First Usutu virus detections in wild birds in Scotland, 2025

Andra‐Maria Ionescu; Ben P. Jones; Robert C. Bruce; Fiona Mccraken; Nicholas Johnson; Charlotte Clough; Caroline Robinson; Heather Stevenson; Fiona Howie; G. W. Kirby; Meshach Lee; Kieran Killen; Davide M. Dominoni; Paul Baker; Emma L. Davies; Ryan M. Carmichael; Jean-Philippe Parvy; Emilie Pondeville; Heather M. Ferguson; Arran J. Folly

doi:10.64898/2026.06.11.731606

MicrobiologybioRxivJun 11, 2026

Preprint

First Usutu virus detections in wild birds in Scotland, 2025

Andra‐Maria Ionescu iD, Ben P. Jones iD, Robert C. Bruce, Fiona Mccraken, Nicholas Johnson iD, Charlotte Clough, Caroline Robinson, Heather Stevenson, Fiona Howie iD, G. W. Kirby iD, Meshach Lee, Kieran Killen, Davide M. Dominoni iD, Paul Baker, Emma L. Davies iD, Ryan M. Carmichael iD, Jean-Philippe Parvy iD, Emilie Pondeville iD, Heather M. Ferguson iD, Arran J. Folly iD

Abstract

In summer 2025, several Eurasian Blackbird (Turdus merula) deaths were reported on the Isle of Arran in Scotland. Initial investigation included post-mortem examination, where no diagnosis was achieved. Following Orthoflavivirus and avian paramyxovirus testing, Usutu virus RNA was detected in two Blackbirds by reverse transcription-PCR. Phylogenetic analysis identified Usutu virus Africa 3.2 lineage which clustered closely with existing UK detections, indicating geographic expansion rather than a new incursion. Subsequent surveillance confirmed the presence of several potential mosquito vector species.

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