Parasitology students examine halibut parasite, Oriental rat flea

Monogenean Entobdella hippoglossi

The Monogenean Entobdella hippoglossi is a skin parasite of Pacific halibut ( Hippoglossus stenolepis).

Oriental rat flea

Oriental rat flea (Xenopsylla cheopis). Carrier of the plague bacillus Yersinia pestis.


Two students from Dr. Granath’s Fall 2011 Parasitology class used the Hitachi SEM to complete independent projects. Jane Sullivan obtained several specimens of a parasite of halibut during her work on a fishing boat in Alaska in the summer of 2011. The Monogenean Entobdella hippoglossi is a skin parasite of Pacific halibut Hippoglossus stenolepis. Several samples were taken from freshly caught halibut and preserved in ethanol prior to processing for SEM in the lab. Jane prepared the samples for SEM using critical point drying where liquid carbon dioxide replaces ethanol in the sample. The dried samples were sputter coated with a layer of gold/palladium, placed on an aluminum stub, and imaged in the SEM. Images of the parasite’s tegument, mouthparts, and suckers will be used in parasitology class and lab and also posted on our web site.

Additionally, Ryan Graebner used the SEM to image the oriental rat flea Xenopsylla cheopis carrier of the plague bacillus Yersinia pestis. The fleas were generously provided by Dr. Tom Schwan, Chief of the Laboratory of Zoonotic Pathogens at Rocky Mountain Laboratories in Hamilton, MT. The fleas required minimal preparation due to their hardened exoskeleton. They were sputter coated with gold/palladium and imaged in the SEM. Ryan took general images of the Oriental rat flea for the web site and the classroom. He also took a series of images of increasing magnification for the Virtual Microscopy section of our web site. This capability allows the visitor to increase or decrease the magnification of an area of the flea to observe details of the organism at either low or high magnification in a single window. The accompanying images are of the E. hippoglossi parasite and of the Oriental Rat Flea.