Parasites are one of the most common health threats that cat owners have to deal with. Although often invisible to the naked eye and without any obvious symptoms, they can cause a lot of damage to the animal's body - from digestive problems, through weakened immune system, to neurological changes, respiratory problems or nutritional deficiencies. Untreated infestations can even lead to death, especially in young kittens or weakened animals.
A threat not only to the cat
It is also worth emphasizing that some cat parasites are zoonotic , meaning they can be transmitted to humans. The following are particularly at risk:
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small children,
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pregnant women,
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elderly and immunocompromised people.
This means that the problem of parasites in cats goes beyond veterinary issues – it also concerns public health and home hygiene.
Is the domestic cat also at risk?
Contrary to popular belief, parasites are not a problem only for outdoor cats. Even indoor cats , those that live exclusively in apartments, can become infected with parasites. How is this possible?
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Parasites can be brought into the home on shoes , clothing , or even by other pets (e.g. dogs).
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Parasite eggs can be found in raw meat, potting soil, and even water.
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Many cats become infected while still infancy – through their mother's milk or contact with an infected birthing environment.
Parasites are not just "worms"
It is also worth understanding that the term "parasites" does not refer only to roundworms or tapeworms. It encompasses a whole range of parasitic organisms:
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internal – such as roundworms, tapeworms, protozoa,
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external – such as fleas, ticks, scabies.
Each of them works differently, manifests differently, and requires different treatment. That is why it is so important to know how to recognize and combat them.
Types of parasites in cats
Parasites in cats can be divided into two main groups:
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Internal parasites (endoparasites) – living inside the cat's body (intestines, lungs, muscles, nervous system)
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External parasites (ectoparasites) – living on the skin, in the fur or in the ear canals of the cat
Both can lead to serious health problems. Below we present the most common parasites found in cats in Poland.
A. Internal parasites (endoparasites)
1. Glisty (Toxocara spp.)
The most common intestinal parasites of cats, especially Toxocara cati. Infection can occur as early as kittenhood – through mother's milk, consumption of contaminated food or contact with eggs present in the environment. Symptoms include:
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diarrhea or constipation,
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abdominal bloating,
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weight loss despite appetite,
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vomiting, in which parasites can sometimes be seen,
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weakness and anemia.
2. Tapeworm (Dipylidium caninum, Taenia taeniaeformis)
Dipylidium caninum is spread by fleas – a cat can become infected by swallowing an infected flea while toileting. Taenia taeniaeformis enters the cat's body mainly by eating an infected mouse or rodent.
Symptoms of infection include:
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weight loss despite good appetite,
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irritability,
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the presence of tapeworm segments (white "grains of rice") in the anus or in the cat's bedding.
3. Lungworm (Aelurostrongylus abstrusus)
A lungworm that can be difficult to diagnose because it doesn't always cause obvious symptoms. Infection occurs through the ingestion of intermediate hosts, such as snails, frogs, and mice.
Symptoms may include:
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chronic cough,
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wheezing,
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shortness of breath,
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weakness and lack of desire to play.
4. Tęgoryjce (Ancylostoma tubaeforme, Uncinaria spp.)
Less frequently diagnosed in cats in Poland, but they cannot be completely ruled out. Hookworms damage the intestinal walls and can cause:
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bloody diarrhea,
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anemia,
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abdominal pain,
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dehydration,
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apathy and exhaustion.
5. Giardia duodenalis (giardia)
A protozoan that causes giardiasis, an infectious disease of the digestive tract. Infection is common in young cats and in large groups (shelters, catteries).
Symptoms:
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recurrent diarrhea (often oily, with an unpleasant smell),
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flatulence,
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weight loss,
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sometimes lack of appetite.
6. Tritrichomonas foetus
Trichomonas occurs mainly in purebred cats, often in breeding. It causes chronic diarrhea, the treatment of which is difficult and long-term.
Symptoms:
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mucous, foul-smelling diarrhea,
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proctitis,
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sometimes without other general symptoms.
7. Cystoisospora spp. (kokcydia)
It causes cystoisosporosis – most often in kittens and cats with reduced immunity. The parasite lives in the small intestine.
