Feline haemoplasmosis or haemotropic mycoplasmosis, previously known as feline haemobartonellosis or feline infectious anemia (FIA) is a worldwide important disease which may be fatal. Feline bartonellosis, on the other hand, is caused by one of several Bartonella species and is not associated with clinical disease in most cases. Due to the historical closely related name of the former (haemobartonellosis), the 2 disease groups were frequently erroneously interchanged. It should be noted that haemoplasmoses and bartonelloses are two different disease groups. This presentation will overview the two different diseases.

Feline haemoplasmoses are caused by small gram-negative bacteria parasitizing erythrocytes, residing on their surface. The haemoplasmoses were reclassified in recent years as Mycoplasma species. Three Mycoplasma species affecting cats have been documented to date: Mycoplasma haemofelis, Candidatus Mycoplasma haemominutum and Candidatus Mycoplasma turicensis. The route of transmission of the haemoplasmas has not yet been determined. However, experimental transmission via oral or parenteral administration of infected blood has been demonstrated (Barker, Tasker 2013). They may cause severe hemolytic anemia and death in affected cats. Parasitemia is usually cyclic and severity of anemia is correlated with the infecting bacterial load. High percentages of the feline populations worldwide are infected and a significant number of cats are asymptomatic carriers (Barker, Tasker 2013).

Mycoplasma haemofelis is considered pathogenic, and typical clinical signs include tachypnea, lethargy, depression, anorexia, pale mucous membranes, icterus, emaciation, dehydration, splenomegaly, fever, decreased body temperature and tachycardia. Regenerative anemia is a typical hematological finding. Some cats may be co-infected with retroviruses such as feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) or other viruses such as feline infectious peritonitis (FIP). Infection with retroviruses was found to be a risk factor for haemoplasmoses (Georges et al. 2012). Candidatus M. haemominutum and Candidatus M. turicensis are infrequently associated with clinical disease (Barker, Tasker 2013). Persistent infections are common and so are co-infections with two or three haemoplasmas species (Barker, Tasker 2013).

Diagnosis is incidental in many cases during blood smear evaluation. Due to the cyclic characteristic of the parasitemia, anemic cats should be evaluated microscopically by multiple blood smear tests (performed every few hours). PCR is a more sensitive diagnostic tool for the haemoplasmas.

Doxycycline treatment (5–10 mg/kg q 12–24 h, respectively, PO) for 3–4 weeks is considered the treatment of choice for haemoplasmosis. Fluoroquinolones such as enrofloxacin, 5 mg/kg q 24 h, PO, for 10–14 days have also been shown effective but have the potential to cause acute retinal damage and blindness in treated cats. Therefore, lower doses (2.5 mg/kg q 24 h, PO, for 10–14 days) should be used. Newer fluoroquinolones (marbofloxacin, pradofloxacin) are also considered effective and safe. As cats may develop immune mediated hemolytic anemia, glucocorticosteroid (prednisone) treatment might also be indicated. Recent studies have shown that treatment is not always effective and cats may remain carriers for years and even for life.

Bartonelloses are a group of diseases caused by Bartonella species. Bartonella are small pleomorphic gram-negative bacilli, belonging to the alpha-2 subdivision of Proteobacteria. They are intracellular bacteria, parasitizing erythrocytes and endothelial cells, and are transmitted by arthropod vectors. They cause persistent bacteremias. Five species have been reported in cats including Bartonella henselae, Bartonella clarridgeiae, Bartonella koehlerae, Bartonella quintana and Bartonella bovis. Bartonella henselae and B. clarridgeiae are commonly reported in cats in high prevalences (5–40% in most geographic regions), while the other species are infrequently reported. While several reports suggested an association between feline infection with Bartonella sp. and either gingivitis, uveitis, endocarditis and several other clinical conditions, no case controlled studies have proven such an association. Most cats experimentally infected with Bartonella spp. exhibited no clinical signs (neither clinical-pathological alterations).

Several of the reported Bartonella spp. reported in cats (B. henselae, B. clarridgeiae, B. koehlerae and B. quintana) can cause a disease in humans. Cat scratch disease (CSD) is the most known disease caused by Bartonella species. The etiologic agent of CSD is B. henselae causing several syndromes in humans. Immunocompetent human individuals present usually more local signs while immunocompromised individuals may present systemic signs which may be fatal. Veterinarians and veterinary staff are at greater risk for CSD. Transmission of B. henselae from cats to humans probably occurs through contamination of cat scratches with flea excrement. Transmission may also occur through cat bites (blood, saliva, flea-excrement).

References

1.  Barker E, Tasker S. Haemoplasmas: lessons learnt from cats. N Z Vet J. 2013;61:184–192.

2.  Georges K, Ezeokoli C, Auguste T, Seepersad N, Pottinger A, Sparagano O, Tasker S. A comparison of real-time PCR and reverse line blot hybridization in detecting feline haemoplasmas of domestic cats and an analysis of risk factors associated with haemoplasma infections. BMC Vet Res. 2012;8:103.

3.  Guptil L. Feline bartonellosis. Vet Clin Small Anim. 2010;40:1173–1190.

4.  Sykes JE. Feline hemotropic mycoplasmas. Vet Clin Small Anim. 2010;40:1157–1170.