The varicella-zoster virus and multiple sclerosis

Area of Science:

• Neurology
• Virology
• Epidemiology

Background:

• Multiple sclerosis (MS) and varicella (chickenpox) share similar geographical prevalence patterns, being more common in temperate zones and rarer near the equator.
• Migration studies indicate that infections acquired before age 14 may increase the risk of developing MS later in life.
• Hutterite communities exhibit lower rates of varicella, MS, and herpes zoster, correlating with reduced varicella-zoster virus seropositivity.

Purpose of the Study:

• To review evidence suggesting a potential link between the varicella-zoster virus (VZV) and multiple sclerosis (MS).
• To explore epidemiological data supporting an infectious etiology for MS.
• To investigate the paradoxical observation of increased herpes zoster incidence in MS patients.

Main Methods:

• Review of existing epidemiological and clinical studies.
• Analysis of geographical prevalence data for MS and VZV.
• Examination of migration patterns and their correlation with MS risk.
• Comparison of VZV seropositivity and clinical disease incidence in specific populations (e.g., Hutterites).

Main Results:

• Geographical distribution of MS and varicella suggests a shared environmental factor, possibly VZV.
• Early-life acquisition of an infectious agent, potentially VZV, appears to be a risk factor for MS.
• Hutterite populations show reduced incidence of varicella, MS, and herpes zoster, with corresponding lower VZV seropositivity.
• Patients with MS report a higher incidence of herpes zoster at a younger age compared to controls.

Conclusions:

• The varicella-zoster virus is a plausible candidate antigen or mimic involved in the etiology of multiple sclerosis.
• Environmental factors, particularly infections acquired in childhood, play a significant role in MS development.
• Further research is warranted to elucidate the precise mechanism linking VZV to MS pathogenesis.