Leprosy control
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"leprosy"[MeSH Terms] AND "elimination" AND "control"
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Leprosy Control
Park's Textbook of Preventive and Social Medicine
Overview
The introduction of multidrug therapy (MDT) has fundamentally reshaped leprosy control. A revised strategy has emerged with MDT at its core. The three main goals of leprosy control are:
- Interrupt transmission of infection to reduce incidence until it is no longer a public health problem
- Treat patients to achieve cure and, where possible, complete rehabilitation
- Prevent the development of associated deformities
Ultimate prevention is achieved by breaking the chain of transmission.
Elements of a Leprosy Control Programme
1. Medical Measures
I. Estimation of the Problem
The first step is to define the disease burden through epidemiological surveys. Random sample surveys collect baseline data on prevalence, age/sex distribution, forms of disease, and available health care. A rough estimate: examining all school-age children, the total prevalence is approximately 4 times the number of cases found. Prevalence estimates are essential for planning, implementing, and evaluating anti-leprosy programmes.
II. Early Case Detection
The aim is to identify and register all cases as soon as possible after they become evident. Because leprosy is frequently symptomless early on, patients may not report until 2-3 years after onset. Social stigma also delays self-reporting. Active case-finding strategies are therefore required.
Key operational definitions:
- Paucibacillary (PB): 1-5 skin lesions and/or only one nerve involvement
- Multibacillary (MB): 6 or more skin lesions and/or more than one nerve involvement
- Defaulter: A patient on MDT who has not collected treatment for 12 consecutive months
- Relapsed case: A patient who, having completed adequate MDT, subsequently develops new signs/symptoms either during or after the surveillance period
III. Multidrug Therapy (MDT)
Drugs used in MDT
Only bactericidal drugs are used in MDT regimens:
| Drug | Mechanism/Notes |
|---|---|
| Rifampicin (RMP) | Only highly bactericidal drug against M. leprae. A single dose of 1500 mg or 3-4 daily doses of 600 mg kills ~99% viable organisms. Effective at monthly intervals. Risk: hepatotoxicity, anaphylaxis. Given in combination to prevent resistance. |
| Dapsone | Bacteriostatic. Well tolerated at 100 mg/day. Drug resistance (primary dapsone resistance) is now widespread, hence always combined with rifampicin. |
| Clofazimine | Weakly bactericidal; also anti-inflammatory. Causes skin discoloration (reddish-brown). Useful for lepra reactions (ENL). |
| Ethionamide/Protionamide | Alternative to clofazimine when skin discoloration is unacceptable. 250-375 mg self-administered daily. |
MDT Regimens
Adult - Multibacillary Leprosy:
- Rifampicin 600 mg once monthly, supervised
- Dapsone 100 mg daily, self-administered
- Clofazimine 300 mg once monthly supervised + 50 mg daily self-administered
Adult - Paucibacillary Leprosy:
- Rifampicin 600 mg once monthly, supervised
- Dapsone 100 mg daily, self-administered
Children (10-14 years):
- MB: Rifampicin 450 mg monthly + Dapsone 50 mg daily + Clofazimine 150 mg monthly and 50 mg alternate days
- PB: Rifampicin 450 mg monthly + Dapsone 50 mg daily
- Under 10 years: appropriately reduced doses
Duration of Treatment
| Type | Duration | Completion window |
|---|---|---|
| Multibacillary | 12 monthly doses (MB blisterpacks) | Within 18 months |
| Paucibacillary | 6 monthly doses (PB blisterpacks) | Within 9 months |
MDT is NOT contraindicated in HIV infection or pregnancy. Small amounts of drugs pass into breast milk; only mild skin discoloration from clofazimine may occur in infants.
Lepra Reactions
Two immunologically-mediated reaction types can occur before, during, or after MDT:
| Feature | Type I (Reversal Reaction) | Type II (ENL) |
|---|---|---|
| Mechanism | Cell-mediated immunity | Antigen-antibody (immune complex) |
| Cases affected | BT, BB, BL types | MB only (BL, LL) |
| Skin changes | Existing lesions become oedematous/erythematous/tender | New painful subcutaneous red nodules (evanescent, episodic) |
| Nerve involvement | Common, multiple, severe | Less common |
| Systemic upset | Less systemic | Fever, malaise, orchitis, iritis |
| Treatment | Prednisolone (12-week course) | Prednisolone + Clofazimine for severe/steroid-dependent cases |
Key rule: Do NOT stop MDT during a lepra reaction. Continue MDT and treat the reaction simultaneously.
