Ehrlichiosis in Cats: Symptoms and Diagnosis
By Dr. Zubair Khalid, DVM, MS, PhD ·
Ehrlichiosis in cats symptoms usually look vague at first, such as fever, tiredness, and not eating, and they often show up weeks after a tick bite. This disease is uncommon in cats, and the exact bacteria behind feline cases is still not fully identified [1]. Because the signs overlap with many other illnesses, diagnosis depends on your vet putting together your cat's tick history, blood work, and specific lab tests.
This article is educational and is not a substitute for veterinary diagnosis or treatment.
Quick Answer
- Ehrlichiosis in cats is rare and is caused by rickettsia, a type of bacteria that lives inside cells and is spread by ticks [1].
- The most common early signs are fever, swollen lymph nodes, poor appetite, depression, and lethargy [1].
- Low platelet counts are common at every stage, which can lead to bruising, nosebleeds, or blood in urine or stool [1].
- Diagnosis is not a single test. Vets use blood counts, PCR, and antibody tests together to build a case [2].
- If your cat has a fever and you have seen ticks or your cat goes outdoors, call your vet the same day.
What Is Ehrlichiosis in Cats?
Ehrlichiosis is a disease caused by rickettsia organisms. These are specialized bacteria that can only live inside other cells [1]. In dogs, the illness is usually caused by Ehrlichia canis, and it is a well-known, globally prevalent disease spread by Rhiphalus ticks [2]. Cats are a different story.
A similar disease has been found occasionally in cats in Africa, France, and the United States, but the exact species causing the infection in cats has not been determined [1]. That means when we say "ehrlichiosis in cats," we are describing a syndrome that looks like the canine disease, not a neatly defined infection with one known culprit.
This matters for owners because it explains why feline ehrlichiosis is hard to pin down. There is no simple, universal test that says "yes, your cat has ehrlichia." Your vet has to reason through the evidence.
Can Cats Get Ehrlichia?
Yes, but it is uncommon. Cats can be infected, and cases have been documented in several countries including the United States [1]. The disease is transmitted by ticks that become infected after feeding on infected animals [1]. So the risk to your cat is tied directly to tick exposure.
If your cat never goes outside and you use year-round tick prevention, the risk is low. If your cat hunts, roams, or lives with dogs that bring ticks indoors, the risk goes up.
Ehrlichiosis in Cats Symptoms: What Owners Notice First
The signs of ehrlichiosis commonly progress from short-term to long-term problems [1]. In the early stage, the signs look like many other infections. This is the frustrating part for owners. Nothing looks specific.
Early Signs
- Fever
- Swollen lymph nodes
- Loss of appetite
- Depression
- Lethargy [1]
You might notice your cat is sleeping more, hiding, or turning away from food. Some cats run a fever that comes and goes. Others just seem "off" for a few days and then improve, which can make you think the problem passed.
Later Signs
In long-term cases, signs become more severe as white blood cells move into internal organs and the bone marrow produces fewer blood cells [1]. Decreased platelet numbers are common in animals with all stages of ehrlichiosis [1]. Platelets are critical for proper blood clotting.
When platelets drop severely, you may see:
- Bruises on the skin or gums
- Blood in the urine or stool
- Spontaneous bleeding from the nose [1]
These are serious signs. Bleeding that starts on its own means the clotting system is failing, and that needs urgent care.
Lameness and Joint Pain
Joint pain and lameness are reported in cats with tick-borne illness, and they can be easy to miss. A cat that is stiff, reluctant to jump, or suddenly lame may have joint inflammation instead of an obvious injury. This is one reason tick exposure history matters so much when your vet is sorting through possible causes.
If your cat is showing pain when urinating or straining in the litter box, that points in a different direction. Our guide to symptoms of urinary infection cats covers those signs in detail.
Causes and Risk Factors
The cause is infection with a rickettsia organism, and the route is a tick bite [1]. Ticks become infected after feeding on infected animals, then pass the bacteria along when they feed on your cat [1].
What Raises Your Cat's Risk
- Outdoor access, especially in wooded or grassy areas
- Living with dogs that go outside and bring ticks in
- A home or yard with a heavy tick population
- Warm months when ticks are most active
- No tick prevention or gaps in prevention
What Does Not Cause It
Ehrlichiosis is not spread from cat to cat through casual contact. It is not a litter box disease. It is a tick-borne disease, so the tick is the link.
