Leprosy: Humanity’s Oldest Disease

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Podcast Transcript

For thousands of years, one of the most terrifying and destructive diseases which afflicted humanity has been leprosy. 

Leprosy is a condition that affects the nerves and skin, and in extreme cases, it can result in the loss of appendages. 

Those who were diagnosed with leprosy would often be consigned to a lifetime of social ostracism. Thankfully, that is no longer the case.

Learn more about leprosy, aka Hansens Disease, its past and its future, on this episode of Everything Everywhere Daily.


Leprosy has been considered by many to be the oldest communicable disease in human history. 

It is impossible to know what the first disease actually was as it would have manifested before written history. It could have been something like tuberculous, but we do have genetic evidence for leprosy, possibly dating back 10,000,000 years, which may have affected early hominid ancestors.

Genetic analysis shows that leprosy probably originated somewhere in East Africa or the Middle East. 

Leprosy is caused by a bacteria known as Mycobacterium leprae. It is almost exclusively spread through human-to-human contact. 

Leprosy spread as humans began to migrate and trade with other civilizations.  As humans left Africa, they took the leprosy bacteria with them, and it spread as they slowly traveled across the globe. 

If people know anything about leprosy, it is the horrific symptoms that manifest in those that suffer from it.  Leprosy affects the skin and the nervous system outside of the brain and spinal cord. 

The bacteria can have an incubation period that lasts anywhere from months to 20 years. Early symptoms usually consist of a skin rash for which the sufferer has no feeling. 

As the disease spreads, it can result in an inability to feel pain, which can result in unintended injuries. 

It also can result in the absorption of cartilage into tissue, particularly in the nose. 

As the disease spreads, it can result in severe skin disfiguration, hair loss, and blindness. 

Many of the most extreme symptoms, such as the loss of fingers and toes, often do not result from leprosy directly but rather from secondary infections which develop or from the development of gangrene, which may require amputation.

Because of the disfiguring symptoms of leprosy, the social response to the disease has always been harsh and severe. 

The historical accounts of leprosy date back about 2,500 years.

There are several mentions of leprosy in the old testament. 

The Book of Numbers Chapter 5, verse 2 says: 

“Command the sons of Israel that they send away from the camp every leper and everyone having a discharge and everyone who is unclean because of a dead person.”

The Book Deuteronomy Chapter 24: verse 8 says:

“Be careful against an infection of leprosy, that you diligently observe and do according to all that the Levitical priests teach you; as I have commanded them, so you shall be careful to do.”

The Hebrew holy texts are far from the only ancient mentions of leprosy. 

In the New Testament, Jesus was said to have cured a leper. That story is repeated in the Koran. 

The Indian Vedas mention leprosy and proscribe the oil from the chaulmoogra tree as a cure. 

The great historical Sri Lankan text, the Mah?va?sa, notes that the ancestors of the Buddha suffered from leprosy and had to go live in the woods. 

The Chinese book, Feng Zhen Shi, written 2,200 years ago, outlines the symptoms of leprosy, including the destruction of the nasal septum. 

The Roman historian Herodotus spoke of the Persian practice of shunning lepers. 

Greek and Roman doctors believed that the disease was transferred by the troops of Alexander the Great, who brought it back with them from Persia and India. The Greeks and Romans called the disease elephantiasis.

In Egypt, the disease was believed to have come up the Nile from Nubia, and it afflicted several pharaohs. 

Basically, every ancient culture, at least in the old world, had leprosy as a disease in their population. 

Their reaction to leprosy was the same in most cultures. The disease had a severe negative social stigma. Lepers were usually shunned and forced to live apart from the rest of society to prevent transmission of the disease. 

In India, lepers were considered untouchable outcasts. 

In the middle ages in Europe, lepers would often have to wear bells to let people know when they were nearby.

The ostracization of lepers from society eventually began to be more formalized. 

One of the first things to be established was leper houses. Leper houses run by monastic orders were documented in the 5th, 6th, and 7th centuries. 

By the start of the Crusades in the 11th century, there were over 700 leper houses in Belgium alone. 

During the Crusades, the Order of Saint Lazarus, the patron saint of lepers, was established to care for lepers in the Holy Land and throughout Europe.

One of the most notable cases of leprosy was King Baldwin IV of Jerusalem, who was king of one of the crusader states. He had leprosy, and his story, in part, was told in the 2005 Ridley Scott film Kingdom of Heaven.

(FYI, it is a good movie, but really make sure you watch the director’s cut. They butchered the theatrical release.)

Eventually, the separation of people with leprosy was taken beyond separate houses to the establishment of entirely separate communities, or as they became known, leper colonies. 

The first leper colony is believed to have been created in Harbledown, England, in 1085. 

Eventually, leper colonies were established in most countries. They were usually established far away from population centers, and they solved the problem of what to do with people who suffered from the disease. 

Colonies allowed people with leprosy to live somewhat normal lives without dealing with the stigma of having the disease from the general population. It also provided a way to limit the transmission of the disease. 

One major problem was that people who had skin conditions like psoriasis were often misdiagnosed with leprosy and sent to these colonies, where they would later actually come down with the disease. 

Leprosy didn’t exist in the New World until the arrival of Europeans, who brought the disease with them, along with many, many others. 

In the 19th century, the United States established several colonies for the entire country. One was Penikese Island in Massachuttes, and another one was the Carville National Leprosarium in Louisiana. 