Symptoms:
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diarrhea, sometimes with blood,
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dehydration,
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lack of appetite,
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growth retardation in young cats.
8. Cryptosporidium felis
Another representative of coccidia. It is difficult to detect in routine tests, but can cause similar symptoms to other protozoa:
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diarrhea,
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weight loss,
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deterioration of coat condition.
9. Toxoplasma gondii
One of the most well-known protozoa. Cats are the main definitive host of this parasite. Infection in cats is usually asymptomatic, but in some animals it can lead to:
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fever,
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apathy,
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neurological symptoms (e.g. muscle tremors, balance disorders),
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breathing difficulties.
10. Hammondia spp.
Rarely diagnosed protozoa with a life cycle similar to Toxoplasma gondii. Usually do not cause clinical symptoms.
11. Sarcocystis spp.
Coccidian parasites that can live in the muscles and nervous system of a cat. Infection is usually asymptomatic, but in some cases it can cause:
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weakness,
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neurological disorders,
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muscle pain.
B. External parasites (ectoparasites)
1. Fleas (Ctenocephalides felis)
The most common ectoparasite in cats. Fleas feed on blood and can transmit other parasites (e.g. tapeworms) and cause:
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itching,
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hair loss,
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flea allergy dermatitis (FAD),
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anemia in kittens.
2. Ticks (Ixodes spp.)
Cats, especially those that go outside, can catch ticks that carry dangerous diseases such as babesiosis, Lyme disease or anaplasmosis (less common in cats than dogs, but still possible).
3. Lice and lice
Rare in cats, but can occur in neglected colonies or in strays. Causes itching, hair loss, and overall skin deterioration.
4. Scabies mites (Otodectes cynotis)
They cause ear mites, a very common ear disease in cats. Symptoms include:
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intense scratching of ears,
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black, dry discharge resembling coffee grounds,
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shaking head,
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sometimes bacterial superinfections.
Symptoms of parasitic infection in cat
Recognizing parasites in cats is not always easy – symptoms can be non-specific and vary depending on the type of parasite, the cat’s age, health condition, and the severity of the infection. Sometimes the course is asymptomatic, especially in adult, healthy cats. However, in kittens, seniors, and animals with weakened immunity, parasites can quickly lead to serious complications.
A. Symptoms of internal parasites
1. From the digestive system:
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Diarrhea – often recurrent, of various nature (watery, mucous, fatty, sometimes with a hint of blood).
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Vomiting – sometimes you can see roundworms in it.
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Abdominal bloating – especially in kittens with ascariasis.
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Constipation – less common, but may occur with tapeworm infections.
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Weight loss – despite normal or even increased appetite.
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Loss of appetite – in advanced stages or with severe intestinal irritation.
2. General symptoms:
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Weakness , apathy, lack of desire to play.
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Dulling of the coat , loss of shine.
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Dehydration – especially visible with diarrhea and vomiting.
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Anemia – pale gums, weakness (especially in cases of hookworms, fleas, tapeworms).
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Growth retardation – in young cats infected with intestinal parasites.
3. Respiratory symptoms:
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Cough , shortness of breath, rapid breathing – characteristic of infection with the lungworm (Aelurostrongylus abstrusus).
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Wheezing or asthma-like symptoms.
4. Neurological symptoms:
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Rare, but may occur with toxoplasmosis or muscle infection with Sarcocystis spp.
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Symptoms: muscle tremors, ataxia, difficulty walking, seizures.
B. Symptoms of external parasites
1. Itching and scratching
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Intensive scratching, especially around the head, ears, neck and back.
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May indicate fleas , ear mites , or allergic reactions.
2. Hair loss and skin lesions
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Local alopecia, scabs, redness.
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Often associated with allergy to flea saliva or secondary bacterial infections.
3. Dark discharge from the ears
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Resembling coffee grounds, a typical symptom of ear mites (Otodectes cynotis).
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It is accompanied by shaking the head and rubbing the ears against objects.
4. Visible parasites
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Sometimes you can see fleas with the naked eye – small, black, jumping insects.
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Tapeworms – segments resembling grains of rice found around the anus or on the cat's bedding.
