Clinical examination and diagnosis
The major clinical signs and symptoms recorded were persistent high fever, pale mucous membranes (Fig 1), presence of ticks on body surface (Fig 2), haemolysed plasma/serum (Fig 3), elevated heart and respiration rates, decreased ruminal motility, and coffee coloured urine (Fig 4).
Microscopic examination of thin blood smears (n=16) of animals having clinical symptoms revealed different intra-erythrocytic forms of haemoparasites which were morphologically compatible with
Babesia piroplasms (Fig 5).
The samples (n=16) that were found microscopically positive for babesiosis showed 408bp amplification on PCR employing
Babesia 18S rRNA gene specific primers (Fig 6). The samples of apparently healthy animals (n=8) were negative on microscopic examination of thin blood smears as well as on the PCR test, indicating that the animals are free from babesiosis infection of any type.
Clinical parameters
The mean rectal temperature, heart rate and respiration rate were increased in both the diseased groups (Table 1). However, Post treatment rectal temperature, heart rate and respiration rate decreased significantly (P<0.05) (Table 1). The pre-treatment mean rumen motility was significantly (P<0.05) lower in diseased groups compared to control group. After treatment significant (P<0.05) increase in rumen motility was recorded (Table 1). Similar results were recorded by
Tufani et al., (2009), Talkhan et al., (2010), Sevinc et al., (2013), Ajith et al., (2017) and
Haq et al., (2021). Pyrexia results from the release of endogenous pyrogens, which activate the hypothalamus and raise body temperature
(Constable et al., 2017). Tachycardia, tachypnea, and decreased haemoglobin concentration may be caused by anoxia, erythrocytopenia, and anaemia
(Radostits et al., 2007). Decreased rumen motility may be brought on by histamine release and reduced muscular tone brought on by anaemia.
Haematological parameters
Haematological parameters recorded before start of treatment (day 0) and after treatment (day 7) in
Babesia affected (n=16) and healthy cattle (n=8) are depicted in Table 2.
The pre-treatment mean Hb, PCV and TEC levels were significantly (P<0.05) lower in diseased cattle due to erythrophagocytosis and erythropoietic suppression.
Jyothisree et al., (2013), and
Mahmoud et al., (2015) reported similar results. Post treatment results showed significant increase in haematological values (Table 2). Pre-treatment TLC count was significantly high compared to the healthy cattle and it was in close agreement with the findings of
Jyothisree et al., (2013). Post treatment TLC values decreased significantly (P<0.05) but remained higher compared to the control group. Increased TLC count is attributed to stress induced by the infection
(Bhikane et al., 2001). DLC showed significantly (P<0.05) higher neutrophils and decreased lymphocytes in both the groups before treatment compared to the healthy group (Table 2). Post treatment neutrophil values decreased and lymphocyte values increased significantly (P<0.05) compared to pre- treatment values (Table 2). The pre-treatment monocyte values were significantly (P<0.05) higher in the diseased group as compared to healthy group (Table 2) however, post treatment monocyte values significantly decreased (P<0.05) in both the treated groups. Both pre and post treatment mean values of eosinophil and basophil showed no significant (P<0.05) difference among diseased and healthy group (Table 2). The pre and post treatment values of erythrocyte indices like MCV, MCH and MCHC are presented in Table 2. Significant decrease (P<0.05) was observed in MCHC in
Babesia affected cattle compared to healthy cattle (Table 2).
Biochemical parameters
The mean values of biochemical parameters are presented in Table 3.
Pre-treatment glucose, total protein, and albumin levels were significantly (P<0.05) lower in Group I and II which is attributed to inappetence and metabolic disturbances
(Pandey and Mishra, 1987). Hypoglycaemia, hypoproteinemia and hypoalbuminaemia in babesiosis corroborates with the findings of
Tufani et al., (2009), Talkhan et al., (2010) and
Singh et al. (2014). Hypoproteinaemia and hypoalbuminaemia is attributed to liver dysfunction, kidney dysfunction and anorexia
(Esmaeilnejad et al., 2012). After treatment a significant rise in glucose, total protein and albumin (P<0.05) was recorded but it was non-significant compared to the control group (Table 3). The pre-treatment globulin levels in Group I and II were low, however after treatment significant increase in globulin levels were recorded but were having non-significant difference compared to the control group (Table 3). Similar findings of decreased á globulin were recorded in babesia affected dogs by
Lobetti et al., (2000). BUN, creatinine, AST, LDH and iron levels were significantly (P<0.05) higher in Group I and II as compared to the healthy cattle (Table 3). After treatment, the BUN, creatinine, AST, LDH and iron levels decreased significantly (P<0.05) in Groups I and II. Babesiosis causes elevated levels of creatinine and BUN because the degraded byproducts of damaged RBCs are deposited in the kidneys during glomerular filtration, which reduces the excretion of BUN and creatinine.
Talkhan et al., (2010) also observed similar increase in BUN and creatinine. Increase in AST level occurs due to massive haemolysis in conjunction with hypoxia. Similar findings of increased AST were reported by
El-Hamed et al., (2016) and
Mohanapriya et al., (2017). LDH is a marker of erythrocyte death and hepatocellular injury since it is present in large quantities in erythrocytes and hepatocytes
(Latimer, 2011). The parasite causes leakage of this enzyme into the bloodstream, which raises the serum level of LDH. Similarly,
Hashem et al., (2018) noted increased LDH concentrations in
Babesia affected cattle. The higher blood iron levels are the consequence of intravascular hemolysis, which releases free haemoglobin, which breaks down to become globin, haeme, and iron.
Talkhan et al., (2010) found similar results.
Therapeutic efficacy
The efficacy of Artesunate was evaluated with Diminazene aceturate in terms of survival rate, clinical recovery, improvements in clinico-haemato-biochemical parameters and clearance of
Babesia parasites. Group I animals treated with Diminazene aceturate recovered uneventfully after 7 days of treatment with normal body temperatures. Microscopy revealed significantly reduced
Babesia piroplasms. The clinical signs gradually disappeared and the levels of haemato- biochemical parameters returned to almost normal. Hence, Diminazene aceturate was 100% effective to cure babesiosis in cattle with no mortality, which is in close agreement with the observations of
Tufani et al., (2009). In Group II animals treated with Artesunate, only four cattle recovered uneventfully and remaining four cattle died during the treatment with 50% recovery rate. The 50% survival of animals in this group could be attributed to the low level of parasitemia, moderate level of anaemia and prompt and early treatment. Animals that survived showed normal clinico-haemato-biochemical parameters after 7 days of treatment. No death was observed in healthy control Group III during the study period. According to
Patel et al., (2001), Artesunate and oxytetracycline together have a 66.7% efficiency against bovine tropical theileriosis. Research is still going on to understand the potential of artesunate in treating
Babesia species infection either alone or in combination with other drugs.
In vitro growth of
B. bovis and
B. gibsoni was suppressed by use of artesunate, which was also successful in treating
B. microti-infected mice
(Goo et al., 2010). Babesia species share a similar life cycle, as well as clinical symptoms, with
Plasmodium species, and Artesunate is quite efficient against the malarial parasite
(Reddy et al., 2010) as well as in several non-malarial parasites
(Goo et al., 2010). Mild parasitemia remained present after 7 days of treatment in both the groups. It could be explained by the fact that the cattle that have recovered from acute infection may have low parasitemia, often microscopically undetectable and turn out to be carriers of the disease.