Epidemiological characteristics of severe fever with thrombocytopenia syndrome in Anhui, 2011−2022

Objective To analyze the epidemiological characteristics of severe fever with thrombocytopenia syndrome (SFTS) in Anhui province from 2011 to 2022, and provide evidence for the prevention and control of SFTS.

Methods The incidence data of SFTS in Anhui during this period were obtained from China Information System for Disease Control and Prevention for a descriptive epidemiological analysis, and Joinpoint regression models were used to analyze the distribution of the disease.

Results From 2011 to 2022, a total of 4 298 SFTS cases were reported in Anhui. The average annual incidence rate was 0.58/100 000 and the average annual mortality rate was 0.02/100 000 with overall increasing trends average annual percent change (AAPC)=19.08%, P<0.001; AAPC=15.30%, P<0.01. The cases mainly occurred during April-October, accounting for 94.97% of the annual total. The incidence rate was 0.55/100 000 in men and 0.62/100 000 in women, with a higher incidence rate in women than in men (χ²=13.872, P<0.001). The cases were mainly distributed in age group 60–75 years (46.21%). Most cases were farmers (85.06%). SFTS cases were reported in 23 counties (district) of 6 prefectures (municipality) in 2011, but in 62 counties of 12 prefectures (municipality) in 2022. The top 3 counties reporting high incidence rate were Nanqiao of Chuzhou (9.40/100 000), Jinzhai of Liu'an( 6.67/100 000) and Mingguang of Chuzhou (4.50/100 000). The top 3 counties reporting high mortality rate were Hanshan of Ma'anshan ( 0.44/100 000), Quanjiao of Chuzhou (0.17/100 000) and Feidong of Hefei (0.12/100 000). Twenty-three SFTS public health emergencies were reported, of which 20 had case clustering, mainly in families (75.00%).

Conclusion The incidence of SFTS showed an increasing trend in Anhui with a wide distribution of the cases and obvious spatial and temporal case clustering. In the disease epidemic season, it is necessary to strengthen the health education about SFTS in middle-aged and elderly people in local mountainous/hilly areas and improve SFTS surveillance.