Abstract：
Background: The largest documented outbreak of hemorrhagic fever with renal syndrome occurred in Primorje-Gorski Kotar County, Croatia, in 2021, marking the first-time cases of hantavirus infection recorded outside of the known endemic region in the north of the county. Aim: To identify the factors contributing to the spread of the outbreak and to compare risk factors for acquiring hantavirus infection in the endemic and newly affected regions. Methods and Results: A total of 189 cases were confirmed by positive Puumala IgM/IgG antibodies (93.6%), and 13 probable cases were identified by clinical and epidemiological data (6.4%) using a structured questionnaire. Of the 179 cases with available clinical data, 59 (33.0%) were hospitalized. Three cases received hemodialysis, and no deaths were reported. Among 170 cases with information on exposures, 66 (38.8%) reported occupational risk. Cases in the northern part of county were more likely to have been infected in early spring (OR 27.1, 95% CI 2.93-250.7), to report seeing a rodent (OR 6.5; 95%CI 2.3-18.4), and to know someone with hemorrhagic fever with renal syndrome (HFRS) (OR 3.0; 95%CI 1.2-8.0) than cases from the southern part of the county. Data from Croatian Forests Ltd. suggested that an unusually good production of beech seeds in 2020 may have contributed to an increased rodent population in 2021. However, average temperature, rainfall, and humidity data from 2021 did not illustrate a significant difference from previous years (Kruskal-Wallis p = 0.837, p = 0.999, p = 0.108). Conclusion: The 2021 HFRS outbreak was likely fueled by an abundant rodent population and virus transmission in rodent hosts. Human activity, environmental factors, and the ensuing animal-human interactions have spread hantavirus infection from Croatia\'s mountainous region to a previously nonendemic coastal area with a Mediterranean climate.
摘要：
背景：有记录的最大的肾综合征出血热暴发发生在Primorje-GorskiKotar县，克罗地亚,2021年，这标志着在该县北部已知的流行地区之外记录的首次汉坦病毒感染病例。目的：确定导致疫情蔓延的因素，并比较流行和新感染地区汉坦病毒感染的危险因素。方法与结果:PuumalaIgM/IgG抗体阳性确诊189例(93.6%),使用结构化问卷通过临床和流行病学数据确定了13例可能病例(6.4%).在有临床资料的179例病例中,59例（33.0％）住院。3例接受血液透析，没有死亡报告。在170个有暴露信息的案例中，66（38.8%）报告了职业风险。县北部的病例更有可能在早春感染（OR27.1，95％CI2.93-250.7），报告看到啮齿动物（OR6.5；95CI2.3-18.4），并且知道患有肾综合征出血热（HFRS）（OR3.0；95CI1.2-8.0）的人比该县南部的病例要多。克罗地亚森林有限公司的数据表明，2020年山毛榉种子的异常良好产量可能导致2021年啮齿动物数量增加。然而,平均温度,降雨,2021年的湿度数据并未说明与往年的显着差异（Kruskal-Wallisp=0.837，p=0.999，p=0.108）。结论：2021年HFRS爆发可能是由丰富的啮齿动物种群和啮齿动物宿主中的病毒传播推动的。人类活动,环境因素,随之而来的动物与人类的相互作用已经将汉坦病毒感染从克罗地亚的山区传播到了一个以前没有流行的地中海气候的沿海地区。
