PhD defence Y. (Yudhy) Dharmawan

Brief summary on the aim of the doctoral thesis:

Leprosy is caused by Mycobacterium leprae. Only a small percentage of those infected with M. leprae develop clinical disease. The incubation period of M. leprae is long, ranging from 2 to 12 years. Person-to-person spread via nasal droplets is believed to be the main route of transmission in the community.

Leprosy has been a public health problem for many centuries due to irreversible disability often resulting in a social stigma. Even now many new leprosy patients are diagnosed with visible impairments and disabilities such as claw hand, foot drop, and lagophthalmos. These are classified by the World Health Organization (WHO) as leprosy grade 2 disability (G2D).

G2D in leprosy represents a considerable disease burden. It is often associated with delays in diagnosis and inappropriate treatment. The percentage of new cases with G2D is clearly associated with case detection delay (CDD). The longer the delay, the higher the percentage with G2D. This might be caused by a lack of community awareness about leprosy, the low capacity of health staff to recognise early signs and symptoms, and to some extent, the quality of leprosy health services. Therefore, if the G2D rate is high, healthcare services must be improved, especially concerning case detection. The WHO’s strategy is to detect cases before visible deformities occur.

Indonesia has the third-highest number of new leprosy cases and G2D in the world after Brazil and India. Although Indonesia obtained the status of leprosy elimination as a public health problem in 2000, the proportion of new leprosy cases with G2D has remained high. In 2021, the number of new cases of leprosy was 10,976, and of these 673 (6.1%) had G2D. However, the 2021 numbers do not represent reality; due to COVID-19, reporting was disrupted, and reported numbers are too low. These numbers indicate that leprosy and G2D due to leprosy still constitute a substantial public health burden in Indonesia. 

It is necessary to know the duration of CDD as baseline and its associated factors to develop interventions to improve early case detection of leprosy in Indonesia. Currently, there is no standard measurement tool for leprosy CDD, so there is no clear information about the scale of CDD of leprosy in Indonesia. Also, factors associated with leprosy CDD in Indonesia are not fully known.

In this thesis, we systematically reviewed published studies reporting the duration of CDD in leprosy and described individual, community and healthcare services factors associated with delayed leprosy CDD worldwide to understand CDD and its associated factors glob- 136 ally. We also described the steps to validate a CDD questionnaire to measure leprosy CDD in Indonesia and measured CDD duration and its associated factors. The overall objective of this thesis is to measure the duration of leprosy case detection reliably and to establish factors associated with detection delay in Indonesia. This study thereby aims to help improve early case detection of leprosy with the purpose to reduce the transmission of M. leprae in the community and to prevent disability caused by leprosy. Our study focusses on Indonesia, the country with the third highest number of cases globally.