Leprosy (Hansen’s disease) - Frequently Asked Questions for the General Public

What is leprosy?
Leprosy is a curable chronic infectious disease caused by a bacterium called Mycobacterium leprae (M. leprae). Historically, leprosy was once feared as a highly contagious and devastating disease. However, following an initiative from the World Health Organization (WHO) to eliminate leprosy, drug treatment was made available free of charge to all patients worldwide since 1995. The elimination of leprosy as a public health problem (with a worldwide prevalence which is currently less than 1 cases diagnosed per 10,000 persons) was achieved in 2000. Now, the disease is rarely seen; but when seen, it can be easily and effectively treated.

The three main types of leprosy are lepromatous, tuberculoid, and borderline. Tuberculoid leprosy is not related to tuberculosis (TB). Lepromatous leprosy is much more contagious than tuberculoid leprosy.

The M. leprae bacteria multiplies very slowly and the incubation period (i.e. time from being exposed to the bacteria to the onset of symptoms) of the disease varies from a few months to 30 years, with an average of about 5 years.

Leprosy mainly affects certain parts of the body such as skin, the peripheral nerves (i.e. the nervous system outside of the brain and spinal cord), the lining of the upper respiratory tract (i.e. the nose and throat), and also the eyes. If left untreated, it can lead to progressive and permanent damage to the nerves, leading to loss of sensation (i.e. feeling) and loss of sweating in the hands and feet, and paralysis of muscles in the hands, feet, and face. In women who have been exposed to persons with untreated leprosy, pregnancy may trigger clinical leprosy.

What are the symptoms of leprosy?
The bacteria that causes leprosy grows very slowly, so in the beginning the person who is infected may not have any symptoms at all. It may take between a few months to 30 years before signs and symptoms appear. On average, it takes about 5 years for symptoms to occur.

Symptoms mainly affect the skin, nerves (in the arms, hands, legs and feet), and mucous membranes (i.e. lining of the mouth, nose, pharynx, larynx, throat, testes, and eyes). The disease can cause:

• Skin lesions that may be faded/discoloured,
• Growths on the skin,
• Thick, stiff or dry skin,
• Severe pain,
• Numbness on affected areas of the skin,
• Muscle weakness or paralysis (especially in the hands and feet),
• Eye problems that may lead to blindness,
• Enlarged nerves (especially those around the elbow and knee),
• A stuffy nose,
• Nosebleeds,
• Ulcers on the soles of the feet.

Since leprosy affects the nerves, loss of feeling or sensation can occur. When loss of sensation occurs, injuries (such as burns or fractures) may go unnoticed by a person with untreated leprosy.

The symptoms experienced are different for the three types of leprosy. In lepromatous leprosy, there is more severe widespread disease involving all systems of the body; in tuberculoid leprosy, there is less widespread disease; however, nerve involvement tends to be severe; and borderline leprosy, this type covers the range of illness somewhere in the middle between lepromatous and tuberculoid leprosy.

How do you get leprosy?
Leprosy is not a highly contagious disease. It can spread from person-to-person when prolonged close contact (as may occur in a household) with a person who has untreated leprosy occurs. Spread might happen when someone with the untreated disease coughs or sneezes, which then can release droplets containing the bacteria into the air. If these are inhaled in, you may become sick from the disease. Spread may also occur if the droplets from an untreated person come into contact with the broken skin of a contact. Untreated pregnant women may pass the infection to the foetus.

Is a person with leprosy contagious?
Leprosy is not highly contagious, and usually after three months of prescribed treatment by a medical doctor (usually an Infectious Diseases/Microbiology Consultant), a person will no longer be infectious to others.

Who gets leprosy?
Leprosy rarely occurs in Ireland, with most of the diagnosed cases being persons who were infected outside of Ireland.

Leprosy can affect anyone. This disease is rarely seen in children less than three years of age. You may be at risk for the disease if you:

• Live in a country where the disease is more common such as:
  • Angola,
  • Brazil,
  • Central African Republic,
  • Democratic Republic of Congo,
  • Federated States of Micronesia,
  • India,
  • Kiribati,
  • Madagascar,
  • Mozambique,
  • Nepal,
  • Republic of Marshall Islands, and
  • United Republic of Tanzania.

OR

• Are in prolonged close contact with persons who have untreated leprosy.

Some armadillos in the southern United States of America are naturally infected with leprosy. Whilst it’s possible to get the disease from an armadillo, the risk is low. Most persons who come into contact with armadillos are unlikely to get leprosy. But, if you decide to see a medical doctor because of your contact with an armadillo, make sure to provide complete history of armadillo contact.

Who is at risk of leprosy?
Most adults around the world, however, might face no risk at all. That is because evidence shows that 95% of all adults are naturally unable to get the disease, even if they’re exposed to the bacteria that cause it. Those at greatest risk are persons who live in the same household as a person with untreated leprosy for more than a month. Long frequent periods of contact are needed for persons to be infected by leprosy.

How is leprosy treated?
It is important to know that leprosy can be cured. Early treatment will prevent disability. Medication should be administered under the supervision of a medical doctor (usually an Infectious Diseases/Microbiology Consultant).

How can leprosy be prevented?
Household contacts of a person with leprosy, especially children, should be examined yearly for at least five years after their last contact with an infectious person. Household contacts of person with lepromatous leprosy who are less than 25 years of age may be considered for preventive treatment under the care of a medical doctor (usually an Infectious Diseases/Microbiology Consultant).

Is leprosy a notifiable disease?
Leprosy is a notifiable disease under the Infectious Diseases (Amendment) Regulations, 2011. Cases should be notified by clinicians or medical laboratories to the Medical Officer of Health (in regional Departments of Public Health). Individual cases should be managed by a medical doctor (usually an Infectious Diseases/Microbiology Consultant).

What is the Public Health response?
Public Health action focuses on the effective treatment of persons with multi drug therapy, follow-up, and education of contacts.

Is there a vaccine available for leprosy?
Currently there is no vaccine available in worldwide against leprosy. However, in 2016, the WHO launched a new global strategy – “The Global Leprosy Strategy 2016 – 2020: Accelerating towards a leprosy-free world” – which aims to reinvigorate efforts for leprosy control and to avoid disabilities, especially among children affected by the disease in countries where the leprosy is common.

Further information is available from:
World Health Organization (WHO), 2016. Available URL: http://www.who.int/mediacentre/factsheets/fs101/en/ (Accessed: 14th July 2016)
World Health Organization (WHO), 2016. Available URL: http://www.searo.who.int/entity/global_leprosy_programme/documents/global_leprosy_strategy_2020/en/ (Accessed: 15th July 2016)
Public Health England (PHE), 2013. Available URL: https://www.gov.uk/guidance/leprosy (Accessed: 14th July 2016)
National Institute for Health and Care Excellence, 2016. Available URL: http://www.evidence.nhs.uk/Search?ps=20&q=Leprosy (Accessed: 14th July 2016)
Centre for Disease Control and Prevention (CDC), 2013. Available URL: https://www.cdc.gov/leprosy/ (Accessed: 14th July 2016)
New South Wales (NSW) Australia, 2012. Available URL: http://www.health.nsw.gov.au/Infectious/factsheets/Factsheets/leprosy.PDF (Accessed: 14th July 2016)
Irish Statue Book (ISB), 2011. Available URL: http://www.irishstatutebook.ie/eli/2011/si/452/made/en/print (Accessed: 26th July 2016)

Last updated: 21 September 2016