Cancer and One Health: tumor-bearing individuals can act as super spreaders of symbionts in communities

Abstract

Recent theoretical advances in the One Health approach propose that greater attention should be paid to cancer pathologies due to their potential to render hosts more susceptible to infectious agents, potentially transforming them into super-spreaders within ecosystems. However, this hypothesis lacks experimental validation. Using a community of Hydra species and a commensal ciliate species (Kerona pediculus) that colonizes them, we tested whether tumoral polyps of H. oligactis, compared to healthy ones, played an amplifying role in ciliate load, potentially resulting in higher likelihood of infection for other community members through spillovers. Results revealed a higher proliferation rate of ciliates on tumoral polyps compared to healthy ones, leading to infection of other hydras, albeit with varying spillover magnitudes among recipient species. This study is the first proof of concept that tumoral individuals within communities could act as super-spreaders of symbionts within and between species, influencing biotic interactions and dynamics in ecosystems.