However, the best-known and largest leper colony was established on the north shore of the island of Molokai in Hawaii in 1866, Kalaupapa.

Kalaupapa was extremely isolated and hard to reach. For starters, the Hawaiian islands were just very hard to reach in the 19th century. Second, Molokai is one of the lesser populated islands and still is today. 

Finally, even if you could make it to Molokai, Kalaupapa was located on the north shore on a peninsula surrounded by some of the largest sea cliffs in the world. The only way there was via donkey on a very treacherous, winding trail. 

The colony was established by King Kamehameha V before Hawaii was part of the United States.

At its peak, the colony had 1,200 people living there. While the colony offered a reasonable life for its people, in some ways, it was also a prison. The people who were sent there were guaranteed a home and a place to live for life, but they also could never leave.

Even when their family members visited, they could only talk to them through a fence. 

The settlement became associated with Father Damien, a Belgian priest who went to live there in 1873 and eventually succumbed to the disease himself in 1889. He was canonized as a saint by the Catholic Church in 2009.

Believe it or not, Kalaupapa still exists today, although there are only a handful of elderly people who still live there. The current residents were brought there as children and promised a home for life, and now they have no desire to leave.

It also happens to be its own county in Hawaii, Kalawao County. It is the smallest county in the United States by area and with only 82 people, the seconds smallest by population.

The thing which forever changed leprosy and the diagnosis for those who suffered from it occurred in 1873. The Norwegian doctor Armauer Hansen identified the bacteria which caused leprosy.  The disease was subsequently officially renamed Hansens Disease in his honor.

It was the first time in history that bacteria was identified as the cause of a disease. 

This wasn’t just a breakthrough in the treatment of leprosy. If you remember back to previous episodes about Ignaz Semmelweis and John Snow, prior to the germ theory of disease, no one was really sure what caused illnesses. 

Having identified a particular bacteria which caused a particular disease was groundbreaking and opened the door to a better understanding of the disease.

The next big breakthrough was in 1940, with the development of an antibacterial medication that could be used to treat the disease. 

The drug which was developed was Promin. 

Other antibiotics were developed, which were used in the treatment of leprosy. Dapsone was introduced in the 1950s with clo-faz-i-mine and rif-amp-in in the 60s and 70s. 

An Indian researcher named Shantaram Yawalkar developed a three-drug treatment in the 1970s, which is still largely used today.

The result of these antibiotic treatments has been the gradual disappearance of leprosy. 

Despite being one of the oldest diseases in human history, it turned out that leprosy was rather easy to cure as diseases go. 

For starters, we learned that 95% of the population has a natural immunity to leprosy, which is why there was never a leprosy epidemic in history. 

Also, the bacteria can’t survive for more than an hour outside of its host. 

Today there are about 200,000 people in the world who have leprosy, and about half of them are in the nation of India. Everyone who suffers from the disease is given free treatment by the World Health Organization and is able to keep the disease under control. 

A full treatment can usually be completed in about one to two years.

As leprosy is transmitted from person to person, there has for several decades been a goal to completely eradicate the disease, just as we did with smallpox.

In 1991 a goal was set to eradicate the disease in the year 2000, but it wasn’t achieved. In fact, leprosy rates have remained low by stable since then. 

One of the things which will help the long-term eradication of the disease will be the increase in living standards in India, which is the country with the highest number of cases. It was this, not the introduction of antibiotics, which saw the biggest reduction in the disease in Europe. 

I should end by noting that while the transmission of the disease is almost exclusively from human to human, it turns out there is another animal that can carry the disease: armadillos. 

At some point, since Europeans brought leprosy to the new world, the disease spread to armadillos. This is actually a concern that armadillos might prevent the eradication of leprosy….unless we can also eradicate it in armadillos as well. 

Leprosy has plagued humanity for thousands of years.  Thanks to advances in antibiotics, it has finally become a disease that can be managed and even cured. 

Hopefully, sometime in the not-so-distant future, this ancient disease will be relegated to the dustbin of history.


The Executive Producer of Everything Everywhere Daily is Charles Daniel.

The associate producers are Thor Thomsen and Peter Bennett.

Today’s review comes from listener TheBarelyBelowAveragePodcast from Apple Podcasts in the United States. They write

My favorite.

I was recommended this podcast by a family fries one day. I decided to give it a try and loved it Instantly. I am currently starting from episode one and working my way to the present. Sitting around 250 episodes in, I can confidently say it is my favorite podcast I have found thus far. As a Native Yooper and a current Brown County resident, the connection was made instantly. Thanks, Gary. Keep ‘em coming!

Thanks, TheBarelyBelowAverage!  I appreciate the comments. However, I think I might have to translate your review for everyone else. 

A Yooper is someone who hails from the UP, and UP stands for Upper Peninsula, which is the northernmost of the two peninsulas of the state of Michigan.  The UP isn’t actually connected to the rest of Michigan, but it is connected to Wisconsin and, by all rights, should be a part of Wisconsin, but it isn’t. The region is known for its Cornish pasties and extreme amounts of snow.

Brown County is the location of the City of Green Bay, the home of the 13x NFL champion Green Bay Packers, who this last season pulled ahead of the Chicago Bears to be the all-time NFL leader in franchise wins. 

Remember, if you leave a review or send me a boostagram, you too can have it read on the show.