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Hansen's disease: explain to eradicate

By: Irene Cavaliere

Photo: Peter Illicciev / Fiocruz

Photo: Peter Illicciev / Fiocruz

Hansen's disease has been eradicated in many countries. However, in Brasil, there is a new case of the disease every 15 minutes (Ministry of Health, 2009). You probably heard terrible things about Hansen's disease — or leprosy —, like how it deforms people or that you should stay away from the sick in order not to get it too.

In the past, there was no cure for Hansen's disease. The sick were usually excluded and suffered with the disease's physical and moral stigmas. However, between the 6th century, when the first known records of the disease were written, and today, science advanced a lot, and the cure of Hansen's disease was one of the achievements of medicine. Despite that, people still have to deal with a lot of myths and prejudice, which hinders both prevention and treatment.

People end up not seeking help because they don't known the symptoms and the treatment or are embarrassed or afraid to be judged. The sick not only can have serious complications, but can also continue to transmit the disease. The treatment for Hansen's disease is long, but it is also free of charge and guaranteed. If people get the treatment, they will get cured and won't have to live in isolation: soon after the beginning of treatment, transmission is interrupted.

Plus, even though there is still no specific vaccine for Hansen's disease, the BCG vaccine — against tuberculosis — helps preventing it, because the causative agents for both diseases are very similar. Therefore, the close contacts of anyone with Hansen's disease should visit the nearest medical centre to be examined and — if they have no symptoms — get the BCG vaccine to help preventing contagion.The sooner treatment is started, the better for everyone!

What is Hansen's disease?

Hansen's disease is a very serious disease affecting the skin and the nerves. If untreated, it may cause serious damage. It is caused by a bacillus of the mycobacterium genus called Mycobacterium leprae, which lives and reproduces inside skin cells and peripheral nerves (that is, those that are not inside the skull or in the medulla).

<EM>Mycobacterium leprae</EM>/OMS

Mycobacterium leprae/OMS

The damage to these nerves is the most important aspect of the disease, which may cause incapacitations that may evolve into deformities in case the person is not treated. The most relevant symptoms of Hansen's disease are: tingling, sharp pain or numbness in the extremities; white, reddish or copper-colored spots in the skin with no sensitivity to heat, cold, pain or touch; areas in the skin that look normal but have changes in sensitivity or sweating; lumps or plaques anywhere in the body; and muscle weakness.


But did you know that, even though Hansen's disease is contagious, only 10% of the people that get in contact with the bacillus get sick? M. leprae is very infectious but not much pathogenic — that is, it infects a lot of people, but very few of them get sick. The evolution of the disease depends on each person's immune system, and, although it is not hereditary, genetic factors determine whether individuals are resistant or susceptible to the disease.

Spot caused by the disease /OMS

Spot caused by the disease /OMS

Besides individual factors, the endemic level of the disease — as well as socioeconomic factors, living and health conditions or the number of people living together — influence the risk of contagion, because transmission takes place through nasal secretions, or little droplets of saliva that are projected when infected individuals speak, cough, sneeze, etc., that is, through the superior respiratory tract.

The time of incubation — that is, how long it takes until symptoms appear — is long, varying between three and seven years. Early treatment is the most important tool against the disease, because it may avoid more serious complications. Plus, people under treatment stop communicating the disease. The disease is only transmitted from person to person, although some animals have been identified as naturally infected, such as the armadillo.

Diagnosis and treatment

Only doctors can really diagnose any disease and indicate a treatment, but anyone with any form of alteration in the sensibility of the skin should suspect of Hansen's disease. To be sure, doctors need to talk to the patient about their health history, carry out a dermatological and neurological evaluation, exclude other possibilities and order a lab exam to identify the presence of the bacillus.

Hansen's disease can be cured. In the past, the sick were quarantined, their houses and belongings were burned, the family was stigmatized, that is, there was a great prejudice around the disease (read more in Hansen's disease in history).

Shelter for patients in India / Erin Collins (Flickr)

Shelter for patients in India / Erin Collins (Flickr)

Research showed that such measures were ineffective. Currently, patients are treated with polychemotherapy, that is, a combination of medications standardized by the World Health Organization (WHO) that kills the bacillus and cures patients. The treatment is offered free of charge in all Brazilian health units.

The treatment, on the other hand, is very effective. From 1990 — when the treatment with the polychemotherapy was introduced — until 2008, the prevalence rate for Hansen's disease (that is, the number of cases per 10,000 individuals) dropped from 19.5 to 2.06 in Brazil. It is now close to the goal established by the WHO to eradicate the disease, one case per 10,000 people.

However, when we isolate regional statistics, there are still places that should be concerning t he country, like Mato Grosso, which had a prevalence rate of 8.76 (data from DataSus) in 2008. In 2009, 37,610 new cases were registered in Brazil, the largest rate in the Americas. Other countries that also still struggle with Hansen's disease include Angola, India, China, Congo, Madagascar, Mozambique, Nepal, Tanzania and the Central African Republic.

See also:

Hansen's disease in history


Agência Fiocruz de Notícias - Hanseníase

Ministério da Saúde - Guia de Hanseníase


World Health Organization - Leprosy

World Health Organization - Leprosy Elimination

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