Bladder Worm in Dogs

The nematode parasite called Capillaria plica infects the urinary tract of dogs, cats and weasels to cause inflammation in their urinary systems. Signs include bladder inflammation (cystitis), frequent urination (pollakiuria), painful or difficult urination (dysuria) and blood in the urine (hematuria) in your pet.  The parasite accomplishes this by infecting the urinary bladder and sometimes the ureter and renal pelvises of dogs and cats. The parasite is introduced into your pet’s system by the consumption of earthworms containing first-stage larvae. Then the larvae infiltrates the intestinal walls of the urinary bladder to lay its eggs to continue the cycle of life. Though this is a worldwide problem, it appears that wild animals are the most common primary hosts.

Capillaria plica (bladder worm) is a nematode parasite of the urinary tract of canids (dogs), felids (cats) and mustelids (weasels) which can cause cystitis, pollakiuria, dysuria and hematuria. These infestations can cause inflammation in the urinary tract.

While most dogs and cats are asymptomatic, meaning that they don’t show symptoms, there are some animals who will display symptoms of pollakiuria (frequent urination), urinary incontinence and urinating in unusual or abnormal places. The host animal may or may not display the other symptoms of cystitis, dysuria or hematuria. Since many animals are asymptomatic, your pet may not exhibit signs of physical pain or discomfort for long periods of time if at all. There is a prepatent period of approximately 60 days in which the larvae will travel and mature and lay eggs for cycle continuation. This means that your pet could likely have these parasitic visitors in his or her urinary system for over 60 days before the first signs are noted if at all.

• Frequent urination
• Lack of bladder control
• Urination in unusual places

Types

There are several types of bladder worm or capillaria plica that can be inhabiting your family pet. Oftentimes, there is a concurrent bacterial or fungal infection such as:

• Bacterial - The most common bacteria found are Escherichia coli, Staphylococcus, Enterococcus and Streptococcus, less common are Klebsiella, Proteus and Pseudomonas 
• Pasteurella is more common in cats than in dogs 
• Mycoplasma is not a common cause of these urinary tract infections and is usually found in a coinfection relationship with bacteria 
• Leptospirosis is a worldwide zoonotic disease which is the result of filamentous bacteria that tend to infect the kidney as well as many other organs
• Fungi, yeast and parasites are considered uncommon causes of urinary tract infections. Bacterial infections are seen far more commonly.

These infections are caused by the dog consuming an earthworm containing a first-stage larvae. The first-stage larvae are eliminated from the earthworm in the small intestine of the host animal, which may be your dog. The larvae molt and invade the walls of the urinary bladder in the intestine via the bloodstream, then it travels into the kidney and down the ureter. Eggs are laid into the lumen of the bladder and later are excreted with the urine. There is a period of approximately 60 days called the prepatent period between the time when the parasite infects its host and the time when the first signs or demonstration of the parasite becomes known; for example, by the discovery of oocysts or eggs noted in blood or feces.

If your pet is exhibiting a change in his urination habits such as urinating inside the home, a veterinary visit is warranted to determine why this change has taken place. The veterinarian may begin with a urine analysis and blood tests to rule out possible cuases for the behavior, like urinary tract infection or tumor. The bladder and kidneys may be scanned.

Diagnosis of the bladder worm infection requires microscopic examination of urine sedimentation and evaluation of possible hematuria. The microscopic examinations will reveal the presence of eggs in the urine sedimentation. Once the culprit is identified, a treatment plan can be developed and started.

Generally, treatment of these infections requires the administration of de wormers like fenbendazole, ivermectin, levamisole, albendazole and moxidectin. These medications may be administered orally, subcutaneously or intramuscularly. Multiple treatments may be required if subsequent testing of urine sedimentation reveals the presence of the parasite in any stage of development. Testing will need to be done to determine if the animal is clear of parasites before treatment will be considered complete and successful.

Additional and subsequent testing will be required to show your dog to be clear of parasitic infection. This additional testing may require another round of medications or administration of another of the recommended drugs to clear the infection. Once it is cleared, it will be necessary to monitor urinary tract health on a regular basis and to treat the dog in a timely manner when and if it occurs again.