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Hemotropic Mycoplasma
Séverine Tasker, BSc, BVSc (Hons), PhD, DSAM, DACVIM-CA, PGCertHE, MRCVS

Bristol Veterinary School, University of Bristol, Bristol, UK

Etiology/Pathophysiology and dogs sampled in studies used to generate these data.
Retroviral‐infected cats are also usually found to be at
The hemotropic mycoplasmas (hemoplasmas) are uncul- increased risk in studies, although results are variable for
turable bacteria that parasitize red blood cells and can FeLV and feline immunodeficiency virus (FIV). A recent
induce hemolysis, causing anemia. Commonly recognized study in the United States reported a low prevalence of
feline and canine hemoplasma species are shown in canine hemoplasma infection in dogs.
Table 97.1. Mycoplasma haemofelis is the most pathogenic The prevalence of feline hemoplasma infections is
of the feline and canine species described, and can cause increased in cats that are male, non-pedigree and with
significant hemolytic disease in immunocompetent cats. access outdoors.
In cats, Mycoplasma haemofelis appears to be most The natural route of transmission of hemoplasma
pathogenic during acute infection, whereas chronic infec- infection in the field has not yet been determined but the
tion is not usually associated with significant anemia. clustered geographic distribution of infection in some
Candidatus Mycoplasma haemominutum and Candidatus studies supports the role of an arthropod vector in
Mycoplasma turicensis infections are not usually associ- hemoplasma transmission. The cat flea, Ctenocephalides
ated with clinical signs, unless concurrent disease or felis, has been implicated in feline hemoplasma trans-
immunusuppression exist in the host cat, such as feline mission, but this has not been definitively proven in
leukemia virus (FeLV) infection, neoplasia. However, ane- experimental studies, and transmission of M. haemocanis
mia due to these agents has occasionally been reported in by the brown dog tick, Rhipicephalus sanguineus, has
immunocompetent cats. Ca. M. haemominutum has also been suggested.
been associated with the development of myeloprolifera- Studies have successfully transmitted feline hemo-
tive diseases in cats with concurrent FeLV infection. plasma infection via subcutaneous inoculation of blood
In dogs, M. haemocanis and Ca. M. haematoparvum containing low numbers of organisms, suggesting that
infections are not often associated with hemolytic ane- transmission by aggressive interaction (e.g., fights) in the
mia unless infection occurs in a splenectomized host field is possible. Blood transfusion is another potential
(particularly for M. haemocanis) or in association with route of transmission, and blood donors should be
concurrent disease or immunosuppression. screened for hemoplasma infection. Vertical transmis-
Asymptomatic carrier status can exist with all of the sion may also occur.
hemoplasma species, and so the detection of hemo-
plasma infection is not always indicative of clinical dis-
ease associated with that species. Signalment

Older cats are more likely to be infected with Ca. M.
Epidemiology haemominutum whilst younger cats are more likely
to show disease due to M. haemofelis infection. Canine
The prevalence of the commonly recognized feline and hemoplasma infections appear to be more common
canine hemoplasma species is shown in Table 97.1; these in kennel‐housed dogs, younger dogs, and dogs with
vary considerably due to the differing populations of cats mange.

Clinical Small Animal Internal Medicine Volume II, First Edition. Edited by David S. Bruyette.
© 2020 John Wiley & Sons, Inc. Published 2020 by John Wiley & Sons, Inc.
Companion website: www.wiley.com/go/bruyette/clinical