Bladder worm (Capillaria plica)
Veterinary & Aquatic Services Department, Drs. Foster & Smith

Capillaria plica and Capillaria felis cati are rare parasites of dogs and cats, respectively. Capillaria is generally found in the eastern United States. It is not of great importance since it rarely causes disease except in young fox. Its eggs can easily be confused with those of the lungworms or whipworms.

What do we know about the life cycle of the bladder worm?

The life cycle of this parasite still eludes us. It may be direct, or it may involve the earthworm as an intermediate host. Adult worms lay eggs in the urinary bladder and these are passed through the urine. Larvae develop in the environment and are somehow ingested, either because of urine contamination of food or water, or through eating infested earthworms. The larvae apparently migrate from the digestive system to the urinary bladder where they develop into adults.

What are the signs of infestation with the bladder worm?

Bladder worms rarely cause disease. If disease does occur, the signs are that of a urinary bladder infection e.g., frequent and painful urination. This is more of a problem in young fox.

How is infestation with this urinary tract parasite diagnosed?

Eggs of C. plica are sometimes found in urine-contaminated feces.

The adult female worms are almost 2½ inches long; the males are half that size. The adult worms can be seen and removed if the bladder is surgically opened. Diagnosis, however, is generally through finding eggs in the urine. As mentioned above, the eggs must be distinguished from those of whipworms and the Capillaria species that infest the lung.

Is there a treatment?

Although no approved treatment is available, an oral dose of 0.1 mg/lb of ivermectin has been suggested.

What are the best methods of prevention and control?

The eggs of Capillaria are very susceptible to drying. At present, the best control is through good sanitation and elimination of earthworm habitat in kennel situations. It is suggested that in kennel situations, animals be kept on impervious surfaces. Fox may be kept off the ground on wire mesh floors.


References and Further Reading

Georgi, JR; Georgi, ME. Canine Clinical Parasitology. Lea & Febiger. Philadelphia, PA; 1992;176-180.

Griffiths, HJ. A Handbook of Veterinary Parasitology. University of Minnesota Press. Minneapolis, MN; 1978;52-53.

Hendrix, CM. Diagnostic Veterinary Parasitology. Mosby, Inc. St. Louis, MO; 1998;131.

Sousby, EJL. Helminths, arthropods and protozoa of domesticated animals. Lea & Febiger. Philadelphia, PA; 1982;337-340. 

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