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Rift Valley fever seroprevalence and abortion frequency among livestock of Kisoro district, South Western Uganda (2016): a prerequisite for zoonotic infection.

BACKGROUND: Rift Valley fever (RVF) is classified as viral hemorrhagic fever and is endemic in East and West Africa. RVF is caused by an arthropod borne virus (RVFV); the disease is zoonotic and affects human, animal health as well as international trade. In livestock it causes abortions, while human infection occurs through close contact with infected animals or animal products. METHODS: A quantitative observational study using stratified sampling was conducted in the western region of Uganda. Blood samples and abortion events from 1000 livestock (goats, sheep and cattle) was collected and r…

Development of a Quantitative RT-PCR Assay to Differentiate Rift Valley Fever Virus Smithburn Vaccine Strain from Clone 13 Vaccine Strain.

A new quantitative RT-PCR assay was developed to differentiate Rift Valley fever (RVF) Smithburn vaccine strain from Clone 13 vaccine strain. The new qRT-PCR assay targeting the S segment (NSs and N gene) was tested on synthesized standard RNA and MP-12 strain viruses. The detection limit of the new qRT-PCR assay is 1 copy/μL of NSs and N, and is able to differentiate the Smithburn vaccine strain of RVF from the Clone 13 vaccine strain. No cross-reactivity with other vector-borne viruses was observed, a factor that is especially important in the Republic of Korea (ROK). To examine the performa…

A single-cycle replicable Rift Valley fever phlebovirus vaccine carrying a mutated NSs confers full protection from lethal challenge in mice.

Rift Valley fever phlebovirus (RVFV) is a pathogen of Rift Valley fever, which is a mosquito-borne zoonotic disease for domestic livestock and humans in African countries. Currently, no approved vaccine is available for use in non-endemic areas. The MP-12 strain is so far the best live attenuated RVFV vaccine candidate because of its good protective efficacy in animal models. However, there are safety concerns for use of MP-12 in humans. We previously developed a single-cycle replicable MP-12 (scMP-12) which lacks NSs gene and undergoes only a single round of viral replication because of its i…

The L, M, and S Segments of Rift Valley Fever Virus MP-12 Vaccine Independently Contribute to a Temperature-Sensitive Phenotype.

UNLABELLED: Rift Valley fever (RVF) is endemic to Africa, and the mosquito-borne disease is characterized by "abortion storms" in ruminants and by hemorrhagic fever, encephalitis, and blindness in humans. Rift Valley fever virus (RVFV; family Bunyaviridae, genus Phlebovirus) has a tripartite negative-stranded RNA genome (L, M, and S segments). A live-attenuated vaccine for RVF, the MP-12 vaccine, is conditionally licensed for veterinary use in the United States. MP-12 is fully attenuated by the combination of the partially attenuated L, M, and S segments. Temperature sensitivity (ts) limits vi…

Nonspreading Rift Valley Fever Virus Infection of Human Dendritic Cells Results in Downregulation of CD83 and Full Maturation of Bystander Cells.

Vaccines based on nonspreading Rift Valley fever virus (NSR) induce strong humoral and robust cellular immune responses with pronounced Th1 polarisation. The present work was aimed to gain insight into the molecular basis of NSR-mediated immunity. Recent studies have demonstrated that wild-type Rift Valley fever virus efficiently targets and replicates in dendritic cells (DCs). We found that NSR infection of cultured human DCs results in maturation of DCs, characterized by surface upregulation of CD40, CD80, CD86, MHC-I and MHC-II and secretion of the proinflammatory cytokines IFN-β, IL-6 and …

Favipiravir (T-705) protects against peracute Rift Valley fever virus infection and reduces delayed-onset neurologic disease observed with ribavirin treatment.

Rift Valley fever is a zoonotic, arthropod-borne disease that affects livestock and humans. The etiologic agent, Rift Valley fever virus (RVFV; Bunyaviridae, Phlebovirus) is primarily transmitted through mosquito bites, but can also be transmitted by exposure to infectious aerosols. There are presently no licensed vaccines or therapeutics to prevent or treat severe RVFV infection in humans. We have previously reported on the activity of favipiravir (T-705) against the MP-12 vaccine strain of RVFV and other bunyaviruses in cell culture. In addition, efficacy has also been documented in mouse an…

Blood meal analysis and virus detection in blood-fed mosquitoes collected during the 2006-2007 Rift Valley fever outbreak in Kenya.

