Images

Photomicrographs from a Bald Eagle (Haliaeetus leucocephalus) with highly pathogenic avian influenza found dead in Wisconsin, USA.  (A) In the brain, there is a region in the cerebrum with small perivascular cuffs of mononuclear cells and rare heterophils (arrow), scattered foci of gliosis (*), and rare acutely necrotic neurons (inset).

Photographs and photomicrographs from a Great-horned Owl (Bubo virginianus) found dead in Arizona, USA. (A) Caseous material is present on the surface of the pharynx (arrows). (B) Multiple small tan foci are present in the liver, which is pale and moderately enlarged. (C) A focus of acute lytic necrosis in the liver (arrows). H&E stain.

Photographs and photomicrographs from a Common Raccoon (Procyon lotor) found dead in a prairie in Wisconsin, USA. (A) There is abrupt segmental reddening of the serosa of the distal jejunum and proximal ileum (arrows). (B) The mucosa of an affected area of the distal jejunum is reddened and bloody (C).

Photographs from a Canada Goose (Branta canadensis) found dead in Wisconsin, USA. A) There was an impaction within the esophagus just proximal to the clavicles (arrows). A hole in the esophagus was caused during dissection. The bird was emaciated, with severe loss of the pectoral skeletal muscles and prominent keel bone (*).

Photomicrographs from a Canada Goose (Branta canadensis) found dead in Wisconsin, USA. A) Unaffected esophagus proximal to the impaction showing normal wall layers of the mucosa (M), submucosa (SM), tunica muscularis (TM), and serosa (S), and the presence of submucosal glands (*).

Distribution of Highly Pathogenic Avian Influenza H5 and H5N1 in North America, in Relation to U.S. Fish & Wildlife Service Refuges and National Park Service Lands, 2021/2022. Updated November 27, 2022.

Distribution of Highly Pathogenic Avian Influenza H5 and H5N1 in North America, in Relation to Tribal Lands in the United States, 2021/2022. Updated November 27, 2022.

Photograph and photomicrographs from a Pacific loon (Gavia pacifica) found dead in Alaska, USA (A) The proventriculus (arrows) is enlarged and the serosal aspect contains many raised serpentine tracts. An asterisk (*) indicates the ventriculus.

Photomicrographs from the intestine of a Brazilian Free-tailed Bat (Tadarida brasiliensis) found dead in Texas, USA.

Photomicrographs from a muskrat (Ondatra zibethicus) found dead in Ohio, USA. (A) Within the liver, there is a cluster of nematode eggs with light brown to eosinophilic bi-operculated shells (arrowheads) with radial striations (arrow) that contain eosinophilic flocculent material (asterisk). H&E stain.

Photograph and photomicrographs from a bottlenose dolphin (Tursiops truncatus) found dead in Florida, USA.  (A) On the right cranial cerebrum is a 3 x 2.5 cm area of hemorrhage and cavitation. (B) There is focal marked cerebral meningeal cavitation and hemorrhage, with fibrin accumulation, neutrophils, and triangular to ovoid trematode eggs (arrows).

Photographs from a Bald Eagle (Haliaeetus leucocephalus) that was found moribund and died in South Dakota, USA. (A) There is abundant liquid and clotted blood (*) in the coelomic cavity surrounding the heart (top), liver (middle), and within the coelomic adipose tissue (bottom). The liver is diffusely pale tan with rounded margins.

Photographs from an American Crow (Corvus brachyrhynchos) found dead in Ohio, USA. (A) The gastrointestinal tract is oriented with the ventriculus to the upper right. The small intestines are diffusely dilated and red-purple on the serosal aspect.

Photomicrographs from an American Crow (Corvus brachyrhynchos) found dead in Ohio, USA. (A) The small intestines contain necrotic material (N) with foci of mineral (arrow) within the lumen. The mucosa is multifocally effaced by hypereosinophilic cellular debris (necrosis) and inflammatory cells (*). H&E stain.

Photomicrographs from a Trumpeter Swan (Cygnus buccinator) found dead in Indiana, U.S.A. (A) Within the small intestine is an area of transmural necrosis (arrow) with abundant luminal necrotic debris and hemorrhage containing few trematode eggs (arrowhead), and an adjacent trematode (*).  H&E stain.  (B) Detail of A.

Photographs from a Trumpeter Swan (Cygnus buccinator) found dead in Indiana, U.S.A.  (A) The majority of the intestinal serosa is dark red. (B) The lumen contains gelatinous dark red material and many <1 mm diameter white structures (trematodes) (arrows). (C) On the serosal surface are two 2 to 5 mm discrete ulcers (arrow).

Photomicrographs with H&E stain from a Bald Eagle (Haliaeetus leucocephalus) found dead in Wisconsin, USA. (A) Hepatocytes contain one or more variably-sized intracytoplasmic round, clear vacuoles (arrowheads). (B) Bile ducts are plugged with bile (asterisk). (C) Multifocally in the brainstem, there are small perivascular hemorrhages (arrows).

Gosner stage 41 Green Frog (Lithobates clamitans) tadpole. (A) There are no apparent external abnormalities. (B)The liver and spleen are markedly pale and enlarged.

Liver from a Green Frog (Lithobates clamitans) tadpole. (A) Over 90% of the organ is infiltrated, effaced and replaced by protozoal spores (Perkinsea) admixed with necrotic debris. (B) Perkinsea spores are 4 to 6-µm in diameter spherical structures with thick, deep basophilic walls, and granular pale basophilic cytoplasm. H&E stain.

Photomicrographs from a European Starling (Sturnus vulgaris) that was euthanized in the District of Columbia, USA. (A) There is an area in the brain with abundant acute hemorrhage (H) surrounding blood vessels and in the neuropil. H&E stain.

Photomicrographs from a Northern Shoveler (Spatula clypeata) from Utah, USA. H&E stain. (A) The air sac epithelium is replaced by or covered with a thick layer of fibrin admixed with heterophils and fewer macrophages and eosinophilic and cellular necrotic debris (*).