Vertical Transmission of Emerging Infections: Investigating the Perinatal Outcomes of Zika, Dengue, and SARS-CoV-2

Abstract

Vertical transmission of emerging viral infections has become a global maternal–fetal health concern, especially with the rise of Zika virus (ZIKV), dengue virus (DENV), and SARS-CoV-2. These pathogens demonstrate distinct mechanisms of placental invasion, immunological evasion, and fetal injury, resulting in varied obstetric and neonatal outcomes. This article synthesizes existing epidemiological and clinical evidence on vertical transmission pathways, maternal immunopathology, and perinatal complications linked to the three infections. ZIKV shows a high neurotropism associated with congenital Zika syndrome, while dengue primarily contributes through maternal complications such as thrombocytopenia, hemoconcentration, and peripartum shock, with limited but documented transplacental infection. SARS-CoV-2 demonstrates a relatively low but significant potential for in-utero transmission, often mediated by placental inflammation, ACE2 expression, and viral persistence in trophoblasts. Comparative analysis reveals that although their transmission efficiency differs, all three infections pose risks including preterm birth, fetal distress, growth restriction, and stillbirth. Understanding these mechanisms is crucial for developing preventive, diagnostic, and clinical management strategies during pregnancy.