Loss of neurovirulence is associated with reduction of cerebral capillary sequestration during acute Babesia bovis infection

Particle and Fibre Toxicology

Audrey OT Lau²  Annie V Chen³  Andrew J Allen³  Terry F McElwain²  Kerry S Sondgeroth¹ 

[1] Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USA;Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USA;Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA 991674-7040, USA

关键词: Neurovirulence;    Attenuation;    Sequestration;    Cytoadherence;    Babesiosis;    Babesia bovis;   

Others  :  1226998
DOI  :  10.1186/1756-3305-6-181

 received in 2013-05-28, accepted in 2013-06-13,  发布年份 2013

【 摘 要 】

Background

Severe neurological signs that develop during acute infection by virulent strains of Babesia bovis are associated with sequestration of infected erythrocytes in cerebral capillaries. Serial passage of virulent strains in cattle results in attenuated derivatives that do not cause neurologic disease. We evaluated whether serial passage also results in a loss of cerebral capillary sequestration by examining brain biopsies during acute disease and at necropsy.

Findings

Cerebral biopsies of spleen intact calves inoculated intravenously with a virulent or attenuated strain pair of B. bovis were evaluated for capillary sequestration at the onset of babesiosis and during severe disease. In calves infected with the virulent strain, there was a significant increase in sequestration between the first and second biopsy timepoint. The attenuated strain was still capable of sequestration, but at a reduced level, and did not change significantly between the first and second biopsy. Necropsy examination confirmed the second biopsy results and demonstrated that sequestration identified at necropsy reflects pathologic changes occurring in live animals.

Conclusions

Loss of neurovirulence after serial in vivo passage of the highly virulent T2Bo strain of B. bovis in splenectomized animals is associated with a significant reduction of cerebral capillary sequestration. Previous genomic analysis of this and two other strain pairs suggests that this observation could be related to genomic complexity, particularly of the ves gene family, rather than consistent gene specific differences. Additional experiments will examine whether differential gene expression of ves genes is also associated with reduced cerebral sequestration and neurovirulence in attenuated strains.

【 授权许可】

   
2013 Sondgeroth et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

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