Date of Award

Spring 2023

Document Type

Open Access Dissertation

Department

Epidemiology and Biostatistics

First Advisor

Melissa Nolan

Abstract

The primary goal of this dissertation was to understand the prevalence of the most regionally salient TORCH pathogens among a group of perinatal women from a highly vulnerable region of El Salvador at the time of parturition. TORCH pathogens, that cause TORCH congenital syndromes, are classically defined as Toxoplasma gondii, other infectious causes of concern (Zika virus, malaria, human immunodeficiency virus, etc), Rubella virus, Cytomegalovirus(CMV), and Herpes Simplex Viruses. These infections can be passed from mother to fetus through the placenta or other perinatal routes and cause severe maternal and neonatal morbidity and mortality. This dissertation sought to understand perinatal prevalence of four of these infections widely circulating in El Salvador: Chagas disease, toxoplasmosis, Zika virus, and Dengue virus. Additionally, this dissertation sought to clarify relationships between these four TORCH pathogens and 1) risk factors for pathogen infection and 2) maternal and neonatal outcomes associated with each pathogen infection. Spatial statistical analyses were also conducted to further investigate clustering of cases in order to define high risk areas for future studies and targeted interventions.

This study was approved by the National Ethics Committee of Health Research of El Salvador. We enrolled 198 patients ≥ 15 years of age presenting for labor and delivery at the national referent hospital of Sonsonate, El Salvador.

Participants donated a small blood sample and completed a demographic and lifetime infection risk questionnaire. We performed serologic assays for the presence of antibodies to the pathogens Toxoplasma gondii (toxoplasmosis), Trypanosoma cruzi (Chagas disease), Zika virus, and Dengue virus. Digital polymerase chain reaction was further performed for the detection of T. gondii and T. cruzi. Fisher’s exact test and logistic regression were used to determine significant associations between these pathogens, maternal and neonatal health outcomes, and risk factors for infection.

We found 35.8% of our study population had evidence of ≥ 1 TORCH pathogen analyzed during this investigation, and 5.1% had evidence of ≥ 2 TORCH pathogens. Approximately 6.0% of enrolled women were positive for Chagas disease. Nearly one quarter of enrolled women had evidence of recent Zika or Dengue virus infection within the last year, and 8.5% had evidence of recent toxoplasmosis infection or reactivation within 16 weeks. Chagas disease positivity was associated with older maternal age (OR=1.12, 95%CI: 1.03, 1.23), mother’s education level (p=0.022), and admission to the NICU (p=0.020). Evidence of a recent arboviral infection was associated with household fumigation within the last year by the Ministry of Health (OR=4.7, 95%CI: 1.78, 13.43), and Ministry of Health mosquito abatement assistance in the last year (OR=0.030, 95%CI: 0.10, 0.83). Evidence of toxoplasmosis infection was associated with keeping animals inside the home (OR=5.4, 95%CI: 1.42, 19.81) and maternal education less than high school (OR=0.08, 95%CI: 0.004, 0.45).

TORCH pathogens may circulate among women of childbearing age in El Salvador at higher rates than previously expected. This project highlights the need for future surveillance studies among pregnant women to clarify vertical transmission of these TORCH pathogens. With a recently implemented maternal-child-health law, the Salvadoran government has increased resources to test for other vertically transmitted pathogens with lower estimated prevalence. Thus, this study presents an opportunity at a critical time-point for maternal-neonatal health resources in El Salvador to test for further pathogens in high risk regions of the country and reduce the risk of congenital infections. Our study population came from two states with among the highest rates of multi-dimensional poverty in the country, a known risk factor for TORCH pathogen infection. This study further clarifies risk factors for each of the pathogens investigated, and could help focus efforts for future investigation, education, and intervention campaigns in this world region. With already high rates of maternal mortality and poor neonatal health outcomes in certain regions, our results warrant further investigation of TORCH pathogens in El Salvador .

Rights

© 2023, Mary Katherine Lynn

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