Evaluating active leprosy case identification methods in six districts of Nepal

Area of Science:

• Public Health
• Epidemiology
• Infectious Disease Control

Background:

• Nepal has achieved national leprosy elimination but faces challenges in 17 districts and 3 provinces, with 41% of the population affected.
• Pediatric cases and grade-2 disabilities (G2D) signal ongoing transmission and delayed diagnosis, necessitating enhanced case-finding strategies.
• Operational research is crucial to identify optimal early case detection methods and understand community-based leprosy epidemiology.

Purpose of the Study:

• To identify the most effective approaches for early leprosy case detection in Nepal.
• To determine the community-based leprosy epidemiology in high-burden areas.
• To identify and promptly treat hidden leprosy cases.

Main Methods:

• Active case detection was conducted in Madhesh and Lumbini Provinces, targeting vulnerable populations through house-to-house visits (n=26,469).
• Contact tracing and examination (n=7608) were performed in Madhesh and Lumbini Provinces.
• Prison populations in Madhesh, Lumbini, and Bagmati Provinces were screened (n=4428); cost-effectiveness analysis was performed for each method.

Main Results:

• Contact tracing yielded the highest detection rate (250/100,000), followed by house-to-house visits (102/100,000) and prison screening (45/100,000).
• House-to-house visits were the most cost-effective (NPR 76,500/case), followed by contact tracing (NPR 90,286/case) and prison screening (NPR 298,300/case).
• Pediatric cases and G2D were observed in 11% and 5-11% of detected cases, respectively; BCG vaccination showed a protective effect (OR=0.42).

Conclusions:

• Contact tracing is the most effective leprosy case identification strategy, with house-to-house visits being a cost-effective alternative.
• The study confirms the existence of hidden leprosy cases, recent transmission, and late diagnoses in the community.
• Early case detection strategies are vital for controlling leprosy transmission and preventing disabilities.