One thing to keep in mind is that ticks can carry more than one pathogen. A single bite can transmit different organisms, and cats can be infected with more than one at the same time. In one study of 311 cats in Türkiye, 13.1 percent tested positive for at least one vector-borne pathogen, and 0.9 percent were co-infected [3]. That does not mean your cat has a 13 percent chance of ehrlichiosis. It means tick-borne infections in cats are real and sometimes overlap.
How Ehrlichiosis in Cats Is Diagnosed
There is no single test that confirms feline ehrlichiosis on its own. Your vet will combine history, physical exam, and lab work.
Step 1: History and Physical Exam
Your vet will ask about tick exposure, outdoor access, travel, and whether other pets in the home have had tick-borne illness. During the exam, they will check for fever, enlarged lymph nodes, pale gums, bruises, and joint pain.
Step 2: Blood Work
A complete blood count often shows low platelets, which is common in all stages of ehrlichiosis [1]. Your vet may also see anemia or changes in white blood cells. A chemistry panel checks organ function and helps rule out other causes of fever and lethargy.
Step 3: Specific Testing
For canine ehrlichiosis, diagnosis typically involves cytology, polymerase chain reaction (PCR), and serological assays such as the indirect immunofluorescence antibody test (IFAT), considered the gold standard, and enzyme-linked immunosorbent assay (ELISA) [2]. These same categories of tests are used when vets suspect a tick-borne infection in cats.
- PCR looks for bacterial DNA in a blood sample. It can be positive early in infection.
- Antibody tests (IFAT or ELISA) look for the cat's immune response. A positive result means exposure, not necessarily active disease.
- Cytology looks at blood cells under a microscope for organisms inside cells, but it is not sensitive and often misses the diagnosis.
A newer rapid ELISA for detecting anti-E. canis antibodies in dogs showed high sensitivity and specificity compared with IFAT in a validation study [2]. That test is for dogs, not cats, but it shows how antibody testing is evolving.
Step 4: Ruling Out Look-Alikes
This is where diagnosis gets tricky. Fever, lethargy, and lameness in a cat can come from many causes. Your vet may test for other tick-borne diseases, cat scratch disease, and other infections.
Cat scratch disease is caused by Bartonella henselae and often causes swollen lymph nodes near a scratch or bite [4]. In atypical cases, diagnosis may require PCR testing of lymph node tissue or fluid [4]. Another report described a child with cat exposure who had persistent fever and liver lesions without any lymph node swelling or skin wounds [5]. The point for cat owners is simple. Fever in a cat with tick or scratch exposure has a broad list of possible causes, and testing helps narrow it down.
Toxoplasmosis is another condition that can mimic these signs. One case report described an adult cat with lethargy, anorexia, and fever, plus joint inflammation and low platelets [6]. That cat was eventually diagnosed with toxoplasmosis, not ehrlichiosis. This is exactly why vets do not guess. They test.
Table: Common Signs and What They Can Mean
| Sign You Notice | Possible Link to Ehrlichiosis | Other Common Causes |
|---|---|---|
| Fever | Common early sign [1] | Any infection, toxoplasmosis [6] |
| Lethargy, hiding | Common early sign [1] | Pain, anemia, many illnesses |
| Swollen lymph nodes | Common early sign [1] | Cat scratch disease [4] |
| Bruising or nosebleeds | Low platelets [1] | Clotting disorders, toxins |
| Lameness or stiffness | Joint involvement | Injury, arthritis, toxoplasmosis [6] |
| Not eating | Common early sign [1] | Dental pain, nausea, stress |
Treatment Options
Treatment for feline ehrlichiosis is based on the same antibiotics used for related tick-borne infections in other species. Your veterinarian will choose the drug and calculate the dose from your cat's weight and health status. Do not use leftover antibiotics from a previous pet or from a human prescription.
Supportive care matters as much as the antibiotic. Cats with fever and poor appetite often need fluids, anti-nausea medication, and sometimes a feeding plan. Cats with severely low platelets may need closer monitoring and, in rare cases, a transfusion.
If your cat is dehydrated or not eating for more than a day, that alone is a reason to call your vet. Cats who stop eating can develop serious liver problems quickly.
Recovery, Outlook, and Long-Term Management
Most cats who are diagnosed and treated early do well. The short-term form of the disease often responds to antibiotics, and fever and lethargy improve within days. The long-term form is more serious because organ damage and low platelets can take longer to resolve [1].
Your vet will likely want to recheck blood work after treatment to confirm that platelet counts are recovering. Some cats need a second course of antibiotics. Some need monitoring for months.
