Identification of a novel hemotropic mycoplasma in a splenectomized dog with hemic neoplasia

Abstract

A 3-year-old sexually intact male Bull Mastiff underwent splenectomy for splenic thrombosis; prior to and after splenectomy, multiple blood transfusions were administered. Two weeks after the procedure, T-cell lymphoproliferative disease was diagnosed. Treatment with prednisone and chlorambucil was initiated, and 2 weeks later, cytologic examination of a blood smear revealed small (0.3 microm), coccoid basophilic bodies on the surface of approximately 70% of the RBCs. Morphologically, these resembled "Candidatus Mycoplasma haemominutum." A polymerase chain reaction assay was used to amplify a partial 16S rRNA sequence in blood obtained from the dog; the product was sequenced and compared with 16S rRNA gene sequences of other hemotropic mycoplasmas. The sequence was 98% homologous to that of "Candidatus M haemominutum", but only 77% homologous to that of M haemocanis and M haemofelis.

Prevalence of Hemotropic Mycoplasmas in Healthy and Unhealthy Cats and Dogs in Spain

“…5,22 Clinical signs attributable to the hemoplasmas in cats and dogs are variable, and severity of illness depends on the infecting hemoplasma species and presence of concurrent diseases or infections. 5,6,14,19 It is possible that acute hemoplasma infections primarily result in anemia, in contrast to chronic infections, as has been previously suggested. 19 The sampling conditions of naturally infected animals in the current study were not able to distinguish between acute and chronic infections, but sampling of chronically infected animals could explain the failure to find an association between anemia and hemoplasma infection.…”

“…Clinical cases of hemoplasmosis in dogs have occasionally been reported, but cofactors such as splenectomy, immunosuppression, or concurrent infections seem to play a role in pathogenesis of disease. 6,14 Worldwide geographical variation in the prevalence of the different feline and canine hemoplasma species has been reported. 1,15,22 In Europe, prevalence studies with the use of polymerase chain reaction (PCR) for the diagnosis of hemoplasmas in cats have only been performed on domestic cats in Switzerland, Germany, northern Italy, and the United Kingdom.…”

“…"content-markup(./author-grp [1]/aff|./author-grp [1]/dept-list)> Three feline hemoplasma species exist: Mycoplasma haemofelis, 'Candidatus Mycoplasma haemominutum', and 'Candidatus Mycoplasma turicensis', 8,10,15,20 whereas dogs can be infected by 2 hemoplasma species: Mycoplasma haemocanis and 'Candidatus Mycoplasma haematoparvum'. 1,7,14,18 The pathogenicity of hemoplasmas species varies from being asymptomatic to inducing severe hemolysis. The most pathogenic feline species is regarded as M. haemofelis.…”

‘Candidatus Mycoplasma haematoparvum’, a novel small haemotropic mycoplasma from a dog

“…We have recently identified a novel haemotropic mycoplasma in a splenectomized dog with haemic neoplasia (Sykes et al, 2004). Of the canine and feline haemoplasmas, this organism most closely resembled 'Candidatus M. haemominutum' in that it was uniformly small in size (0?3 mm in diameter) and chains of organisms were not seen.…”

“…In this report, we have characterized an additional canine haemoplasma. The infected dog was both splenectomized and immunocompromised due to concurrent lymphoid neoplasia and immunosuppressive drug therapy, and haemolysis was suggested by the appearance of marked reticulocytosis following the appearance of organisms on blood smears (Sykes et al, 2004).…”