The release of non-native gamebirds is associated with amplified zoonotic disease risk

Spillback – where non-native species increase native pathogen prevalence – is potentially an important mechanism by which non-natives contribute to zoonotic disease emergence. However, spillback has not yet been directly demonstrated because it is difficult to disentangle from confounding factors which correlate with non-native species abundance and native pathogen prevalence. Here, we capitalise on replicated, quasi-experimental releases of non-native pheasants (Phasianus colchicus) to compare vector abundance and native pathogen prevalence between sites with similar local conditions but different non-native densities. Prevalence of Borrelia sp. (the causative agent of Lyme disease) in questing ticks was almost 2.5x higher in woods where pheasants are released compared to control woods, with a particularly strong effect on Borrelia garinii, a bird specialist genospecies. Furthermore, adult (but not nymphal) ticks tended to be more abundant at pheasant-release woods. This work provides ..., , , # Data from: The deliberate release of a non-native species amplifies zoonotic disease risk via spillback

[https://doi.org/10.5061/dryad.d7wm37q9d](https://doi.org/10.5061/dryad.d7wm37q9d)

Code can be found in the 'related works' box on right of the DRYAD landing page. Or via the DOI [https://doi.org/10.5281/zenodo.13919564](https://doi.org/10.5281/zenodo.13919564 \"Go to software\")

## Description of the data and file structure

*I.ricinus* tick abundance and *Borrelia* prevalence data from 89 woods across the southwest of England. Including woods in which pheasants were released, and woods in which pheasants were not released.

### Files and variables

#### File: distance\_matrix.csv

**Description:** pairwise distances for the 25 shoots included in the present study.

#### File: tick\_abundance\_2024.csv

**Description:**

##### Variables

* area: a unique identity number attributed to each shoot
* edge: distance from woodland edge, either 'interior' (-0.5) or 'edge' (0.5)
* temp: t...,