Using novel molecular approaches to understand the transmission dynamics of Mycobacterium leprae in the Comoros

Leprosy, a severely mutilating disease and although Mycobacterium leprae was the first human pathogen discovered, its exact way of spreading between humans is still a mystery. This is part of the reason why leprosy control is failing despite available effective treatments. Over 200,000 new leprosy patients are diagnosed worldwide each year, and the high proportion in children indicates its ongoing spread. To stop transmission dead in its tracks once and for all, new approaches to leprosy control are needed. Therefore, this study will revisit fundamental questions regarding transmission in an innovative way. Firstly, I will evaluate if minimally invasive, field-friendly tests can quantify the amount of bacteria in each patient and correlate with the effectiveness of the treatment and the identification of the most infectious patients. In my PhD thesis, I will be the first to use targeted Next Generation Sequencing of M. leprae. Within the “ComLep” study in the Comoros, I will classify the bacteria into M. leprae subtypes and associate with the GPS of each patient’s house, allowing me to identify transmission links. Once these transmission chains are established I can define where transmission occurs and if a reservoir of asymptomatic people is sustaining transmission of the disease. This in turn will inform which contacts should receive leprosy preventive therapy. These findings will inform optimal control strategies to eliminate leprosy in the Comoros and elsewhere.