Gerhard Hansen and Leprosy


Diana and I just returned from a riverboat/cycling trip with almost 400 other bicyclists from Memphis to New Orleans. We visited the National Hansen’s Disease (leprosy) Museum in Carville, Louisiana and learned about Dr. Gerhard Hansen, a Norwegian physician who discovered the bacteria that cause leprosy in 1873. This was the first bacterium to be identified as the cause of a disease in humans.

In 1856, Daniel Danielson, a Norwegian chemist, proposed that leprosy was an inherited disease. He injected himself and several of his assistants with material extracted from nodules in people who had leprosy and they did not get the disease. In 1873, Danielson’s son-in-law, Dr. Gerhard Hansen, found a bacterium in nodules of leprosy patients. He announced that since this same bacterium was found in all of the leprosy patients he examined, it was likely to be the cause of the disease. He was ridiculed by his colleagues and laughed at by doctors at his lectures. In 1879 he gave tissue samples to Albert Neisser, who successfully stained the bacteria to show that indeed the germ was in the tissues of people who had leprosy. However most doctors did not accept his brilliant discovery because he was unable to culture the bacteria in the laboratory. Thoroughly frustrated, Hansen injected the leprosy bacteria into the eye of a 33-year-old patient without telling her what he had done. Although she did not develop leprosy, she sued him and he lost his hospital appointment.

Hansen continued as a medical officer for the treatment of leprosy in Norway and was the primary driving force for Norway’s leprosy laws of 1877 and 1885. These laws were based on the idea that since leprosy was a contagious disease, rather than an inherited condition or a curse from God, patients should be isolated in a special hospital (leprosarium). The number of leprosy cases in Norway dropped from 1,800 in 1875 to just 575 cases in 1901. At that time the spectacular reduction in cases was attributed to isolation preventing the spread of leprosy, but we now know that leprosy is not very contagious. The reduction in cases had more to do with improved nutrition and sanitation for the patients, which would help to build their immunity so they could kill the bacteria (Int. J. Epidemiol. (2002; 31(5): 991-1000).

Dr. Hansen was diagnosed with syphilis in the late 1860s and in 1912, he died of heart disease that was possibly caused by his syphilis. Unknown to him, syphilis is also caused by bacteria and like leprosy, is now curable with antibiotics.

What is Leprosy?
In an infected person, the bacteria that cause leprosy spread through the nerves under the skin in the coolest parts of the body: the hands, feet, face and earlobes. The first signs of leprosy are numb, off-color patches of skin, which most doctors incorrectly diagnose as a fungus, psoriasis or lupus. Infected people then develop repeated breaks in the skin, then their feet develop sores and they lose feeling in their hands and feet. As the bacteria kill nerves, including nerves that move muscles, the muscles waste away and disappear, so fingers and toes curl into claws. Lack of movement causes bones to become so small that the fingers and toes shrink away and disappear. They do not fall off, as many people believe. The patient loses eyebrows, earlobes, and nasal cartilage. After six months, the nerve damage can become permanent. Since nothing could be done for people with leprosy before the development of antibiotics, victims lost the use of their hands and feet, and went blind as the blinking muscles degenerated and their eyes dried out.

Leprosy Is Not Very Contagious
Approximately 95 percent of the world’s population has immunity against the leprosy bacterium, so the disease does not spread easily. Lack of this natural immunity may run in families, which can make it appear that leprosy is inherited. Poor living conditions including lack of sanitation, clean water and sufficient food all contribute to impaired immunity, which explains why leprosy has always been found primarily in poorer societies.

Carville Leprosarium
In 1894, the State of Louisiana followed Norway’s example and established an isolation hospital for leprosy patients on an old sugar plantation in Carville. In 1917, the United States Senate passed Senate Bill 4086 establishing a national leprosarium, and four years later, the U.S. Public Health Service named Carville as its location. Leprosy patients were brought from all over the country and dropped at Carville’s gates. These unfortunate people were sentenced by law to be removed from their families and society. Their living conditions in Carville were often better than what the patients had come from, but they were essentially prisoners and experimental guinea pigs for the doctors who were searching for a cure.

