Epidemiological Characteristics of Leprosy and the Effects of its Control in Chongqing, China, 1949-2018

Abstract Objective: To analyse the epidemiological characteristics of leprosy in Chongqing from 1949 to 2018 and evaluate the prevention and treatment effects over time to provide a basis for improving leprosy prevention and treatment strategies in Chongqing.Methods: Epidemiological indicators such as the incidence rate, prevalence rate, and annual estimated percentage change (EAPC) were used to evaluate the prevalence of leprosy. The prevention and treatment of leprosy patients were evaluated by indexes representing delay in diagnosis, the cure rate and the course of the disease. The statistical software used mainly include SPSS20.0, GraphPad Prism 8, ArcGIS 10.7.Results: From 1949 to 2018, a total of 3698 cases of leprosy were reported in Chongqing, with a sex ratio (male:female) of 3.814:1. The incidence of leprosy in the city peaked at 0.848/105 people in 1960 and remained below 0.100/105 people after 2004, achieving the World Health Organization (WHO) standard for the elimination of leprosy. The mortality rate remained at or below 0.100 per 100,000 people. The median time between disease onset and diagnosis in the whole population was 3.576(1.435, 7.621) years.The early detection rate was 31.314%, and the rate of patients with grade 2 disability was 31.989%, which decreased significantly over time (χ2=5.063, P=0.024). Compared with dapsone(DDS), multidrug therapy (MDT) was associated with a higher cure rate and a shorter disease course (χ2=608.346, P=0.000).Conclusions: Currently, leprosy in Chongqing remains in a low epidemic state. However, to maintain the status of meeting the WHO standards for the elimination of leprosy, there are some challenges that should not be overlooked by leprosy prevention workers. For example, the early detection of leprosy and the prevention and treatment of related disability still need to be strengthened.