Feline Mycoplasma: The Blood Parasite Your Cat's Blood Test Can Detect

Mycoplasma haemofelis is an obligate intraerythrocytic parasite: it lives on and within red blood cells, causing immune-mediated haemolytic anaemia. It was formerly known as Haemobartonella felis and was reclassified in 2001 based on genetic analysis. Despite the name, it is not closely related to the respiratory Mycoplasma organisms responsible for mycoplasma pneumonia in other species.

Three haemotropic Mycoplasma species infect cats: Mycoplasma haemofelis (the most pathogenic), Candidatus Mycoplasma haemominutum (usually causes mild or subclinical disease), and Candidatus Mycoplasma turicensis (intermediate pathogenicity). Co-infections with more than one species are possible and may result in more severe disease.

The parasite is globally distributed but is significantly more common in warm climates where the flea vector thrives year-round, making Dubai and the wider Gulf region higher-risk environments.

Flea transmission is the most important and best-documented route. The cat flea, Ctenocephalides felis, is the primary vector. Fleas acquire the organism from infected cats and transmit it to new hosts through their bites. In Dubai's climate, where fleas are active throughout the year, exposure risk is continuous for cats without flea prevention.

Cat bites and fighting can also transmit the organism, as haemotropic mycoplasmas are found in the saliva of infected cats. This is particularly relevant for outdoor cats in areas with high densities of feral and community cats. Blood transfusions from infected donor cats are another potential route, which is why blood screening is important in veterinary transfusion medicine.

In-utero transmission from infected queens to kittens is suspected but not definitively established. Some studies have also implicated ticks as a potential secondary vector.

The cardinal sign of Mycoplasma haemofelis infection is pale or white gums, indicating anaemia. Other signs include lethargy, weakness, rapid or laboured breathing (as the body tries to compensate for reduced oxygen-carrying capacity), inappetence, and weight loss. Affected cats may feel cold, particularly in their extremities, due to reduced circulation.

Acute haemofelis can progress to life-threatening levels of anaemia within days. In the acute phase, the packed cell volume (PCV, a measure of red blood cell mass) can drop below 10%, compared to a normal range of 25 to 45%. Cats with PCV below 15% often require emergency blood transfusion.

Chronic or subclinical infection with Candidatus M. haemominutum is common in apparently healthy cats. Many cats test positive on PCR without visible illness. These cats may have mildly low PCV on routine blood work, which can be the only finding.

Blood smear examination remains the classic diagnostic test. A thin smear of peripheral blood is examined under a microscope; the organisms appear as small basophilic dots, rings, or short rod-shaped structures on the surface of red blood cells. Parasitaemia can be cyclic, however, meaning the organisms may not always be visible on smear even in infected cats.

PCR (polymerase chain reaction) testing is significantly more sensitive than blood smear and can detect low levels of infection and identify which species is present. It is the recommended diagnostic approach when haemotropic mycoplasma is suspected.

Complete blood count (CBC) typically shows a regenerative anaemia (with increased reticulocytes as the bone marrow responds) though a non-regenerative pattern occurs in some cases, particularly with chronic infection. A Coombs test (direct antiglobulin test) is often positive, confirming an immune-mediated component to the red blood cell destruction.

Doxycycline at 10 mg/kg/day orally for 28 to 42 days is the traditional first-line antibiotic. It reduces parasitaemia and resolves clinical signs in most cats but does not fully eliminate the organism; cats may remain subclinical carriers after treatment.

Pradofloxacin (a veterinary fluoroquinolone) has demonstrated high efficacy against Mycoplasma haemofelis in clinical studies and is increasingly preferred as a first-line treatment, particularly in cats that cannot tolerate doxycycline.

In cats with evidence of significant immune-mediated haemolysis (a positive Coombs test and rapidly falling PCV), immunosuppressive doses of prednisolone are added to reduce immune-mediated red blood cell destruction. Cats with PCV below 12 to 15% are candidates for blood transfusion to stabilise them while antibiotic therapy takes effect.

Concurrent flea prevention must be implemented as part of treatment to break the transmission cycle and prevent reinfection.

Year-round flea prevention is the most important step in preventing Mycoplasma haemofelis in Dubai's climate. Monthly topical treatments (such as selamectin or fipronil) or oral isoxazoline products (such as fluralaner) are highly effective when administered consistently.

All cats in a household should be treated, not just the affected cat. Flea prevention in multi-cat environments requires treating all animals and addressing the environment (washing bedding, vacuuming, treating soft furnishings). Given year-round flea risk in Dubai, there is no seasonal break during which prevention can lapse.

Community and rescue cats in Dubai represent a significant reservoir for haemotropic mycoplasmas. Studies from similar warm climates have documented seroprevalence rates of 15 to 30% in cat populations. Cats that have been living outdoors, are FIV or FeLV positive, or have had frequent contact with feral populations are at greatest risk.

Many cats adopted from shelters or directly from the street in Dubai come with incomplete medical histories. If a newly adopted cat shows any signs of lethargy or pale gums, a blood test including CBC, blood smear, and PCR should be considered as an early priority.