EPIDEMIC OR LETHARGIC ENCEPHALITIS (NONA)

The name "encephalitis lethargica" was coined by Economo,¹ who described a group of cases of this disease occurring in epidemic form in Vienna in 1917. It describes a condition primarily characterized clinically by lethargy and pathologically by poliencephalitis. This term has been cricitized by English observers since it applies a clinical adjective to a pathologic substantive; the term "epidemic encephalitis" has seemed to some English authorities preferable. In this connection, Economo referred to a mysterious condition called "nona" which occurred in Italy and Hungary in the spring of 1890. Netter² has pointed out that, although this disease is new to present observers, on two occasions previously it has manifested itself in epidemic form, following the influenza epiedmic of 1890 in northern Italy and in Hungary, and appearing in the United States and practically all of Europe in 1895.

The first cases noted in England occurred in February, 1918,