Livestock Seroreactivity.

BackgroundCrimean-Congo Hemorrhagic Fever (CCHF) is a potential high-threat zoonotic disease caused by the Crimean-Congo hemorrhagic fever virus (CCHFV). Transmission of CCHFV occurs primarily through bites of infected Hyalomma ticks or direct contact with infected animals or humans. This study presents a cross-sectional assessment of CCHFV seroprevalence and risk factors associated with occupational and environmental exposures among cattle, swine, and agricultural workers.MethodsNine provinces across the Democratic Republic of the Congo (DRC) were selected and collection took place from June 2023 to July 2024. Five herds per species in each province were randomly visited, and at each facility or herd, up to 20 animals were chosen for serum sampling and attached tick collection. In five provinces, farm workers present on the day of collection were enrolled. Detection of anti-CCHFV Immunoglobulin G (IgG) antibodies was assessed via an in-house nucleoprotein-based enzyme-linked immunosorbent assay (ELISA).ResultsAmong the 1,118 cattle surveyed across nine provinces 57.0% (95%CI: 54.1-59.9%) were seroreactive. Cattle from two provinces in the southeast, Tanganyika and Lualaba, had 94.6% (95%CI: 89.9-99.2%) and 90.7% (95%CI: 84.9-96.5%) reactivity, respectively. Among the 1,020 swine surveyed 13.4% (95%CI: 11.1-15.2%) were seroreactive. Among the 180 agricultural workers surveyed, 12.8% (95%CI: 7.9-17.6%) were seroreactive for CCHF antibodies.ConclusionsThis serologic survey indicated that CCHFV is circulating in the DRC and the southeast provinces are particularly at risk for spillover and morbidity among humans. Though no human cases have been reported since 2008, surveillance for CCHF should be considered among veterinary professional and healthcare workers.研究背景：克里米亚-刚果出血热（Crimean-Congo Hemorrhagic Fever, CCHF）是一种由克里米亚-刚果出血热病毒（Crimean-Congo hemorrhagic fever virus, CCHFV）引发的潜在高威胁人畜共患病。CCHFV的传播主要通过感染的璃眼蜱（Hyalomma ticks）叮咬，或直接接触受感染动物与人类。本研究针对牛、猪及农业从业者，开展了关于CCHFV血清流行率及职业与环境暴露相关危险因素的横断面调查。 研究方法：本研究选取刚果民主共和国（Democratic Republic of the Congo, DRC）的9个省份，采样时段为2023年6月至2024年7月。每个省份按畜禽种类随机走访5个畜群，在每个养殖场或畜群中选取至多20头动物进行血清采样，并收集其体表附着的蜱虫。在其中5个省份，招募采样当日在场的农场工作人员纳入研究。采用自主建立的核蛋白基酶联免疫吸附试验（enzyme-linked immunosorbent assay, ELISA）检测抗CCHFV免疫球蛋白G（Immunoglobulin G, IgG）抗体。 研究结果：在9个省份共调查的1118头牛中，57.0%（95%置信区间：54.1%~59.9%）的血清呈血清学反应阳性。来自东南部坦噶尼喀（Tanganyika）与卢阿拉巴（Lualaba）两省的牛群，其血清阳性率分别为94.6%（95%CI: 89.9%~99.2%）与90.7%（95%CI: 84.9%~96.5%）。在共调查的1020头猪中，13.4%（95%CI: 11.1%~15.2%）的血清呈阳性反应。在共调查的180名农业从业者中，12.8%（95%CI: 7.9%~17.6%）的CCHF抗体检测结果为阳性。 研究结论：本次血清学调查显示，CCHFV在刚果民主共和国存在循环传播，且东南部省份尤其面临病毒溢出至人类并引发发病的高风险。尽管自2008年以来未报告人类感染病例，但仍应将CCHF监测纳入兽医专业人员与医护人员的监测范围。