Descriptive Investigation of a Newly Detected Leprosy Case in Nakhon Si Thammarat, Thailand, 2025

Objective: Leprosy is a curable but neglected disease. Delays in diagnosis and treatment contribute to disability. Although certain achievements have been made in the prevention and control of leprosy, there are still deep-rooted misunderstandings and prejudices regarding this long-term infectious disease. Consequently, patients and their families suffer from discrimination and exclusion in many aspects of life. Newly detected cases provide important insights into ongoing transmission and gaps in early diagnosis. On 5 Feb 2025, a joint investigation team was notified of a 59-year-old Thai female with grade 2 leprosy in Nakhon Si Thammarat Province, Thailand. An investigation was initiated to identify the epidemiological characteristics, assess factors related to the delay in diagnosis and treatment, and determine the source of the disease and whether screening was done among contacts. Methods: A descriptive investigation was conducted using provincial reports, medical records, patient interviews, and active contact tracing. Results: The case was diagnosed with multibacillary leprosy with an average bacterial Index of +5.3. Lesions were present on both sides of the body. The duration from onset to diagnosis was 18 years. A factor contributing to the long delay was misdiagnosis by physicians who were not dermatologists and were unaware of leprosy. Screening of 55 close contacts, including 5 household contacts, 47 neighbors, and 3 social contacts, revealed no clinical features consistent with leprosy. Public health recommendations: All contacts will be followed for 10 years with annual screening. The patient’s medication intake will be monitored and psychological support and social care has been arranged. Thasala hospital should strengthen their early case detection system by looking for cardinal signs of leprosy and by taking a history of risk factors for screening, diagnosis, and treatment.