Do Cats Poop Out Worms After Being Dewormed? Everything You Need to Know
If you’ve recently dewormed your cat and are wondering what comes next, you’re not alone. Many pet owners notice unusual changes in their cat's waste and question whether it's normal. When it comes to intestinal parasites like roundworms or tapeworms, it’s common for cats to pass worms or worm segments in their feces after treatment. But with less common parasites such as Capillaria (also known as bladder worms), the situation is slightly different.
Understanding Capillaria in Cats
Capillaria are small parasitic worms that can infect cats, mainly targeting the urinary tract. The two primary species affecting cats are Capillaria plica (Pearsonema plica) and Capillaria feliscati (Pearsonema feliscati).
Unlike intestinal parasites, these worms reside in the bladder wall, kidneys, or even other parts of the urinary system. They release eggs into the urine, not the feces, which sets them apart from most common feline parasites.
Transmission and Life Cycle
The life cycle of Capillaria is quite complex and includes an intermediate host:
- The adult worms in the cat’s bladder lay eggs that are excreted through urine.
- The eggs reach the environment and must be ingested by an earthworm.
- Inside the earthworm, the eggs develop into an infectious form.
- Cats become infected by eating earthworms or creatures that have consumed infected earthworms.
This life cycle means indoor-only cats have a much lower risk of infection, while outdoor cats are more susceptible.
Do Dewormed Cats Pass Worms in Stool?
For intestinal worms like roundworms and tapeworms, it's typical for treated cats to pass some dead or dying worms in their feces after deworming. Pet owners might visibly notice these parasites in the litter box.
However, in Capillaria infections, worms are usually not passed in stool. Since these worms inhabit the bladder or kidney regions, their eggs are passed in urine rather than feces. It is rare for a cat with Capillaria to ever pass visible worms in their poop unless co-infected with an intestinal parasite.
Clinical Signs of Capillaria Infection
Most cats infected with Capillaria do not show clinical signs. When symptoms do occur, they depend on the site of infection:
- Bladder and urinary tract: blood in urine, frequent urination, incontinence, discomfort while urinating.
- Respiratory tract (rare): coughing, wheezing, or sneezing if Eucoleus species are involved.
- Nasal passages: nasal discharge, sneezing (uncommon).
Diagnosis
Veterinarians diagnose Capillaria infection primarily through urinalysis, where eggs are identified under a microscope. These eggs are distinctively oval and feature bipolar plugs. Because egg shedding can be inconsistent, multiple urine samples may be required for accurate diagnosis.
Treatment Options
Most asymptomatic cats may not require treatment. However, if there are clinical signs or persistent egg shedding, antiparasitic medications are administered, such as:
- Fenbendazole: 50 mg/kg orally for 4–10 days.
- Ivermectin: 0.2 mg/kg by injection.
These medications are generally effective, though a full course may be necessary. Supportive care, including anti-inflammatory therapy, may be prescribed if bladder inflammation is significant.
Prognosis and Recovery
With appropriate treatment, the prognosis is typically very good. Follow-up urinalysis ensures the infection has cleared. Cats not showing symptoms often live comfortably without any clinical issues. If symptoms persist, further evaluations may be needed to rule out other urinary tract conditions.
Can Humans Catch Capillaria from Cats?
Capillaria species infecting cats are not a human health concern. Humans can contract related species via other routes (like eating undercooked fish or frogs), but these are not the same worms found in feline species. Regardless, washing hands after cleaning the litter box and practicing good hygiene is always recommended.
Preventing Capillaria Infections
Capillaria is relatively rare in domestic cats, but prevention is worthwhile, especially for cats that go outside. Prevention methods include:
- Keep cats indoors to avoid exposure to soil and earthworms.
- Do not allow hunting of small animals such as rodents or birds.
- Regular deworming for at-risk pets as advised by your vet.
- Maintain a clean litter box and hygiene practices, especially in multi-cat homes.
When to Call the Vet
If your cat shows signs like straining to urinate, blood in urine, or confusion about litter box habits following deworming, a veterinary visit is recommended. These symptoms might indicate a Capillaria infection or another urinary issue that needs attention.
Conclusion
Although cats commonly pass worms in their feces after deworming, this is specific to intestinal parasites. In the case of Capillaria, which targets the urinary system, the worms do not exit via the stool. Eggs are instead shed in the cat’s urine and are often not visible to the naked eye. If your cat has been treated with a dewormer and is behaving normally, there's usually no cause for concern. When symptoms arise, a vet consultation and proper diagnosis are key for managing the infection effectively and keeping your cat healthy.





