Photomicrographs of pectoral muscle from a Northern Pintail Duck

Photomicrographs from a Northern Pintail Duck (Anas acuta) found dead in Arizona, US.  (A) Low magnification of a Sarcocystis sp. cyst in the pectoral muscle of a Northern Pintail Duck. H&E stain.  (B) Higher magnification of the cyst showing the cyst wall (arrowheads) and septations (arrow), a zone containing zoites (solid line) and a zone containing degenerative material (*).