# Leptospirosis in Cats: Symptoms, Treatment, and Contagion Leptospirosis in cats is a bacterial infection that usually causes few or no obvious signs, and many infected cats never look sick at all [1]. Cats can carry the bacteria in their urine, so the infection matters for both feline health and human health [2][3]. Leptospirosis in cats symptoms are often subtle, which is why the disease is easy to miss without testing. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - Leptospirosis is caused by spiral-shaped bacteria in the genus Leptospira, and it can infect nearly all mammals, including people [1]. - Most infected cats show no signs, but the bacteria may play a role in long-term kidney disease [1]. - Cats can shed Leptospira in their urine, so an infected cat can be a source of human exposure [2][3]. - Diagnosis usually relies on urine PCR testing and blood antibody tests, and your veterinarian will choose the right combination [4][5]. - There is no widely used cat vaccine for leptospirosis in the United States, so prevention focuses on limiting exposure to rodents, wildlife, and contaminated water. ## What Is Leptospirosis in Cats? Leptospira are bacteria that live in the kidneys and reproductive tracts of infected animals and pass into urine. The disease they cause, leptospirosis, ranges from mild infection with no signs to multiple-organ failure and death in mammals generally [1]. For years, experts believed cats were not susceptible to infection at all [1]. That view has changed. Current thinking is that the bacteria might contribute to long-term kidney disease in cats, and infected cats are unlikely to show the dramatic signs seen in other species [1]. The role of cats in spreading leptospirosis is still not fully understood. In dogs, the picture is clear and well studied. In cats, researchers describe a significant lack of studies on how often they transmit the bacteria and which species they carry [6]. What is clear is that exposure happens. A study in Thailand found Leptospira DNA in 22 of 264 cats tested during neutering, about 8.3 percent [3]. A study in Iran detected Leptospira DNA in 15 of 76 cats, about 19.7 percent, with positive results from both urine and vaginal samples [2]. These numbers show that cats do encounter these bacteria, even when they seem healthy. ## Leptospirosis in Cats Symptoms: What Owners Notice Most cats with leptospirosis look normal. When signs do appear, they tend to be vague and easy to attribute to other problems. Because the bacteria can settle in the kidneys, liver, and eyes, the signs owners notice often reflect those organs. ### Common or Subtle Signs - Increased drinking and urination, which can point to kidney involvement - Weight loss or a decreased appetite - Lethargy or reduced activity - Vomiting or diarrhea - Fever - Jaundice, a yellow tint to the gums, skin, or whites of the eyes ### Eye-Related Signs Leptospira can cause inflammation inside the eye in dogs and horses, and researchers have looked at whether the same happens in cats. In one pilot study of 37 cats with uveitis (inflammation inside the eye), 2 cats had antibodies to Leptospira interrogans, about 5.4 percent, though none of the eye fluid samples tested positive for bacterial DNA [4]. Eye signs such as redness, cloudiness, squinting, or a change in pupil appearance are worth a veterinary exam, whatever the cause. ### Kidney and Liver Signs Leptospirosis is associated with kidney and liver injury in animals generally [2]. In cats, the link to long-term kidney disease is suspected but not fully proven [1]. If your cat has been diagnosed with kidney disease, your veterinarian may consider leptospirosis as one possible cause and may recommend antibiotics if the infection is confirmed [1]. Other conditions can cause similar signs, including [Pancreatitis In Cats Symptoms](/knowledge/veterinary-medicine/symptom-guides/pancreatitis-in-cats-symptoms), so testing matters. ## Causes and Risk Factors Leptospira bacteria survive in water and moist soil and enter the body through mucous membranes, small cuts, or by drinking contaminated water. Rodents and wildlife are common sources. A global review of wildlife found that many wild species carry pathogenic Leptospira, and host-pathogen relationships in wildlife remain poorly understood [7]. That means outdoor cats face exposure from prey, puddles, and shared environments. Risk factors for cats include: - Outdoor access, especially hunting rodents or drinking from puddles, ponds, or slow-moving water - Living in areas with high rodent or wildlife populations - Contact with other infected animals, including through urine - Living in regions where leptospirosis is common in animals and people [6][5] Indoor cats can still be exposed if rodents enter the home or if contaminated water or soil is tracked inside. Age, immune status, and the specific Leptospira type all influence whether an exposed cat becomes ill [5]. ## How Leptospirosis in Cats Is Diagnosed Diagnosis is not straightforward, and no single test is perfect. Your veterinarian will combine history, physical exam, blood work, urinalysis, and specific tests for Leptospira. ### Tests Your Veterinarian May Use - **PCR testing on urine.