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[Virus and demyelination: why suspect that a virus may be involved in the aetiology of multiple sclerosis?]
R Fernández-Muñoz1, M Celma-Serrat
1Servicio de Virología. Hospital Ramon y Cajal. Facultad de Medicina, Madrid, España. rafael.fernandez@hrc.es
Introduction:
Epidemiological data indicate that environmental factors, possibly infections, are associated with the development of multiple sclerosis. Different viruses are known to produce demyelination in natural and experimental animal infections. In humans some virus cause acute or chronic diseases that course with central nervous system demyelination. A series of virus have been claimed to be etiological agents of multiple sclerosis, although a causal role for any of them has so far been demonstrated.
Method:
The mechanisms of viral demyelination are diverse,ranging from direct destruction of infected oligodendrocytes to triggering autoimmune responses without virus multiplication in target cells. The potential indirect mechanisms of viral demyelination and the heterogeneous histopathology shown in multiple sclerosis patients, suggesting an heterogeneus etiology, might explain why not a single virus has been as yet identified as the cause of this disease.
Conclusions:
Viral infections that cause demyelination in animals and humans are briefly reviewed, focusing on the potential myelin destruction mechanisms and obstacles to the identifying viruses that might cause multiple sclerosis.
Insights
Environmental factors, including viral infections, are linked to multiple sclerosis (MS). While viruses can cause demyelination, identifying a specific causative agent for MS remains challenging due to diverse mechanisms.
Area of Science:
- Neuroimmunology
- Virology
- Epidemiology
Context:
- Epidemiological studies suggest environmental factors, particularly infections, play a role in multiple sclerosis (MS) development.
- Viruses are known to induce demyelination in both animal models and human diseases affecting the central nervous system.
Purpose:
- To review viral infections causing demyelination in animals and humans.
- To explore potential mechanisms of viral-induced myelin destruction.
- To discuss challenges in identifying viruses as etiological agents of MS.
Summary:
- Viral demyelination mechanisms are varied, including direct oligodendrocyte destruction and autoimmune responses.
- The heterogeneity in MS histopathology suggests a multifactorial etiology, complicating the identification of a single viral cause.
- Despite evidence linking viruses to demyelination, a definitive causal role in MS has not been established for any specific virus.
Impact:
- Provides a comprehensive overview of viral demyelination relevant to multiple sclerosis research.
- Highlights the complexity of viral-induced neurological damage and its implications for MS pathogenesis.
- Informs future research directions aimed at elucidating the role of viral infections in multiple sclerosis etiology.