Short Communication Cardiac arrhythmias associated with piroplasmosis in the horse: A case report Alessia Diana a, * , Carlo Guglielmini b , Daniela Candini a , Marco Pietra a , Mario Cipone a a Veterinary Clinical Department, Alma Mater Studiorum-Universita ` di Bologna, Via Tolara di Sopra 50, I-40064 Ozzano Emilia (BO), Italy b Department of Veterinary Clinical Sciences, Universita ` degli Studi di Teramo, Viale Crispi 212, I-64020 Teramo, Italy Accepted 10 April 2006 Abstract Cardiac dysfunction is a rare complication of babesiosis in domestic animals. The horse in this report showed clinical signs of anor- exia, depression, fever, icterus and brown urine, and laboratory results (monocytosis, thrombocytopenia, azotemia, hyperbilirubinemia and bilirubinuria) indicated sub-acute piroplasmosis. Furthermore, junctional and polymorphic ventricular premature complexes and tachycardia associated with increased serum cardiac troponin I and myocardial-bound creatine kinase concentration were found. The diagnosis of piroplasmosis was confirmed by serology. Specific and supportive therapy for babesiosis allowed remission of clinical signs and laboratory profile abnormalities, including those of myocardial involvement. Myocardial damage associated with cardiac arrhyth- mia may be a complication of equine babesiosis as already demonstrated in other species. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Equine; Babesia; Protozoa; Cardiac disorder; Electrocardiography Equine babesiosis (piroplasmosis) is a tick-borne multi- systemic disease caused by haemoprotozoan parasites in the tropics, subtropics and warm temperate zones (de Waal, 1992). Both Babesia caballi and Theileria equi may be responsible for piroplasmosis in South Europe (Fried- hoff and Soule, 1996). Electrocardiographic (ECG) abnor- malities consistent with ischemia and myocarditis have been described in humans (Rakita et al., 1995), but are poorly documented in animals with babesiosis. Recently, ECG abnormalities and cardiac arrhythmias associated with high serum cardiac troponin I (cTnI) concentration were reported in dogs with babesiosis (Lobetti et al., 2002; Dvir et al., 2004). We describe here a case of cardiac arrhythmias associated with piroplasmosis in a horse. A 9-year-old gelding Quarter Horse was referred with a one-week history of anorexia, weakness and brown urine. The horse had been treated by the referring veterinarian with two doses of imidocarb diproprionate (Carbesia, Schering-Plough, 2.2 mg/kg IM) at 24-h interval on the basis of suspected piroplasmosis. On admission (day 1), the horse was depressed, tachypnoeic and pyretic (rectal temperature: 39 °C). Haemorrhagic skin lesions and many ticks were seen on cutaneous inspection. The mucous mem- branes were congested and icteric with visible petechiae. The arterial pulse was weak and arrhythmic with pulse def- icit. Auscultation of the thorax revealed no heart murmur or abnormal lung sounds. The heart rate (HR) was 80 bpm. Differential diagnoses included immune-mediated haemolytic anaemia, piroplasmosis, equine infectious anae- mia (EIA), equine ehrlichiosis, hepatic disorders and hae- matopoietic neoplasia. The results of complete blood count (CBC) indicated mild leukocytosis (16,200 cells/lL) with monocytosis (2916 monocytes/lL) and severe thrombocytopenia (18,000 platelets/lL). Packed cell volume (PCV, 46%) and red blood cell (RBC, 10.95 · 10 6 cells/lL) counts were normal and no Babesia-infected erythrocytes in Giemsa- stained blood smears were found. Serum biochemical anal- yses revealed mildly elevated urea nitrogen (29.5 nmol/L) 1090-0233/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.tvjl.2006.04.003 * Corresponding author. Tel.: +39 051 2097318; fax: +39 051 2097593. E-mail address: adiana@vet.unibo.it (A. Diana). www.elsevier.com/locate/tvjl The Veterinary Journal 174 (2007) 193–195 The Veterinary Journal