Abstract

Equine granulocytic anaplasmosis is a tick-borne infection characterized by fever, weakness, thrombocytopenia, and anaemia. Severe cases may require blood transfusion—a procedure infrequently practised in equine medicine in Nigeria. A 12-year-old Sudanese Country-Bred mare weighing 400kg, presented to the veterinary team at the Ibadan Polo Club, Ibadan, Oyo State, Nigeria, with a two-week history of hyporexia and lethargy after participating in a polo tournament in Kano State, Nigeria. Clinical examination revealed intermittent fever (up to 40.3℃), pale mucous membranes, prolonged capillary refill time (> 2 seconds), slightly elevated pulse rates (54 beats/min), slightly high respiratory rates (25 breaths/min), and infestation with hard-bodied ticks. Laboratory tests showed severe anaemia (PCV 9.5%), leukopenia, thrombocytopenia, and the presence of Anaplasma phagocytophilum morulae within the neutrophils. Initial supportive treatment included vitamin B complex, phenylbutazone, ivermectin, and whole blood transfusion (2.5 litres). Upon confirmation of Anaplasma phagocytophilum infection, the horse received intravenous 5% oxytetracycline for five days, followed by two weeks of oral doxycycline. Fluid therapy was administered to correct fluid and electrolyte deficits. Complete clinical recovery was observed three weeks post-treatment, with haematologic parameters returning to near-normal levels. This case highlights the importance of early diagnosis, antimicrobial therapy, and timely blood transfusion in managing severe equine granulocytic anaplasmosis. Routine tick control and health checks before and after polo tournaments are essential preventive measures.

Key words: Anaplasmosis, anaemia, blood transfusion, intermittent fever, ticks