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Liver flukes and redwater disease in Minnesota beef cattle

Quick facts

  • There are two different types of liver flukes of veterinary importance that can infect cattle in the United States: Fasciola hepatica, the common liver fluke and Fascioloides magna, the deer liver fluke.

  • Both flukes are completely different from each other in terms of their distribution, infection process, diagnosis and economic importance.

  • Fascioloides magna (F. magna), the deer liver fluke, is the primary species affecting beef cattle in Minnesota. F. hepatica is generally not found in Minnesota.

  • F. magna is found in the Great Lakes region of the U.S.; north of I-94 in Minnesota.

How do beef cattle get infected by flukes?

Close-up of a herd of beef cattle in grass.
Deer liver flukes can be present in feedstuffs, mainly hay, and fresh forages.

Livestock can get infected by grazing vegetation or feedstuffs, primarily hay, containing F. magna metacercaria (enclosed in a protective sac).

Do cattle die from deer flukes?

Yes, through liver damage as a result of F. magna migrations or through secondary infections like Redwater disease (Bacillary hemoglobinuria).

How do you treat deer flukes?

Albendazole (Valbazen®) at 10 mg/kg, is effective at controlling F. magna. The flukes need to be mature (more than 90 days old) for treatment to be effective.

If I increase the label dose of Valbazen® is it more effective?

The label dose of Valbazen is effective. Increasing the dose does not increase efficacy. However, using 1.5 times the label dose may be useful to account for application losses.

Can I use Curatrem® or Ivomec Plus® instead of Valbazen® to control deer flukes?

Curatrem® (clorsulon at 7 mg/kg) and Ivermectin plus (clorsulon at 2 mg/kg) are not labelled for treatment against F. magna infections.

When should I treat beef cattle for deer flukes?

Treatment of beef cattle following heavy killing frost is recommended. Retreatment after 90 days may be necessary in heavily infected areas to address potentially immature flukes at time of initial treatment.

The deer liver fluke life cycle

  • In Minnesota, F. magna is carried primarily by white-tailed deer, fluke eggs pass through the deer, hatch in water and infect Lymnaeid snails. The young flukes then migrate from snails to vegetation where they are consumed by livestock. Once ingested, F. magna migrates through the intestinal wall to the liver. Cattle are the dead-end host for F. magna.
  • Once they reach the liver of the dead-end host (cattle) they become encased in fibrous cysts and develop into adults, causing extensive damage to the liver and creating favorable conditions for secondary infections of the liver.

Can deer flukes be spread to areas that don’t currently have them?

  • Cattle are a dead-end host and do not shed F. magna.

  • F. magna depends upon the distribution of an intermediate host, the lymnaeid snail. Therefore, these infections will not propagate in areas where the intermediate host snails are not present.

What is redwater disease?

  • Bacillary hemoglobinuria is also known as redwater disease.

  • It is caused by the bacteria Clostridium haemolyticum, which is a soil-borne bacterium. The bacteria spores are ingested and are naturally found in the rumen and liver of healthy cattle.

  • It is not until there is local liver damage and necrosis (usually caused by a migrating liver fluke infection) that the bacteria spores germinate into vegetative cells that multiply and produce toxins that destroy the red blood cells in the body.

How do you prevent redwater disease in cattle?

The best way to prevent this disease is to vaccinate (a primer and booster vaccine) against Clostridium haemolyticum (found within the eight-way Clostridial vaccine).

Other control methods include rotating pastures and controlling liver fluke infections.


Eric Mousel, Extension educator; Jeremy Schefers, DVM and Tim Goldsmith, DVM, College of Veterinary Medicine

Reviewed in 2021

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