Abstract:

Objective To understand the epidemiological characteristics of fatal cases associated with major mosquito-borne infectious diseases in China for a reference for prevention and control of this infection. Methods Data on fatal cases of dengue fever, malaria and Japanese encephalitis (JE) reported in China from 2005 to 2025 were collected from the Chinese Disease Prevention and Control Information System. Descriptive epidemiology was applied to analyze the temporal, regional and demographic distribution characteristics of these deaths, as well as the time intervals between disease onset, diagnosis, and death. Results From 2005 to 2025, a total of 431 542 cases of dengue fever, malaria, and JE were reported nationwide, including 2 312 fatal cases. Overall, the number of deaths showed fluctuating downward trend. Fifteen deaths occurred in the 152 739 cases of dengue fever (case fatality rate: 0.01%), and 361 and 1 936 deaths were from 239 371 cases of malaria (case fatality rate: 0.15%) and 39 432 cases of JE (case fatality rate: 4.91%), respectively. By temporal distribution, the deaths involved in dengue fever were dominant from August to October (86.67%), yet the deaths from malaria showed no obvious seasonality. The deaths caused by JE were mostly from June to September (96.07%). By regional distribution, the highest number of deaths from dengue fever, malaria and JE were reported respectively in Guangdong Province (11 cases, 73.33%), Yunnan Province (93 cases, 25.76%) and Guizhou Province (284 cases, 14.67%). In terms of demographic characteristics, dengue fever deaths were predominantly observed in the age group of 40 years and older (13 cases, 86.67%), mainly consisting of house workers and unemployed individuals (4 cases, 26.67%) and retirees (3 cases, 20.00%). Male-to-female ratio was up to 11.03∶1 for the deaths from malaria, and the cases were mostly seen in the age group of 30-59 years (274 cases, 75.90%), with farmers (126 cases, 34.90%), migrant workers (56 cases, 15.51%) and industrial workers (53 cases, 14.68%) constituting the top three in terms of occupational proportions. Deaths from JE were concentrated in the 0-9 years group (1 112 cases, 57.44%), dominated by children living at home (765 cases, 39.51%), farmers (474 cases, 24.48%) and students (409 cases, 21.13%). The median interval from onset to death was 7 days for all three infections. Conclusion Overall, the number of fatal cases of major mosquito-borne infectious diseases in China exhibited a downward trend. Deaths from dengue fever were sporadic and rare, and mortality associated with malaria and JE has been effectively reduced. It is recommended that, in light of the epidemiological characteristics of major mosquito-borne infectious diseases, efforts be continuously strengthened in surveillance and early warning, vector control, case management and treatment as well as health education, in order to further reduce the mortality burden posed by these diseases.

Key words: Mosquito-borne infectious diseases, Dengue fever, Malaria, Japanese encephalitis, Fatal cases, Epidemiological characteristics