EQUINE BABESIOSIS ASSOCIATED WITH STRENUOUS EXERCISE - CLINICAL AND PATHOLOGICAL-STUDIES IN JORDAN

Clinical, haematological and pathological studies were undertaken in J ordan in a stud of 103 racing horses clinically suffering from babesio sis and apparently healthy animals. Out of 47 horses which participate d in strenuous exercise, three mares showed sudden onset of immobility and reluctance to move and two mares died. Clinical examination revea led that these five horses (group I) had fever, anorexia, weakness and severe icterus and, in two mares, haemoglobinuria. Haematological exa mination revealed that all five horses were heavily parasitized with B abesia equi. This was also found in four horses (group 2) with no evid ence of clinical babesiosis. In group 3 (94 horses), neither clinical signs nor B. equi were observed in the blood. The horses in group 1 an d 2 recovered after treatment with imidocarb. When the mean values of white blood cell count, red blood cell count, haemoglobin and packed c ell volume in group 1 were compared with those for groups 2 and 3, a s ignificant difference was found (P <0.05). A significant difference wa s also found when the mean values were compared before and after treat ment. Examination of serum total protein, bilirubin and serum enzymes revealed a significant decrease in the mean value of total serum prote in (P <0.05), and a significant increase in the mean values of bilirub in (P <0.05) in group 1 compared to groups 2 and 3. A significant elev ation in the mean value of aspartate aminotransaminase, gamma-glutamyl transferase and creatine phosphokinase and a substantial elevation in the mean value of alkaline phosphatase was also observed in group 1 co mpared to groups 2 and 3. Postmortem examination of the dead horses sh owed that the animals had icterus, hepatomegaly and full urinary bladd er with deep-red urine. Histopathological examination of the liver sho wed massive centrilobular degeneration and necrosis. The bile canalicu li and bile ducts were prominent and plugged with dark-brown to canary -coloured bile pigments. The lungs had congestion, oedema, and thrombo sis of pulmonary veins. Our results suggest that the horses suffered f rom B. equi with clinical manifestation following exercise. The clinic al, haematological and pathological findings indicate that the animals suffered from haemolytic anaemia which responded to imidocarb therapy .