Family clustering of Viliuisk encephalomyelitis in traditional and new geographic regions

Abstract

Viliuisk encephalomyelitis is an acute, often fatal, meningoencephalitis that tends to develop into a prolonged chronically progressive panencephalitis. Clinical, neuropathologic, and epidemiologic data argue for an infectious cause, although multiple attempts at pathogen isolation have been unsuccessful. To assess mechanisms of disease transmission and spread, we studied 6 multiplex families. Secondary cases occurred among genetically related and unrelated persons in a setting of prolonged intrahousehold contact with a patient manifesting the disease. Transmission to unrelated persons was documented in a densely populated region around the city of Yakutsk in which Viliuisk encephalomyelitis..