Vertical Transmission of Oropouche Virus in a Newly Affected Extra-Amazon Region: A Case Study of Fetal Infection and Death in Ceará, Brazil

The recent geographic spread of Oropouche virus (OROV), coupled with an increase in cases and the emergence of previously unrecognized severe manifestations, has raised significant public health concerns. We report the case of a 40-year-old family farmer at 31 weeks of gestation who presented with fever, myalgia, and headache. OROV infection was confirmed by RT-qPCR, followed by nucleotide sequencing and phylogenomic inference, with other infections ruled out. Initially, maternal and fetal health assessments revealed no complications. However, within a week, the patient noted decreased fetal movements, and ultrasound confirmed fetal demise. Molecular diagnostics identified OROV RNA in multiple fetal tissues, confirming vertical transmission. This case highlights the urgent need to protect pregnant women against viral vectors and include OROV into the differential diagnosis of febrile illnesses. Furthermore, it is critical to further investigate the pathogenic mechanisms of this virus, which may lead to changes in public health policies and clinical guidelines.