Up to 1940, the only available treatment was oil of chaulmoogra nuts (from India), taken orally or by injection. The injections caused abscesses in the skin and oral doses caused terrible nausea and vomiting. The treatment made patients miserable and did nothing to cure their leprosy.

In the 1940s, doctors at Carville developed successful antibiotic treatments that changed the lives of their patients. First they used promin, but as is common with all antibiotics, the bacterium quickly became resistant to it. Then they found that dapsone was highly effective, and to help overcome the problem of resistance they moved to combinations of three drugs, usually clofazimine, rifampicin, and dapsone given for at least a year.

Life at Carville
Diaries, books and articles by former Carville residents describe their life there:
* They were told to adopt a new name so their family and friends would not be shunned
* They could not leave the grounds, which were surrounded by barbed wire fencing
* They were not allowed to marry, or if already married, they could not live with their non-infected spouse
* They could not vote
* All mail had to be sterilized by steaming, which often made it unreadable
* They could not use telephones or send emergency messages
* They were given untested drugs and were not told anything about the experiments or drugs
* Males and females were kept apart and not allowed to fraternize
When they died, most of the residents were buried in the leprosarium’s graveyard with a headstone that contained only their case number or a false name. Very few families came to claim the body for burial at home.

By 1945, the US Public Health Service advised against isolating people with leprosy because those with the disease were being cured with antibiotics, and most people have a natural immunity that will never allow them to develop leprosy. In 1948, Carville’s doctors had the name of the disease officially changed to Hansen’s Disease, partly to honor the discoverer of the bacterium but primarily to help patients avoid the stigma of the words “leprosy” and “leper”.

In 1960, the term “detention” was removed from the Federal Code of Regulations on leprosy. In 1985, Congress passed PL99-117 that mandated that the Public Health service provide treatment without isolation from society. By the 1990s Carville had only a few residents left and the grounds were converted to a military installation. The hospital buildings were placed on the National Register of Historic Places with a museum to honor the patients and staff. In North America today, leprosy is a rare disease that is curable and if the diagnosis is made early enough, patients suffer no permanent disabilities.

Leprosy and the Armadillo
Doctors at Carville had trouble testing drugs and trying to develop a vaccine because the leprosy bacteria could not be grown in petri dishes and was difficult to grow in animals. They noted that leprosy invades only the cooler parts of the human body, growing only in the nerves near the surface of the skin. In the 1970s, they found an animal that has leprosy in the wild: the homely armadillo. This armored mammal, found throughout the southeastern states, has a body temperature of 93 F while human’s body temperature averages 98.6 F. The doctors were able to transmit leprosy to armadillos who were not already infected and use them to test potential treatments and prevention.

Today, of about 200 new cases of Hansen’s Disease in the U.S. each year, researchers estimate that about one third are caught from contact with wild armadillos. They are often hunted and even eaten, and a susceptible person (lacking natural immunity) can acquire leprosy through an open cut or other contact with the infected armadillo’s blood. If the person has not had contact with an armadillo, the infection can usually be traced to travel overseas in countries that still have higher rates of leprosy.

Early Diagnosis
Now that there is a cure for Hansen’s Disease, early diagnosis is critical because once nerve damage occurs the patient can suffer permanent disability even after he has been cured. The first symptom of leprosy is usually loss of feeling in the skin. The most common cause of loss of feeling in the skin is diabetes. Today, doctors can rule out leprosy with a drop of blood, a test strip and a smartphone with a test strip reader, and get results in less than 10 minutes. This test was developed by Malcolm S. Duthie at the Infectious Disease Research Institute in Seattle. It can detect infections a year before symptoms appear.

Eradicating Hansen’s Disease
Hansen’s disease is rare in North America today, but worldwide there are more than 200,000 new cases each year, with 50 percent occurring in India. The World Health Organization has an active campaign to get free drugs to patients around the world, yet every two minutes, a new case is diagnosed. Even though it is curable, children, men and women are still being crippled by this terrible disease.

Gerhard Hansen
July 29, 1841-February 12, 1912

Leprosy or Hansen’s Disease