Institute for Global Health (IGH), University College London, London, UK.
Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, London, UK.
J Infect. 2022 Dec;85(6):683-692. doi: 10.1016/j.jinf.2022.09.016. Epub 2022 Sep 22.
Crimean-Congo haemorrhagic fever (CCHF) is a widespread tick-borne viral infection, present across Africa and Eurasia, which might pose a cryptic public health problem in Uganda. We aimed to understand the magnitude and distribution of CCHF risk in humans, livestock and ticks across Uganda by synthesising epidemiological (cross-sectional) and ecological (modelling) studies.
We conducted a cross-sectional study at three urban abattoirs receiving cattle from across Uganda. We sampled humans (n = 478), livestock (n = 419) and ticks (n = 1065) and used commercially-available kits to detect human and livestock CCHF virus (CCHFV) antibodies and antigen in tick pools. We developed boosted regression tree models to evaluate the correlates and geographical distribution of expected tick and wildlife hosts, and of human CCHF exposures, drawing on continent-wide data.
The cross-sectional study found CCHFV IgG/IgM seroprevalence in humans of 10·3% (7·8-13·3), with antibody detection positively associated with reported history of tick bite (age-adjusted odds ratio = 2·09 (1·09-3·98)). Cattle had a seroprevalence of 69·7% (65·1-73·4). Only one Hyalomma tick (CCHFV-negative) was found. However, CCHFV antigen was detected in Rhipicephalus (5·9% of 304 pools) and Amblyomma (2·9% of 34 pools) species. Modelling predicted high human CCHF risk across much of Uganda, low environmental suitability for Hyalomma, and high suitability for Rhipicephalus and Amblyomma.
Our epidemiological and ecological studies provide complementary evidence that CCHF exposure risk is widespread across Uganda. We challenge the idea that Hyalomma ticks are consistently the principal reservoir and vector for CCHFV, and postulate that Rhipicephalus might be important for CCHFV transmission in Uganda, due to high frequency of infected ticks and predicted environmental suitability.
UCL Global Challenges Research Fund (GCRF) and Pan-African Network on Emerging and Re-Emerging Infections (PANDORA-ID-NET) funded by the European and Developing Countries Clinical Trials Partnership (EDCTP) under the EU Horizon 2020 Framework Programme for Research and Innovation.
克里米亚-刚果出血热（CCHF）是一种广泛存在的蜱传病毒感染，分布于非洲和欧亚大陆，可能在乌干达构成一个隐匿的公共卫生问题。我们旨在通过综合流行病学（横断面）和生态学（建模）研究来了解乌干达人类、牲畜和蜱虫中 CCHF 风险的规模和分布。
我们在三个接收来自乌干达各地的牛的城市屠宰场进行了横断面研究。我们对 478 名人类、419 名牲畜和 1065 只蜱虫进行了采样，并使用商业试剂盒检测蜱虫样本中的人类和牲畜 CCHF 病毒（CCHFV）抗体和抗原。我们开发了增强回归树模型，以评估预期的蜱虫和野生动物宿主以及人类 CCHF 暴露的相关因素和地理分布，该模型利用了全大陆范围的数据。
横断面研究发现人类的 CCHFV IgG/IgM 血清阳性率为 10.3%（7.8-13.3），抗体检测与报告的蜱虫叮咬史呈正相关（年龄调整后的优势比=2.09（1.09-3.98））。牛的血清阳性率为 69.7%（65.1-73.4）。仅发现一只（CCHFV 阴性）钝缘蜱。然而，在 Rhipicephalus（304 个样本中 5.9%）和 Amblyomma（34 个样本中 2.9%）物种中检测到 CCHFV 抗原。模型预测，乌干达大部分地区的人类 CCHF 风险较高，Hyalomma 对环境的适宜性较低，而 Rhipicephalus 和 Amblyomma 的适宜性较高。
我们的流行病学和生态学研究提供了互补的证据，表明 CCHF 暴露风险在乌干达广泛存在。我们对钝缘蜱始终是 CCHFV 的主要储存宿主和传播媒介的观点提出了挑战，并推测由于感染蜱虫的高频率和预测的环境适宜性，Rhipicephalus 可能在乌干达的 CCHFV 传播中很重要。
伦敦大学学院全球挑战研究基金（GCRF）和泛非新兴和再发传染病网络（PANDORA-ID-NET），由欧洲和发展中国家临床试验伙伴关系（EDCTP）通过欧盟地平线 2020 研究和创新框架计划资助。
