Identification of a novel neuropathogenic Theiler's murine encephalomyelitis virus

Area of Science:

• Virology
• Neuroscience
• Molecular Biology

Background:

• Theiler's murine encephalitis virus (TMEV) is classified into persistent (TO subgroup) and neurovirulent subgroups based on disease outcome.
• Persistent TMEV strains cause polioencephalomyelitis and chronic demyelinating disease, while neurovirulent strains induce acute encephalitis and rapid death.

Purpose of the Study:

• To characterize a novel, highly neurovirulent TMEV strain, designated NIHE, identified through pyrosequencing.
• To investigate the genetic makeup and pathogenic features of the NIHE strain and compare it to known TMEV subgroups.

Main Methods:

• Pyrosequencing technology for complete genome coverage of the novel TMEV strain.
• Comparative nucleotide sequence analysis to determine genetic relatedness to known TMEV strains.
• Histopathological examination of infected brain and spinal cord tissues to assess disease manifestations.

Main Results:

• The NIHE strain shares <90% nucleotide sequence identity with known TMEV strains, with significant variability in leader and capsid protein genes.
• Histopathology revealed inflammatory lesions and neuronal necrosis during acute infection, with no signs of viral persistence or chronic disease.
• Genetic analysis suggested the expression of the L protein, typically associated with persistent TMEV strains.

Conclusions:

• The novel NIHE strain represents a unique TMEV variant with neurovirulent properties but also features associated with persistent strains.
• This discovery provides a valuable model for studying TMEV evolution and the molecular determinants of neurovirulence.
• Further research on NIHE can elucidate the mechanisms underlying the dichotomy of TMEV pathogenesis.