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Molecular Characterization of Rift Valley Fever Virus From the 2025 Outbreak in Northern Senegal Reveals Lineage H Persistence and Key Polymerase Mutations.

Rift Valley fever virus (RVFV) is a mosquito-borne phlebovirus that causes severe febrile and hemorrhagic illness in humans. In September 2025, an outbreak in northern Senegal led to 119 confirmed infections and 15 deaths as of October 7, 2025. We performed rapid genomic sequencing to characterize the virus responsible for this epidemic. RNA from RT-qPCR-confirmed samples was sequenced using the Twist Comprehensive Viral Research Panel on an Illumina iSeq 100 platform. Consensus genomes were analyzed with and compared with all complete RVFV genomes in GenBank. Nine genomes were recovered, incl…

Заболеваемость вирусом лихорадки Брюселла и Рифт-Вэлли в общинных скотоводах на стыке живой природы, район Замбези, Намибия.

ВВЕДЕНИЕ: Брюслоз и лихорадка Рифт-Вэлли (RVF) не учитывают зоонотические заболевания (NZD), которые угрожают здоровью населения, здоровью животных и производству в странах с ограниченными ресурсами, включая Намибию. Цель этого перекрестного исследования состояла в том, чтобы определить распространенность серопов Brusella spp. и RVFV у скота на стыке живой природы в южном округе Каббе (область Замбези) Намибии. Sera (n = 371) была произвольно собрана у 18 стада скота в шести избирательных округах и испытана на антитела против Brusella [комплексный тест на фиксацию (CFT) и непрямого иммуносорбе

Совпадение в аннотации оригинала
INTRODUCTION: Brucellosis and Rift Valley fever (RVF) are neglected zoonotic diseases (NZD) that threaten public health, animal health, and production in resource-limited countries including Namibia. METHODS: The objective of this cross-sectional study was to determine Brucella spp. and RVFV seroprevalence in cattle at the wildlife-livestock interface in th…

Paving the way for human vaccination against Rift Valley fever virus: A systematic literature review of RVFV epidemiology from 1999 to 2021.

BACKGROUND: Rift Valley fever virus (RVFV) is a lethal threat to humans and livestock in many parts of Africa, the Arabian Peninsula, and the Indian Ocean. This systematic review's objective was to consolidate understanding of RVFV epidemiology during 1999-2021 and highlight knowledge gaps relevant to plans for human vaccine trials. METHODOLOGY/PRINCIPAL FINDINGS: The review is registered with PROSPERO (CRD42020221622). Reports of RVFV infection or exposure among humans, animals, and/or vectors in Africa, the Arabian Peninsula, and the Indian Ocean during the period January 1999 to June 2021 …

Risk factors for Rift Valley fever virus seropositivity in one-humped camels (Camelus dromedarius) and pastoralist knowledge and practices in Northern Nigeria.

Rift Valley fever (RVF) is a complex emerging arboviral hemorrhagic disease that causes significant illness in animals and humans. Camel trade across the land borders between Nigeria and the Niger Republic occurs frequently and poses a significant risk for RVF transmission to pastoralists and traders. We carried a cross-sectional study between November 2016 and April 2017 in two northern States (Katsina and Jigawa) known for camel trade in Nigeria to investigate the seroprevalence and potential risk factors for RVFV occurrence. We collected 720 sera and administered questionnaire to pastoralis…

Evaluation of an Indirect Enzyme-Linked Immunosorbent Assay Based on Recombinant Baculovirus-Expressed Rift Valley Fever Virus Nucleoprotein as the Diagnostic Antigen.

The increasing risk of Rift Valley fever virus (RVFV) infection as a global veterinary and public health threat demands the development of safe and accurate diagnostic tests. The aim of this study was to assess the suitability of a baculovirus expression system to produce recombinant RVFV nucleoprotein (N) for use as serodiagnostic antigen in an indirect enzyme-linked immunosorbent assay (ELISA). The ability of the recombinant N antigen to detect RVFV antibody responses was evaluated in ELISA format using antisera from sheep and cattle experimentally infected with two genetically distinct wild…

Anti-Rift Valley fever virus activity in vitro, pre-clinical pharmacokinetics and oral bioavailability of benzavir-2, a broad-acting antiviral compound.

