Erythrocytic oxidative damage in crossbred cattle naturally infected with Babesia bigemina Mostafa A. Saleh * Biochemistry Unit, Regional Animal Health Research Laboratory, Animal Health Research Institute, EL-Kharga, El-Wadi El-Gadid, 725211, Egypt Accepted 9 May 2008 Abstract This study aimed to determine the erythrocytic lipid peroxidation and haemoglobin oxidation as contributory factors causing anaemia in cattle (Friesian  Egyptian native breed) infected with Babesia bigemina. Blood was collected from 32 cows infected with B. bigemina along with 18 healthy cows as controls for determination of erythrocytic malondialdehyde (MDA), blood methaemoglobin (MetHb), plasma free haemoglobin (PHb), corpuscular osmotic fragility (COF), red blood cell count (RBC), total haemoglobin (Hb) and packed cell volume (PCV). Percentage of parasitaemia varied from 14% to 36%. MDA, MetHb, COF and PHb were significantly increased (P < 0.001) in infected cows versus controls. Parasitaemia was positively correlated (P < 0.001) with MDA, MetHb, COF and PHb. MDA was positively correlated (P < 0.001) with COF and PHb and negatively correlated (P < 0.001) with RBC, Hb and PCV. MetHb was negatively correlated (P < 0.001) with RBC, Hb and PCV and positively correlated (P < 0.001) with COF. In conclusion, B. bigemina infection in cattle is associated with a parasitic burden-dependent corpuscular oxidative damage as indicated by membrane lipid perox- idation and methaemoglobin formation, which are contributed to COF and intravascular haemolysis. Ó 2008 Elsevier Ltd. All rights reserved. Keywords: Babesia bigemina; Cattle; Oxidative stress; Anaemia 1. Introduction Babesiosis is economically the most important arthro- pod-borne disease of cattle worldwide (Bock et al., 2004). The two species of greatest economic importance are Babesia bovis and Babesia bigemina, which affect cattle industries in tropical and subtropical parts (Bo ¨se et al., 1995). Previous studies provide information on the relative susceptibility of various breeds of cattle to Babesia infec- tion (Bock et al., 1997). Marked differences in pathogenic- ity and clinical manifestations of babesiosis may occur between the different geographic areas (Vial and Gorenflot, 2006). Mahoney (1977) reported that the Australian B. bigemina rarely causes disease, whereas B. bigemina in Africa is highly pathogenic. The erythrocyte stage of B. bigemina results in severe clinical symptoms in the infected cattle such as fever, anae- mia and haemoglobinuria (Radostits et al., 2000). Haemo- lytic anaemia caused by destruction and removal of parasitized and non-parasitized erythrocytes from the bloodstream is a contributory factor to the weakness and loss of condition seen in babesia-infected cattle that sur- vives the acute phase of the disease (Bock et al., 2004). In babesiosis, erythrocytes are destroyed by the physical effect of parasite multiplication (Wright, 1981), the increase of phagocytosis of erythrocytes by activated macrophages (Shoda et al., 2000; Court et al., 2001), the production of an anti-erythrocyte antibody (Goe ´s et al., 2007) and the increase in the erythrocytic membrane permeability (Alkhalil et al., 2007). Oxidation of the erythrocytes includes membrane injury, methaemoglobin formation, osmotic fragility and destruc- tion of the cell (Harvey, 1997). Lipids especially polyunsat- urated fatty acids are sensitive to oxidation, leading to the 0034-5288/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.rvsc.2008.05.005 * Tel.: +20 927920813; fax: +20 927920866. E-mail address: salehmahmad@yahoo.com www.elsevier.com/locate/rvsc Available online at www.sciencedirect.com Research in Veterinary Science 86 (2009) 43–48