Objective: To analyze the epidemiological characteristics of severe fever cases, with thrombocytopenia syndrome (SFTS) in Zhoushan,Zhejiang, 2011-2013 and to provide evidence for the development of related strategies for prevention and control of the disease.
Methods: Data was collected from the studies and related demography of the cases with SFTS in Zhoushan, 2011-2013. Clinical and epidemiological characteristics of the cases with SFTS were analyzed descriptively.
Results: During 2011-2013, 45 SFTS cases were reported in Zhoushan city, with fatality rate as 11.11% (5/45), including 41 cases(91.11%)reported in Daishan county. Most cases aged 50 or over, residing in hilly regions (93.33%). The epidemic peak was seen from May to July (84.44%). Incidence rates of the disease did not show significant statistical differences between males and females. Most cases were farmers (42.22% ) and housewives (31.11% ). Most patients complained of fever (97.78%), anorexia (91.11%), fatigue (62.22%), chill (44.44%) and other non-specific clinical manifestations but all appeared progressive thrombocytopenia and leucopenia. Sanitation condition of the patients was generally poor. 68.89% (31/45) of cases had farmed, mowed or involved in other outdoor activities in the previous two weeks, with some of them reported having exposed to tick bites. Three events were reported, epidemiologically.
Conclusion: SFTS in Zhoushan was a infectious disease with natural foci and caused by SFTSV. Ticks might serve as the main vectors for SFTSV, and might cause direct transmission between humans. Improving the environment for living and carrying out essential protective measures in outdoor activities seemed to be significant in decreasing the incidence rate of the disease.