Rift Valley fever virus (RVFV) is a mosquito-borne hemorrhagic fever virus affecting both humans and animals with severe morbidity and mortality and is classified as a potential bioterror agent due to the possible aerosol transmission. At present there is no human vaccine or antiviral therapy available. Thus, there is a great need to develop new antivirals for treatment of RVFV infections. Benzavir-2 was previously identified as potent inhibitor of human adenovirus, herpes simplex virus type 1, and type 2. Here we assess the anti-RVFV activity of benzavir-2 together with four structural analog…

Association between Rift Valley fever virus seroprevalences in livestock and humans and their respective intra-cluster correlation coefficients, Tana River County, Kenya.

We implemented a cross-sectional study in Tana River County, Kenya, a Rift Valley fever (RVF)-endemic area, to quantify the strength of association between RVF virus (RVFv) seroprevalences in livestock and humans, and their respective intra-cluster correlation coefficients (ICCs). The study involved 1932 livestock from 152 households and 552 humans from 170 households. Serum samples were collected and screened for anti-RVFv immunoglobulin G (IgG) antibodies using inhibition IgG enzyme-linked immunosorbent assay (ELISA). Data collected were analysed using generalised linear mixed effects models…

An equine herpesvirus type 1 (EHV-1) vector expressing Rift Valley fever virus (RVFV) Gn and Gc induces neutralizing antibodies in sheep.

Rift Valley fever virus (RVFV) is an arthropod-borne bunyavirus that can cause serious and fatal disease in humans and animals. RVFV is a negative-sense RNA virus of the Phlebovirus genus in the Bunyaviridae family. The main envelope RVFV glycoproteins, Gn and Gc, are encoded on the M segment of RVFV and known inducers of protective immunity. In an attempt to develop a safe and efficacious RVF vaccine, we constructed and tested a vectored equine herpesvirus type 1 (EHV-1) vaccine that expresses RVFV Gn and Gc. The Gn and Gc genes were custom-synthesized after codon optimization and inserted in…

High-Throughput Screening Using a Whole-Cell Virus Replication Reporter Gene Assay to Identify Inhibitory Compounds against Rift Valley Fever Virus Infection.

Rift Valley fever virus (RVFV) is an emerging virus that causes serious illness in humans and livestock. There are no approved vaccines or treatments for humans. The purpose of the study was to identify inhibitory compounds of RVFV infection without any preconceived idea of the mechanism of action. A whole-cell-based high-throughput drug screening assay was developed to screen 28,437 small chemical compounds targeting RVFV infection. To accomplish both speed and robustness, a replication-competent NSs-deleted RVFV expressing a fluorescent reporter gene was developed. Inhibition of fluorescence…

Complete Genome Sequence of Two Rift Valley Fever Virus Strains Isolated from Outbreaks in Saudi Arabia (2000) and Kenya (2006 to 2007).

The complete genome sequence, including the untranslated regions, of two Rift Valley fever virus (RVFV) strains isolated from mosquitoes that were collected from disease outbreaks in Saudi Arabia (2001) and Kenya (2006 to 2007) were sequenced using next-generation sequencing technology.

Biochemical and biophysical characterization of cell-free synthesized Rift Valley fever virus nucleoprotein capsids enables in vitro screening to identify novel antivirals.

BACKGROUND: Viral capsid assembly involves the oligomerization of the capsid nucleoprotein (NP), which is an essential step in viral replication and may represent a potential antiviral target. An in vitro transcription-translation reaction using a wheat germ (WG) extract in combination with a sandwich ELISA assay has recently been used to identify small molecules with antiviral activity against the rabies virus. RESULTS: Here, we examined the application of this system to viruses with capsids with a different structure, such as the Rift Valley fever virus (RVFV), the etiological agent of a se…

A complex adenovirus-vectored vaccine against Rift Valley fever virus protects mice against lethal infection in the presence of preexisting vector immunity.

Rift Valley fever virus (RVFV) has been cited as a potential biological-weapon threat due to the serious and fatal disease it causes in humans and animals and the fact that this mosquito-borne virus can be lethal in an aerosolized form. Current human and veterinary vaccines against RVFV, however, are outdated, inefficient, and unsafe. We have incorporated the RVFV glycoprotein genes into a nonreplicating complex adenovirus (CAdVax) vector platform to develop a novel RVFV vaccine. Mice vaccinated with the CAdVax-based vaccine produced potent humoral immune responses and were protected against l…

Exposure to Arboviruses in Cattle: Seroprevalence of Rift Valley Fever, Bluetongue, and Epizootic Hemorrhagic Disease Viruses and Risk Factors in Baringo County, Kenya.

