Multiple sclerosis and canine distemper in Iceland

Area of Science:

• Epidemiology
• Neurology
• Veterinary Medicine

Background:

• A potential link between canine distemper virus and multiple sclerosis (MS) has been suggested.
• Iceland provides a unique setting to study this relationship due to the absence of endemic canine distemper and limited vaccination.
• Occasional canine distemper outbreaks have occurred in Iceland following importations.

Purpose of the Study:

• To investigate the association between canine distemper prevalence and multiple sclerosis incidence in Iceland.
• To determine if high rates of MS correlate with canine distemper exposure.

Main Methods:

• Analysis of multiple sclerosis case data (129 cases from 1946-1965) in Iceland.
• Subdivision of cases by region of birth to assess regional prevalence rates.
• Correlation of MS prevalence with historical canine distemper epizootics and dog population density.

Main Results:

• Highest regional multiple sclerosis prevalence rates were observed in areas with limited or no past canine distemper exposure.
• Significant MS prevalence was found in Reykjavik, an area with a very low dog population for over 50 years.
• These findings challenge the hypothesis of a direct causal link between canine distemper and multiple sclerosis.

Conclusions:

• The Icelandic experience suggests that multiple sclerosis can occur at high incidence independently of canine distemper.
• The study indicates that canine distemper is unlikely to be a primary etiological factor for multiple sclerosis.
• Further research is needed to understand the complex factors contributing to multiple sclerosis development.