What Long-Term Care Looks Like
- Recheck exams and blood work on your vet's schedule
- Strict tick prevention all year
- Keeping your cat indoors or supervising outdoor time
- Checking your cat for ticks after any outdoor access
- Watching for return of fever, lethargy, or bleeding
If your cat has a chronic illness or a weakened immune system, recovery can be slower. Talk with your vet about what to expect for your specific cat.
Prevention
Prevention comes down to tick control. There is no vaccine for ehrlichiosis in cats.
- Use a veterinarian-recommended tick preventive every month, all year.
- Check your cat's coat, ears, and paws after any time outdoors.
- Keep grass and brush trimmed around your home.
- Treat dogs in the household with tick prevention too, since they can carry ticks indoors.
- Remove attached ticks promptly with fine-tipped tweezers.
If you find a tick on your cat, do not panic. Not every tick carries disease, and not every bite leads to infection. But do note the date and tell your vet if your cat gets sick in the following weeks.
If your cat has ear issues along with head shaking or scratching, that is a separate problem. See our guide to ear infections in cats symptoms for help telling those signs apart.
Limitations and When to Contact a Veterinarian
Feline ehrlichiosis is uncommon, and no article can diagnose your cat. Individual cases need a veterinarian who can examine your cat, run tests, and track changes over time.
Call your veterinarian the same day if your cat has:
- A fever that lasts more than 24 hours
- Sudden lethargy or refusal to eat
- Swollen lymph nodes that do not go away
- New lameness or joint pain
- A known tick bite in the past month
Go to an emergency clinic now if your cat has:
- Bleeding from the nose, gums, or rectum that will not stop
- Blood in the urine or stool
- Bruises appearing without injury
- Pale gums, weakness, or collapse
- Difficulty breathing
Schedule a routine visit if:
- Your cat had a tick attached and you want it checked
- Your cat has had ehrlichiosis before and you see old signs return
- You need help choosing a tick preventive
Frequently Asked Questions
Can indoor cats get ehrlichiosis?
Yes, though the risk is lower. Ticks can hitch a ride indoors on dogs, on clothing, or on people, and then attach to your cat. If your cat never goes outside but you have outdoor pets, keep everyone on tick prevention.
Is ehrlichiosis contagious to other cats or to people?
Ehrlichiosis is not spread by casual contact between cats. The infection moves through tick bites [1]. Some rickettsia organisms have zoonotic potential, meaning they can affect people, but people get them from tick bites, not from petting an infected cat [7].
How long after a tick bite would my cat get sick?
Tick-borne infections often cause signs days to weeks after a bite. Keep a note of when you found the tick. That timeline helps your vet decide which tests to run.
Will my cat need antibiotics for a long time?
Many cats improve with a standard course of antibiotics, but some need longer treatment or a repeat course. Your vet will decide based on your cat's response and follow-up blood work. Never stop antibiotics early without asking your vet.
Can ehrlichiosis come back after treatment?
Reinfection is possible if your cat gets bitten by another infected tick. Treatment clears the current infection, but it does not protect against future ones. Year-round tick prevention is the best way to lower that risk.
Related Articles
- Symptoms Of Urinary Infection Cats
- Cat Urinary Infection Symptoms
- Cat Urinary Tract Infection Symptom
- Cat Uti Symptoms
- Ear Infections In Cats Symptoms
- Urinary Tract Infection In Cats Symptoms
References
- Ehrlichiosis and Related Infections in Cats - Cat Owners. Merck Veterinary Manual.
- Evaluation of a newly developed rapid ELISA to detect anti-Ehrlichia canis antibodies in dogs. Parasite (Paris, France), 2025.
- Molecular detection and characterization of vector-borne pathogens in domestic cats (Felis catus) in Türkiye: The first report of Coxiella burnetii from cats in Türkiye. Parasitology international, 2026.
- Treatment-Resistant Femoral Lymph Node Abscess Caused by Cat Scratch Disease: A Case Confirmed by Polymerase Chain Reaction. Cureus, 2025.
- Atypical Presentation of Pediatric Cat Scratch Disease: A Case Report. Cureus, 2026.
- Systemic toxoplasmosis manifested as protozoal arthritis and secondary immune mediated thrombocytopenia in an apparently immunocompetent adult cat. Veterinary parasitology, regional studies and reports, 2026.
- Molecular prevalence of Ehrlichia canis in dogs examined at the Hospital de Clínicas Veterinárias of Universidade Federal de Pelotas, Southern Rio Grande do Sul, Brazil. Parasite epidemiology and control, 2026.