Rift Valley fever virus (RVFV) causes disease outbreaks in livestock and humans; however, its inter-epidemic circulation is poorly understood, similar to other arboviruses affecting cattle such as bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV). Serum samples were collected in Baringo County, Kenya from 400 cattle, accompanied by a risk factor questionnaire. Serological tests were then conducted to determine the exposure of cattle to RVFV, BTV, and EHDV. RVFV, BTV, and EHDV IgG seroprevalence rates were 15.5%, 91.5%, and 91%, respectively. Seropositivity for RVFV, BTV, an…

Evaluation of the Efficacy, Potential for Vector Transmission, and Duration of Immunity of MP-12, an Attenuated Rift Valley Fever Virus Vaccine Candidate, in Sheep.

Rift Valley fever virus (RVFV) causes serious disease in ruminants and humans in Africa. In North America, there are susceptible ruminant hosts and competent mosquito vectors, yet there are no fully licensed animal vaccines for this arthropod-borne virus, should it be introduced. Studies in sheep and cattle have found the attenuated strain of RVFV, MP-12, to be both safe and efficacious based on early testing, and a 2-year conditional license for use in U.S. livestock has been issued. The purpose of this study was to further determine the vaccine's potential to infect mosquitoes, the duration …

Deletion of the NSm virulence gene of Rift Valley fever virus inhibits virus replication in and dissemination from the midgut of Aedes aegypti mosquitoes.

BACKGROUND: Previously, we investigated the role of the Rift Valley fever virus (RVFV) virulence genes NSs and NSm in mosquitoes and demonstrated that deletion of NSm significantly reduced the infection, dissemination, and transmission rates of RVFV in Aedes aegypti mosquitoes. The specific aim of this study was to further characterize midgut infection and escape barriers of RVFV in Ae. aegypti infected with reverse genetics-generated wild type RVFV (rRVF-wt) or RVFV lacking the NSm virulence gene (rRVF-ΔNSm) by examining sagittal sections of infected mosquitoes for viral antigen at various ti…

The 2006-2007 Rift Valley fever outbreak in Kenya: sources of early warning messages and response measures implemented by the Department of Veterinary Services.

The authors characterised sources of early warning messages about occurrences of Rift Valley fever (RVF) and examined the response measures that were used by the Department of Veterinary Services (DVS) to manage the 2006-2007 RVF outbreaks in Kenya. The study was conducted between November 2009 and March 2010 and it included national, provincial and district veterinary officers who were involved in the management of the outbreak. Structured questionnaires were used to collect the data. Although the majority of the respondents reported having limited capacity to implement response measures, the…

Comparison of enzyme-linked immunosorbent assay-based techniques for the detection of antibody to Rift Valley fever virus in thermochemically inactivated sheep sera.

Different enzyme-linked immunosorbent assay (ELISA)-based techniques for the detection of antibodies to Rift Valley fever virus (RVFV) have been developed in recent years, but their diagnostic sensitivity was not directly compared. In addition, their use might still be restricted to high biocontainment facilities when sera to be tested are collected from viremic individuals. In this study, we report on direct comparison of various ELISA forms for the detection of anti-RVFV antibody in preinactivated sera using a simple thermochemical treatment. Results in naive and treated sera from experiment…

Evaluation of pathways for release of Rift Valley fever virus into domestic ruminant livestock, ruminant wildlife, and human populations in the continental United States.

OBJECTIVE: To evaluate the feasibility for Rift Valley fever virus (RVFV) to enter the continental United States by various routes as well as to identify states in which domestic and wild ruminant and human populations would be most vulnerable to exposure to RVFV. STUDY DESIGN: Pathways analysis. SAMPLE POPULATION: Animals, commodities, and humans transported from RVFV-endemic countries to the continental United States between 2000 and 2005. PROCEDURES: Initially, agent, host, and environmental factors important in the epidemiologic aspects of RVFV were used to develop a list of potential p…

Rescue of infectious rift valley fever virus entirely from cDNA, analysis of virus lacking the NSs gene, and expression of a foreign gene.

Rift Valley fever virus (RVFV) (genus Phlebovirus, family Bunyaviridae) has a tripartite negative-strand genome, causes a mosquito-borne disease that is endemic in sub-Saharan African countries and that also causes large epidemics among humans and livestock. Furthermore, it is a bioterrorist threat and poses a risk for introduction to other areas. In spite of its danger, neither veterinary nor human vaccines are available. We established a T7 RNA polymerase-driven reverse genetics system to rescue infectious clones of RVFV MP-12 strain entirely from cDNA, the first for any phlebovirus. Express…