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Upper Iowa University
Division of Science and Mathematics
Rick Klann
Delano Professor of Science
Research on Parasites of Fish and Wildlife
Meningeal Worm in White-tail Deer
The meningeal worm (Parelaphostrongylus tenuis), is a roundworm parasite that lives in the
brain of deer and other cervids. The life cycle of this parasite is somewhat complex. Adult worms
feed on blood in the meninges surrounding the brain. Gravid females release eggs into the blood
which travel to the lungs, where they are coughed up and swallowed and passed with the feces.
Larvae hatch from the eggs and penetrate the foot of terrestrial snails or slugs which feed on the
mucus coat surrounding the feces. Deer acquire the parasite by accidentally ingesting infected snails
or slugs. In the stomach, the larvae penetrate the stomach wall and enter a spinal nerve. They
migrate to the spinal cord, where they attain maturity. Adult worms migrate to the brain to
complete the life cycle.
Pathology associated with this parasite depends upon the host. White-tailed deer rarely
show any evidence of infection. In all other cervids however, including moose, elk, reindeer and
caribou, one worm is fatal. This presents management concerns as the range of white-tailed deer
spreads and encroaches upon these other cervids.
During the deer hunting season, we collect deer heads from local lockers and examine
them for the presence of meningeal worm. The worm is fairly common in northeast Iowa, with
anywhere from one-third to one-half of the heads examined carrying the parasite.
Parasites of Volga River Fishes
The Volga River is a small, spring-fed stream that flows through Fayette, IA. Water levels
fluctuate dramatically, and the stream is impacted by agricultural practices. We are interested in
identifying the helminth parasites of fish occupying this ecosystem. Much of our efforts have been
directed towards the parasite fauna of two species that are common inhabitants of the river, the
rock bass and the creek chub. Both species host depauperate helminth communities, with very few
species of parasites found, and with few numbers of parasites per individual fish.
The most common parasite encountered is a digenetic trematode, Crepidostomum cooperi.
This parasite has a three host cycle, with larval stages infecting fingernail clams and, following a
period of development in the mussel, mayfly larvae. Fish acquire the parasite by ingesting infected
mayfly larvae.