Epidemiological aspects of an outbreak of encephalomyelitis at the Royal Free Hospital, London, in the summer of 1955

Abstract

An outbreak of encephalomyclitis of unknown actiology occurred in the Royal Free Hospital Teaching Group in 1955. The disease which affected about 9% of the population was probably a viral infection spread by personal contact. People of all ages were attacked but those under 30 were most susceptible. Institutional life was an important factor in determining the case incidence which was highest among nurses, orderlies and resident domestic staff. The clinical picture was one of encephalomyelopathy, with lympho-reticular reaction and relapsing myalgia.