1919–1930 Encephalitis Lethargica Epidemic
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encephalitis lethargica Encephalitis lethargica (EL) is an atypical form of encephalitis. Also known as "von Economo Encephalitis", "sleeping sickness" or "sleepy sickness" (distinct from tsetse fly–transmitted sleeping sickness), it was first described in 1917 by ne ...
epidemic lasted from around 1918 to 1930. The cause is still unknown. Though the cause was once attributed to the coinciding
Spanish flu epidemic The 1918–1920 flu pandemic, also known as the Great Influenza epidemic or by the common misnomer Spanish flu, was an exceptionally deadly global influenza pandemic caused by the H1N1 subtype of the influenza A virus. The earliest document ...
, modern research has disputed this claim. The mortality was as high as 20%. The epidemic is thought to have started in
Romania Romania is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to ...
during 1915, and the disease supposedly spread through the movement of the various troops during
World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
. In 1917, it reached the
epidemic An epidemic (from Greek ἐπί ''epi'' "upon or above" and δῆμος ''demos'' "people") is the rapid spread of disease to a large number of hosts in a given population within a short period of time. For example, in meningococcal infection ...
status in
Vienna Vienna ( ; ; ) is the capital city, capital, List of largest cities in Austria, most populous city, and one of Federal states of Austria, nine federal states of Austria. It is Austria's primate city, with just over two million inhabitants. ...
, where it was first described. Disease outbreaks of encephalitis were first reported in England and France during 1918, followed by Canada,
Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...
, India, and the United States in 1919. Disease outbreaks were also reported in Germany and the
Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...
during 1920. The epidemic peaked between 1920 and 1929, with an estimated one million people diagnosed with encephalitis lethargica during the epidemic period. The disease suddenly disappeared in the beginning of the 1930s. In the aftermath of the epidemic, many cases of post-encephalitic parkinsonism were reported. This condition was distinctive from idiopathic Parkinson's disease, as it occurs in younger patients than typical idiopathic Parkinson's disease, and lacks the "pill-rolling tremor" of idiopathic Parkinson's disease.


Background

Encephalitis lethargica Encephalitis lethargica (EL) is an atypical form of encephalitis. Also known as "von Economo Encephalitis", "sleeping sickness" or "sleepy sickness" (distinct from tsetse fly–transmitted sleeping sickness), it was first described in 1917 by ne ...
is a neurological syndrome that causes lethargy, a "mask like" face, excessive blood in the meninges, and other general neurological symptoms. Officially recognized as its own condition in 1917, it is believed to have existed far longer in human history. It is known to cause
post-encephalitic parkinsonism Post-encephalitic parkinsonism is a disease believed to be caused by a viral illness that triggers degeneration of the nerve cells in the substantia nigra. Overall, this degeneration leads to clinical parkinsonism. Historically, starting in 1917 a ...
.