C. Symptoms in humans (in case of zoonoses)
Some cat parasites are potentially dangerous to humans , especially children and people with weakened immune systems:
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Toxocara cati – may cause toxocariasis (larva migrans).
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Giardia duodenalis – causes gastrointestinal symptoms.
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Toxoplasma gondii – especially dangerous for pregnant women (risk of damage to the fetus).
Diagnosis of parasites in cat
Early diagnosis of parasites in cats is crucial to prevent health complications and quickly implement effective treatment. Not all parasitic infections produce clear symptoms, which is why preventive check-ups are so important , especially in outdoor cats, kittens and those living in large groups (catteries, shelters).
A. Diagnosis of internal parasites
1. Stool examination (coproscopy)
This is the basic and most frequently performed test for intestinal parasites:
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detects eggs of roundworms, tapeworms, coccidia (e.g. Isospora, Cryptosporidium), giardia cysts, roundworm larvae;
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it is recommended to collect a 3-day stool sample – this increases the chance of detecting parasites (excretion may be irregular);
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the examination is performed under a microscope or using flotation tests.
Note: Not all parasites are detectable in every phase of the life cycle – a negative result does not always mean no infection.
2. Immunoenzymatic tests (ELISA, SNAP, strip tests)
Particularly used when suspected:
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gardens ,
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Tritrichomonas foetus,
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Cryptosporidium felis .
These are rapid tests that detect parasite antigens in feces. They have higher sensitivity than microscopy, especially for protozoa.
3. Blood test
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It may help indirectly assess the effects of infection (anemia, elevated inflammatory markers, eosinophilia).
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In the case of toxoplasmosis, IgG and IgM antibodies against Toxoplasma gondii are determined .
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In severe infections, liver or kidney dysfunction may be evident .
4. Chest X-ray
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Used when lungworm (Aelurostrongylus abstrusus) is suspected .
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The image may reveal inflammatory changes, lung compaction, and traces of larval migration.
5. PCR (polymerase chain reaction)
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The most accurate method for detecting the genetic material of the parasite (e.g. Tritrichomonas foetus, Giardia).
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More expensive and available in specialized laboratories, but very sensitive.
B. Diagnosis of external parasites
1. Inspection of the cat's fur and skin
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Visible fleas, lice, biting lice or their feces (black dots on the back or belly).
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The presence of tapeworm larvae in the anus (white "grains of rice").
2. Flea comb test
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Combing with a fine-toothed comb allows you to detect fleas or their droppings (after contact with damp paper, the droppings turn red – this is digested blood).
3. Otoscopy and ear swab examination
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If ear mites (Otodectes cynotis) are suspected , the veterinarian examines the ear canal with an otoscope.
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An ear swab under a microscope reveals the presence of scabies mites.
4. Skin microscopic tests (scrapings)
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Helpful in cases of suspected infection with lice, scabies, demodex (rarely in cats).
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They require a skin or fur sample.
C. When should I see a vet?
You should not delay a visit if your cat has:
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chronic or recurrent diarrhea,
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vomiting (especially with visible parasites),
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weight loss for no apparent reason,
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visible parasites on the fur or around the anus,
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itching, shaking head, dark discharge from ears,
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cough or difficulty breathing,
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neurological symptoms or general weakness.
Treating parasites in cat
Treatment of parasites in cats must be well-matched to the type of parasite , age and health of the animal. In many cases, the use of a "universal pill" is not enough - an accurate diagnosis and precise selection of the preparation are necessary . Below we present detailed information on the treatment of individual groups of parasites.
A. Treatment of internal parasites (endoparasites)
1. Glisty (Toxocara spp., T. cati)
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Drugs: pyrantel, fenbendazole, milbemycin, moxidectin, emodepside.
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Form of administration: tablets, pastes, spot-on (e.g. Advocate, Profender).
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Note: roundworms are common in kittens – deworming should begin as early as the 3rd week of life and continue every 2–3 weeks until the 3rd month of life.
2. Tapeworm (Dipylidium caninum, Taeniaeformis)
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Drugs: praziquantel (often in combination preparations).
