Cats can get tuberculosis, though it’s relatively uncommon. They’re most often infected by two strains of the bacteria: one carried by cattle and one carried by small rodents like voles and mice. A third strain, the one most associated with human TB, rarely causes disease in cats, likely due to a natural resistance.
Which Bacteria Cause TB in Cats
Three members of the tuberculosis family can infect cats, but they don’t all pose the same level of risk. The two most common culprits are M. bovis (the cattle strain) and M. microti (the rodent strain). A large UK study of 339 cats with confirmed mycobacterial disease found that 15% were infected with M. bovis and 19% with M. microti. The human strain, M. tuberculosis, is rare in cats. Experimental studies have shown it doesn’t even cause clinical disease when cats are deliberately exposed to it.
How Cats Get Infected
The route of infection depends on the strain. Cats pick up M. microti through hunting. The bacteria enter through bite wounds from infected rodents, which is why the face and legs are the most common sites of initial infection. Outdoor cats that actively hunt voles, shrews, and mice are at the highest risk.
M. bovis has historically reached cats through two main pathways: drinking raw (unpasteurized) milk from infected cattle, or direct contact with infected wildlife like badgers. More recently, commercial raw pet food diets have been linked to outbreaks. In one documented UK cluster, multiple cats in different households developed TB after being fed the same brand of raw cat food. This is a meaningful shift from the older pattern, where M. bovis typically appeared in older outdoor cats known to hunt wildlife.
Direct transmission from an infected person or another pet in the household is also possible, though far less common.
Symptoms to Recognize
The most common form of feline TB today is the skin form. It causes non-healing sores and lumps, often around the head, neck, or legs. These wounds look like they should heal but don’t, sometimes draining or crusting over for weeks. This is the presentation veterinarians see most frequently.
Less common forms affect the gut or lungs, depending on how the bacteria entered the body. A cat that ingested contaminated milk or raw food may develop intestinal TB, showing up as chronic diarrhea and weight loss. Respiratory TB can cause coughing, labored breathing, and lethargy. Some cats develop signs in more than one body system, particularly if the infection has spread through the bloodstream. General signs like fever, poor appetite, and progressive weight loss can accompany any form.
How Vets Diagnose It
Diagnosing TB in cats is not straightforward. There’s no quick in-clinic test the way there is for many other infections. Veterinarians rely on a combination of approaches: culturing bacteria from tissue samples, PCR testing to detect bacterial DNA, and a blood test called an interferon-gamma release assay that measures the immune system’s response to TB proteins. Culture is considered the gold standard but is slow, sometimes taking weeks, and over half of cases in one large study couldn’t be identified through culture alone. PCR is faster and can sometimes pinpoint the exact strain, but it requires enough bacterial DNA in the sample to work reliably.
Antibody-detection tests also exist and have been validated for detecting M. bovis and M. microti infections in cats. In practice, vets often use a combination of these tools alongside imaging and tissue biopsies to build a complete picture.
Treatment and Survival
Feline TB can be treated with long courses of antibiotics, but the outcomes vary significantly depending on how advanced the disease is at diagnosis. In routine cases caught relatively early, veterinary specialists report a 70 to 80% successful treatment rate. That sounds encouraging, but outbreaks linked to raw food diets have told a grimmer story. In one cluster of six clinically ill cats, five were either too sick to treat or got worse despite therapy, a mortality rate of 83%.
Treatment typically involves multiple antibiotics given over many months. It demands commitment, regular veterinary monitoring, and careful attention to whether the cat is actually improving. Not every cat is a candidate for treatment. Some are too debilitated by the time they’re diagnosed, and in those cases euthanasia may be recommended both for the cat’s welfare and to reduce the risk of spreading infection.
Can Your Cat Give You TB
This is the question that tends to worry people most, and the honest answer is that the risk is low but not zero. For a long time, experts considered cat-to-human transmission negligible because no cases had been clearly documented. That changed in a UK investigation where a cat with confirmed M. bovis infection passed the bacteria to two people in close contact. Genetic sequencing of the bacterial samples from the cat and one of the humans showed they were indistinguishable, and the timeline of illness in the cat preceded the human cases by several months.
Out of 24 people screened during that cluster (all had close contact with infected cats), three tested positive for latent TB infection, meaning the bacteria were present but not causing active disease. Two people eventually developed active TB with chest symptoms and required treatment. Following this evidence, public health authorities in the UK upgraded the assessed risk of cat-to-human M. bovis transmission from “negligible” to “low.”
If your cat is diagnosed with TB, your veterinarian will likely coordinate with public health officials to arrange screening for household members. People with weakened immune systems are at greater risk of progressing from latent infection to active disease.
Reducing Your Cat’s Risk
The most practical steps come down to controlling the known routes of exposure. Feeding a commercially prepared, heat-treated diet eliminates the risk from contaminated raw meat or milk. If your cat hunts rodents regularly, particularly in areas where M. microti is known to circulate (parts of the UK and continental Europe especially), that’s a harder risk to manage, but keeping cats indoors or limiting outdoor access during peak hunting hours reduces contact with infected wildlife.
In regions where bovine TB is endemic in wild animal populations, outdoor cats that roam farmland or areas with badger activity face higher exposure to M. bovis. There is no vaccine currently available for cats, so prevention relies entirely on reducing contact with infected animals and contaminated food sources.