Renal (Kidney) Parasites in Cats

Parasites That Infect the Kidneys in Cats

Renal parasites are worms that invade the urinary tract. Affected individuals usually have no clinical signs, especially with Capillaria species. Some pets may be extremely ill if they have associated kidney failure or severe infection.

There are several types of renal parasites that affect cats and dogs.

Capillaria plica

• Found in the urinary bladder of cats and dogs
• The affected individual ingests earthworms that are infected with the parasite

Dioctophyma renale

• Found in the kidneys of dogs
• Eggs are ingested by fish or frogs that in turn, infect dogs

What to Watch For

• Bloody urination
• Abdominal pain
• Recurrent urinary tract infections
• Painful urination
• Frequent urination

Diagnosis of Feline Kidney Parasites

Diagnosis is often made by characteristic ova (eggs) in urine sediment. In case of Dioctophyma renale, diagnosis may occur with identification of adult worms upon surgical exploration, in the kidney and/or in the peritoneal (abdominal) cavity. In addition, other tests may include:

• Complete blood count (CBC)
• Biochemical profile
• Urinalysis
• Bacterial urine culture
• Radiographs (X-rays)

Treatment of Feline Kidney Parasites

Depending on the patient and parasite, recommended treatment options may vary.

• Capillaria plica is usually self-limiting: within 3 to 4 months the infection has usually resolved.
• Parasiticides (dewormers) can be used to expedite the resolution of infection.
• In unilateral (one sided) kidney infestation, Dioctophyma renale may be removed from the kidney; however, in cases where the kidney has been severely damaged because of the worms, a nephrectomy (removal of the kidney) may be indicated.
• In bilateral (both kidneys) infestation, surgically removing the worms may be the only option unless irreversible kidney damage has occurred.

Home Care and Prevention

Administer all medication and return for follow-up as directed by your veterinarian. Control is difficult as ova can live for years in the environment.

D. renale is a public health concern; human infection can occur by ingesting infective larvae via raw fish or frogs.

Proper sanitation is the key to preventing infection. Eliminate exposure to the intermediate hosts (earthworms, fish and frogs) and do not allow your pet to eat raw or improperly cooked fish.