Abstract:

Objective To understand the historical incidence and epidemic characteristics of scrub typhus in Hefei for scientific evidences in prevention and treatment of scrub typhus in Hefei area. Methods The data of scrub typhus cases reported in Hefei from 2014 to 2022 were collected through the Monitoring and Reporting Management System of China Disease Prevention and Control Information System. Descriptive epidemiological methods were used to analyze the incidence and characteristics of spatial, regional and time distribution, and SatScan software was used to analyze the spatial clustering. Results A total of 301 cases of scrub typhus were reported in Hefei from 2014 to 2022, including 167 clinically diagnosed cases and 134 confirmed cases. All the cases were reported by 21 tertiary medical institutions in Hefei City. One hundred and ninty-three cases (64.12%) were reported by provincial medical institutions, 65 cases (21.59%) by municipal medical institutions, and 43 cases (14.29%) by county-level medical institutions. The average annual incidence was 0.41/100 000 and annual reported incidence ranged from 0.20/100 000 to 0.63/100 000, showing a decreasing trend (χ²_trend=10.608, P<0.001). The median time interval from onset to diagnosis was 9 (1, 67) days. The cases mainly occurred in October-November each year (242 cases, 80.40%). One hundred and fifty-four cases were males, and 147 females. The gender ratio was 1.05∶1. The median age of the cases was 59 (48, 68) years old, and the number of cases aged 60 and above was the largest (149 cases, 49.50%). The incidence of different age groups showed an increasing trend (χ²_trend=271.445, P<0.001). The occupations were mainly involved in farmers (198 cases, 65.78%), domestic workers and unemployed workers (61 cases, 20.27%). The top 3 counties (districts) with reported cases were Feixi County (110 cases, 36.54%), Feidong County (64 cases, 21.26%) and Shushan District (48 cases, 15.95%). The spatial scanning results showed that 10 towns in Feidong County and Chaohu City were type A clustering areas from 2014 to 2022. Conclusion Scrub typhus primarily occurs in autumn in Hefei area. Farmers and middle-aged and elderly people should be the key groups. It is recommended to strengthen the monitoring of scrub typhus in epidemic season, improve the diagnosis and treatment level of medical staff and the awareness of reporting. At the same time, it is necessary to strengthen health knowledge education, intensify the elimination of host and vector, and control the occurrence and epidemic of scrub typhus.

Key words: Scrub typhus, Epidemic characteristics, Hefei City