What is leprosy?

Leprosy is an infectious disease that affects mainly the skin, peripheral nerves, mucosa of the upper respiratory tract, and the eyes. It is classified as a neglected tropical disease. Notably, the condition is curable, and when treated timely with multi-drug therapy, development of disability can be prevented most of the time.

Hansen’s Disease

Leprosy is caused by a bacterium, Mycobacterium leprae. The disease was discovered in 1873 by Norwegian physician Armauer Hansen, which is why it is often dubbed “Hansen’s Disease”. Leprosy affects the nerves to such a degree that sensory loss and loss of strength in hands and feet ensues. When left untreated, sizable wounds, infections, blindness, and severe disfiguration like a claw hand and deformed feet may result.

Long incubation period

Intensive and prolonged interaction with untreated leprosy patients increases the likelihood of contacts developing leprosy. However, it is estimated that only around one in 100 contacts develops the disease. Most people eliminate the bacteria through their own immune system. While some bacteria multiply every minute, the leprosy bacillus only divides once every two weeks. This means that it may take as long as two to five years before a person who is infected develops symptoms. The disease’s long incubation period underpins the need for prevention, since an infected person may spread the bacilli for years without being aware s/he has leprosy.

The incidence of leprosy

In the global fight against leprosy, a critical breakthrough came in the mid-1980s, when multi-drug therapy was introduced. This treatment type led to a significant reduction in the prevalence of the disease, from the 5.4 million registered in that time. Still today more than 200,000 people are diagnosed with leprosy annually. This means that every two minutes, someone is found to have the disease; nine out of every 100 cases concern a child. Since the year 2000, global leprosy strategies have aimed to reduce disease burden measured in terms of new cases, with a special focus on those with visible impairments, also called ‘grade-2 disabilities’.

Prevention of disabilities

NLR has a long track record in promoting the prevention of disabilities, both through promoting early detection and treatment of disabling complications of leprosy in the health services, and through promoting self-care of persons who already developed leprosy-related disabilities. This is often done through facilitating the formation of self-care groups. In these groups, participants encourage and empower each other to continue self-care in the long term.

Towards zero leprosy

A recent breakthrough development has been the introduction of prevention of leprosy by prescribing preventive chemotherapy to contacts of newly-diagnosed leprosy patients. This treatment is referred to as “post-exposure prophylaxis” and is hence also known as “PEP.” The current regimen uses a single dose of one antibiotic (rifampicin). The treatment reduces the risk of contacts developing leprosy by nearly 60%. NLR strives to promote the implementation of PEP as widely as possible, believing that it will be a definitive step towards zero leprosy.

Physical impacts

If not treated, the consequences of leprosy can be severe. The disease affects peripheral nerves, which may lead to loss of sensation in a patient’s hands, feet and eyes. As a result, the patient becomes oblivious to injuries such as cuts or burns, which hampers treatment and healing of these injuries. This opens the door to infections that may cause other permanent impairments. While treatment stops further progression of the disease itself, acquired impairments can often not be reversed. Paralysis of muscles in hands and feet may be mitigated through reconstructive surgery, but loss of sensation is permanent. This means that patients may repeatedly injure themselves, leading to sustained and new disabilities. Between one and two million people globally are estimated to live with disabilities as a result of leprosy.

Social exclusion

Beyond the physical consequences of the disease, leprosy often leads to social exclusion. Leprosy most frequently occurs in low-income communities in countries such as India, Indonesia, and Brazil. Misperceptions about causation, contagiousness, and curability are commonplace and lead to fear and (public or internalised) stigma. The perceptions about leprosy may cause those affected to hide their condition. By doing so, they undermine early treatment and control of the disease.