** This looks for bacterial DNA and can detect active shedding. In the Iran study, urine PCR was positive in 10 of 76 cats [2]. In the Thailand study, urine PCR identified Leptospira DNA in 22 of 264 cats [3]. - **Microscopic agglutination test (MAT) on blood.** This measures antibodies and can suggest exposure. In the uveitis study, MAT was positive in 2 of 37 cats at a low titer [4]. In the Indonesia study, MAT was used alongside blood work to estimate exposure in cats [5]. - **Blood chemistry and urinalysis.** These show how the kidneys and liver are functioning and help your veterinarian judge the severity of illness [5]. - **Additional testing for other causes.** Because many diseases cause similar signs, your veterinarian may also test for other infections or conditions. A positive antibody test does not always mean active infection, and a negative PCR does not rule it out if shedding is intermittent. Your veterinarian interprets results together with your cat's signs and lab work. ## Treatment Options for Leptospirosis in Cats Treatment depends on how sick your cat is and which organs are affected. Antibiotics are the core of treatment when leptospirosis is confirmed or strongly suspected [1]. Your veterinarian will choose the antibiotic and calculate the dose based on your cat's weight and health. Do not give any antibiotic without veterinary guidance. Supportive care is often just as important as antibiotics. If the kidneys are involved, treatment for long-term kidney disease may include a special diet, intravenous or subcutaneous fluids, or medications [1]. Cats with liver involvement, dehydration, or vomiting may need hospitalization for fluids and monitoring. Eye inflammation may need separate treatment from a veterinary ophthalmologist. If your cat has kidney disease and your veterinarian determines leptospirosis is the cause, antibiotics may be necessary as part of the plan [1]. In many cases, the kidney disease itself needs ongoing management regardless of the original trigger. ## Recovery, Outlook, and Long-Term Management The outlook varies widely. Cats with mild or no signs often do well, especially when the infection is identified and treated. Cats with significant kidney or liver damage have a more guarded prognosis, and some continue to need kidney support for life [1]. Long-term management may include: - Regular blood work and urinalysis to track kidney and liver values - A kidney-supportive diet if your veterinarian recommends one - Fluids or medications for chronic kidney disease [1] - Recheck testing to confirm the bacteria are cleared - Keeping your cat indoors to reduce repeat exposure Because infected cats can shed bacteria in urine, hygiene at home matters during and after treatment. Wear gloves when cleaning the litter box, wash your hands afterward, and keep the box away from food preparation areas. Your veterinarian will give recommendations about how to protect yourself and your family when handling a known or suspected infected cat [1]. ## Prevention There is no widely available vaccine for leptospirosis in cats in the United States, so prevention centers on reducing exposure. If you have heard about a leptospirosis in cats vaccine, understand that the vaccine is used in dogs, not cats. Ask your veterinarian about your cat's specific risk. Practical steps include: - Keep cats indoors to limit contact with rodents, wildlife, and contaminated water - Control rodents around your home and yard - Prevent your cat from drinking from puddles, ponds, or outdoor water bowls that collect rain - Wash your hands after handling your cat, especially before eating - Clean the litter box daily and dispose of waste safely - Isolate a cat with confirmed infection from people who are immunocompromised until your veterinarian says shedding has stopped If your cat has other skin or allergic conditions that require ongoing care, see [Cat Skin Infection: Signs and Treatment Options](/knowledge/veterinary-medicine/skin-allergy-and-ear-care/cat-skin-infection) and [Cat Allergy Treatment](/knowledge/veterinary-medicine/clinical-methods/cat-allergy-treatment). For tick-borne illness that can look similar, see [Lymes Disease In Cats: Comprehensive Veterinary Reference Guide](/knowledge/veterinary-medicine/bacterial-diseases/lymes-disease-in-cats). ## Is Leptospirosis in Cats Contagious? Yes, leptospirosis is a zoonotic disease, meaning it can pass from animals to people [6][5]. Infected cats can shed the bacteria in urine, and transmission to humans can occur from companion animals living in close contact with people, not only from rodents and wildlife [5]. That does not mean you should panic. Simple hygiene greatly reduces risk. People usually become infected through contact with contaminated urine, water, or soil, especially through broken