Epidemiological analysis of malaria in Nanchang City, Jiangxi Province from 1950 to 2015

Objective To analyze the epidemiological characteristics of malaria and to discover the regularity of malaria outbreaks in Nanchang City from 1950 to 2015, so as to provide a scientific basis for developing control strategies after the goal of malaria elimination has been achieved. Method Malaria related data, report forms and work summary in Nanchang from 1950 to 2015 were collected and analyzed to indicate malaria distribution characteristics via the descriptive epidemiological methods. Results The total number of malaria cases reported in Nanchang City was 1 449 878 from 1950 to 2015. The particular years with the three peaks of malaria epidemic from 1950s to 1970s were 1954, 1970 and 1977. The climax of annual mean incidence rate of malaria (6 948.75 per 100 thousand) was reached in 1970. Totally 1 449 739 local recurrence cases were reported between 1950 and 1999. There were 484 292 local recurrence cases (accounting for 68.80%, 484 292/703 911) that were diagnosed in the malaria epidemic seasons, May to August. There were 44 931, 25 684, 22 614 and 5 842 cases reported in Nanchang County, Xinjian County, Jinxian County and Qingshanhu District, which ranked the top 4 of epidemic focus areas (accounting for 90.65%, 99 071/109 293) between 1980 and 1989. The 13 245 cases reported between 1972 and 1985 in the three county/districts (Jinxian County, Xihu District and Wanli District), included 8 513 cases of male and 4 732 cases of female. The 126 cases reported between 2005 and 2015, included 122 imported cases who were mostly returnees after overseas labor output and 57 falciparum malaria cases with a increasing trend year by year. There was no correlation between the seasonal change and the occurrence of malaria. Conclusions The comprehensive prevention and control measures based on eliminating the source of infection can effectively control the epidemic of malaria. It is suggested that the surveillance on imported falciparum malaria cases should be the focus in prevention and control of the disease at the late-stage because the epidemiological characteristics of local malaria cases have died out completely. Key words: Malaria; Epidemiological analysis; Annual mean incidence rate