Photomicrographs from a big brown bat (Eptesicus fuscus) from Wisconsi

Photomicrographs from a big brown bat (Eptesicus fuscus) from Wisconsin, USA. H&E stain. (A) Low magnification of a cross section through the nares showing nasal cavity (*), oral mucosa (arrowhead), and haired skin (arrow). (B) Higher magnification showing a normal hair follicle (arrow) surrounded by sebaceous glands. (C) An ulcer with hemorrhage (*) is present at the junction of the oral mucosa (arrowhead) and haired skin (arrow). Subjacent to the ulcer, a hair follicle is expanded by arthropods. (D) Higher magnification of the hair follicle shows it is filled with multiple cross sections of mites measuring up to 40 μm in diameter. Moderate numbers of lymphocytes, fewer macrophages, and scattered eosinophils are present in the wall of and surround the hair follicle. Free red blood cells (*) surround the follicle. (E) The mites have a thin, eosinophilic, chitinous exoskeleton (arrowheads), striated muscle (arrows), a hemocoel, digestive and reproductive tracts. (F) Jointed appendages are also present (arrow).