From 1916 until the late 1920s, the world was plagued by a mysterious disease, even more terrifying than the Spanish flu.
Patients suffered from worsening health conditions. They experienced pain, lost control over their eye movements, and could not swallow. As their condition deteriorated, they became prisoners in their own bodies, falling into a coma for decades. They were called “the living dead,” and children who recovered often transformed into “little monsters.”
A century later, this disease has almost been forgotten. This article briefly explores the terrifying "living dead" disease.
Constantin von Economo
During the chaos of World War I, Dr. Constantin von Economo, working at the Vienna University Clinic for Psychiatry and Neurology, noticed a strange pattern. He documented his findings in the article “Die Encephalitis lethargica” and later expanded on them in the monograph “Encephalitis lethargica. Its sequelae and treatment.”
In the autumn of 1916, hospitals began admitting patients with various diagnoses such as meningitis, multiple sclerosis, and delirium. However, none of these cases fully matched known disease patterns, and many symptoms remained unexplained.
The most terrifying and mysterious symptom of this disease was lethargy—a state of deep sleep that struck patients unexpectedly, even while walking or having dinner. Families were horrified as their loved ones slipped into an unresponsive state. Although they could sometimes wake them momentarily, they soon returned to their stupor.
The Epidemic of Economo’s Lethargic Encephalitis
Doctors across Europe began identifying this unknown disease, which differed from anything previously seen. French doctors Calmette, Cruchet, and Moutier also reported similar cases.
By 1917, the mysterious illness was named encephalitis lethargica, or sleepy sickness. However, its cause and treatment remained unknown—a mystery that still persists today.
Spread and Symptoms of the Disease
The first known cases were recorded in 1915 in Romania, and by 1916, the disease had spread across Europe due to wartime troop movements. It later reached France, the United Kingdom, and the United States. The epidemic peaked between 1920 and 1924, affecting hundreds of thousands of people.
The early symptoms of lethargic encephalitis resembled influenza: sore throat, headaches, dizziness, chills, and nausea. However, as the disease progressed, the symptoms worsened dramatically.
In 1921, American physician H.F. Smith documented common symptoms:
- Vision impairment
- Eye paralysis (inability to move the eyes normally)
- Speech difficulties
- Dysphagia (difficulty swallowing)
- Asthenia (severe weakness)
- Mild fever
- Chronic constipation
- Urinary incontinence
- A vacant facial expression and extreme lethargy, often leading to a deep coma
Day by day, the patients' conditions worsened, causing extreme fear and helplessness among families. Some could not swallow food, while others vomited or had food return through their noses, leading to death by starvation.
Some lost control of their facial muscles, resulting in grotesque expressions. Others could not move their eyeballs or look in certain directions. Many suffered from horrifying hallucinations. Patients who entered a lethargic state (sleeping for one to two weeks) and then fell into a coma rarely woke up again.
Reports indicate that out of 11 recorded cases of Economo’s lethargic encephalitis, 4 were fatal. Although the exact number of cases is unknown, the disease had a mortality rate of approximately 40%, killing more than 500,000 people at its peak after 1916.
Some patients developed akinetic mutism—they could keep their eyes open, follow objects, and respond with a few syllables but were otherwise trapped in their bodies, unable to communicate or move for the rest of their lives.
The "Little Monsters" Disease
Lethargic encephalitis most commonly affected people aged 10 to 20, but children suffered the most severe consequences. Although many recovered physically, the disease altered their brain function permanently.
Historical records describe children who were once kind and cheerful but became aggressive and violent after the illness.
According to Jennifer Wright’s book "What Doesn’t Kill Us":
“Some children who were completely calm before the disease later smeared themselves with excrement and became extremely aggressive. Others tried to kill their siblings. Some attempted to rape or harm other children. One child even tried to bite off another boy’s genitals. In 1928, a former patient pulled out all their teeth and gouged out their own eyes.”
The most disturbing aspect was that these children understood their destructive behavior but could not control it. Unlike psychopaths, who feel no remorse, these patients were horrified by their actions. Some begged to be locked away because they couldn’t restrain their impulses.
Possible Causes of the Disease
The exact cause of lethargic encephalitis remains unknown, but researchers hypothesize it was an autoimmune disease. Many scientists suspect it was linked to a streptococcal infection.
This theory is supported by research from the Department of Neurology at a Berlin Medical University, which found that bacteria first attacked the throat, triggering an immune response that mistakenly attacked the brain, leading to brain inflammation.
People who survived the coma often developed permanent neurological disorders such as Parkinson’s disease and catatonia.
Although streptococcal infection is the most likely cause, Economo’s lethargic encephalitis remains one of the greatest medical mysteries of all time.
