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What is Encephalitis lethargica?

You have probably heard about the African Sleeping Sickness which is caused by microscopic parasites transmitted by tsetse flies. But have you heard of the Sleepy Sickness which caused an epidemic in Europe and the United States after the war?

Encephalitis lethargica was a disease that attacked the brain. The victims were literally left speechless and motionless. Around 500,000 died or were incapacitated because of it. There is no recurrence of the epidemic, but there are isolated cases.

What Caused Encephalitis lethargica?

Unlike most diseases that caused epidemics and pandemics, the cause of Encephalitis lethargica are unknown. It was first described by Dr. Constantin von Economo and Dr. Jean-René Cruchet in 1917. Economo, was able to identify the unique pattern of damage among the brains of deceased patients. He gave the disease its name.

During the winter of 1916 to 1917 the disease appeared in Vienna, over the next three years it started to spread across Europe. The communication about the disease was slow due to the fact that the symptoms varied from one individual to another. In addition to this, disseminating information during the war was quite difficult.

The exact number of individuals that were affected by the disease is unknown. Some survivors of the illness have not returned to their pre-morbid state.

Although there is no recurrence of the epidemic, there are isolated cases of the disease that are diagnosed and treated with modern medicine. (Source: Oxford Academic)

What are the Signs and Symptoms of the Disease?

The disease is characterized by the following:

  1. High Fever
  2. Sore Throat
  3. Lethargy
  4. Double Vision
  5. Delayed Physical and Mental Response
  6. Sleep Inversion
  7. Catatonia
  8. Abnormal Eye Movements
  9. Muscular Pains
  10. Tremros
  11. Neck Rigidity
  12. Psychosis

How was the Disease Transmitted?

Since no one knows the true origin of Encephalitis lethargica, it is hard to determine how it was transmitted. There have been many theories on its transmission but they were often conflicting or lacked empirical proof.

There was an incident where 12 out of 21 women from the Derby and Derbyshire Rescue and Training Home for Girls were affected with the disease. Six of them died 10 days onset. This lead the epidemiologist, Dr. Salsbury MacNalty to think that the disease was transmitted from person to person.

Cases like that of the Derby school suggested that the disease was contagious. However, this was disproven by other cases where one family member had acquired the disease, but the rest of the family did not in spite of them living in a small apartment. (Source: Oxford Academic)

What is the Modern Day Treatement for Encephalitis lethargica?

For cases that are diagnosed today, the approach to treating Encephalitis lethargica includes immunomodulating therapy and treatment for specific symptoms.

A consistent and effective treatment for the disease are in the initial stages of testing. Some patients are given a dose of steroids, and it does show some promising results. Other treatment options include the use of Levodopa and other anti-Parkinson drugs but improvements seem to be short and inconsistent. (Source: Oxford Academic)

How Many Cases of Encephalitis lethargica are Seen in Modern Times?

There have been 80 reports of Encephalitis lethargica since 1940. The diagnoses of these cases were solely based on Dr. Economo’s criteria from 1929. By 1987, Howard and Lees proposed a new criteria to diagnose the disease which included oculogyric crises. (Source: Oxford Academic)

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