From Rift to Global Risk: A One Health Perspective on Rift Valley Fever as an Emerging Public Health Threat

Abstract

The zoonotic illness known as Rift Valley Fever (RVF) is spread by mosquitoes and poses a serious risk to public and human health. Within the order Bunyavirales, the genus Phlebovirus and family Phenuiviridae comprise the causal agent, Rift Valley fever phlebovirus (RVFV). The transboundary spread of RVFV is seriously threatened by the substantial presence of competent vectors in regions where the disease is often absent as well as the effects of global climate change. The development of innovative vaccinations, such as DIVA (differentiating infected from vaccinated animals) vaccines, has been greatly aided by advances in the last ten years in our understanding of the molecular biology of RVFV. Despite these developments, non-endemic nations still lack a completely approved vaccination for human or animal use. It is clear that endemic nations lack clear policies or procedures pertaining to the routine or strategic immunization of cattle with the goal of averting or mitigating any RVF disease outbreaks. In addition to offering insights on the best methods for managing the illness, this study aims to give a current summary of the state of RVF vaccine development. This study argues that the most effective way to prevent future disease outbreaks and disease spread. First discovered and characterized in Kenya in 1931, Rift Valley Fever (RVF) is a viral zoonosis spread by mosquitoes. Significant losses have been caused by RVF outbreaks, as seen in the rise in animal abortions and deaths as well as human sickness and mortality. The epidemiology of RVF is thoroughly examined in this research, which covers topics like ecology, molecular diversity, spatiotemporal analysis, and predictive risk modeling. Aedes mosquitoes are recognized as the main cause of outbreaks, whereas Culex mosquitoes act as secondary vectors for the Rift Valley fever virus (RVFV). Nonetheless, the function of Culex species in transmission dynamics could be impacted by environmental change. Our work’s objectives were to compile a thorough set of published research from Kenya and Tanzania, pinpoint knowledge gaps on Culex groups, and determine whether there was enough spatiotemporal published data available for a future meta-analysis. This represents a first effort to use the data currently available to gain a deeper comprehension of Culex’s function in sustaining RVFV transmission. Using Web of Science, a comprehensive review of the literature was conducted to identify research that sampled Culex in Tanzania or Kenya up until April 28, 2023. In respect to an RVFV risk map, the study identified the major factors impacting the studies, such as their duration and geographic coverage. After that, we evaluated the various methods for identifying species and examined how they could have affected the outcomes. Out of 275 investigations, 17 clearly demonstrated that RVFV served as the catalyst for the inquiry. There was substantial documentation of studies focused on mosquito sampling in regions linked to the risk of RVFV outbreaks, even though different studies examined a variety of topics. Fifty experiments in all were carried out for a minimum of 12 months. Studies on species identification revealed that using a Culex-specific key increased the chance of finding new species outside of the Culex pipiens complex by almost 14 times. We suggest that the data from these broader investigations might potentially provide significant insights into the persistence of RVFV transmission, even though many published studies sampling Culex in Kenya and/or Tanzania did not explicitly specify RVFV as a key study topic.