I had never heard of encephalitis lethargica before. Fascinating and a bit frightening. >Although there were neuropathological differences in the brains of pat

I had never heard of encephalitis lethargica before. Fascinating and a bit frightening. >Although there were neuropathological differences in the brains of patients who died of encephalitis lethargica compared with those who died of influenza encephalitis, von Economo could not deny that there seemed to be an epidemiological connection between influenza and encephalitis lethargica. Based on experimental studies using brain tissue from deceased patients, von Economo concluded that encephalitis lethargica was caused by an infectious virus. He, and other clinicians at the time, proposed that influenza might predispose a person to infection with encephalitis lethargica, possibly by increasing the permeability of the nasal mucous membranes allowing the encephalitic virus to enter more easily. https://academic.oup.com/brain/article/140/8/2246/3970828 https://academic.oup.com/brain/article/140/8/2246/3970828