# How Long Does Coccidia Last in Cats? Coccidia in cats how long does it last depends on the cat, the treatment, and how heavy the infection is. Most kittens and cats with diarrhea from coccidia start to improve within a few days of starting the right medication, but they can keep shedding the parasite in their stool for one to three weeks or longer. That gap between feeling better and no longer being contagious is the part owners most often miss. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - Diarrhea from coccidia often improves within 3 to 7 days of starting treatment, but mild cases can take longer and some cats need a second course. - Cats can shed oocysts (the infectious form of the parasite) in stool for 1 to 3 weeks after diarrhea stops, so keep them isolated from other cats during that window. - A follow-up fecal test is usually done about 2 to 4 weeks after treatment ends to confirm shedding has stopped. - Coccidia is most common in kittens, cats in shelters or catteries, and cats living in crowded or unsanitary conditions. - Most cats recover fully with treatment, supportive care, and thorough cleaning of litter boxes and bedding. ## What Is Coccidia in Cats? Coccidia are tiny single-celled parasites that live in the lining of a cat's intestine. The most common type in cats is Cystoisospora, also called Isospora, and cats have two main species: I felis and I rivolta [1]. These parasites are host-specific, which means the coccidia that infect cats do not infect dogs, and the ones that infect dogs do not infect cats [1]. Coccidia are not worms. They are not the same as Toxoplasma, though Toxoplasma is technically a related parasite. Cats do not carry Eimeria, which is the coccidia species that affects many other animals [1]. The parasite has a life cycle that includes stages inside the cat's intestinal cells and a stage in the environment. When a cat swallows an infected oocyst from contaminated soil, litter, food, or water, the parasite invades the intestinal lining, multiplies, and eventually produces new oocysts that pass out in the stool. Those oocysts then mature in the environment and can infect the same cat again or another cat. ## Signs Owners Notice The main sign of coccidia in cats is diarrhea. It is often soft, watery, or mucusy, and it may contain blood or have a foul smell. Kittens tend to show more severe signs than adult cats because their immune systems are still developing. Other signs you might see include: - Weight loss or poor growth in kittens - Dehydration - Straining to defecate - A dull or rough coat - Reduced appetite - Lethargy in more serious cases Some adult cats carry coccidia without any signs at all. They shed oocysts in their stool and can infect other cats without ever looking sick. This is one reason coccidia spreads so easily in multi-cat homes and shelters. If your cat stops eating for more than a day or two, that is a separate concern worth checking. You can read more about when appetite loss becomes urgent in [Cat Not Eating: How Long Is Too Long?](/knowledge/veterinary-medicine/digestive-and-urinary-care/cat-not-eating-how-long-too-long). ## Causes and Risk Factors Coccidia spreads through the fecal-oral route. A cat becomes infected by swallowing oocysts from contaminated surfaces, soil, or objects. This can happen through grooming, walking on contaminated floors and then licking paws, or sharing a litter box with an infected cat. Risk factors include: - Being a kitten (under 6 months old) - Living in a shelter, cattery, or rescue - Living in a multi-cat household - Being immunosuppressed from illness, stress, or medication - Living in crowded or unsanitary conditions - Having a weakened immune system from another infection A 2026 study of free-roaming cats in New York City found that 11.5% were infected with coccidia [2]. A large 2026 study of client-owned cats across the United States found Cystoisospora in 3.40% of fecal samples tested [3]. These numbers show that coccidia is common, especially in cats with outdoor access or crowded living situations. Stress can also play a role. A new kitten in the home, a move, or a stay in a boarding facility can trigger shedding in a cat that was carrying the parasite quietly. If you are introducing a new cat and seeing tension, our guide on [Cat Hissing at New Kitten: How Long Will It Last?](/knowledge/veterinary-medicine/anxiety-and-behavior-support/cat-hissing-at-new-kitten) may help you manage the transition. ## How Coccidia Is Diagnosed Your veterinarian will diagnose coccidia by examining a fresh stool sample under a microscope. This is called a fecal flotation test. The test looks for oocysts, which are the egg-like stage of the parasite. Because oocysts are shed in waves, a single fecal test can miss the infection. Your vet may recommend testing a sample collected over one to three days, or repeating the test if the first one is negative but your cat still has diarrhea. Other tests your vet might run include: - A