Mycoplasma Infections in Cats: Blood, Respiratory and Joint Disease

By Dr Duncan Houston

The word Mycoplasma on a laboratory report does not describe one single feline illness. Some species affect red blood cells, while others are found in the respiratory tract or associated with infection at other sites.

Knowing which organism was detected, where it was found and whether it explains your cat's signs makes the result useful.

Quick Answer

Mycoplasma infections vary by bacterial species and body site. Haemoplasmas can cause anaemia, whereas respiratory Mycoplasma may be associated with eye or airway disease and can also be detected without proving causation. Pale gums, severe weakness, collapse or breathing difficulty require urgent veterinary assessment.

How do the main forms differ?

Blood-associated haemoplasmas

These bacteria attach to red blood cells and can contribute to their destruction. Mycoplasma haemofelis is particularly important in feline haemolytic anaemia, while other haemoplasma species are often less pathogenic unless additional illness is present. Some infected cats remain carriers without obvious signs. The ABCD haemoplasmosis guidance explains why species identification and clinical context matter.

Respiratory and eye-associated organisms

Mycoplasma felis and related organisms may be detected in cats with conjunctivitis or respiratory disease. However, detection in upper-airway samples does not necessarily prove it is the main cause, particularly when viruses or other bacteria coexist. ABCD respiratory Mycoplasma guidance discusses this diagnostic distinction.

Joint and other infections

Mycoplasma can occasionally be implicated in joint or other tissue infection. A painful swollen joint requires appropriate sampling rather than assuming that a positive respiratory swab explains lameness.

How urgently does my cat need care?

What else could explain the signs?

Blood loss, immune-mediated disease, toxins and marrow disorders can cause anaemia. Herpesvirus, calicivirus, Chlamydia and Bordetella can cause respiratory or eye signs. Arthritis, trauma and other bacteria may explain a swollen joint. More than one disease may be present.

How are tests interpreted?

For suspected haemoplasmosis, a blood count and smear assess anaemia, while PCR is useful for detecting and identifying haemoplasmas. A negative smear does not reliably exclude infection. Respiratory sampling must be selected for the affected site and interpreted alongside examination and imaging if needed. Joint disease may need fluid analysis and specific culture or PCR arrangements.

Transmission is not identical for all Mycoplasma species. Blood exposure, including transfusion, is relevant to haemoplasmas; the exact role of fleas and other routes remains incompletely established. Respiratory contact risks should not be assumed to describe haemoplasma transmission.

When is this an emergency?

Seek immediate care for collapse, serious weakness or breathing effort, especially with very pale gums. Keep handling gentle and do not force oral medications into a breathless cat. An eye that is painful, held closed or appears cloudy also needs prompt assessment rather than delayed home treatment.

What treatment involves

Mycoplasmas lack a cell wall, so antibiotics targeting that structure alone are ineffective. The vet chooses an appropriate medication for the species, site and cat, with attention to feline adverse effects. Anaemic cats may need transfusion and supportive care. Improvement may not mean eradication, and follow-up testing or blood counts may be recommended.

1. Ask which Mycoplasma species or group the test detected.
2. Follow the prescribed medication and safe tablet-administration instructions.
3. Monitor appetite, gum colour, activity and breathing.
4. Attend scheduled blood or clinical rechecks and report deterioration.

Common mistakes

• Calling every positive PCR a confirmed cause of illness.
• Using one transmission story for all Mycoplasma infections.
• Giving another animal's antibiotics or eye drops.
• Assuming clinical improvement means no follow-up is needed.

Reducing risk

Use cat-safe parasite control, reduce fighting and follow a sensible introduction and respiratory hygiene plan. Blood donor screening reduces transfusion-associated risks. These measures support prevention without claiming that every transmission route is fully understood.

Frequently asked questions

Is haemoplasmosis the same as a respiratory Mycoplasma infection?

No. Different organisms and tissues are involved.

Can an apparently healthy cat test positive?

Yes. Carriage and disease must be distinguished.

Will a routine penicillin-type antibiotic treat it?

Not reliably for Mycoplasma itself, because these bacteria lack the target cell wall.

Can severe anaemia be treated?

Yes, but it may require urgent hospital care as well as organism-specific treatment.

The right question is not just whether Mycoplasma was found, but whether that particular organism explains what is happening to your cat.

For help understanding your cat's health and preparing questions for your veterinary team, visit ASK A VET™. If your cat has emergency signs, contact an emergency clinic directly.