Abstract:

Objective To analyze the epidemiological characteristics of fatal cases of scrub typhus in China for a reference for scientific prevention and control of this mite-borne disease. Methods Fatal cases of scrub typhus registered in China from 2006 to 2025 were obtained from the Chinese Disease Prevention and Control Information System. Descriptive epidemiology was used to analyze the characteristics of temporal, regional, and population distribution of fatal scrub typhus cases, as well as the time intervals among onset, diagnosis, and death. Results From 2006 to 2025, a total of 359 017 scrub typhus cases and 114 fatal cases were reported in China, with an average annual case fatality rate of 0.03%. Deaths were reported every year except in 2006 and 2009. Scrub typhus deaths were concentrated between May and November, accounting for 98.25% (112/114) of the total deaths. The fatal cases were distributed across 11 provinces (autonomous regions), 46 prefecture-level cities, and 77 counties (cities, districts). Among the provinces (autonomous regions), Guangdong (55 deaths), Yunnan (28 deaths), Fujian (11 deaths), and Guangxi (10 deaths) added up to 91.23% (104/114) of all deaths. The prefecture-level cities with relatively higher number of fatal cases comprised Guangzhou City (17 deaths), Foshan City (7 deaths), and Heyuan City (6 deaths) in Guangdong Province, and Chuxiong Yi Autonomous Prefecture (10 deaths) and Lincang City (5 deaths) in Yunnan Province. Of the fatal cases, 65 were in males and 49 in females, with a gender ratio of 1.33∶1. The age group of 50-79 years contributed to 67.54% (77/114) of the total deaths. In terms of occupation distribution, 75.44% (86/114) of the deaths were in farmer, retiree, housekeeper and the unemployed. The median time interval from infection onset to confirmed diagnosis for fatal cases was 7 (3, 11) days, and the median time interval from onset to death was 7 (3, 10) days. A total of 30 cases were diagnosed only after death (26.32%), while 54 cases (47.37%) died on the day of definitive diagnosis. Conclusion The number of reported cases of scrub typhus in China presents an increasing trend, and deaths have been yearly reported since 2010. The fatal cases exhibit distinct seasonal and spatial clustering characteristics. It is recommended to enhance case surveillance, early diagnosis, standardized treatment, and health education on prevention and control of scrub typhus in high-incidence seasons, key regions and populations at high risks.

Key words: Scrub typhus, Chigger mite, Fatal cases, Epidemiological characteristics