Siller Anita, Chitimia-Dobler Lidia, Hitzl Wolfgang, Astl Manfred, Schennach Harald, Fraunberger Peter, Cadamuro Janne, Borde Johannes P, Willeit Peter, Dobler Gerhard, Mink Sylvia
Central Institute for Blood Transfusion and Immunology, University Hospital of Innsbruck, Tirol Kliniken GmbH, Innsbruck, Austria.
Bundeswehr Institute for Microbiology, National TBEV Consultant Laboratory, Munich, Germany.
J Med Virol. 2024 Dec;96(12):e70109. doi: 10.1002/jmv.70109.
Reported tick-borne-encephalitis (TBE) cases have been increasing in Western Austria, but no data are available on vaccination- and infection-specific seroprevalence. This study aimed to estimate current TBEV-seroprevalence in the region and inform prevention programs by comparing anti-NS1-based-incidence rates with reported case numbers and vaccination coverage. Between December 2023 and February 2024, serum samples from 4619 blood donors in Western Austria were collected and analyzed using TBEV- and WNV-IgG-ELISA assays. Seropositive samples were tested with a TBEV-anti-NS1-IgG-ELISA to distinguish infections from vaccinations. Borderline samples were retested with serum neutralization and triple-NS1-assays. The overall anti-TBEV-IgG-seroprevalence was 80.1% (95%CI 78.9-81.3); 2.7% (95%CI 2.3-3.2) of donors tested positive for anti-TBEV-NS1 IgG antibodies, indicating previous infection. The notified incidence rate in Western Austria was 2.7/100 000/year, compared to 136.2/100 000/year based on anti-TBEV-NS1-seropositive donors, denoting a substantial number of unreported cases (mean manifestation index 1.9%). The number of donors with TBEV-infections varied considerably by district, highlighting potential hotspots for TBEV-infections. The high anti-NS1-based, estimated annual TBE incidence rates show significant differences between districts, highlighting the need for targeted prevention programs. The high rate of undiagnosed TBE cases further suggests that estimated anti-NS1-based incidence rates should be considered when defining high-risk areas.
据报告，奥地利西部蜱传脑炎（TBE）病例一直在增加，但尚无关于疫苗接种和感染特异性血清阳性率的数据。本研究旨在估计该地区目前的蜱传脑炎病毒（TBEV）血清阳性率，并通过比较基于抗NS1的发病率与报告的病例数及疫苗接种覆盖率，为预防计划提供信息。2023年12月至2024年2月期间，收集了奥地利西部4619名献血者的血清样本，并使用TBEV和西尼罗河病毒（WNV）IgG酶联免疫吸附测定（ELISA）进行分析。对血清阳性样本进行TBEV抗NS1 IgG ELISA检测，以区分感染和疫苗接种。临界样本用血清中和试验和三重NS1试验重新检测。总体抗TBEV IgG血清阳性率为80.1%（95%置信区间78.9 - 81.3）；2.7%（95%置信区间2.3 - 3.2）的献血者抗TBEV NS1 IgG抗体检测呈阳性，表明既往感染。奥地利西部的报告发病率为每年2.7/10万，而基于抗TBEV NS1血清阳性献血者的发病率为每年136.2/10万，这表明有大量未报告病例（平均表现指数1.9%）。TBEV感染的献血者数量在不同地区差异很大，突出了TBEV感染的潜在热点地区。基于抗NS1的估计年度TBE发病率在不同地区之间存在显著差异，突出了制定针对性预防计划的必要性。未诊断出的TBE病例比例很高，这进一步表明在确定高风险地区时应考虑基于抗NS1的估计发病率。
