Haematobiochemical alterations in canine babesiosis

Introduction

Canine babesiosis is a globally distributed tick-borne haemoprotozoan disease of dogs caused by parasites of the genus Babesia. The infection is transmitted mainly by Rhipicephalus sanguineus and ixodid ticks, although transmission may also occur via blood transfusion, bite wounds or transplacental routes. Among the Babesia species infecting dogs, Babesia canis vogeli and Babesia gibsoni are most prevalent in India, differing in morphology, epidemiology and pathogenicity (Malinovská, 2024) [6] . The pathogenesis of babesiosis involves both direct destruction of erythrocytes by intraerythrocytic replication and indirect immune-mediated haemolysis, leading to regenerative anaemia and thrombocytopenia. Secondary hepatic and renal dysfunctions are also common (Norbury et al., 2023) [8] . Clinical signs vary depending on the infecting species and disease stage but typically include fever, lethargy, pallor, icterus, haemoglobinuria and splenomegaly. Alterations in haematological and biochemical parameters are critical diagnostic and prognostic indicators in canine babesiosis. Haematological changes primarily include anaemia, leucocytic alterations and thrombocytopenia. Whereas, biochemical changes may involve hepatic and renal parameters such as ALT, ALP, bilirubin, BUN, creatinine and proteins (Stegman, 2019) [11] . The present study aimed to document haematobiochemical alterations in naturally infected dogs confirmed by PCR.

Materials and Methods

Serum samples from 24 PCR-positive dogs for babesiosis and 10 PCR-negative apparently healthy dogs were used for biochemical analysis. The parameters estimated included blood urea nitrogen (BUN), creatinine, albumin, globulin, total protein, alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total bilirubin using a fully automated biochemistry analyser with diagnostic reagent kits.

Results

The haematological analysis of babesiosis-affected dogs revealed marked alterations when compared to healthy controls. The mean total leukocyte count (TLC) was significantly higher (27.98 ± 3.37 × 10³/µL) than in controls (11.50 ± 3.20 × 10³/µL), with leukocytosis recorded in 54.17% of cases, leukopenia in 16.67% and normal counts in 29.17%. Erythrocyte parameters showed a pronounced decline, with haemoglobin (7.19 ± 0.51 g/dL), red blood cell count (3.00 ± 0.22 × 10⁶/µL) and packed cell volume (20.08 ± 1.12%) markedly reduced, indicating that anaemia was present in almost all infected dogs. Platelet counts were also severely affected with a significantly reduced mean value (92.25 ± 11.15 × 10³/µL) compared to controls (275.00 ± 85.00 × 10³/µL), and thrombocytopenia was observed in 75% of cases. Biochemical alterations further highlighted systemic involvement. Mean creatinine levels were mildly elevated (1.60 ± 0.15 mg/dL), with 20.83% of dogs showing values above normal. Liver enzymes were markedly raised, with ALT (80.69 ± 13.45 IU/L) and ALP (266.51 ± 60.42 IU/L) significantly higher than controls (35.00 ± 15.00 IU/L and 85.00 ± 35.00 IU/L, respectively). The mean total protein (5.73 ± 1.21 g/dL) remained within the normal range, but hypoalbuminaemia was evident, with mean albumin (2.17 ± 0.47 g/dL) significantly lower than controls (3.25 ± 0.75 g/dL). In contrast, globulin levels were slightly elevated (3.85 ± 1.04 g/dL) compared to controls (2.75 ± 0.75 g/dL). Indicators of renal involvement showed significant elevation, with BUN levels (28.16 ± 8.50 mg/dL) higher than controls (17.00 ± 10.00 mg/dL). Total bilirubin was also significantly raised (0.66 ± 0.18 mg/dL) compared to healthy dogs (0.35 ± 0.25 mg/dL), confirming haemolysis and hepatic dysfunction.

Discussion

The present study revealed significant haematobiochemical alterations in dogs naturally infected with Babesia spp. The marked anaemia observed in all infected dogs is consistent with reports by Sathish et al. (2023) [10] and Gollapalli et al. (2024) [4] and is attributed to intravascular haemolysis, immune-mediated erythrocyte destruction and bone marrow suppression. Leucocytic alterations varied, with leukocytosis being the most common, reflecting systemic inflammation and immune response, similar to findings of Kumar and Kumar (2018) [5] and Mittal et al. (2019) [7] . However, leukopenia in a subset of cases indicates immunosuppressive effects of Babesia as also reported by Lavanya et al. (2022). Thrombocytopenia, observed in 75%age of cases, is a consistent feature of canine babesiosis, corroborating earlier studies (Reddy et al., 2014; Brahma et al., 2019) [9,2] . It is likely due to immune-mediated platelet destruction, splenic sequestration, and bone marrow suppression. Biochemical changes indicated multi-organ involvement. Elevated ALT and ALP reflect hepatocellular injury and cholestasis, consistent with previous reports. Hypoalbuminaemia and hyperglobulinaemia suggest impaired liver function and chronic antigenic stimulation respectively. Renal involvement was evidenced by elevated creatinine and BUN, in agreement with Brahma et al. (2019) [2] . Increased bilirubin confirms haemolysis and hepatic dysfunction, aligning with findings of Gollapalli et al. (2024) [4] . These findings highlight the complex pathophysiology of canine babesiosis, involving haematological destruction, immune dysregulation and multi-organ impairment.

Conclusion

Canine babesiosis induces profound haematological and biochemical alterations, including anaemia, thrombocytopenia, leucocytic changes, hepatic enzyme elevations, renal dysfunction and protein imbalances. These findings underscore the importance of comprehensive laboratory evaluation in suspected cases to support early diagnosis, assess disease severity and guide therapeutic interventions.

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