Timeline

According to Urechia (1921), the pandemic possibly started in 1915, Romania. It is believed that the disease spread through the movement of the troops during
World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
. In 1917, it reached the
epidemic An epidemic (from Greek ἐπί ''epi'' "upon or above" and δῆμος ''demos'' "people") is the rapid spread of disease to a large number of hosts in a given population within a short period of time. For example, in meningococcal infection ...
status in
Vienna Vienna ( ; ; ) is the capital city, capital, List of largest cities in Austria, most populous city, and one of Federal states of Austria, nine federal states of Austria. It is Austria's primate city, with just over two million inhabitants. ...
, where it was first described. It was followed by France and England in 1918. In 1919, the disease was present in
Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
, the US,
Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
,
Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...
, and
India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
. In 1920, the disease was present in the
Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...
and
Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
. Neurologist
Constantin von Economo Constantin Freiherr von Economo (; 21 August 1876 – 21 October 1931) was an Austrian psychiatrist and neurologist of Romanian origin. He is mostly known for his discovery of encephalitis lethargica and his atlas of cytoarchitectonics of ...
published a paper in April 1917 on six cases he encountered in the winter months of 1916 and 1917 in the Psychiatric-Neurological Clinic of the
University of Vienna The University of Vienna (, ) is a public university, public research university in Vienna, Austria. Founded by Rudolf IV, Duke of Austria, Duke Rudolph IV in 1365, it is the oldest university in the German-speaking world and among the largest ...
. These patients, despite their various previous diagnoses, had a similar pattern of symptoms. This led him to suggest a novel disease, which he named Encephalitis lethargica. In France, physician René Cruchet was encountering similar patterns, and published his findings within a few days of Constantin von Economo. Following these two reports, many more cases were reported, first in Europe, but quickly spreading around the globe. Reviews from both works considers Economo as the first to describe the disease, while Cruchet reported a group of heterogeneous conditions. Initially, ''encephalitis lethargica'' main symptoms were described as
somnolence Somnolence (alternatively sleepiness or drowsiness) is a state of strong desire for sleep, or sleeping for unusually long periods (compare hypersomnia). It has distinct meanings and causes. It can refer to the usual state preceding falling aslee ...
and
lethargy Lethargy is a state of tiredness, sleepiness, weariness, fatigue, sluggishness, or lack of energy. It can be accompanied by depression, decreased motivation, or apathy. Lethargy can be a normal response to inadequate sleep, overexertion, overw ...
, but after 1919 cases of
insomnia Insomnia, also known as sleeplessness, is a sleep disorder where people have difficulty sleeping. They may have difficulty falling asleep, or staying asleep for as long as desired. Insomnia is typically followed by daytime sleepiness, low ene ...
and
hyperkinesia Hyperkinesia refers to an increase in muscular activity that can result in excessive abnormal movements, excessive normal movements, or a combination of both. Hyperkinesia is a state of excessive restlessness which is featured in a large variet ...
appeared. Economo also described
hiccup A hiccup (scientific name singultus, from Latin for "sob, hiccup"; also spelled hiccough) is an spasm, involuntary contraction (myoclonic jerk) of the diaphragm (anatomy), diaphragm that may repeat several times per minute. The hiccup is an in ...
s as a symptom, which was later linked to the hyperkinetic–insomniac variety of ''encephalitis lethargica'', but no case between 1920 and 1930 showed this symptom.
Endocrine The endocrine system is a messenger system in an organism comprising feedback loops of hormones that are released by internal glands directly into the circulatory system and that target and regulate distant organs. In vertebrates, the hypotha ...
symptoms, such as
diabetes Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or the cells of th ...
, were only present in cases described between 1922 and 1923. Following von Economo description of the disease, many speculated that it had the same cause as the
Spanish flu The 1918–1920 flu pandemic, also known as the Great Influenza epidemic or by the common misnomer Spanish flu, was an exceptionally deadly global influenza pandemic caused by the H1N1 subtype of the influenza A virus. The earliest docum ...
. Many poorly conducted experiments pointed to that hypothesis, but in 1923
Simon Flexner Simon Flexner (March 25, 1863 – May 2, 1946) was a physician, scientist, administrator, and professor of experimental pathology at the University of Pennsylvania (1899–1903). He served as the first director of the Rockefeller Institute for ...
highlighted the problems with the investigations. William Matheson founded the Matheson Commission in 1927, promising to find a cure to encephalitis lethargica within two years. They worked with two main hypothesis, that encephalitis lethargica was a form of
herpes Herpes simplex, often known simply as herpes, is a viral infection caused by the herpes simplex virus. Herpes infections are categorized by the area of the body that is infected. The two major types of herpes are oral herpes and genital herp ...
or it was a focal infection resulting from a neurotropic form of ''
Streptococcus viridans The viridans streptococci are a large group of commensal streptococcal Gram-positive bacteria species that are α-hemolytic, producing a green coloration on blood agar plates (hence the name "viridans", from Latin "vĭrĭdis", green), although ...
''. The commission ended in 1940 without finding the cure, but it produced data about the disease. The epidemic peaked between 1920 and 1929, with an estimated million people diagnosed with encephalitis lethargica during the epidemic period. In the beginning of 1930s, the disease suddenly disappeared, and the attention of the medical community changed to more pressing matters. During the pandemic, approximately 9000 papers about encephalitis lethargica were published.


Causes

The causes of encephalitis lethargica are still unknown. Though the connection to the Spanish flu epidemic is often made, the encephalitis outbreak did begin slightly earlier. However, this cannot disprove the claim, simply point out that not all of the existing evidence lines up.


Aftermath

In the aftermath of the epidemic, many cases of post-encephalitic parkinsonism were reported. This condition was distinctive from idiopathic Parkinson's disease, as it occurs in younger patients than typical idiopathic Parkinson's disease, and lacks the "pill-rolling tremor" of idiopathic Parkinson's disease. The number of people infected varies greatly, from a thousand to a million. The estimate mortality varies between 15% and 40%. It is estimated that 50–75% of cases went unreported. At the same time, there happened
overdiagnosis Overdiagnosis is the diagnosis of disease that will never cause symptoms or death during a patient's ordinarily expected lifetime and thus presents no practical threat regardless of being pathologic. Overdiagnosis is a side effect of screening ...
due the description of generic symptoms and lack of established diagnostic criteria.


Popular culture


Books

* Crosby, Molly Caldwell: ''Asleep: the Forgotten Epidemic That Remains One of Medicine's Greatest Mysteries'' (2010)


Other works

Both ''Sandman''
comic books A comic book, comic-magazine, or simply comic is a publication that consists of comics art in the form of sequential juxtaposed panel (comics), panels that represent individual scenes. Panels are often accompanied by descriptive prose and wri ...
and
series Series may refer to: People with the name * Caroline Series (born 1951), English mathematician, daughter of George Series * George Series (1920–1995), English physicist Arts, entertainment, and media Music * Series, the ordered sets used i ...
depict the epidemic. In the story,
Dream A dream is a succession of images, ideas, emotions, and sensation (psychology), sensations that usually occur involuntarily in the mind during certain stages of sleep. Humans spend about two hours dreaming per night, and each dream lasts around ...
is locked against his will, thus causing his realm to collapse and the epidemic to start.


References

{{DEFAULTSORT:1919-1930 encephalitis lethargica epidemic 1919 disease outbreaks 1930 disease outbreaks 1910s epidemics 1920s epidemics 1930s epidemics Encephalitis Pandemics Disease outbreaks in Romania