Book Excerpt: An Epidemic of Absence - Wired Science
Today, 1 in 430 Sardinians has multiple sclerosis, a degenerative disease of the central nervous system that, as it progresses, steals one’s ability to move limbs, to see, and eventually to breathe. (That’s the official number, but Sotgiu confides that unpublished data put it higher still.) One in every 270 Sardinians has type-1 diabetes, an autoimmune condition in which the immune system attacks the body’s insulin-producing organ, the
pancreas.
The stats weren’t always like this here. In Sardinia, there’s a distinct Year Zero for autoimmune disease. Just after the eradication of malaria in the 1950s, immune-mediated diseases began increasing precipitously. Sotgiu thinks the timing isn’t coincidental.
Malaria may have selected for autoimmunity-prone genes. But infection with the malaria parasite Plasmodium falciparum likely protected against the dark side of the very genes it helped shape. In this aspect, Sotgiu’s hypothesis departs from more run-of-the-mill invocations of genetics.
He suspects that the highly specialized Sardinian immune system functions properly only in the context of the invader it evolved to thwart. Sardinians need to engage with their old foe, in essence, to avoid the demons lurking within.
