Page 990 - Clinical Small Animal Internal Medicine

928 Section 9 Infectious Disease

Table 97.1 Hemoplasma species, their prevalence ment of hemoplasma‐associated anemia has not been
VetBooks.ir Hemoplasma Prevalence Pathogenicity summary confirmed.
and pathogenicity
Serum biochemistry may reveal elevated liver
parameters (ALT and AST) due to anemia‐associated
hypoxia, mild to moderate hyperbilirubinemia due to
Mycoplasma 0.4–46.6% Can result in hemolytic hemolysis, and prerenal azotemia due to dehydration.
haemofelis anemia in
immunocompetent cats Hyperproteinemia may occur. Hemoplasmas are
Candidatus 8.1–46.7% Can result in a drop in currently unculturable in vitro.
Mycoplasma erythrocyte parameters Cytologic detection of hemoplasma organisms on
haemominutum but not usually severe blood smears is occasionally possible but this is known
Candidatus 0.4–26% enough to cause anemia to be very insensitive and shows poor specificity, and
Mycoplasma unless cat has concurrent cytology cannot differentiate between hemoplasma spe-
turicensis disease or is cies. When organisms are visible, they appear as small
immunocompromised,
e.g., retrovirus infection basophilic organisms on the surface of erythrocytes with
Mycoplasma 0–45% Hemolytic anemia Romanowsky‐based stains (e.g., Wrights’, Diff‐Quik™).
haemocanis primarily seen in M. haemocanis has a tendency to form chains on the sur-
Candidatus 0–33% splenectomized dogs, face of erythrocytes, and so may be easier to differentiate
Mycoplasma and occasionally in from stain artifacts and other erythrocyte inclusions
haematoparvum immunocompromised with which hemoplasmas are confused.
dogs (e.g., with neoplasia) Polymerase chain reaction (PCR) assays are usually
sensitive and specific, if designed appropriately, for the
diagnosis of hemoplasma infection, and species‐specific
History and Clinical Signs assays exist for both dogs and cats. EDTA‐anticoagu-
lated blood is usually the appropriate sample type for
When anemia results from hemoplasma infection, his- PCR. Real‐time PCR (qPCR) assays are now increasingly
torical features can include lethargy, inappetence, pallor, used, and these allow for quantification of hemoplasma
weakness, pica, and weight loss. In immunocompro- organism numbers (Figure 97.1), as well as detection of
mised hosts, evidence of concurrent disease is present. infection. Organism numbers in feline hemoplasma
Dogs may have a history of splenectomy. infections are often high during acute infection but it
Clinical signs can include pyrexia, weakness, pallor, should be noted that large fluctuations in blood organ-
tachypnea, tachycardia (sometimes with a hemic mur- ism numbers can occur over time in some M. haemofe-
mur), bounding pulses, dehydration, cardiac murmurs, lis‐infected cats, meaning that qPCR results may not be
sometimes splenomegaly (in nonsplenectomized hosts) correlated with anemia.
and, occasionally, jaundice. In addition, PCR results may be negative in an infected
cat if a sample is obtained when the number of circulating
organisms is very low, below the limit of detection of the
PCR assay. Furthermore, the existence of asymptomatic
Diagnosis carrier cats for all hemoplasma species means that the PCR
results should always be interpreted in conjunction with
Acute hemoplasma infections are typically associated the patient’s clinical signs, the degree and nature of the
with a regenerative anemia with reticulocytosis, mac- anemia present, and any concurrent signs or diseases that
rocytosis, polychromasia, and anisocytosis. However, could be contributing to the clinical presentation.
the anemia may be nonregenerative if the animal is
sampled early in the disease process (i.e., during the
preregenerative phase) or if concurrent disease is pre- Therapy
sent that inhibits regeneration (e.g., concurrent FeLV
infection, neoplasia). Therapy for hemoplasmosis is required if infection is diag-
Acute M. haemofelis and M. haemocanis infections nosed in an animal with clinical signs and clinicopatho-
can be associated with the presence of persistent saline logic changes consistent with hemoplasma infection.
autoagglutination or positive Coombs’ testing, indicat- However, no treatment regime has yet been described that
ing the presence of erythrocyte‐bound antibodies. Auto- consistently eliminates hemoplasma infection with all
agglutination may be noted on blood smear examination species and the aim of most treatment protocols is resolu-
but the contribution of such antibodies to the develop- tion of clinical signs associated with infection.