Comparative analysis of host responses to Oropouche viruses in placental cell infection models

2022-2024 saw a major outbreak of midge-borne Oropouche virus (OROV, Peribunyaviridae ) that affected Brazil and countries across the region and was associated with a novel reassortant of this pathogen. The description of fetal deaths, microcephaly and congenital malformations in newborns led to the question whether such pathologies had previously been overlooked or are associated with novel properties of reassortant OROV, raising the question of infection and transfer across the placenta. Here we compared infection of cultured placental cell lines (BeWo and JEG-3) with an earlier OROV isolate and a Cuban isolate from 2024. Our data suggest minor, but noticeable differences between these OROV and respective host cell responses, for example relating to IFNL3. It remains to be investigated whether characteristics of these different isolates translate to effects on fetal development, but these findings suggest that cellular responses can differ between ancestral and recent isolates of this virus.