fecal smear to look for other parasites - A Giardia test, since Giardia is the most commonly detected parasite in U.S. cats [3] - Blood work if your cat is very sick or dehydrated - A PCR test in some cases for more precise identification Coccidia can be confused with other causes of diarrhea, including Giardia, Cryptosporidium, food intolerance, and inflammatory bowel disease. That is why a fecal test matters before starting treatment. ## Treatment Options Most coccidia infections in cats are treated with a prescription medication that targets the parasite. Common drugs include sulfadimethoxine, ponazuril, toltrazuril, and diclazuril. Your veterinarian will choose the drug and calculate the dose based on your cat's weight, age, and overall health. Do not use over-the-counter dewormers for coccidia. Dewormers treat worms, not coccidia. Using the wrong product wastes time and can delay real treatment. Supportive care matters just as much as the antiparasitic drug. Your vet may recommend: - Fluids if your cat is dehydrated - A bland or easily digestible diet during recovery - Probiotics to support gut health - A follow-up fecal test after treatment In severe cases, especially in very young or immunocompromised kittens, hospitalization with intravenous fluids may be needed. Coccidiosis can cause oxidative stress and an acute phase response in the body, which is part of why sick cats feel so run down [4]. Treating the parasite and supporting the cat through that response both matter. If your cat is not eating or drinking during treatment, that is a reason to call your vet. Our article on [Cat Not Eating: How Long Is Too Long?](/knowledge/veterinary-medicine/digestive-and-urinary-care/cat-not-eating-how-long-too-long) explains when to seek help. ## Recovery, Outlook, and Long-Term Management ### How long does coccidia last in cats? Most cats with coccidia start to feel better within 3 to 7 days of starting treatment. Diarrhea usually resolves within one to two weeks, though mild cases can linger longer. Kittens and cats with weakened immune systems may take longer to recover. The bigger timeline question is shedding. A cat can continue to pass oocysts in its stool for one to three weeks after diarrhea stops. Some cats shed for even longer. This means your cat may look and act normal while still being able to infect other cats. ### How long is coccidia contagious in cats? Coccidia is contagious as long as your cat is shedding oocysts in its stool. That window typically lasts one to three weeks after treatment ends, but it can be longer in some cats. A follow-up fecal test is the only way to know for sure that shedding has stopped. ### When to recheck a fecal test Your veterinarian will usually recommend a follow-up fecal test about 2 to 4 weeks after treatment ends. If the test is still positive, another round of treatment may be needed. Do not skip this step, even if your cat seems completely fine. ### Isolation and cleaning during recovery While your cat is shedding, keep it away from other cats in the home. Use a separate litter box and clean it daily. Oocysts are tough and can survive in the environment for a long time, so regular cleaning matters. Here is a simple timeline table to help you plan: | Phase | Typical Duration | What to Do | |---|---|---| | Diarrhea and active illness | 3 to 7 days after starting treatment | Give medication, offer fluids, monitor appetite | | Shedding oocysts | 1 to 3 weeks after diarrhea stops | Isolate from other cats, clean litter box daily | | Follow-up fecal test | 2 to 4 weeks after treatment ends | Confirm shedding has stopped | | Full recovery | Usually 2 to 4 weeks total | Resume normal routine once vet clears your cat | ### Long-term outlook Most cats recover completely from coccidia. The parasite does not cause permanent damage in otherwise healthy cats. Kittens who receive prompt treatment grow normally. Cats with weakened immune systems may need longer treatment or repeated courses. Reinfection is possible if the environment is not cleaned well. If you have multiple cats, all of them may need testing or treatment, even if only one has diarrhea. ## Prevention Preventing coccidia comes down to hygiene and reducing exposure. - Scoop litter boxes daily and change litter regularly. - Wash litter boxes with hot water and a pet-safe disinfectant. - Wash bedding, toys, and food bowls often. - Keep new cats separated from resident cats for at least two weeks. - Have new cats tested for parasites before introducing them to others. - Reduce stress in multi-cat homes by providing enough resources. - Keep kittens away from outdoor soil and areas where stray cats roam. Coccidia oocysts are resistant to many common cleaners. Regular mechanical cleaning (scrubbing and rinsing) plus a disinfectant labeled for coccidia is your best approach. Ask your veterinarian which products they recommend. If you have an older cat with chronic health issues, parasite prevention is part of overall care. Our