Disseminated Toxoplasma gondii Infection in an Adult Osprey (Pandion haliaetus)

Abstract

An adult female osprey (Pandion haliaetus) was found weak and unable to fly in Auburn, Alabama in August 2019. The bird was captured and submitted to the Southeastern Raptor Center of the Auburn University College of Veterinary Medicine for evaluation. On presentation, the bird was thin with a body condition score of approximately 1.5 out of 5. The bird died during the examination and was submitted for necropsy. At the necropsy, there was a severe loss of muscle mass over the body, and the keel was prominent. The liver and spleen were moderately enlarged with pale tan to red foci randomly scattered throughout the parenchyma. A histopathologic observation revealed multifocal to coalescing areas of necrosis and hemorrhage with intralesional protozoans in the liver, spleen, lungs, kidney, sciatic nerve, esophagus, cerebrum, heart, and proventriculus. Immunohistochemistry using anti-Toxoplasma gondii-specific antibodies showed a strong positive labeling of the parasite. Semi-nested PCR, specific for the B1 gene of T. gondii, successfully identified T. gondii. This is the first confirmed case of T. gondii infection in an osprey.

Keywords: IHC; Pandion haliaetus; Toxoplasma gondii; histopathology; osprey.

Figure 1

Gross images of affected liver (a) and spleen ((b), *). The liver contains multifocal to coalescing, well-demarcated, smooth foci; scale bar = 1 cm (a). The spleen is enlarged (*), has a diffusely pale tan and is firm with multifocal, smooth, and dark red circular foci; scale bar = 1 cm. Proventriculus (green arrowhead) and ventriculus (blue arrowhead) (b).

Figure 2

Photomicrograph of liver showing multifocal to coalescing hepatocellular necrosis. H&E. Original magnification 200X. Scale bar = 50 µm. Insert shows parasitic cyst containing bradyzoites of T. gondii (arrowhead). H&E. Original magnification 600X. Scale bar = 20 µm (a). Photomicrograph of spleen showing severe multifocal to coalescing necrosis with intralesional Toxoplasma tachyzoites (arrow). H&E. Original magnification 200X. Scale bar = 50 µm. Insert shows parasitic cyst containing bradyzoites of T. gondii (arrowhead). H&E. Original magnification 600X. Scale bar = 20 µm (b). Toxoplasma immunohistochemical staining of splenic tissue with multifocal, positively staining, intracellular protozoa (arrowhead). H&E. Original magnification 600X. Scale bar = 20 µm (c). Toxoplasma immunohistochemical staining of lung with positively staining intracellular protozoa (arrowhead). H&E. Original magnification 600X. Scale bar = 20 µm (d).

Figure 2

Photomicrograph of liver showing multifocal to coalescing hepatocellular necrosis. H&E. Original magnification 200X. Scale bar = 50 µm. Insert shows parasitic cyst containing bradyzoites of T. gondii (arrowhead). H&E. Original magnification 600X. Scale bar = 20 µm (a). Photomicrograph of spleen showing severe multifocal to coalescing necrosis with intralesional Toxoplasma tachyzoites (arrow). H&E. Original magnification 200X. Scale bar = 50 µm. Insert shows parasitic cyst containing bradyzoites of T. gondii (arrowhead). H&E. Original magnification 600X. Scale bar = 20 µm (b). Toxoplasma immunohistochemical staining of splenic tissue with multifocal, positively staining, intracellular protozoa (arrowhead). H&E. Original magnification 600X. Scale bar = 20 µm (c). Toxoplasma immunohistochemical staining of lung with positively staining intracellular protozoa (arrowhead). H&E. Original magnification 600X. Scale bar = 20 µm (d).