Mycobacteriosis in cats – signs and vet care

Updated 2026-09-30 · 1 sources

Based on: International Cat Care (iCatCare)

Book a vet visit

Book a vet appointment if you think your cat has this – a vet needs to confirm it and plan the treatment. Mycobacteriosis is an infection caused by mycobacteria, a specific group of bacteria that can cause disease in animals and people.

What to do now

What you can do now

Contact your vet.
Note when it started, how often it happens and what else you see.
Take a photo or short video to show the vet.
Keep fresh water available.

Don't

Do not give any human medicine.
Do not wait if it gets worse.

What it is

Mycobacteria are a specific group of bacteria capable of causing disease in animals and people.^[1] Signs can affect digestion, appetite, weight, skin, lymph nodes and breathing.^[1]

Signs

Diarrhoea
Vomiting
Loss of appetite
Weight loss
Non-healing sores or wounds
Small firm swellings or lumps in the skin
Skin nodules may lose the overlying hair or become ulcerated
Swollen lymph nodes or glands
Coughing
Difficulty breathing

How a vet finds out

Blood tests
X-rays
Ultrasound
Biopsy

How vets treat it

Surgery
Antibiotics

What the experts say

“Infection may be suspected based on the signs your cat is showing, but further tests such as blood samples, x-rays, ultrasound and a biopsy (surgical removal of a small piece of tissue) will be needed to confirm a diagnosis.”
— International Cat Care (iCatCare) [1]

If your pet is struggling to breathe, has collapsed, is having a seizure or can't stand up: go to the nearest vet now.

Not sure how serious it is?

OkPaw asks a few quick questions about your pet and tells you in 30 seconds whether it can wait. Free on Google Play for Android.

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Common questions

What is mycobacteriosis?

Mycobacteriosis is an infection caused by mycobacteria, a specific group of bacteria that can cause disease in animals and people.^[1]

What signs can my cat have?

Signs can include diarrhoea, vomiting, loss of appetite, weight loss, non-healing sores or wounds, skin nodules, swollen lymph nodes, coughing and difficulty breathing.^[1]

How is mycobacteriosis treated?

Treatment is difficult in cats, so your vet will discuss the options with you. Antibiotics may be used, treatment can take many months and may involve a combination of two or three antibiotics, and antibiotic resistance may develop.^[1]

Sources

International Cat Care (iCatCare)

How this page was made: written with the help of AI from the sources below, then checked claim by claim against those sources. Urgency levels follow OkPaw’s fixed safety rules. It is guidance, not a diagnosis. How we write our pages