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What Is the Relationship Between Flukes and Elk?

The giant liver fluke is a parasitic flatworm that reproduces in the liver of elk. It is particularly prevalent in the elk found in the southeastern United States and Canada. Liver flukes exist in a parasitic relationship with the elk. They benefit by feeding on the host elk's blood, but the liver itself may be damaged.

Description
- Together with roundworms and tapeworms, flukes are one of the three main groups of helminths --- a division of eukaryotic parasites. According to West Valley College, the types of fluke include liver flukes, lung flukes, intestinal flukes and blood flukes. Elk are just one of the host animals that liver flukes (Fascioloides magna) use to survive. Adult liver flukes can be up to 4 inches long and an inch wide. They are purple-gray in color, with a flat oval body that resembles a leech's.
Life Cycle
- Adult flukes living in the liver of the elk deposit their eggs in the ducts and cavities of the organ. from here, they pass through to the intestinal tract and are excreted through feces. Eggs hatch in aerated water after about 25 days, according to the Michigan Department of Natural Resources. The hatched eggs enter a snail host where they continue to develop. After about four days, they leave the snail and take up residence on nearby vegetation. If an elk ingests flukes, they penetrate the animal's intestinal wall and migrate towards its liver, where they develop into adults and mate over a period of about three months. The entire cycle takes about five months.
Effects
- Elk tolerate light to moderate infestations of liver fluke reasonably well and show few symptoms. In heavier infestations, the livers of infected elk may appear enlarged and distended. Symptoms can include drowsiness, sluggishness and a poor appetite. Flukes cause changes in the elk's liver structure as the worms migrate. This can lead to liver damage, a process which increases as the elk ages or the number of flukes multiplies.
Prevalence
- In the liver of infested elk, flukes are usually found in groups of two or more within thin-walled capsules that contain a dark, muddy-colored fluid. According to University of Northern British Columbia, adult flukes are more likely to be found in elderly elk. Fluke infections are more common in wetlands habitats that support large numbers of aquatic snails. Most elk are infected between late summer and fall.

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