Viliuisk encephalomyelitis (VE) is a fatal progressive neurological disorder found only in the Sakha (Iakut/Yakut) population of central Siberia.
Initially, the infected patients experience symptoms such as: severe headaches, delirium, lethargy, meningism, bradykinesia, and incoordination.
It begins with the characteristic rigidity of the muscles, accompanied by slurred speech, severe headaches, and exaggeration of cold-like symptoms.
Routine post-mortem examinations yield: severe inflammation of the brain lining, clusters of dead cells and tissue, and largely increased amounts of macrophages and lymphocytes.
Eventually the disease developed fully and those infected were stricken with the characteristic symptoms of rigidity, slurred speech, and deterioration of cognitive functions.
The trademark changes in the brain include: thickened inflamed meninges, necrotic cortical lesions, increased number of lymphocytes, and neuronal death.
[1][7] Research has concluded that Viliuisk encephalomyelitis has been present in the Viuli valley for many centuries among the Evenk populations of northern Siberia.
The locals and Northern Evenks referred to this illness as "Bokhoror" or "the stiffness" because of the typical rigidity of the limbs those infected individuals experienced.
[1] Fifty years ago it was believed that the Yakut people had extremely degraded immune systems as result of malnourishment and starvation from the World War.