Descriptive Epidemiology of Multiple Sclerosis (MS) Multiple Sclerosis

Course of Disease ` ` Acute - Very Rapid Course, Death in a few months ` ` Progressive - Gradually becoming worse, well defined remissions and exacerbations exacerbations ` ` Benign - Exacerbations with very long remissions ` ` Subclinical - No Symptoms, identified at autopsy

Progressive Acute

Epidemiology : Incidence of MS in Denmark

Incidence of MS in Iceland

Incidence of MS in Faroe Islands

Incidence of MS in Faroe Islands by age

Years since 1942: in Faroe Islands

Incidence of MS in South Africa

Prevalence of MS

Unusual Occurrence of MS in Tropical Island

Risk Factors : Unusual Stress in 2 Yrs Before Cases Controls p value 79% 54% <0.01

Risk factors : Exposed to Animal Illness Cases Controls 43% 19%

Risk Factors : Exposed to Canine Distemper Cases Control 17% 6%

Physical Activity and MS

Immunologic Involvement ` `Autoantibodies ` `Encephalomyelitis developing- -Similar to the administration of rabies virus vaccine ` ` Evidence for a superantigen?

Frequency of Viral Infection

Concordance Rates in Twins MZ DZ 31/107 13/

Prevalence of MS in First Degree Relatives Sibs Parents Offspring 125/10,682 41/6,521 9/1,

DZ Risk versus Sibling Risk DZ Sibling

HLA Antigens and MS: Northern Europeans

Conclusions ` `MS caused by environmental factors, but not clear what they are ` `For MS there is evidence for HLA associations, however, there is more than HLA ` `MS is a multiloci diseaseMS is a multiloci disease