Demyelination induced in mice by avirulent Semliki Forest virus. I. Virology and effects on optic nerve

Area of Science:

• Neuroscience
• Virology
• Ophthalmology

Background:

• Semliki Forest virus (SFV) is an alphavirus known to cause neurological disease.
• Ocular involvement in viral infections can lead to vision impairment.

Purpose of the Study:

• To investigate the pathological effects of Semliki Forest virus (SFV) infection on the optic nerve, retina, and brain in a mouse model.
• To characterize the temporal progression of viral load and histological changes in ocular and neural tissues.

Main Methods:

• Swiss A2G mice were inoculated intraperitoneally with an avirulent SFV strain.
• Virus titration was performed on optic nerves, retina, and brain at specific post-inoculation days.
• Light and electron microscopy were used to examine tissue pathology.

Main Results:

• High virus titers were detected in the optic nerve, retina, and brain between post-inoculation days 3 and 8.
• Histopathological examination revealed inflammatory changes, microcystic alterations, and demyelination in the optic nerve.
• These observed changes in the optic nerve were comparable to those found in the central nervous system.

Conclusions:

• The avirulent SFV strain effectively infects ocular and neural tissues in mice.
• SFV infection induces neuropathological changes in the optic nerve, including inflammation and demyelination.
• The findings suggest a potential for SFV to cause optic nerve damage similar to central nervous system pathology.