Deer Liver Fluke

1. Deer Liver Fluke By: Kara

2. Basic Information • Scientific name~ Facioloides magna from Latin: fasciola=band, magna=large • Class~ Trematode (Flukes) • Phylum~ Platyhelminthes (Flatworms)

3. Description • Flat, enlongated, oval, & look like “blood suckers”/ “leaches” • Purple-gray color • looks like a blood clot (in liver) • Surrounded by fibrous capsule, bathed in a dark, muddy-appearing fluid. • 15-30mm wide by 30-100mm long by 2-5mm thick

4. The natural host is the deer, which is also a reservoir host found in captive elk, but has not been observed in free elk. The fluke can also infect cattle, sheep, and llama. Some other states and Canadian report the fluke in moose, elk, white-tailed deer, mule deer, bison, and yak. It has also been reported in red deer, fallow deer, and sambar deer in Europe. Where it likes to live

5. Steps to infection • Adult flukes deposit eggs in the ducts and cavities of the liver of the host. • the eggs pass to the intestinal tract and are eliminated in the feces. • The eggs need moisture for development, and will hatch in moist feces or shallow water

6. It takes about 25 days for eggs to hatch into the next stage, miracidia. Miracidia enter the snail as its next host In the snail, development proceeds to a sporoscyst form which can produce redia and daughter redia these redia produce cercaria, the final intramolluscan form Cercaria leave the redia while immature, and leave the snail after about four days Steps continued

7. cercaria encyst on vegetation these encysted forms are called metacercaria. They represent infective larvae, or young flukes, that are very resistant to the elements These are ingested by deer (or other host) the larvae penetrate the wall of the intestine, and migrate to the liver. The flukes develop in about three months. If all conditions are right, the cycle can be completed in five months. Once outside the snail….

8. Damage to sheep • In sheep these parasites do great damage to the liver • uninterrupted migration throughout the liver causes massive hemorrhage and a peritonitis may develop • sheep are the only host where the fluke causes such damage; two or three of these parasites can cause death in a sheep.

9. No damage here • Cattle, bison, yak, and deer will encapsulate mature flukes in the liver, restricting their migration, and damage • under experimental conditions, mule deer fawns and elk calves have died from fluke infection.

10. It is also possible to diagnose flukes by microscopic examination of the feces for eggs of the parasite. Finding a Fluke • examining visually for the parasites by making slices at 0.5 inch intervals through the entire liver • Fibrous capsules may be visible on the lung surface

11. fasciolicide drugs have been developed which are effective against mature Flukes. Triclabendazole in a medicated corn bait was given to white-tailed deer in a wildlife refuge in Texas resulting in the population of liver flukes being significantly lower Treatment

12. Summary • Deer liver flukes are not harmful to deer. The life cycle takes about 5 months for the Fluke and it spends 4 days living in a snail before it makes its way into the deer. (all information from http://www.michigan.gov/dnr/ Pictures from google and that website)