CongenitalTrypanosoma cruziTransmission in Santa Cruz, Bolivia

Abstract

Background We conducted a study of congenital Trypanosoma cruzi infection in Santa Cruz, Bolivia. Our objective was to apply new tools to identify weak points in current screening algorithms, and find ways to improve them. Methods Women presenting for delivery were screened by rapid and conventional serological tests. For infants of infected mothers, blood specimens obtained on days 0, 7, 21, 30, 90, 180, and 270 were concentrated and examined microscopically; serological tests were performed for the day 90, 180, and 270 specimens. Maternal and infant specimens, including umbilical tissue, were tested by polymerase chain reaction (PCR) targeting the kinetoplast minicircle and by quantitative PCR. Results Of 530 women, 154 (29%) were seropositive. Ten infants had congenital T. cruzi infection. Only 4 infants had positive results of microscopy evaluation in the first month, and none had positive cord blood microscopy results. PCR results were positive for 6 (67%) of 9 cord blood and 7 (87.5%) of 8 umbilical tissue specimens. PCR-positive women were more likely to transmit T. cruzi than were seropositive women with negative PCR results (P < .05). Parasite loads determined by quantitative PCR were higher for mothers of infected infants than for seropositive mothers of uninfected infants (P < .01). Despite intensive efforts, only 58% of at-risk infants had a month 9 specimen collected. Conclusions On the basis of the low sensitivity of microscopy in cord blood and high rate of loss to follow-up, we estimate that current screening programs miss one-half of all infected infants. Molecular techniques may improve early detection.

Mother-to-Child Transmission of Trypanosoma cruzi

“…In addition, maternal age has also been associated with congenital T cruzi infection; however, study findings have been inconsistent. Investigators have reported higher odds of T cruzi with increasing maternal age [6,36]. Another study indicates higher risk of congenital T cruzi infection was associated with younger maternal age, perhaps a result of recent maternal infection [20].…”

“…The results are used to identify infants at risk of congenital infection [9]. However, concordance between different rapid tests has been low in some countries, and there is a need to develop new valid and reproducible tests [6]. Diagnostic protocols require use of 2 or more different tests and a lengthy follow-up schedule for appropriate and complete examination of infants born to infected mothers [2].…”

“…Maternal parasitic load has been associated with congenital transmission [6,13,33,34]. Among pregnant T cruzi-infected women in Bolivia, Hermann et al [33] observed increased risk of congenital T cruzi transmission for women with high maternal parasitic load.…”

“…The immunological state of the mother [6,[33][34][35] and fetus [16,[43][44][45][46] may be important for congenital transmission. Hermann et al [33] observed that decreased maternal immune response to parasitic antigens was associated with increased risk of congenital transmission.…”

“…Control of blood supply sources for T cruzi infection has been rigorously addressed in many countries [3]. The success with vector control has led to a relative increase in the burden attributed to congenital transmission of T cruzi [5][6][7][8]. This review will highlight gaps in the literature and focus on diagnosis, clinical features, prevention, treatment, epidemiology, and pathophysiology of mother-to-child transmission (MTCT) of T cruzi.…”