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Rift Valley fever dynamics in Senegal: a project for pro-active adaptation and improvement of livestock raising management.

The multi-disciplinary French project "Adaptation à la Fiévre de la Vallée du Rift" (AdaptFVR) has concluded a 10-year constructive interaction between many scientists/partners involved with the Rift Valley fever (RVF) dynamics in Senegal. The three targeted objectives reached were (i) to produce--in near real-time--validated risk maps for parked livestock exposed to RVF mosquitoes/vectors bites; (ii) to assess the impacts on RVF vectors from climate variability at different time-scales including climate change; and (iii) to isolate processes improving local livestock management and animal hea…

Relationship of climate, geography, and geology to the incidence of Rift Valley fever in Kenya during the 2006-2007 outbreak.

We estimated Rift Valley fever (RVF) incidence as a function of geological, geographical, and climatological factors during the 2006-2007 RVF epidemic in Kenya. Location information was obtained for 214 of 340 (63%) confirmed and probable RVF cases that occurred during an outbreak from November 1, 2006 to February 28, 2007. Locations with subtypes of solonetz, calcisols, solonchaks, and planosols soil types were highly associated with RVF occurrence during the outbreak period. Increased rainfall and higher greenness measures before the outbreak were associated with increased risk. RVF was more…

Culex pipiens, an experimental efficient vector of West Nile and Rift Valley fever viruses in the Maghreb region.

West Nile fever (WNF) and Rift Valley fever (RVF) are emerging diseases causing epidemics outside their natural range of distribution. West Nile virus (WNV) circulates widely and harmlessly in the old world among birds as amplifying hosts, and horses and humans as accidental dead-end hosts. Rift Valley fever virus (RVFV) re-emerges periodically in Africa causing massive outbreaks. In the Maghreb, eco-climatic and entomologic conditions are favourable for WNV and RVFV emergence. Both viruses are transmitted by mosquitoes belonging to the Culex pipiens complex. We evaluated the ability of differ…

Reverse genetics technology for Rift Valley fever virus: current and future applications for the development of therapeutics and vaccines.

The advent of reverse genetics technology has revolutionized the study of RNA viruses, making it possible to manipulate their genomes and evaluate the effects of these changes on their biology and pathogenesis. The fundamental insights gleaned from reverse genetics-based studies over the last several years provide a new momentum for the development of designed therapies for the control and prevention of these viral pathogens. This review summarizes the successes and stumbling blocks in the development of reverse genetics technologies for Rift Valley fever virus and their application to the fur…

NSm and 78-kilodalton proteins of Rift Valley fever virus are nonessential for viral replication in cell culture.

Rift Valley fever viruses carrying mutations of the M gene preglycoprotein region, one lacking NSm protein expression, one lacking 78-kDa protein expression, and one lacking expression of both proteins, were compared in cell culture. All of the mutants and their parent virus produced plaques with similar sizes and morphologies in Vero E6 cells and had similar growth kinetics in Vero, C6/36, and MRC5 cells, demonstrating that the NSm and 78-kDa proteins were not needed for the virus to replicate efficiently in cell culture. A competition-propagation assay revealed that the parental virus was sl…

Application of knowledge-driven spatial modelling approaches and uncertainty management to a study of Rift Valley fever in Africa.

BACKGROUND: There are few studies that have investigated uncertainties surrounding the scientific community's knowledge of the geographical distribution of major animal diseases. This is particularly relevant to Rift Valley fever (RVF), a zoonotic disease causing destructive outbreaks in livestock and man, as the geographical range of the disease is widening to involve previously unaffected regions. In the current study we investigate the application of methods developed in the decision sciences: multiple criteria decision making using weighted linear combination and ordered weighted averages,…

Validation of IgG-sandwich and IgM-capture ELISA for the detection of antibody to Rift Valley fever virus in humans.

