Photomicrographs from a muskrat (Ondatra zibethicus) found dead in Ohio

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. Inset: The shell is birefringent under polarized light. (B) Nematode eggs are surrounded by macrophages (asterisk) and occasional multinucleated giant cells (arrowhead). H&E stain.