BACKGROUND: Rift Valley fever (RVF) is a zoonosis of domestic ruminants in Africa. Blood-fed mosquitoes collected during the 2006-2007 RVF outbreak in Kenya were analyzed to determine the virus infection status and animal source of the blood meals. MATERIALS AND METHODS: Blood meals from individual mosquito abdomens were screened for viruses using Vero cells and RT-PCR. DNA was also extracted and the cytochrome c oxidase 1 (CO1) and cytochrome b (cytb) genes amplified by PCR. Purified amplicons were sequenced and queried in GenBank and Barcode of Life Database (BOLD) to identify the putative …

Common host-derived chemicals increase catches of disease-transmitting mosquitoes and can improve early warning systems for Rift Valley fever virus.

Rift Valley fever (RVF), a mosquito-borne zoonosis, is a major public health and veterinary problem in sub-Saharan Africa. Surveillance to monitor mosquito populations during the inter-epidemic period (IEP) and viral activity in these vectors is critical to informing public health decisions for early warning and control of the disease. Using a combination of field bioassays, electrophysiological and chemical analyses we demonstrated that skin-derived aldehydes (heptanal, octanal, nonanal, decanal) common to RVF virus (RVFV) hosts including sheep, cow, donkey, goat and human serve as potent att…

A DNA vaccine encoding ubiquitinated Rift Valley fever virus nucleoprotein provides consistent immunity and protects IFNAR(-/-) mice upon lethal virus challenge.

Current vaccine candidates against Rift Valley fever virus (RVFV) incorporate the viral structural glycoproteins as antigens, since triggering antibody responses against them usually correlates with protection. Here, we have focused solely on the nucleoprotein of RVFV as a potential target for vaccine development. Previous studies in mouse models have already demonstrated that RVFV nucleoprotein can elicit partial protection when administered by means of a DNA vaccine or in recombinant, soluble, protein form. To determine whether this partially protective immune response could be augmented to …

Intramuscular inoculation of calves with an experimental Newcastle disease virus-based vector vaccine elicits neutralizing antibodies against Rift Valley fever virus.

In the past decade, the use of Newcastle disease virus (NDV) as a vaccine vector for the prevention of economically important livestock diseases as well as for human diseases has been extensively explored. In this study, we have constructed a recombinant NDV vaccine virus, named NDFL-Gn, that produces the Rift Valley fever virus (RVFV) Gn glycoprotein. Calves were immunized via either the intranasal route or the intramuscular route. Delivery via the intranasal route elicited no detectable antibody responses, whereas delivery via the intramuscular route elicited antibodies against both NDV and …

Production of monoclonal antibodies against Rift Valley fever virus Application for rapid diagnosis tests (virus detection and ELISA) in human sera.

This paper describes the production and characterization of RVFV monoclonal antibodies. The characteristics of 32 out of 55 ELISA and/or IFA positive monoclonal antibodies were determined, including the RVFV components against which they are directed. One monoclonal antibody recognized the nucleoprotein, 15 the Gc and 16 the Gn. Among the latter ones, five monoclonal antibodies possess another specificity and recognized both Gn and either the nucleoprotein (four of them) or the NSs protein (one). To validate the use of these monoclonal antibodies for diagnosis tests, a pool of monoclonal antib

Aspects of bioecology of two Rift Valley Fever Virus vectors in Senegal (West Africa): Aedes vexans and Culex poicilipes (Diptera: Culicidae).

The dispersal, population dynamics, and age structure of two Rift Valley Fever Virus (Phlebovirus: Bunyaviridae) (RVFV) vectors, Aedes vexans Meigen and Culex poicilipes Theobald, were investigated in northern Senegal. The main objective was to investigate possible factors that mediate RVFV emergence and propagation at a site where humans and livestock live in proximity to temporary surface pools. In mark-release-recapture studies, recapture rates of 0.18% (156/85,500) and 3.46% (201/5,800) were obtained for Ae. vexans and Cx. poicilipes, respectively. The number of mosquitoes recaptured decre…

Changes in Rift Valley fever neutralizing antibody prevalence among small domestic ruminants following the 1987 outbreak in the Senegal River basin.

Following the Rift Valley fever (RVF) epizootic of 1987 in the Senegal River basin, 2 series of serosurveys were carried out. In 1988 and 1989, respectively, 303 and 331 randomly selected sheep and goats were investigated and sera tested for the presence of specific RVF-virus-neutralizing antibodies. In 1988, 24.4% of the sera was found to have anti-RVF neutralizing antibodies and in 1989, 19.3% was found. In 1988, we observed in the Dagana district, including the 1987 epizootic area, a significantly higher prevalence (71.1%) than in the two other more distant districts of Podor (21.5%) and Ma…

Human and livestock exposure to Rift Valley fever virus and Coxiella burnetii in Eastern Ethiopia: a One Health cross-sectional study.

