Detection of Rift Valley Fever Virus Interepidemic Activity in Lower Moshi Area of Kilimanjaro Region, Northeastern Tanzania: A Community Survey
Loading...
Date
2025-08
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
NM-AIST
Abstract
Rift Valley fever virus (RVFV) is a zoonotic viral disease of public health importance that affects livestock, wildlife and humans, mainly in sub-Saharan Africa. Despite its public health importance, the ways in which RVFVs circulate during the inter-epidemics (IEPs) stages and potentially spread to new areas remain unclear. The IEPs are the period during which transmissions pass without being detected, whereas surveillance is not performed. This study aimed to compare the rates of exposure to RVFV and RVFV infection among humans, goats and mosquito vectors in an agricultural and pastoral community in the lower Moshi area of the Moshi rural district. The area is located along the Great Rift Valley and is characterized by animal maintenance and heavy seasonal rains, making it swampy and favoring mosquito reproduction throughout. Although the spread of RVFV by mosquito vectors to animals and humans during interepidemic periods has been established, less is known about the roles that animals, humans, and vector mosquitoes play in maintaining the virus during IEPs. The reservoirs in the IEPs have become an area of interest for research. Therefore, a cross-sectional study survey was conducted in Lower Moshi in the Kilimanjaro region from June to December 2020. The RVFV exposure was determined via the detection of IgG/IgM to RVFV via a competitive enzyme-linked immunosorbent assay (cELISA), whereas infection was determined via real-time quantitative polymerase chain reaction (RT‒qPCR). In humans, male sex was more related to RVFV seropositivity than female sex was (χ² = 5.351; p=0.030). People aged 50 years and above were seropositive (χ² =14.430; p=0.006). The RVFV seropositivity in goats was related to increased seropositivity in humans (χ² =6.003; p=0.021, χ² =23.213; p=0.000 and 27.053; p=0.000). The RVFV antibody concentrations were only marginally higher in humans than in goats [t (112) =0.526; p=0.60)]. The RT‒qPCR revealed that goats presented the highest RVFV infection rate (4.1%), followed by humans (2.6%), Aedes aegypti (2.3%), and the Culex pipiens complex (1.5%). Similarly, a greater proportion of goats (23.3%) were RVFV seropositive than were humans (13.2%). These findings suggest that northeastern Tanzania may serve as a persistent hotspot for RVF transmission and call for the implementation of integrated, health-based active surveillance strategies targeting livestock, humans and vectors. Enhanced diagnostics, targeted vaccination and climate-informed risk mapping are recommended to enable timely interventions and reduce the likelihood of future RVF outbreaks.
Sustainable Development Goals
SDG: 2- Zero Hunger
SDG: 3- Good Health and Well-Being