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Form: tablets (e.g. Drontal, Milbemax), spot-on (Profender).
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Important: in the case of Dipylidium, it is also necessary to combat fleas - cats become infected with tapeworm by swallowing them.
3. Tęgoryjce (Ancylostoma tubaeforme)
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Drugs: fenbendazole, milbemycin, moxidectin.
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Note: Hookworms can cause severe anemia – treatment requires monitoring of blood parameters.
4. Lungworm (Aelurostrongylus abstrusus)
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Medications: moxidectin (e.g. Advocate), imidacloprid + moxidectin.
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Sometimes additional therapies are necessary: anti-inflammatory, inhalation, oxygen therapy.
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Recommended: Follow-up X-ray after treatment.
5. Giardia duodenalis (giardia)
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Medications: fenbendazole, metronidazole – combination therapy often necessary.
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Key hygiene: disinfecting bowls, litter boxes, washing bedding.
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Asymptomatic cats in breeding groups/shelters should also be treated.
6. Tritrichomonas foetus (rzęsistek)
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Medications: ronidazole – prescription only, due to side effects (neurotoxicity).
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Long and difficult therapy , often with relapses – PCR tests necessary.
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Metronidazole treatment is not recommended – ineffective.
7. Cystoisospora spp., Cryptosporidium felis, Toxoplasma gondii
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Isospora: sulfonamides (np. sulfadimethoxyna).
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Toxoplasma: clindamycin + sulfonamides.
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Cryptosporidium: no effective treatment – immune support and hydration important.
8. Other rare parasites (Hammondia, Sarcocystis)
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They usually do not require treatment – they are of low pathogenicity .
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If symptoms occur, consult a veterinarian and treat symptomatically.
B. Treatment of external parasites (ectoparasites)
1. Fleas
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Preparaty spot-on: fipronil (Frontline), imidacloprid (Advantage), selamektyna, fluralaner (Bravecto), sarolaner (Stronghold Plus).
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Oral tablets: e.g. Comfortis, Bravecto.
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Environment: vacuuming, washing bedding and spraying the environment with insecticide is necessary.
2. Ear mite (Otodectes cynotis)
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Local medications: ear preparations (e.g. Oridermyl), spot-on with ivermectin or selamectin.
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Ear cleaning necessary before application.
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Treating all cats at home!
3. Lice and lice
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Similar treatment to fleas.
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Sometimes a haircut and thorough washing with medicated shampoos are required.
C. Home treatment support
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Hydration and an easily digestible diet – especially in cases of diarrhea and weakness.
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Probiotics and protective preparations – support intestinal flora after therapy.
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Environmental hygiene – cleaning bowls, litter boxes, washing hands after contact with the cat.
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Isolation of the infected cat – if there are other animals in the house.
D. Preventive treatment (deworming)
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Kittens: every 2–3 weeks from 3 weeks to 3 months of age.
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Adult indoor cats: every 3–6 months.
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Outdoor cats: every 1–3 months, depending on risk.
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Pregnant cats: only under veterinary supervision - not all medications are safe!
Prevention of parasites in cats
Parasites can cause serious health problems in cats, and some are also dangerous to humans (zoonoses). Preventing infection should be a standard part of your cat's care, whether it's an indoor or outdoor cat.
A. Regular deworming
1. Kittens
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Deworming should begin at 3 weeks of age , then repeated every 2–3 weeks until 12 weeks of age .
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Then deworming once a month until 6 months old .
2. Adult cats
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Indoor cats: deworm every 3–6 months , depending on veterinarian recommendations.
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Outdoor cats: more often – as often as every 1–3 months , especially if they hunt or have contact with other animals.
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Cats in breeders, shelters, animal hotels : schedule determined individually, depending on the risk.
3. Preventive preparations
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It is best to use broad-spectrum preparations that act on both intestinal and external parasites (e.g. Profender, Milbemax, Broadline, Stronghold Plus ).
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Form: tablets, pastes, spot-on – the choice depends on the preferences of the owner and the cat.
B. Control and eradication of external parasites
1. Protection against fleas, ticks, lice
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Use of preventive spot-on or tablet preparations (e.g. Bravecto, Frontline, Stronghold, Advantage).