BACKGROUND: Rift Valley fever (RVF) virus and Coxiella burnetii are high-priority zoonotic pathogens posing health and economic threats in Africa. Data from Ethiopia are limited. This study estimated the prevalence and associated factors of RVF virus and C. burnetii among humans and livestock in Eastern Ethiopia using a One Health approach. METHODS: A multi-site cross-sectional study was conducted from May 1 to November 30, 2023, in the Shinile district, Somali Region, and Dire Dawa Administration. Data and blood samples were collected from 512 humans, and blood samples were collected from 11…

Field studies of Culex mosquitoes in Tanzania and Kenya: A systematic review motivated by changing Rift Valley fever virus transmission patterns.

Culex mosquitoes are assumed to be secondary vectors of Rift Valley fever virus (RVFV), with Aedes being the most important for initiating outbreaks. However, environmental change may be affecting the role Culex species play in transmission. We aimed to curate a collection of published studies from Tanzania and Kenya, identify gaps in research concerning Culex communities and establish whether sufficient spatio-temporal published data may be available for future meta-analysis. This presents a first step in leveraging published data to better understand the role of Culex in maintaining RVFV tra…

Single-cycle Rift Valley fever virus particles from stable replicon cells enable discovery of antiviral CNX-1351 for multiple RNA viruses.

Rift Valley fever virus (RVFV) is a high-containment pathogen that causes severe diseases in humans, with no approved therapeutics available. Its classification as a biosafety level 3 (BSL-3) agent has limited research and therapeutic development due to safety concerns. In this study, we developed a stable replicon cell line maintaining the replication of L and S genomic segments of RVFV. Single-cycle viral replicon particles (VRPs) could be efficiently packaged through trans-complementation of glycoproteins from different strains, recapitulating authentic viral entry and replication while min…

Местные движущие силы вспышки лихорадки Рифт-Вэлли в Мавритании: один из подходов в области здравоохранения, сочетающий экологические данные, векторные данные, данные о перемещении скота и данные о его перемещении.

лихорадка Рифт-Вэлли (RVF) — зоонотическая болезнь, переносимая переносчиками, сопровождающаяся периодическими эпидемиями и эпизоотическими вспышками в Мавритании, вызванными вирусом RVF (RVFV). В последние годы вспышки происходят с все более короткими межэпидемическими периодами. Основная цель этого исследования состояла в том, чтобы использовать модель спонтанности с высоким разрешением и определить движущие силы и экологическую пригодность для заражения ОВТС, а также районы вспышек ОВФ и появления соответственно у людей и животных в Мавритании. Мы использовали геолокационные данные за перио

Совпадение в аннотации оригинала
Rift Valley fever (RVF) is a vector-borne zoonotic disease with recurrent epidemic and epizootic outbreaks in Mauritania caused by the RVF virus (RVFV). In recent years, outbreaks have occurred with increasingly shorter inter-epidemic periods. The primary objective of this study was to utilise a high-resolution spatiotemporal model and identify the drivers a…

Severe morbidity and hospital-based mortality from Rift Valley fever disease between November 2017 and March 2020 among humans in Uganda.

BACKGROUND: Rift Valley fever (RVF) is a zoonotic viral disease of increasing intensity among humans in Africa and the Arabian Peninsula. In Uganda, cases reported prior to 2016 were mild or not fully documented. We report in this paper on the severe morbidity and hospital-based mortality of human cases in Uganda. METHODS: Between November 2017 and March 2020 human cases reported to the Uganda Virus Research Institute (UVRI) were confirmed by polymerase chain reaction (PCR). Ethical and regulatory approvals were obtained to enrol survivors into a one-year follow-up study. Data were collected …

Characterization of mosquito host-biting networks of potential Rift Valley fever virus vectors in north-eastern KwaZulu-Natal province, South Africa.

BACKGROUND: Rift Valley fever virus (RVFV) is a zoonotic mosquito-borne virus with serious implications for livestock health, human health, and the economy in Africa, and is suspected to be endemic in north-eastern KwaZulu-Natal (KZN), South Africa. The vectors of RVFV in this area are poorly known, although several species, such as Aedes (Neomelaniconion) mcintoshi, Aedes (Neomelaniconion) circumluteolus, Aedes (Aedimorphus) durbanensis, and Culex (Lasioconops) poicilipes may be involved. The aim of the study was to determine the vertebrate blood meal sources of potential RVFV mosquito vector…