Evaluation of Cattle Inoculated with Babesia bovis Clones Adhesive In Vitro to Bovine Brain Endothelial Cells

Abstract

A comparative assessment of the virulence of Babesia bovis clones that adhere or not to bovine brain endothelial cells was done using two clones of B. bovis: (1) a clone phenotypically characterized as virulent (2F8) and (2) a clone of reduced virulence (RAD). Of these subpopulations, we selected those that had adhesive characteristics (a) or nonadhesive characteristics (na) in cultured endothelial cells. Twenty Holstein cattle, 12 months of age or older, were used in this study, and these cattle were randomly assigned to five groups of four animals each. The clones and their respective subpopulations were inoculated via intramuscular injection at a 0.5 x 10(7) infected erythrocyte dosage. Group A was inoculated with aRAD, group B with naRAD, group C with a2F8, group D with na2F8, and group E remained as a control. All inoculated animals showed a decrease in the packed cell volume (PCV), with group D showing the largest decrease (39.53%) and longest time (7 days) with rectal temperature above 39.5 degrees C. Babesia was observed in stained blood smears from only six cattle. While the four parasite subpopulations were pathogenic, significant differences were not noted among them, despite that the subpopulations considered to be virulent caused the greatest reduction in PCV per individual.

New insights into the altered adhesive and mechanical properties of red blood cells parasitized by Babesia bovis

“…Unlike human malaria, babesia has the advantage of being a natural host‐parasite system in which such a relationship can be determined. Interestingly, two previous studies have failed to detect differences in the adhesive properties between B. bovis parasites that cause mild or severe infections in vivo when adhesion was tested in static adhesion assays (Molloy et al ., 2003; Canto et al ., 2006). Our observations suggest that it would be clearly worthwhile to revisit these earlier studies and infect cattle with PRBCs that had been selected for adhesion under flow conditions to monitor the severity of the resulting disease.…”

A retrospective study of Babesia macropus associated with morbidity and mortality in eastern grey kangaroos (Macropus giganteus) and agile wallabies (Macropus agilis)

“…Putative pathogenic mechanisms include those reported for cerebral babesiosis and cerebral malaria, specifically hypoxic injury and/or inflammatory cytokine release caused by sludging of parasitised erythrocytes in brain capillaries (obstructive sequestration) and possible endothelial damage ( Schetters and Eling, 1999 ). Some species of Babesia such as B. bovis in cattle ( Canto et al., 2006 ), Babesia lengau in cats ( Bosman et al., 2013 ) and Brucella canis in dogs ( Jacobson, 2006 ) can cause such cerebral localisation of infection, which is associated with a poor prognosis ( Canto et al., 2006; Jacobson, 2006 ). Certain species and strains of Babesia can alter the physiology of the infected erythrocyte and increase its adherence to other cells, including endothelial cells ( Wright, 1972; O'Connor and Allred, 2000 ).…”

Antecedentes y perspectivas de algunas enfermedades prioritarias que afectan a la ganadería bovina en México

“…El más común es el frotis de sangre periférica con el que se hace la identificación de B. bovis y B. bigemina mediante la observación microscópica; igualmente se elaboran improntas de tejido cerebral particularmente para la detección de B. bovis (141,142) . También se puede hacer el análisis histopatológico de tejidos recolectados a la necropsia (143,144,145) . Se han desarrollado métodos indirectos cuyo fundamento es inmunológico, con los que se detectan anticuerpos circulantes anti-B.…”