui; Billy Scola; Edward Valencia Ayala; María del Carmen Menduiña; Sassan Noazin; Natalie M. Bowman; Freddy Tinajeros; Robert H. Gilman
    The mechanism of vertical transmission of Trypanosoma cruzi is poorly understood. In this study, we evaluated the role of IgG subclasses in the congenital transmission of Chagas disease. We conducted a case-control study in a public maternity hospital in Santa Cruz, Bolivia, enrolling women at delivery. Thirty women who transmitted T. cruzi to their newborns (cases), and 51 women who did not (controls) were randomly selected from 676 total seropositive women. Trypanosoma cruzi-specific IgG1, IgG2, and IgG3 levels were measured by in-house ELISA. The IgG4 levels were unmeasurable as a result of low levels in all participants. Quantitative polymerase chain reaction results and demographic factors were also analyzed. One-unit increases in normalized absorbance ratio of IgG1 or IgG2 levels increased the odds of congenital T. cruzi transmission in Chagas-seropositive women by 2.0 (95% CI: 1.1-3.6) and 2.27 (95% CI: 0.9-5.7), adjusted for age and previous blood transfusion. Odds of congenital transmission were 7.0 times higher in parasitemic mothers (95% CI: 2.3-21.3, P < 0.01) compared with nonparasitemic mothers. We observed that all mothers with IgG1 ≥ 4 were transmitters (sensitivity = 20%, specificity = 100%). Additionally, no mothers with IgG2 < 1.13 were transmitters (sensitivity = 100%, specificity = 21.6%). We demonstrated that IgG subclasses and parasite presence in blood are associated with vertical transmission of T. cruzi and could identify women at increased risk for congenital transmission by measuring IgG subclasses. These measures have potential as objective screening tests to predict the congenital transmission of Chagas.
  • Thumbnail Image
    Item type: Item ,
    Multiplex Real-Time PCR Assay Using TaqMan Probes for the Identification of Trypanosoma cruzi DTUs in Biological and Clinical Samples
    (Public Library of Science, 2015) Carolina Cura; Tomás Duffy; Raúl Horacio Lucero; Margarita Bisio; Julie Péneau; Matilde Jiménez‐Coello; Eva Muñoz; María-José Giménez; Edward Valencia Ayala; Sonia A. Kjos
    Typing is resolved after a single or a second round of Real-Time PCR, depending on the DTU. This format reduces carryover contamination and is amenable to quantification, automation and kit production.
  • Thumbnail Image
    Item type: Item ,
    Use of a Chagas Urine Nanoparticle Test (Chunap) to Correlate with Parasitemia Levels in T. cruzi/HIV Co-infected Patients
    (Public Library of Science, 2016) Yagahira E. Castro-Sesquen; Robert H. Gilman; Carolina Mejía; Daniel E. Clark; Jeong Won Choi; Melissa Reimer-McAtee; Rosario Castro; Edward Valencia Ayala; Jorge Flores; Natalie M. Bowman
    Chunap shows potential for early detection of Chagas reactivation. With appropriate adaptation, this diagnostic test can be used to monitor Chagas disease status in T. cruzi/HIV co-infected patients.