Intestinal Helminths of the Wisconsin Muskrat (Ondatra zibethicus)
Date
2023-06Author
Cuevas, Pedro Cachu
Advisor(s)
Michalski, Michelle
Metadata
Show full item recordAbstract
Ondatra zibethicus, also known as the muskrat, is a semiaquatic rodent commonly found
in North America. These rodents contribute significantly to the local economy,
environment, and public health. Every year, from October to March, trappers capture
these rodentss in Horicon Marsh located in Dodge County, Wisconsin. Once caught, the
animals are skinned, and the pelts are sold. The role of this rodent, as a bioindicator,
cannot be ignored. Due to its sensitivity to change, the muskrat population can be viewed
as an alert system for a deteriorating ecosystem. Several environmental conditions
afflicting Ondatra zibethicus include drought, anthropogenic contamination, and
predation. Most importantly, their ability to be a host for a variety of diseases makes the
fur bearer a useful model. In collaboration with trappers at Horicon Marsh, the carcasses
of 45 muskrats were examined in this two-part study. Thirty-six carcasses were collected
by Sarah Woody, a previous graduate student at UWO, and necropsied in May of 2021. In
January 2023 nine more were collected for the same purpose. The tongues retrieved from
the muskrats were assayed for the presence of helminths. Trichinella spp. is an
intracellular nematode that can encyst in the muscle of many hosts including mammals,
birds and reptiles. In order to establish their presence within a muskrat, the tongues
collected were digested with the help of artificial digestive fluids concocted using HCL
and Pepsin. The tongues were cut into pieces, blended, and the mixture observed under a
dissecting microscope for the presence of Trichinella spp. The small and large intestines
were assayed all parasites recovered from the small and large intestines were placed in
80% ethanol. Thereafter, the collected parasites were separated based on visual
differences, fixed in formaldehyde, mounted on slides, and morphologically identified.
Morphologic identification revealed the presence of intestinal helminths such as
Plagiorchis proximus, Quienquiseriales quienquiserialis, Echinostoma spp., Trichuris
opaca, and a Cestode spp. Mitochondrial and Ribosomal DNA was extracted, and the
genetic samples were sent out for sequencing via third party to confirm morphologic
identification.
Subject
Wisconsin muskrat
Ondatra zibethicus
helminths
Permanent Link
http://digital.library.wisc.edu/1793/85634Type
Thesis