1Encephalitis Lethargica aka Sleepy Sickness Epidemic 1915-1926
Around the same time of the deadly Spanish Influenza (1918-1920), there was another rampant illness that many have forgotten about. It was called Encephalitis Lethargica, which at its peak killed a million people and left millions of others paralyzed in their bodies. While it was dubbed the “sleepy sickness,” it had a variety of symptoms including sore throat and seizures. Eventually, the infected person would end up in a coma or dead as it had a 40% mortality rate. But then, as mysteriously as it appeared, the epidemic ended in 1926. It is still not known what caused it and it has no cure.
2Sleeping Sickness in Kazakhstan 2013-?
In the tiny town of Kalachi, Kazakhstan, up to one-quarter of its residents have been coming down with a sleeping sickness unrelated to Encephalitis. The illness began appearing in 2013, causing people to fall asleep for days at a time and then wake up with nausea, headaches, or memory loss. Over 20,000 tests have been conducted on the air, water, food, and people of the area, but so far there are no answers. As of 2015, 152 cases have been reported.
3Dancing Epidemic of 1518
In July 1518, a strange dancing epidemic attacked the town of Strasbourg, now a part of France. It began with a woman named Frau Troffea, who began dancing in the streets for no reason (and with no music). Within a week, 34 others had joined in and by August there were 400. At first, musicians were brought in to facilitate the dancing, but when people's feet were bloodied and they began to die of heart attacks, they were moved to a mountaintop where they prayed for help. Eventually, most recovered.
At the time, the dancing was attributed to a curse placed by St. Vitus, but modern historians attribute it to mass hysteria/psychosis due to stress.
4The June Bug Epidemic
In 1962, a woman working at a textile mill in the southern United States suddenly developed a rash and fever, claiming to have been bitten by a June bug. Within days, there were dozens of others in the same department also exhibiting similar symptoms, and many were hospitalized even though they had not been bitten. The factory was evacuated, but only two insects were found, and there were no hazardous chemicals on the premises that could cause such a reaction. It was later determined to be stress-induced mass hysteria.
Here's a disease/epidemic that doesn't fit neatly into hysteria, yet its cause is still unknown. There is some debate as to whether it is a disease at all.
It's called Morgellons, named by Mary Leito, a biologist at the University of Massachusetts Boston. Although it seems to affect primarily middle-aged white women, it was Mary's son who complained of feeling bugs under his skin, prompting her own investigation which led to the naming of the disease. Since then, tens of thousands of other people from around the world have claimed to have Morgellons, including singer Joni Mitchell. Symptoms range from itching or burning sensations, memory loss, and tiny fibers on the skin. However, an investigation by the CDC found most of these fibers to be cotton from bandages and found no virus or environmental causes, postulating that it may be a mental illness. Still, many people believe Morgellons is a physical condition and doctors are still trying to fully understand it.
6Tanganyika Laughter Epidemic of 1962
On January 30, 1962, in the new nation of Tanganyika (now part of Tanzania) three young girls laughed at a joke. However, instead of the laughter dying down after a few minutes, it spread throughout the school, affecting 60% of the students. It even expanded through the region.
While it has been reported that people of the town laughed continuously for a year, that is not true. There were spurts of laughter, as well as tears, fainting, and rashes. Several schools were forced to close down, and it was said to have affected a thousand people. While this is thought to be another example of Mass Psychogenic Illness (MPI), the laughter only affected children and is the only known instance of this type of epidemic.
This unusual epidemic currently affects children in Africa, which also first appeared in Tanzania. Nodding Disease is a condition where children between 5-15 suddenly drop their head forward and/or have convulsions, often when starting to eat. This leads to injuries from falling as well as mental retardation. One researcher noticed, however, that children with the disease do not start nodding when eating an unfamiliar food, like chocolate. Nodding Disease is said to currently affect 3,000 children in the region, and there is no identified cause or cure.
8LeRoy Twitching Epidemic
In 2013, an epidemic of involuntary twitching took over a high school in LeRoy, a suburb 50 miles east of Buffalo, NY. It started when a cheerleader named Katie Krautwurst woke from a nap and began jerking so uncontrollably she bruised her face with her cell phone. Then it spread to her best friend, and to other honor students, mostly girls, in the small school of 600. As the story went viral, some of the children appeared on national television talking about their symptoms. It was first thought to be chemical poisoning. However, it turned out to be conversion disorder, where a small group of people unconsciously mimic the behavior of their peers. The condition was aggravated by social media – those that didn't post their symptoms to YouTube or appear or on TV recovered much faster than those that did.