article on [How Long Can An Older Cat Live With Kidney Disease](/knowledge/veterinary-medicine/clinical-methods/how-long-can-an-older-cat-live-with-kidney-disease) covers how chronic conditions affect long-term management. ## Limitations and When to Contact a Veterinarian Coccidia is usually treatable, but some situations need urgent attention. Contact your veterinarian the same day if your cat: - Has bloody diarrhea - Is vomiting and cannot keep water down - Shows signs of dehydration (tacky gums, skin that does not spring back) - Is a kitten under 8 weeks old with diarrhea - Has a known immune condition or is on immunosuppressive medication Go to an emergency clinic now if your cat: - Is collapsed, unresponsive, or having seizures - Is breathing rapidly or struggling to breathe - Has severe abdominal pain or a distended belly - Has not urinated in more than 24 hours Call your vet for a routine visit if: - Diarrhea lasts more than 3 days despite treatment - Your cat is losing weight - You see blood or mucus in the stool for more than a day - Your cat stops eating Every cat is different, and individual cases need a veterinarian who can examine your cat, run tests, and set a treatment plan. This article gives you a general timeline, but your vet will give you the timeline that fits your cat. ## Frequently Asked Questions ### Can my cat still be contagious after diarrhea stops? Yes. Cats can shed oocysts in their stool for one to three weeks after diarrhea resolves. Keep your cat isolated from other cats during that time and follow your vet's advice on when to recheck a fecal sample. ### Do I need to treat all my cats if only one has coccidia? Often yes. Coccidia spreads easily through shared litter boxes and grooming. Your veterinarian may recommend testing or treating all cats in the home, especially if any are kittens or immunocompromised. ### Can I get coccidia from my cat? The coccidia species that infect cats are host-specific and do not infect people [1]. However, cats can carry other parasites that do affect humans, so good hygiene around litter boxes is always wise. ### How do I clean my home after a coccidia infection? Remove all feces from litter boxes daily, scrub boxes with hot water and a disinfectant labeled for coccidia, and wash bedding and toys in hot water. Oocysts are resistant to many cleaners, so mechanical scrubbing matters as much as the product you use. ### Will my kitten grow out of coccidia? Kittens do develop better immunity as they get older, but they do not simply grow out of an active infection. Treatment is needed to clear the parasite and prevent dehydration or poor growth. Most kittens recover fully with prompt care. ## Related Articles - [Cat Hissing at New Kitten: How Long Will It Last?](/knowledge/veterinary-medicine/anxiety-and-behavior-support/cat-hissing-at-new-kitten) - [Cat Not Eating: How Long Is Too Long?](/knowledge/veterinary-medicine/digestive-and-urinary-care/cat-not-eating-how-long-too-long) - [How Long Can An Older Cat Live With Kidney Disease](/knowledge/veterinary-medicine/clinical-methods/how-long-can-an-older-cat-live-with-kidney-disease) - [How Long Can A Healthy Cat Go Without Peeing](/knowledge/veterinary-medicine/symptom-guides/how-long-can-a-healthy-cat-go-without-peeing) - [How Long Can A Cat Live Without Peeing](/knowledge/veterinary-medicine/symptom-guides/how-long-can-a-cat-live-without-peeing) - [How Long Can A House Cat Go Without Peeing](/knowledge/veterinary-medicine/symptom-guides/how-long-can-a-house-cat-go-without-peeing) - [Coccidia in Cats: Symptoms to Watch For](/knowledge/veterinary-medicine/parasitic-diseases/coccidia-cats-symptoms) - [Coccidia in Cats: Treatment and Medication Options](/knowledge/veterinary-medicine/pet-medication-guide/coccidia-cats-treatment-medication) - [Is Coccidia in Cats Contagious to Other Cats?](/knowledge/veterinary-medicine/parasitic-diseases/coccidia-in-cats-contagious) ## References 1. [Coccidiosis of Cats and Dogs - Digestive System](https://www.merckvetmanual.com/digestive-system/coccidiosis/coccidiosis-of-cats-and-dogs). Merck Veterinary Manual. 2. [Zoonotic endoparasites and Toxoplasma gondii seropositivity in free-roaming cats (Felis catus) from New York City boroughs](https://pubmed.ncbi.nlm.nih.gov/42418442/). PloS one, 2026. 3. [Prevalence and epidemiologic patterns of feline parasitism detected by fecal examination in the United States, 2023](https://pubmed.ncbi.nlm.nih.gov/42184502/). Veterinary parasitology, 2026. 4. [Acute phase response and oxidative stress in coccidiosis: A review in domestic animals](https://pubmed.ncbi.nlm.nih.gov/39128326/). Veterinary parasitology, 2024. ## Further Reading - [Merck Veterinary Manual: Cat Owners](https://www.merckvetmanual.com/cat-owners) - [Cornell Feline Health Center: Health Information](https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information) - [American Veterinary Medical Association: Pet Care](https://www.avma.org/resources-tools/pet-owners/petcare)