# Comparative analysis of placental transmission mechanisms for Dengue and Zika viruses: outcomes and future directions

## TL;DR

This paper compares how Dengue and Zika viruses cross the placenta during pregnancy, highlighting their transmission mechanisms and effects on maternal and fetal health.

## Contribution

The paper provides a comparative analysis of placental transmission mechanisms and clinical outcomes of Dengue and Zika viruses in pregnancy.

## Key findings

- Dengue virus can lead to pre-term birth and thrombocytopenia in infants.
- Zika virus infects placental cells and causes Congenital Zika Syndrome with microcephaly.
- Both viruses disrupt placental signaling pathways like JAK/STAT and mTOR.

## Abstract

Zika and Dengue viruses are arboviral pathogens capable of crossing the placental barrier, representing major global health risks for maternal and fetal outcomes. In this narrative review, we compare their epidemiology, clinical consequences in pregnancy, and underlying mechanisms of vertical transmission. Emerging molecular insights are highlighted, including disruptions to placental signaling pathways such as JAK/STAT and mTOR, and strategies to evade Hofbauer cells and the immune system. A comparative analysis of these processes underscores a critical need for improved understanding of placental pathophysiology, immune regulation, and molecular pathways of transmission. Identifying such mechanisms may promote vaccine development, improved diagnostics, and therapies to reduce adverse outcomes in the mother-infant dyad during maternal infection.

Vertical transmission of orthoflaviviruses (DENV or ZIKA) during pregnancy and associated clinical consequences. Aedes mosquitoes harboring DENV or ZIKV can infect a pregnant mother through a bite, which can be transmitted to the fetus via the placenta. DENV passes through the placenta through unknown mechanisms, but DENV has been detected in umbilical cord blood and can lead to pre-term birth and thrombocytopenia in the infant. ZIKV is known to infect syncytiotrophoblasts, cytotrophoblasts, and Hofbauer cells and can cause Congenital Zika Syndrome.Illustration explaining vertical flavivirus transmission from an infected Aedes mosquito to a pregnant woman, leading to placental passage and congenital infection. Clinical consequences of maternal dengue virus include pre-term birth, stillbirth, and hemorrhagic complications, while maternal Zika virus can cause congenital Zika syndrome with microcephaly and neurodevelopmental abnormalities.

Vertical transmission of orthoflaviviruses (DENV or ZIKA) during pregnancy and associated clinical consequences. Aedes mosquitoes harboring DENV or ZIKV can infect a pregnant mother through a bite, which can be transmitted to the fetus via the placenta. DENV passes through the placenta through unknown mechanisms, but DENV has been detected in umbilical cord blood and can lead to pre-term birth and thrombocytopenia in the infant. ZIKV is known to infect syncytiotrophoblasts, cytotrophoblasts, and Hofbauer cells and can cause Congenital Zika Syndrome.