Epidemiology : it strikes exclusively in eastern Siberia in the Republic of Sakha (Yakutia / Yakutija) in Vilyui river basin (mainly in Vilyuisk and Kobyaisk regions) among natives Yukat (among which also SCA1 is much common; more they have fewer T cells than Russian), Evenks and Evens; it is known there since the middle of the last century. The Vilyuy region is a diamond province where a complex of chemical pollutants from diamond mining, products of wood decay in places of flooding of the water reservoir for the Vilyuisk power station, highly mineralised underground waters and consequences of underground explosions have caused a substantial negative effect on the environment and people.
Aetiology : previously considered caused by Theiler's murine encephalomyelitis virus (TMEV), but it was just a contaminant. Hypothetical role for an Herpesvirus
or autoimmune disorder similar to neuro-Behçet
: anyway infective aetiology hypothesis is supported by infection of Ludmila
Alekseeva, a Russian lab technician that tried to kill herself by injecting
into her hand CSF from a man who died from VE.
Pathogenesis : multiple micronecrotic foci surrounded by inflammatory infiltrates are observed throughout the cerebral cortex and other gray matter areas
=> the incubation time could be possibly 14 years or more.
- rapid (subacute) form : severe subacute meningo-encephalitis progressing to a more prolonged pan-encephalitic syndrome, stiff gait, slurred speech, rigid, spastic muscles, encephalitis lethargica (sleeping sickness), die within months
- slowly progressive form : recover from the acute onset, recurrences followed by remissions
chronic form : lack inflammatory cells, in people who never have had an acute attack
Prognosis : fatal outcome within 1 to 10 years. Some patients survive to a steady state of global dementia and severe spasticity that may last for over 20 years
