Onderstepoort Veterinary Academic Hospital, Faculty of Veterinary Science, University of Pretoria
Onderstepoort, South Africa
Virulent canine babesiosis is characterised by marked and life threatening changes in homeostasis. These changes are partly reflected in the serum biochemistry parameters of patients suffering from severe and complicated canine babesiosis. Various smaller studies have briefly investigated the serum biochemical and other electrolyte changes, but failed to ascertain and publish their association with mortality in canine babesiosis molecularly confirmed to be caused by Babesia rossi.
We undertook a prospective study to determine the serum biochemistry concentrations of dogs with canine babesiosis at presentation and observed the associated mortality. Ninety five patients were studied. The initial diagnosis of canine babesiosis was made on stained thin capillary blood smears. Diagnosis and Babesia subtype was confirmed as B. rossi and all patients were negative for Ehrlichia canis by polymerase chain reaction (PCR) and reverse line blotting (RLB). Three outcomes were defined: dogs treated as outpatients, (n = 32); hospitalised dogs that survived, (n = 56); and hospitalised dogs that died, (n = 7). The following biochemical parameters were determined: total protein, albumin, globulin, creatine kinase (CK), creatinine, alkaline phosphatase (Alp), alanine aminotransferase (Alt), bile acids, glucose, sodium (Na), potassium (K), chloride (Cl), ionised calcium (Ca), magnesium (Mg), phosphorus (P), amylase and lipase. Data was tested for normality with the Kolmogorov Smirnov test and analysed by the non-parametric Kruskal Wallis test for comparison of more than two groups. To compensate for the testing of multiple parameters, significance was set at P < 0.001. Data is expressed as the median value.
Overall mortality was 7/95 (7.5 %). Median serum bile acid, Mg and P concentrations were significantly higher (P < 0.001) while median Ca concentrations were significantly lower (P < 0.001) in dogs that died. Less severely affected dogs treated as outpatients had significantly lower median serum CK (p < 0.001) concentrations than the other two groups. No significant differences at P < 0.001 were detected between the groups in any of the other parameters.
This study demonstrated that mortality was associated with elevated bile acid, Mg and P and with lower ionised Ca concentrations in dogs with virulent B. rossi infection. Lower serum CK concentrations were clearly associated with milder disease, while elevated bile acid concentrations support the notion of hepatic dysfunction playing a role in adverse outcome. The respective roles of elevated serum Mg and P and decreased calcium concentrations warrant further study.