What is Leprosy?
Leprosy (now also known as Hansen's disease) is a chronic (long-lasting) infectious disease caused by an organism called Mycobacterium leprae. This bacterium is sometimes referred to as Hansen's bacillus and is similar to the bacterium that causes tuberculosis (TB).
Leprosy affects thousands of people throughout the world, mostly in the less developed countries. In 2011 the top 10 countries in new case detection were India, Brazil, Indonesia, Bangladesh, Democratic Republic of Congo, Nepal, Myanmar, Sri Lanka, Nigeria and Sudan.
The number of people with leprosy has decreased dramatically over the past 20 years, following a World Health Organisation (WHO) campaign to eradicate the disease. In 1985 the global registered prevalence of leprosy was 5.2 million compared with 189,018 at the end of 2012. During 2012, there were 232,857 new cases reported.
Historically, people infected with leprosy were isolated in leper colonies. Today, leprosy can be treated effectively with drug therapies and isolating patients with the disease is not necessary.
What are the symptoms of leprosy?
The bacteria that cause leprosy live in the tissues of the skin and the upper respiratory tract, in particular the lining of the nose. The bacteria multiply very slowly and it may take up to 20 years for symptoms to appear. Early symptoms may include a non-itchy rash or a bloodstained discharge from the nose. In addition, skin lesions and muscle weakness may develop.
The bacteria slowly accumulate in the main nerves of the face and limbs causing them to become inflamed. This inflammation gradually destroys the nerve fibres, resulting in paralysis of the muscles and loss of feeling in the hands and feet. This loss of feeling means that people also lose the automatic reflexes that cause them to draw away from hot or sharp objects. This can result in burns and other wounds which may then become infected. People with leprosy often lose fingers and toes as a result of such infections.
If left untreated, paralysis of the facial nerves can lead to a loss of the blinking reflex, dryness and ulceration of the eye, and blindness.
In severe cases, the nose may collapse as a result of internal damage and scarring caused by the bacteria.
How is leprosy spread?
Leprosy is an airborne disease that is spread via droplets in the air. When a person with the disease sneezes, coughs or even talks, dropets containing the bacteria are released into the air. The disease is spread when these air droplets are then breathed in by an uninfected person.
It is not easy to catch leprosy - over 95 per cent of people are naturally immune to the bacteria, particularly those who live in areas of disease.
Contrary to popular belief, the disease is not spread through contact with ulcerations on the limbs of leprosy sufferers.
What treatment is available?
The bacteria that cause leprosy have gradually become resistant to single drug treatments so the recommended treatment for the disease is now with a combination of drugs (referred to as Multi-Drug Therapy or MDT).
The infection is treated with various doses and combinations of the antibiotics dapsone, clofazimine, rifampicin, ofloxacin and minocycline as recommended by the WHO to prevent the development of resistance. Treatment is continued for six to 12 months. The inflammation is controlled with prednisolone and thalidomide. It is very important to diagnose this disease early in order to properly treat it.
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Fact sheet provided by MIMS
Date last reviewed: October 2014
What is Leprosy?