Prednisolone regimen (moderate-severe reactions):
- 40 mg/day - weeks 1-2
- 30 mg/day - weeks 3-4
- 20 mg/day - weeks 5-6
- 15 mg/day - weeks 7-8
- 10 mg/day - weeks 9-10
- 5 mg/day - weeks 11-12 (Prolonged to 4 weeks from 20 mg onwards for neuritis)
IV. Surveillance (Post-treatment)
Clinical surveillance after treatment completion is essential to detect relapses early:
- PB cases: Clinical examination at least once yearly for a minimum of 2 years after treatment
- MB cases: Clinical examination at least once yearly for a minimum of 5 years after treatment
The phrase "release from control" is no longer used in the MDT era.
V. Immunoprophylaxis
No validated tool for detecting asymptomatic infection is yet available. BCG vaccine trials (alone or combined with killed M. leprae or atypical mycobacteria) have shown protective efficacy ranging from 28% to 60%. High BCG coverage remains an important contribution to reducing the leprosy disease burden.
VI. Chemoprophylaxis
Household contacts of leprosy cases (especially MB) have a higher risk than the general population. However, due to inconsistent results from trials with dapsone, acedapsone, and rifampicin, chemoprophylaxis is not yet recommended as a routine public health measure. Further research is needed.
VII. Disability Prevention
About 25% of patients not treated early develop anaesthesia and/or deformities of the hands and feet. Leprosy is one of the foremost causes of deformity and crippling as a single disease entity.
Disability grading:
- Grade 0: No anaesthesia/deformity
- Grade 1: Anaesthesia present but no visible deformity
- Grade 2: Visible deformity/damage
Types of deformities:
| Area | Deformities |
|---|---|
| Face | Mask face, facies leonina, lagophthalmos, madarosis (loss of eyebrows/eyelashes), perforated/depressed nose, corneal ulcers |
| Hands | Claw hand, wrist-drop, plantar ulcers, absorption of digits, thumb-web contracture |
| Feet | Plantar ulcers, foot-drop, inversion of foot, claw toes, absorbed toes |
| Other | Gynaecomastia, perforation of palate |
Preventive measures for disability:
- Care for dry denervated skin (moisturisation of palms/soles)
- Heal wounds, ulcers, skin cracks
- Protective gloves and footwear
- Prevent joint stiffness with physiotherapy
- Eye protection for lagophthalmos
- Periodic nerve function assessment
Treatment of established deformity: prostheses, orthopedic devices, corrective splints, corrective surgery.
VIII. Rehabilitation
WHO defines rehabilitation as: "The physical and mental restoration, as far as possible, of all treated patients to normal activity, so that they may be able to resume their place in the home, society and industry."
The cheapest and surest rehabilitation is preventing deformities through early diagnosis and adequate treatment - termed "preventive rehabilitation". Community-based rehabilitation (CBR) integrates governmental and NGO efforts in health, education, vocational, and social services.
IX. Health Education
No anti-leprosy campaign is complete without health education:
- For patients/families: Emphasize regular treatment compliance (reduce drop-out), contact examination, self-care for disability prevention
- For general public: Correct misconceptions - leprosy is NOT hereditary; it is a bacterial disease like TB; it is curable; not all patients are infectious; patients need sympathy and social support. A nationwide mass education campaign is needed to remove stigma.
2. Social Support
Chemotherapy alone cannot solve the whole leprosy problem. Economic and social needs of the patient and family must be addressed: assistance with transport to clinic, food/clothing for needy families, child education, job placement, slum improvement programmes. These are best provided through voluntary agencies and Departments of Social Welfare.
3. Programme Management
Leprosy control is a long-term activity requiring planned infrastructure, trained health personnel, adequate drug supply, vehicles, and financial allocation. The National Leprosy Eradication Programme (NLEP) in India incorporates all these elements. India achieved the leprosy elimination target (< 1 case per 10,000 population) by the end of 2005.
4. Evaluation
Epidemiological Indicators (measure programme effectiveness on disease burden):
- Prevalence rate
- New case detection rate (NCDR)
- Child rate (CR) per 100,000
- Proportion of MB among new cases (PMBANC)
- Proportion of females among new cases (PFANC)
- Proportion of Grade 2 disability among new cases (PG2DANC)
Operational Indicators (measure quality of programme delivery):
- Proportion of child cases (PCANC) - reflects recent transmission
- Scheduled caste/tribe detection rates
- BCP (blister calendar pack) stock in months (PMBCP)
- Absolute number of patients released from treatment (RFT)
WHO Elimination Goal
The WHO definition of elimination as a public health problem is prevalence < 1 case per 10,000 population at the national level. India achieved this milestone by end 2005. However, leprosy remains endemic in pockets, and new case detection continues, making sustained NLEP activities and active surveillance necessary.
Source: Park's Textbook of Preventive and Social Medicine
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