Wednesday, September 10, 2014

Shunning the Lepers

To people in Western societies leprosy is usually the punchline of a joke.  To us leprosy is now rare and fairly treatable, although interestingly around 200 people a year are still diagnosed in the USA.

However Leprosy still affects around 180, 000 people worldwide acutely, with up to a million suffering chronic complications most of them in Africa and Asia. It is a disease that has only been controlled in very recent history, mainly due to increased hygiene practices.  Prior to that it has been something that has stalked humanity for almost all of known history.

The earliest recorded account of a disease resembling leprosy appears in an Egyptian papyrus document in 1550 BC. Indian writings also mention a similar illness in 600 BC.  It appears that the army of Alexander the Great may have brought leprosy back from India with them - as accounts of it appeared in their writings around this time.  Similarly it began to be recorded by the Romans around 62 BC when Pompeii's soldiers came back from Asia minor.

Leprosy is a disease that primarily affects the nerves and the upper respiratory tract.  Lesions are formed on the nerves that cause the typical disfiguring skin lesions.  Chronic damage to nerves eventually results in numbness, typically starting at the ends of nerves and moving upwards, so fingers, toes, noses etc.  Contrary to folklore patients with leprosy don't have parts fall off.  Instead generally due to the numbness patients become more susceptible to infection and injury, leading to deformity and tissue loss.

 Bones of the hands of two lepers 1895 - Wellcome images

Leprosy is transmitted by droplet spread but is not very contagious.  It has a long incubation period - usually of between 3 and 5 years, but sometimes up to 20 years.  Of course this meant that until science found an answer, a leper seemed to appear out of nowhere.  Which meant that the myths surrounding leprosy were many.

Shunning and seperation has been the most common way to deal with lepers throughout history.  Isolated leper colonys and leper asylums, known as leperosriums were often mandated by force once leprosy was detected.   In medieval Europe leper hospitals were often run by religious orders who saw leprosy as a punishment from God and therefore that by caring for it a form of penance.  If lepers were not forced to isolate and quarantine they were often made to wear bells or use clappers to worn of their approach and walk on certain sides of the road depending on the direction of the wind - so the potential miasma of their illness could not blow across and affect others.

 Leper clapper - from the Wellcome collection

I'd like to say that leper colonies are a thing of the past - but in the remotes of China 'Recovery Villages' still exist - where you guessed it, patients were sent by force and are still living in quite appalling conditions.  

Various treatments were used with limited success.  We have previously heard of the unfortunate soul and his bandages dipped in brandy.  Other treatments; arsenic, mercury, elephants teeth, snake venom, bees stings, scarification, castration, blood as a beverage or a bath, chaulmoogra oil and prayer.  None were particularly efficacious.

In 1873 Norwegian Dr. Gerhard Hansen discovered that leprosy was caused by a bacteria called mycobacterium leprae, hence the reason leprosy is often also known as Hansen's disease.  This is also, interestingly enough, the first bacteria to be identified as causing disease in humans and was three years prior to Robert Koch's definitive study. 

It was also fairly murky science.  Hansen discovered the rod like structures in tissue samples, although did not realise they were bacteria until some years later.  That work was done by another scientist, Neisser, who then tried to steal credit for Hansen's discovery.  Hansen successfully managed to defend his position.  However the conflict between the two scientist continued for the rest of their lives.

Mycobacteria, then, as now, are difficult to culture.  Hansen was also unable to infect rabbits.  He wanted to prove his organisms caused leprosy.  So he decided to infect a woman by inoculating her eye.  However - he didn't ask her permission first.  Fortunately the patient didn't suffer any clinical consequences.  She did, however, state she suffered pain and vision problems and took Hansen to court.  He lost the case and his position at the hospital and never did any research again until his death from syphilis.  (Unlike Neisser who went on to discover the bacteria that causes gonorrheoa - which we love here at medical history).

Knowing that leprosy had an infectious cause, treatment finally became possible.  However this took until 1908 with the arrival of promin.  Sulfones were first synthesised by Fromm and Wittmann.  The medical value of the compounds were not investigated until the 1940s when the anti-bacterial nature of sulfonamides were found.  Promin was not terribly good at most infections - but seemed to work quite well on mycobacterial infections such as leprosy and tuberculosis.  Promin which had to be injected was eventually superseded by it's much simpler tablet form, dapsone.

With treatment available stigma around leprosy finally began to reduce and today it is curable although as with many other diseases, it is threatened by antibiotic resistance.  Some strains are beginning to show resistance to dapsone.  Today the World Health Organisation recommends a multi drug treatment for up to a year.

Efforts are being made to develop a vaccine - although they progress slowly because this is not a disease people know much about.

If it is something that you are interested in however:

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