In the present study, a total of 54 highly suspected cases of hemoparasitic cattle blood smears were examined, out of which 32 animals were found to be positive for haemoprotozoa. Among 32 blood smear examined, 14 revealed
Anaplasma sp, 10 smears showed
Babesia sp and 8 had
Theileria sp) (Fig 3-6). Since the animal shows clinical disease and confirmed for blood parasitic infection, then treatment was given as per standard protocol
(Radostits et al., 2000).
In the ultrasonographic examination the hyperechogenic pericardium and epicardium were separated by varying quantity of hypoechogenic exudate (Fig 7and 8). When the heart was ultrasonographically examined from the left side, the evenly spread hypoechogenic pericardial effusion could be seen in 6 of these 32 cows. Ultrasound guided pericardial fluid yielded aseptic pericardial effusion without any foreign body in such cases and no bacterial growth observed on culture.
In the current study, significantly elevated cTnI levels observed in naturally infected
Anaplasma,
Theileria and
Babesia animals (Table 1) whereas, the mean cTnI concentration was 0.08±0.03 ng/ml in healthy control group. Among 32 animals, two of them showed very high cTnI value, in
Theileria (34.98 ng/ml) and
Anaplasma (24.16 ng/ml) affected cattle, respectively. The measured CK-MB in
Theileria,
Babesia and
Anaplasma affected cattle were also above the normal range. There were significant differences in cTnI, CK-MB and LDH values between healthy and diseased groups.
Electrocardiographic assessment showed prolonged QTc and STc interval in the animals affected with hemoparasites. The prolonged QT interval (>0.40 seconds) and ST interval (>0.32 sec) in cows with hemoparasites confirmed the electrolyte imbalance or cardiac changes in 6 animals (Fig 9). The Corrected QT interval (QTc) and ST interval (STc) based on Bazett’s formula showed >0.45 sec and >0.36 sec in all six cows (Fig 10) which indicated subclinical hypocalcemia in the hemoprotozoan affected animals. ECG interpretations showed that 18 infected cattle had sinus tachyarrthymia and 14 cattle had normal sinus rhythm. The affected animals don’t have any bradycardia.
The animals positive for Anaplasmosis was treated with Inj. Oxytetracycline @ 20 mg/kg b.wt. in 500 ml normal saline i/v, Meloxicam @ 0.5 mg/kg b.wt. i/m, liver extract @ 12-15 ml i/m for consecutive five days along with supportive fluid therapy and oral iron supplements (Bol. Ferritas). Those animals positive for Babesiosis were treated with a single dose of Inj. Diminazene aceturate @ 5.0mg/Kg b.wt. i/m and the Theileria positive cases were treated with Inj. Buparvaquone @ 2.5 mg/kg b.wt. i/m (single dose) along with Inj. Oxytetracycline @10mg/kg body weight for a period of 10 days followed by supportive therapy and oral hematinics.
The incidence of haemoprotozoan diseases varies on climatic conditions such as temperature, humidity, rainfall and geographical area
(Radostits et al., 2000). An increased number of Anaplasmosis, Babesiosis and Theileriosis were observed in this study might be due to the involvement of vector (tick)
Rhipicephalus sp in the transmission of haemoprotozoan diseases, as it is the most common tick species found in cattle in the Cauvery delta region
(Jayalakshmi et al., 2019). Measurement of cTnI is a very sensitive way of demonstrating myocardial cell damage in animals with clinically suspected myocarditis
(Tunca et al., 2008). Serum cardiac troponins are the earliest appearing biochemical markers during myocardial damage. During myocardial cell damage increased in cTnI proteins have a high sensitivity and absolute specificity; they are released even in micro injuries into the blood stream
(Oyama and Sisson, 2004). These proteins are usually present in blood either at very low concentrations or below the limit of detection for most of the assays
(Gunes et al., 2008). Overall, the degenerative changes in the internal organs as indicated by cardiac biomarkers may be due to anemic hypoxia. Infiltration of circulating immune complexes may further complicate the problem
(Aulakh et al., 2005).
Myocardial effects are very rare in protozoan diseases. On the other hand, increasing serum cTnI levels have been reported in equine piroplasmosis, canine babesiosis, trypanosomiasis and bovine theileriosis. Cardiac troponin I is released from myocytes in both reversible and irreversible myocardial injury. The changes in myocyte membrane permeability resulting from the injury could be enough for the release of cardiac troponins from the free cytosolic pool of myocytes without structural damage. It may be speculated that increased oxygen consumption by the myocardium during a prolonged period of tachycardia is combined with a reduced oxygen supply to myocardium attributed the release of troponins from the heart secondary to anemia in cattle.
CK-MB and LDH are cytoplasmic enzymes with a high activity in heart, skeletal muscle, liver, kidney and red blood cells. These enzymes are indicators of a higher level of cellular damage and their increased activity is a consequence of their increased release from the damaged cells and a reflection of metabolic changes in the inflamed tissues especially in the heart
(Graeber et al., 1990). Higher levels of AST and CK-MB have been detected in cattle with babesiosis than in healthy cattle. In anaplasmosis, degenerative changes are observed in different organs due to hypoxic conditions created by anemia. Further changes may be due to immunological reactions produced by parasite. Very few published reports are available in literature on histopathological changes in bovine anaplasmosis.
LDH activity rises slowly after myocardial infarction and becomes maximal after CK-MB elevations
(Ohman et al., 1982). Determinations of LDH activity have been used diagnostically to determine whether acute myocardial infarction occurred in the days before a patient was evaluated
(Adams et al., 1993). Measurement of cTnI is clearly more sensitive than the LDH cutoff value for retrospective diagnoses of acute myocardial injuries. Resolution of this problem has been advanced by the development of techniques that separate CK into its three isoenzymes containing MM, MB and BB
(Van Der Veen and Willebrands, 1966). Separation and quantification of MB isoenzyme, which is found almost exclusively in heart muscle, provides a more specific indicator of acute myocardial infarction than total CK alone. CK-MB as a cardio specific enzymehas been introduced as a sensitive marker ofmyocardial injury
(Roe et al., 1972). Recent studiesreport that although the sensitivity of cTnI iscomparable to that of CK-MB, its specificity seemsto be higher
(Adams et al., 1994). In the diagnosis ofacute myocardial infarction, the measurement of elevated levels of CK-MB and LDH are well known
(Jaffe et al., 1984).
The changes in the length of the QT interval depend on the heart rate and various other factors. Shortening of the QT interval typically occurs in pathological conditions such as hypercalcemia and digitalis intoxication. QT interval prolongation can be caused by various factors, including imbalance of electrolytes such as hypokalemia and hypocalcemia
(Koyama et al., 2004).
It was well established that cardiac troponins are cleared from blood faster than CK-MB, but concentrations stay elevated longer.Because 94% of troponins are bound in the structure of myofibrilla and 6% are dissolved in cytosol,in cases of severe cell damage the proportion that is dissolved in the cytosol can immediately be released into blood by diffusion. In contrast, the major proportion of troponins can only be released after proteolytic disintegration. The animal with very high troponin values might be due to above said reason. This delayed release from the injured cell is the reason for the relatively long period during which increased troponin concentration is detectable in serum, although the fragments continue to be subjected to proteolytic disintegration within the blood stream. These findings indicate continued, delayed release of troponins from necrotic myocytes.