skin, the eyes, nose, or mouth. If you are pregnant, immunocompromised, or have young children at home, tell your veterinarian so they can advise you on precautions [1]. ## Limitations and When to Contact a Veterinarian Individual cases need a veterinarian. Testing and treatment decisions depend on your cat's specific signs, lab results, and risk factors. **Contact your veterinarian the same day if your cat:** - Drinks and urinates much more than usual - Vomits repeatedly or stops eating - Seems weak, wobbly, or unusually tired - Has yellow gums, skin, or eyes **Go to an emergency clinic now if your cat:** - Collapses or cannot stand - Breathes with effort or open-mouth breathes - Has a seizure or sudden blindness - Produces no urine for many hours **Schedule a routine visit if your cat:** - Has occasional vomiting or mild appetite changes - Has been diagnosed with kidney disease and you want to discuss possible infectious causes - Has eye redness or squinting that comes and goes ## Frequently Asked Questions ### Can indoor cats get leptospirosis? Yes, indoor cats can be exposed, though the risk is lower than for outdoor cats. Rodents can enter homes, and contaminated soil or water can be tracked inside on shoes or paws. Keeping rodents out and washing hands after handling your cat reduces the chance. ### How do cats catch leptospirosis? Cats catch it through contact with urine from infected animals or with contaminated water and soil. The bacteria enter through the mouth, nose, eyes, or small breaks in the skin. Hunting rodents and drinking from outdoor water sources are common routes. ### Can I get leptospirosis from my cat? Yes, leptospirosis can pass from cats to people, and transmission from companion animals in close contact with humans is documented [5]. The risk is manageable with good hygiene, especially hand washing and careful litter box cleaning. Talk to your veterinarian if anyone in your home has a weakened immune system. ### Is there a leptospirosis vaccine for cats? No cat vaccine for leptospirosis is in common use in the United States. The vaccine is used in dogs, not cats. Prevention for cats relies on reducing exposure to rodents, wildlife, and contaminated water. ### How long does treatment take? Antibiotic treatment typically continues for several weeks, and your veterinarian will set the exact length based on your cat's response and test results. Some cats also need ongoing kidney support after the infection clears [1]. Follow-up testing helps confirm the bacteria are gone. ## Related Articles - [Feline Hypereosinophilic Syndrome: Diagnosis and Management](/knowledge/veterinary-medicine/clinical-methods/feline-hypereosinophilic-syndrome-diagnosis-management) - [Lymes Disease In Cats: Comprehensive Veterinary Reference Guide](/knowledge/veterinary-medicine/bacterial-diseases/lymes-disease-in-cats) - [Pancreatitis In Cats Symptoms](/knowledge/veterinary-medicine/symptom-guides/pancreatitis-in-cats-symptoms) - [Cat Skin Infection: Signs and Treatment Options](/knowledge/veterinary-medicine/skin-allergy-and-ear-care/cat-skin-infection) - [Cat Allergy Treatment](/knowledge/veterinary-medicine/clinical-methods/cat-allergy-treatment) - [Feline Hyperthyroidism: Signs, Diagnosis, and Treatment](/knowledge/veterinary-medicine/clinical-methods/feline-hyperthyroidism-signs-diagnosis-and-treatment) ## References 1. [Leptospirosis in Cats - Cat Owners](https://www.merckvetmanual.com/cat-owners/disorders-affecting-multiple-body-systems-of-cats/leptospirosis-in-cats). Merck Veterinary Manual. 2. [Molecular detection of Leptospira spp. in urinary and vaginal samples of domestic and free-roaming cats in Tehran, Iran](https://pubmed.ncbi.nlm.nih.gov/42700683/). Comparative immunology, microbiology and infectious diseases, 2026. 3. [Pathogenic Leptospira species identified in dogs and cats during neutering in Thailand](https://pubmed.ncbi.nlm.nih.gov/41637464/). PLoS neglected tropical diseases, 2026. 4. [Evaluation of Leptospira species as a cause of endogenous uveitis in cats: a pilot study](https://pubmed.ncbi.nlm.nih.gov/41378760/). Journal of feline medicine and surgery, 2026. 5. [Clinical and sero-diagnosis of feline leptosprosis in the sleman region of Yogyakarta, Indonesia](https://pubmed.ncbi.nlm.nih.gov/42376408/). Open veterinary journal, 2026. 6. [Molecular detection and phylogenetic analysis of Leptospira interrogans and Leptospira borgpetersenii in cats from Central region of Rio Grande do Sul state, Brazil](https://pubmed.ncbi.nlm.nih.gov/39644868/). Comparative immunology, microbiology and infectious diseases, 2025. 7. [A systematic review of Leptospira and leptospirosis in wildlife: A global perspective](https://pubmed.ncbi.nlm.nih.gov/42733754/). One health (Amsterdam, Netherlands), 2026. ## Further Reading - [American Veterinary Medical Association: First Aid Tips for Pet Owners](https://www.avma.org/resources-tools/pet-owners/emergencycare/first-aid-tips-pet-owners) - [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)