Endemicity and increasing incidence of leprosy in Kenya and other world epidemiologic regions: A review

Introduction: Leprosy ancient disease also called Hansen’s disease, is a chronic, progressive infectious disease caused by the bacterium Mycobacterium leprae. An obligate intracellular parasite, and a close relative of the Mycobacterium tuberculosis. It primarily affects the nerves of the extremities (peripheral nerves), the lining (mucous membranes) of the nose, eyes, and the upper respiratory tract. It produces skin sores, nerve damage, and muscle weakness leading to deformity and erosion. Aim: This review article was to theorize and hypothesize the recurrence of unique human, M. leprae or environmental characteristics that favour the endemicity, prolonged survival and Leprosy transmission in the affected epidemiologic regions, including parts of Kenya. Highlight the age old traditional line of perception about this disease Objective: Even though global efforts to control Leprosy by intensive multi-drug chemotherapy (MDT) since 1964 have led to a significant decrease in the number of reported new cases. The disease continues to be endemic in many epidemiologic regions. Some regions experiencing increasing incidence.  The disease has afflicted humankind throughout history leaving evidence in both early texts and archaeological record. Leprosy’s origins have reportedly existed as late as 3,500 BC. However, some of the earliest written records that accurately reflect leprosy appears to be from the 600 BC Sushruta Samhita text from India. The interplay of emotional and social factors modify or transform the life programme of persons afflicted with leprosy. Just like the current pandemic cancers, Leprosy is still a crucial global health concern. The MDT for leprosy was designed to prevent emergence and transmission of drug-resistant M. leprae strains. However, in the African epidemiologic regions, Peer reviewed articles on the Internet, Journals and Relevant topics in textbooks were reviewed. Methodology:  A literature review was done to up-date the socio-cultural perception of leprosy in Indian religions and ancient texts' references were obtained through examining relevant bibliographies and the views/suggestions of eminent scholars engaged in this field39 A Sociological study was carried out in respondents of a Lepers Colony (Gandhi Kusth Ashram), Jodhpur, India. An attempt was made to study the knowledge about causation of Leprosy, age at onset, and treatment. The reason for leaving their original place of origin (South India) was asked. A majority (95.2%) of patients were Hindus, had onset of leprosy in the age group of below 20 to 30 years (80.94%) they had a literacy rate of 6.3% only.  Leprosy is most challenging to behavioral scientists interested in the description and theory of medical sociology as a psychosocial phenomenon. However, the country is currently battling with resurgence of the disease, which is characterized with high numbers of relapses. Conclusion: The observed continued endemicity and increasing incidence of leprosy in some epidemiologic regions raised the assumption of the existence of unique human, M. laprae or environmental factors that favour prolonged survival and transmission of M. leprae. Unique strains of M. leprae with selective advantage to circumvent BCG induced immunity, or resistant to anti-leprotic drugs may also have emerged. Further interrogation of this assumption could generate valuable information for improved control of leprosy.  Key words: Mycobacterium leprae, leprosy, endemicity, incidence, re-emergence, contro