Scanning electron microscopy of pneumocoptes penrosei (Weidman) from the black-tailed prairie dog, Cynomys ludovicianus

Abstract

Pneumocoptes penrosei (Weidman 1917) is a parasitic mite that infests the lungs of the prairie dog, Cynomys ludovicianus. Taxonomic characterization of these mites has been previously described using light microscopy, however, scanning electron microscopy (SEM) provides a more detailed view of these arthropods.In December, 1987, a black-tailed prairie dog was submitted to the Wyoming State Veterinary Laboratory, Laramie, WY. The prairie dog had been in captivity for several years and had recently lost weight. No lesions were observed on gross examination. The lung was normal on light microscopic examination, however, numerous cross sections of mites were observed within the alveoli. Samples of the mite infested tissue were prepared for scanning electron microscopy. One group of formalin-fixed lung tissue was digested in acid pepsin at 37°C in a shaker waterbath for 12 hours. The mites were removed from the digested tissue, transferred into phosphate buffer, and centrifuged at 1500 rpm for two minutes prior to post-fixation in 1% OSO4 on ice for 30 minutes.