Situma Silvia, Omondi Evans, Nyakarahuka Luke, Odinoh Raymond, Mweu Marshal, Mureithi Marianne W, Mulinge Martin M, Clancey Erin, Dawa Jeanette, Ngere Isaac, Osoro Eric, Gunn Bronwyn, Konongoi Limbaso, Khamadi Samoel A, Michiels Johan, Ariën Kevin K, Bakamutumaho Barnabas, Breiman Robert F, Njenga Kariuki
Department of Medical Microbiology and Immunology, University of Nairobi, Nairobi 00202, Kenya.
Washington State University Global Health Program-Kenya, Nairobi 00200, Kenya.
Viruses. 2024 Dec 17;16(12):1927. doi: 10.3390/v16121927.
Although the highlands of East Africa lack the geo-ecological landmarks of Rift Valley fever (RVF) disease hotspots to participate in cyclic RVF epidemics, they have recently reported growing numbers of small RVF clusters. Here, we investigated whether RVF cycling occurred among livestock and humans in the central highlands of Kenya during inter-epidemic periods. A 2-year prospective hospital-based study among febrile patients (March 2022-February 2024) in Murang'a County of Kenya was followed by a cross-sectional human-animal survey. A total of 1468 febrile patients were enrolled at two clinics and sera tested for RVF virus RNA and antiviral antibodies. In the cross-sectional study, humans (n = 282) and livestock (n = 706) from randomly selected households were tested and questionnaire data were used to investigate sociodemographic and environmental risk factors by multivariate logistic regression. No human (n = 1750) or livestock (n = 706) sera tested positive for RVFV RNA. However, 4.4% livestock and 2.0% humans tested positive for anti-RVFV IgG, including 0.27% febrile patients who showed four-fold IgG increase and 2.4% young livestock (<12 months old), indicating recent virus exposure. Among humans, the odds of RVF exposure increased significantly ( < 0.05, 95% CI) in males (aOR: 4.77, 2.08-12.4), those consuming raw milk (aOR: 5.24, 1.13-17.9), milkers (aOR: 2.69, 1.23-6.36), and participants residing near quarries (aOR: 2.4, 1.08-5.72). In livestock, sheep and goats were less likely to be seropositive (aOR: 0.27, 0.12-0.60) than cattle. The increase in RVF disease activities in the highlands represents a widening geographic dispersal of the virus, and a greater risk of more widespread RVF epidemics in the future.
尽管东非高地缺乏裂谷热（RVF）疾病热点地区的地理生态标志来参与RVF的周期性流行，但最近有报道称该地区小规模RVF聚集病例数量不断增加。在此，我们调查了肯尼亚中部高地在疫情间期家畜和人类中是否发生RVF循环。在肯尼亚穆朗加县对发热患者进行了一项为期两年的前瞻性医院研究（2022年3月至2024年2月），随后进行了一项横断面人畜调查。在两家诊所共招募了1468名发热患者，并对其血清进行RVF病毒RNA和抗病毒抗体检测。在横断面研究中，对随机选取家庭中的人类（n = 282）和家畜（n = 706）进行检测，并使用问卷数据通过多因素逻辑回归分析来调查社会人口统计学和环境风险因素。没有人类（n = 1750）或家畜（n = 706）血清的RVFV RNA检测呈阳性。然而，4.4%的家畜和2.0%的人类抗RVFV IgG检测呈阳性，其中包括0.27%发热患者的IgG呈四倍增加以及2.4%的幼畜（<12个月大），表明近期有病毒暴露。在人类中，男性（aOR：4.77，2.08 - 12.4）、饮用生奶者（aOR：5.24，1.13 - 17.9）、挤奶工（aOR：2.69，1.23 - 6.36）以及居住在采石场附近的参与者（aOR：2.4，1.08 - 5.72）感染RVF的几率显著增加（<0.05，95% CI）。在家畜中，绵羊和山羊血清阳性的可能性低于牛（aOR：0.27，0.12 - 0.60）。高地地区RVF疾病活动的增加表明该病毒的地理传播范围在扩大，未来发生更广泛RVF疫情的风险也更大。
