Skip to content

Type A Trichomonas Was More Than Twice as Prevalent in British Birds at Supplementary-fed Sites

European greenfinch at a bird feeder in Birmingham, United Kingdom
Research · Disease, parasites & microbiology

The single-celled parasite Trichomonas gallinae causes trichomonosis in birds. It is widespread in columbids, while the Type A strain is associated with the finch trichomonosis epidemic in Europe. In this study, Type A was more than twice as prevalent in British birds at sites with supplementary feeding as at unfed sites. The analyses covered 363 wild birds: columbid samples from the United Kingdom, France, Burkina Faso and Senegal, and non-columbids from the United Kingdom. Researchers also sampled 51 shared food and water resources at 12 UK sites.

T. gallinae was detected in 79% of the columbids in the combined dataset, 36% of non-columbids and 39% of the shared environmental resources. Strain composition in columbids, passerines and shared resources also changed in parallel between years, which the authors interpret as strong evidence that shared resources help transmit the parasite between bird families.

Subtype A1 was confirmed in European greenfinches (Chloris chloris), yellowhammers (Emberiza citrinella) and house sparrows (Passer domesticus), and the same subtype was found in stock doves (Columba oenas) and common wood-pigeons (Columba palumbus). This cross-family pattern supports the role of columbids as reservoir hosts — hosts that can maintain the parasite and act as sources of infection — with spillover into passerines through shared resources.

In the environmental samples, T. gallinae was detected nearly three times as often in high-density food resources such as feeders and seed piles as in lower-density resources such as sown plots and naturally regenerating vegetation. The authors therefore suggest that, where supplementary food is provided, spreading it over a larger area could reduce opportunities for transmission. They emphasise that the practical effectiveness of such measures still needs to be tested.

Sources and image credit

  1. Thomas, R. C., Dunn, J. C., Hipperson, H., Morris, A. J., Grice, P. V., Hamer, K. C., & Goodman, S. J. (2026). Multiple strains of Trichomonas gallinae are widespread in reservoir hosts and environmental resources in UK farmland.Primary peer-reviewed open-access article first published 4 September 2026. The analyses covered 363 birds: columbid samples from the United Kingdom, France, Burkina Faso and Senegal, plus non-columbids from the United Kingdom, as well as 51 shared food/water resources at UK sites. Type A prevalence in British birds was more than twice as high at supplementary-fed sites as at unfed sites. Subtype A1 was confirmed in European greenfinches, yellowhammers, house sparrows, stock doves and common wood-pigeons. High-density food resources were positive for T. gallinae nearly three times as often as lower-density resources.

Image: European greenfinch at a bird feeder in Birmingham, United Kingdom, 22 December 2009. Photo: Tony Hisgett / Wikimedia Commons / Flickr. CC BY 2.0. Representative feeding image; not a study bird. · CC BY 2.0 · Source

About this content: This story was produced with AI assistance within an editorial workflow developed by Wildlife Vagabond. Editorial responsibility remains with Wildlife Vagabond.How AI is used

Disease, parasites & microbiology

SPECIES IN THIS STORY

Species in this story

European Greenfinch Chloris chloris Explore species Yellowhammer Emberiza citrinella Explore species House Sparrow Passer domesticus Explore species Stock Dove Columba oenas Explore species Common Wood-Pigeon Columba palumbus Explore species

Independent research and conservation news archive

Did you find this information useful?

Wildlife Vagabond is independently built and maintained. Voluntary support helps cover source verification, hosting and continued work on research and conservation news.

Support Wildlife Vagabond

The news archive will remain freely available.