Abstract：
Severe fever with thrombocytopenia syndrome (SFTS), an emerging tick-borne disease first reported in rural areas of central China, has become a major public health concern in endemic areas. The epidemic dynamic and ecologic factors of SFTS incidence at a village scale remain unclear. Here we analyzed the epidemiological characteristics of SFTS cases in Shangcheng County, the first reported areas of SFTS in China. A retrospective space-time cluster analysis was conducted to identify the dynamics of hotspot areas, and the negative binomial regression model was conducted to examine potential factors contributing to the incidence of SFTS at the village level. A total of 1,219 SFTS cases were reported in Shangcheng County from 2011 to 2020, with a case fatality rate of 12.0%. The median age of patients was 64 years, and 81.7% of patients were over 50 years old. Women accounted for 60.3% of all cases, and the incidence rate was significantly higher than that of men (Pearson χ2 test, P<0.001). Five spatial-temporal clusters were identified, and mostly distributed in the central part of the county. Higher risk of SFTS incidence was shown in villages with higher percentage coverages of forest and tea plantation, and higher goat density. In villages where the ratio of cultivated land area to forest land area was between 0.2 and 1.2, the risk of SFTS incidence increased significantly, with an incidence rate ratio of 1.33 (95% CI: 1.04‒1.72, p = 0.024). Our findings indicated that ecotone between forest and cultivated land might be the most important risk settings for exposure and infection with SFTS virus in endemic areas of central China. Precise identification of risk factors and high-risk areas at a suitable scale is conducive to carrying out targeted measures and improving the surveillance of the disease.
摘要：
严重发热伴血小板减少综合征（SFTS），中国中部农村地区首次报道了一种新兴的蜱传疾病，已成为流行地区的主要公共卫生问题。农村SFTS发病率的流行动态和生态因素尚不清楚。分析了商城县SFTS病例的流行病学特征,中国首次报道SFTS地区。进行了回顾性时空聚类分析，以确定热点区域的动态，并进行负二项回归模型，以检查影响村一级SFTS发病率的潜在因素。2011年至2020年，商城县共报告1,219例SFTS病例，病死率为12.0%。患者的中位年龄为64岁，81.7%的患者年龄超过50岁。女性占所有病例的60.3%,发病率明显高于男性(Pearsonχ2检验,P<0.001)。确定了五个时空集群，主要分布在县中部。在森林和茶园覆盖率较高的村庄中，SFTS发病率较高，和更高的山羊密度。在耕地面积与林地面积之比在0.2至1.2之间的村庄，SFTS发生的风险显着增加，发病率比为1.33(95%CI：1.04~1.72，p=0.024)。我们的发现表明，森林和耕地之间的过渡带可能是中国中部流行地区暴露和感染SFTS病毒的最重要风险环境。以合适的规模精确识别危险因素和高危区域,有利于开展针对性措施,提高对该病的监测水平。
