Epidemic characteristics and infection sources of severe fever with thrombocytopenia syndrome in Hangzhou,China from 2014 to 2023
Objective To analyze the population,regional,and time distribution characteristics and infection sources of severe fever with thrombocytopenia syndrome (SFTS) in Hangzhou,China from 2014 to 2023,so as to provide evidence for the prevention and control of SFTS.Methods The cases data of SFTS in Hangzhou from 2014 to 2023 were collected from the China Information System for Disease Control and Prevention.Descriptive epidemiological methods were used to analyze the distribution characteristics and infection sources of SFTS cases.The spatial map was plotted with ArcGlS 10.2 software,and the Mann-Kendall Z trend test was carried out with R 4.3.0.Results A total of 90 SFTS cases were reported in Hangzhou from 2014 to 2023,with an average annual reported incidence of 0.08/100000 and an average fatality rate of 15.56% (14/90).The overall incidence rate of SFTS in Hangzhou City has shown an overall upward trend (Z=1.789,P=0.037),and the incidence rate of SFTS rose rapidly in 2023.There were 46 males and 44 females with a sex ratio of 1︰0.96.The high incidence was observed in the middle-aged and elderly population (≥45 years old),accounting for 92.45% (86/90).Farmers were the main occupation,accounting for 81.11% (73/90).The onset was mainly in summer in the early stage and increased to the whole year over years,with the majority in spring,summer,and autumn.From 2014 to 2023,the number of SFTS cases reported in Hangzhou increased from 1 (Chun'an County) to 8 counties (cities or districts) year by year.with the largest number of cases in Chun'an County (50 cases),followed by Lin'an District (26 cases) and other counties (cities or districts,<5 cases).The analysis of sources of infection showed that 5 cases were infected from contact with SFTS deaths.Among the other infected cases (n=85),18 (21.18%) had a definite history of tick bites 2 weeks before the onset,37 (43.53%) denied the history of tick bites,and 30 (35.29%) had unknown sources of infection.Conclusions The incidence of SFTS in Hangzhou gradually expanded,and the incidence trend of reported cases also increased significantly.The sources of infection include tick bites and contact infection.The prevention and control of SFTS should be strengthened on case surveillance,epidemic response,and integrated control of ticks.
Severe fever with thrombocytopenia syndromeEpidemic characteristicSources of infection