A total of 1,35,485 new cases were detected during the year 2016-17, which gives Annual New Case Detection Rate (ANCDR) of 10.17 per 100,000 population. A total of 88,166 leprosy cases are on record as on 1st April 2017, giving a Prevalence Rate (PR) of 0.66 per 10,000 population.
The Rights of Persons with Disabilities Act, 2016(1) includes “leprosy cured” as a locomotor disability (a person's inability to execute distinctive activities associated with movement of self and objects resulting from affliction of musculoskeletal or nervous system or both). It’s been defined as:
A person who has been cured of leprosy but:
- is suffering loss of sensation in hands or feet as well as loss of sensation and paresis in the eye and eye-lid but with no manifest deformity;
- manifests deformity and paresis while having sufficient mobility in their hands and feet to enable them to engage in normal economic activity;
- suffers extreme physical deformity as well as advanced age which prevents him/her from undertaking any gainful occupation.
Leprosy, also known as Hansen's disease (HD), is a chronic infectious disease caused by becteria affecting especially the skin and marginal nerves. It is characterized by the formation of nodules or macules that enlarge and spread with loss of sensation and eventually paralysis, wasting away of muscle, and production of deformities. This infection is caused by the bacteria Mycobacterium leprae and Mycobacterium lepromatosis. It is primarily a granulomatous disease of the peripheral nerves and mucosa of the upper respiratory tract; skin lesions are the primary external sign. If left untreated, leprosy can be progressive, causing permanent damage to the skin, nerves, limbs and eyes.
It has the following symptoms:
- 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 toblindness
- Enlarged nerves (especially those around the elbow and knee)
- A stuffy nose
- Ulcers on the soles of feet
There are three systems for classifying leprosy:
1. Tuberculoid leprosy vs. lepromatous leprosy vs. borderline leprosy
The first system recognizes three types of leprosy: tuberculoid, lepromatous, and borderline. Aperson’s immune response to the disease determines which of these types of leprosy they have:
- In tuberculoid leprosy, the immune response is good. A person with this type of infection only exhibits a few lesions. The disease is mild and only mildly contagious.
- In lepromatous leprosy, the immune response is poor. This type also affects the skin, nerves, and other organs. There are widespread lesions, including nodules (large lumps and bumps). This form of disease is more contagious.
- In borderline leprosy, there are clinical features of both tuberculoid and lepromatous leprosy. This type is considered to be between the other two types.
2. World Health Organization (WHO) classification
WHO categorizes the disease based on the type and number of affected skin areas:
- The first category is paucibacillary. There are five or fewer lesions and no bacterium detected in the skin samples.
- The second category is multibacillary. There are more than five lesions, the bacterium is detected in the skin smear, or both.
3. Ridley-Jopling classification
There’s also a form a leprosy called indeterminate leprosy that isn’t included in the Ridley-Jopling classification system. It’s considered to be a very early form of leprosy where a person will have only one skin lesion that’s just slightly numb to the touch. Indeterminate leprosy may resolve itself or progress further to one of the five forms of leprosy within the Ridley-Jopling system.
Mycobacterium leprae and Mycobacterium lepromatosis are the causative agents of leprosy. Mycobacterium can spread from person to person. It is not known exactly how Hansen’s disease spreads between people. At least until recently, the most widely held belief was that the disease was transmitted by contact between cases of leprosy and healthy persons. More recently scientists think it may happen when a person with Hansen’s disease coughs or sneezes, and a healthy person breathes in the droplets containing the bacteria. There are also other possibilities such as transmission through insects which cannot be completely ruled out.
Leprosy is curable with a combination of drugs known as multidrug therapy (MDT), as the treatment of leprosy with only one antileprosy drug (monotherapy) will result in development of drug resistance to that drug. The combination of drugs used in the MDT depends on the classification of the disease. Rifampicin, the most important antileprosy medicine, is included in the treatment of both types of leprosy. For the treatment of patients with multibacillary leprosy, WHO recommends a combination of rifampicin, clofazimine and dapsone; for patients with paucibacillary leprosy, MDT uses a combination of rifampicin and dapsone.
Multidrug therapy (MDT), first recommended by a WHO Expert Committee in 1984, rapidly became the standard treatment of leprosy and has been supplied by WHO free of charge to all endemic countries since 1995.
The treatment will last for months and possibly up to 1 to 2 years. Antibiotics used during the treatment will kill the bacteria that cause leprosy. But while the treatment can cure the disease and prevent it from getting worse, it does not reverse nerve damage or physical disfiguration that may have occurred before the diagnosis. Thus, it is very important that the disease be diagnosed as early as possible, before any permanent nerve damage occurs.
Prevention -The BCG vaccine offers a variable amount of protection against leprosy in addition to tuberculosis. This vaccine appears to be about 25% effective with two doses working better than one. Development of a more effective vaccine is still ongoing.
Statistics in India
A total of 1,35,485 new cases were detected during the year 2016-17, which gives Annual New Case Detection Rate (ANCDR) of 10.17 per 100,000 population. A total of 88,166 leprosy cases are on record as of 1st April 2017, giving a Prevalence Rate (PR) of 0.66 per 10,000 population.
References for More Reading and Understanding/Sources1
- Disability Affairs
- National Health Portal
- Healthline - Leprosy
- World Health Organisation
- Centers for Disease Control and Prevention
- NATIONAL LEPROSY ERADICATION PROGRAMME
- World Health Organisation - Weekly epidemiological record
- YouTube - leprosy (mycobacterium leprae)-cause, symptoms, diagnosis,treatment and pathology.