Bagaza Virus in Wild Birds, Portugal, 2021

Abstract

Bagaza virus emerged in Spain in 2010 and was not reported in other countries in Europe until 2021, when the virus was detected by molecular methods in a corn bunting and several red-legged partridges in Portugal. Sequencing revealed high similarity between the 2021 strains from Portugal and the 2010 strains from Spain.

Keywords: Alectoris rufa; BAGV; Bagaza virus; Emberiza calandra; Portugal; birds; flavivirus; outbreak; viruses.

Figure

Microscopic lesions caused by Bagaza virus infection in liver, heart, kidney, and brain tissue of red-legged partridges (Alectoris rufa), Portugal, 2021. A) In liver, congestion, hemozoin presence in Kupffer cells, focal hepatocyte necrosis, and a moderate mononuclear infiltrate are visible despite some freezing artifacts. B) In heart, congestion, hemorrhage, edema, degeneration of myofibers of the myocardium, and endothelial swelling and moderate to abundant diffuse mononuclear infiltrates are visible. C) In kidney, tubulointerstitial nephritis characterized by congestion, hemorrhage necrosis of proximal convoluted tubular epithelium, and diffuse moderate to abundant mononuclear inflammatory infiltrate are visible. D) In brain, mild nonpurulent encephalitis with congestion, mononuclear cell extravasation, and endothelial cell swelling are visible. Hematoxilin eosin staining; original magnification ×400.