Spillback
Spillback is a term used in disease ecology and epidemiology to describe the transmission of a pathogen from humans or domestic animals back into wildlife, with the possibility that the pathogen then re-enters human or livestock populations. It represents a reverse or bidirectional spillover: a pathogen first crosses from a reservoir (often humans or domestic animals) into wildlife, becomes established in the wildlife population, and may subsequently spill back into humans or domestic animals.
Spillback is facilitated by close contact at the wildlife–livestock–human interface, including farming operations, companion animals, zoos,
Notable cases include SARS-CoV-2 spillback from infected humans to farmed mink in Europe and North America,
Spillback complicates disease control and eradication efforts by creating wildlife reservoirs that are difficult to monitor