# Oropouche virus infects primary human intestinal organoids and is inhibited by type I and III interferon treatment

## TL;DR

Oropouche virus can infect human intestinal cells and is effectively inhibited by interferon treatment, suggesting the gut as a target and interferons as potential therapies.

## Contribution

Demonstrates intestinal tropism of Oropouche virus and the efficacy of interferons in inhibiting its replication in human organoid models.

## Key findings

- Oropouche virus replicates in primary human intestinal organoids, as shown by RNA accumulation and infectious particle release.
- Endogenous type III interferon response is insufficient to limit OROV replication in intestinal cells.
- Exogenous type I and III interferons strongly inhibit OROV replication, with interferon-alpha abolishing infectious virus production.

## Abstract

Oropouche virus (OROV), a neglected arbovirus, has historically been considered a self-limiting infection associated with febrile illness. However, the recent surge in cases since late 2023 has been marked by atypical outcomes, highlighting its underestimated clinical impact. Gastrointestinal symptoms such as diarrhea have also been reported, but the prevalence and mechanistic insight remain largely elusive. Here, through a meta-analysis of 12 identified clinical studies, we revealed a pooled prevalence of diarrhea as 15% (95% CI, 10%–20%) among the Oropouche patient population. In primary human intestinal organoid-based experimental models, we demonstrated productive infection by both a recent patient isolate (OROV-2024) and a historical strain (Be An19991). This is shown by the accumulation of intracellular OROV RNA, release of infectious particles, and immunostaining of OROV glycoprotein Gc. Interestingly, OROV infection mildly triggered the expression of type III interferons, but this endogenous response was insufficient to limit viral replication. In contrast, exogenous treatment with type I and III interferons strongly inhibited OROV replication, with interferon-alpha completely abolishing infectious virus production. Together, these results suggest the human intestine as a potential target organ for OROV infection and highlight interferons as potential therapeutic candidates.

Oropouche virus (OROV) is an emerging arbovirus with rapidly increasing incidence and recent reports of severe disease outcomes. While gastrointestinal symptoms have been described, the intestinal tropism of OROV has not been experimentally explored. By combining meta-analysis of clinical data with human intestinal organoid infection models, we demonstrate that OROV can replicate in intestinal epithelial cells. We further show that, in a human intestinal organoid model, endogenous interferon responses are insufficient to restrict replication, while treatment with interferons exerts potent antiviral activity. These findings highlight the susceptibility of intestinal epithelial cells to OROV infection and the therapeutic potential of interferons.