CLINICO-PATHOLOGICAL AND HAEMATOLOGICAL FINDINGS IN EQUINE PIROPLASMOSIS IN IBADAN

R. A. M Adedokun, B. A. Alaba*, O. O. Alaka and D. Omoniwa

ABSTRACT

Equine piroplasmosis (EP), a disease naturally transmitted by ticks is endemic and widely spread in Nigeria among horses and donkeys. This disease has remained a challenge, particularly as the movement of horses across Nigeria has increased. Hence, there is need for concerted and continuous in-depth research to check the menace of equine piroplasmosis in Nigeria. A total of Fifty-eight (58) horses from three different locations in Ibadan, Southwest Nigeria, were clinically examined in their state of rest. Haemoparasites identification and haematological parameters were evaluated according to standard procedures. Five (8.6%) of the 58 horses examined were positive for the disease. Observed clinical signs in Babesia-positive horses included emaciation, severe dehydration, fever, hyperpnoea, tachycardia, dullness, ecchymosis of the third eyelids, icterus, haemoglobinuria, tick infestation, oedema of the head, ventral abdominal wall, scrotal sac and fetlock joints, reluctance to move, weak hind quarters and unsteady gait were observed in clinically positive horses. Haematological examination revealed intraerythrocytic and extraerythrocytic Theleira equi and Babesia caballi. The haematology result showed that infected horses presented a significant decrease (p<0.05) in PCV, Hb, RBC, WBC, lymphocytes counts and significant elevation (P<0.05) in neutrophils and monocytes. Of the 5 (8.6%) Babesia positive horses, fatalities were recorded in 3(5.2%). Post mortem findings included generalized inflammation, necrosis, congestion and oedema with diffused subcapsular ecchymotic and petechial haemorrhages of the visceral organs such as lungs, heart, liver, spleen, kidney and brain. The histopathological findings of the affected organs revealed alveolar and interstitial pulmonary oedema and thrombosis of the pulmonary blood vessels. There was severe multifocal hepatic necrosis, portal fibrosis, presence of macrophages and neutrophils in the necrotic areas and presence of haemosiderin in kupffer cells. Haemosiderin laden macrophages were present in the spleen while the renal tubules were markedly dilated and contained proteinaceous casts. There were also stunting of intestinal villi, necrosis of epithelial surface, as well as oedema and haemorrhages in the lamina propia. Brain sections showed marked congestion and thickening of the meningeal blood vessel walls with moderate lymphocytic infiltrations of the meninges and margination of leucocytes in the meningeal vessels. The role of major managemental negligence such as heavy tick infestation and poor nutrition cannot be ruled out as possible causes of the predisposition of infected horses to piroplasmosis in this study. It is hereby recommended that best equine management practices are instituted.

Keywords: Equine piroplasmosis, haematology, gross, histopathological lesions.