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Regularity: every 4–12 weeks depending on the agent.
2. Environmental hygiene
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Vacuuming beds, furniture and carpets.
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Wash bedding at min. 60°C.
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Possibility of using environmental sprays to control flea larvae and eggs.
C. Quarantine and testing of new animals
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Newly adopted cats (from a shelter, street, breeder) should undergo quarantine and fecal testing before they are allowed to live with other animals.
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This also applies to temporary wards , e.g. those taken in for the duration of the holidays.
D. Cleanliness of the litter box and surroundings
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Daily cleaning of the litter box – reduces the risk of spreading intestinal parasites.
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Regularly disinfect the litter box (preferably once a week) with preparations that are safe for animals.
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Separate bowls for each cat, frequent washing of dishes and waterers.
E. Proper diet and immunity
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Avoiding raw meat – it may contain Toxoplasma gondii larvae or tapeworms.
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Choice of complete food or heat-treated meat.
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Immunity-supporting diet – a healthy body copes better with parasite invasion.
F. Educating household members and exercising caution
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Washing hands after contact with the litter box, cat, fur – especially important for children and the elderly.
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Regular preventive examinations and consultations with a veterinarian.
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Avoiding contact between the cat and rodents and birds (reservoir of parasites).
G. Special precautions for humans (zoonoses)
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Toxocara cati, Giardia, Toxoplasma gondii – can be transmitted to humans, therefore:
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Pregnant women should avoid cleaning the litter box,
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children should be taught not to kiss a cat on the face,
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The litter box should be located away from the kitchen.
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Summary and When to See a Vet
Parasites in cats are a common problem that can be effectively controlled with proper prevention and vigilance. Parasitic infections can be asymptomatic or cause serious health problems, and some of them are also a threat to humans . Therefore, every cat owner should know the basics of recognizing the symptoms and know when specialist help is necessary.
A. The most important information to remember
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Internal parasites (e.g. roundworms, tapeworms, protozoa) and external parasites (e.g. fleas, mites) can occur in both indoor and outdoor cats.
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Symptoms of parasitic infection vary – from diarrhea and vomiting to coughing, itchy ears or neurological problems.
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Regular stool examination , health check-ups and preventive deworming are the foundations of protecting your cat's health.
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Treatment must be targeted – the choice of medication depends on the species of parasite, the age of the cat and its general health.
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Many parasites are invisible to the naked eye , so don't rely solely on the lack of visible signs in the stool or fur.
B. When is it necessary to go to the vet?
Some situations require immediate consultation with a veterinarian. Here are the symptoms that should cause you concern:
1. Persistent diarrhea or vomiting
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Especially when they persist for more than 24-48 hours.
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When blood, mucus , or parasites are visible in the stool .
2. Sudden weight loss or weakness
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May indicate a serious parasitic infection or anemia.
3. Breathing problems
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Sneezing, shortness of breath, coughing may be symptoms of lungworm invasion.
4. Neurological changes or seizures
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Among other things, toxoplasmosis must be excluded.
5. Severe itching of the ears or shaking of the head
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May indicate the presence of ear mites.
6. Loss of appetite and apathy
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A general symptom of many diseases, but also of strong parasitic invasions.
7. Presence of fleas, ticks, parasite eggs in the stool
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It requires immediate action – both in the cat and in its environment.
C. Cooperation with a veterinarian
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The veterinarian has diagnostic tests (including fecal flotation, PCR, microscopic tests) that allow for the precise determination of the type of parasite.
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After diagnosis, an individual treatment plan is implemented – taking into account the cat’s age, lifestyle, health condition and any co-occurring diseases.
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Remember: never treat your cat "by eye" with home remedies or medications intended for dogs!
End
Parasites are the invisible enemy of every cat - but a well-informed owner is their greatest adversary. Regular prophylaxis, observation of the pet's behavior and cooperation with a veterinarian can effectively protect your cat from invasion, and if necessary - quickly and effectively cure it.
By taking care of your cat's health, you are also taking care of the health of your whole family.
Parasites in cats – symptoms, treatment, and prevention
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