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Pathology Research International
Volume 2011 (2011), Article ID 374286, 13 pages
Research Article

Role of Apoptosis in Rabies Viral Encephalitis: A Comparative Study in Mice, Canine, and Human Brain with a Review of Literature

1Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560 029, India
2Department Neurovirology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560 029, India

Received 16 October 2010; Accepted 9 June 2011

Academic Editor: C. Sundaram

Copyright © 2011 M. S. Suja et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


To evaluate the role of apoptosis in rabies encephalitis in humans and canines infected with wild-type street virus, in comparison with rodent model infected with street and laboratory passaged CVS strain, we studied postmortem brain tissue from nine humans, six canines infected with street rabies virus, and Swiss albino mice inoculated intramuscularly (IM) and intracerebrally (IC) with street and CVS strains. Encephalitis and high rabies antigen load were prominent in canine and human brains compared to rodents inoculated with street virus. Neuronal apoptosis was detectable only in sucking mice inoculated with CVS strain and minimal in street virus inoculated mice. In a time point study in suckling mice, DNA laddering was noted only terminally (7 days p.i.) following IC inoculation with CVS strain but not with street virus. In weanling and adult mice, apoptosis was restricted to inflammatory cells and absent in neurons similar to human and canine rabies-infected brains. Absence of neuronal apoptosis in wild-type rabies may facilitate intraneuronal survival and replication while apoptosis in inflammatory cells prevents elimination of the virus by abrogation of host inflammatory response.