Rift Valley fever (RVF) virus is an important zoonotic and a potential biothreat agent. This paper describes validation of sandwich and capture enzyme-linked immunoassays (ELISA) based on gamma-irradiated antigens for the detection of RVFV-specific IgG and IgM antibody in humans. Validation data sets derived from testing field-collected sera from Africa (n=2400) were dichotomised according to the results of a virus neutralisation test. In addition, sera from laboratory workers immunized with inactivated RVF vaccine (n=93) and serial sera (n=3) from a single RVF case were used. ELISA data were …

Genetic analysis of viruses associated with emergence of Rift Valley fever in Saudi Arabia and Yemen, 2000-01.

The first confirmed Rift Valley fever outbreak outside Africa was reported in September 2000, in the Arabian Peninsula. As of February 2001, a total of 884 hospitalized patients were identified in Saudi Arabia, with 124 deaths. In Yemen, 1,087 cases were estimated to have occurred, with 121 deaths. Laboratory diagnosis of Rift Valley fever virus (RVFV) infections included virus genetic detection and characterization of clinical specimens by reverse transcription-polymerase chain reaction, in addition to serologic tests and virus isolation. Genetic analysis of selected regions of virus S, M, an…

Effect of the developmental stage at infection on the ability of adult Anopheles stephensi to transmit Rift Valley fever virus.

The ability of adult Anopheles stephensi to transmit Rift Valley fever virus was determined for mosquitoes inoculated at selected times during development. None of 109 female An. stephensi inoculated as adults transmitted virus to hamsters. In contrast, 83% (50 of 60) of those inoculated as larvae transmitted virus by bite to hamsters. Transmission rates decreased as the stage of the mosquito at the time of inoculation changed from larva to pupa to adult. Transmission rates for adult mosquitoes inoculated as larvae, as pupae < 4 hr after pupation, as pupae > 24 hr after pupation, or as adults …

Isolation of the Rift Valley fever virus by inoculation into Aedes pseudoscutellaris cells: comparison with other diagnostic methods.

The Rift Valley fever epidemic, which arose in the south of Mauritania beginning on October 15, 1987, enabled a comparative study of different diagnostic methods among humans. During the first two weeks of the epidemic, four parallel methods were used: inoculation into Aedes pseudoscutellaris cells, inoculation intracerebrally into suckling mice, tests by immunocapture of the circulating antigen and detection of type IgM gammaglobulins. Of 370 examined sera, 181 showed at least one marker of recent infection. Inoculation into A. pseudoscutellaris cells was by far the most sensitive and easiest…

Enzyme-linked immunosorbent assay for detection of antibodies to Rift Valley fever virus in ovine and bovine sera.

An enzyme-linked immunosorbent assay (ELISA) was developed for the rapid detection of antibodies to Rift Valley fever virus (RVFV) in ovine and bovine sera. Conditions to reduce nonspecific reactions were optimized. The ELISA results correlated with those of a plaque-reduction neutralization test, revealing 100% specificity and 90.7% sensitivity. In sera from sheep and cattle inoculated against RVFV, the hemagglutination-inhibition test in combination with the ELISA provided a better indication of response to killed RVFV vaccine than did either test alone.

Serological evidence of rift valley fever Phlebovirus and Crimean-Congo hemorrhagic fever orthonairovirus infections among pygmies in the east region of Cameroon.

BACKGROUND: Rift Valley Fever Phlebovirus (RVFV) and Crimean-Congo Hemorrhagic Fever Orthonairovirus (CCHFV) specific antibodies had been documented among humans in urban settings of the southwestern and northern Cameroon in the late 1980s. Recently, evidence for enzootic circulation of RVFV was reported among livestock in both rural and urban settings in Cameroon. However, current estimates of human exposure to RVFV and CCHFV are still to be documented in Cameroon, especially in rural areas. The aim of this study was to assess the seroprevalence of RVFV and CCHFV in rural settings in the Sout…

Совместный сигнал о прекращении транскрипции на негативных и амбисенсных сегментах генома РНК лихорадки Рифт-Вэлли, сицилианских и тосканских вирусов песчаной лихорадки.

Флебовирусный род (семейство Bunyaviridae) состоит из разнообразной группы арбовирусов, которые вызывают синдромы заболеваний: от легкого фебрилического заболевания до геморрагической лихорадки с высокой смертностью. Несмотря на антигенное сходство, эти вирусы отличаются примерно на 25% на уровне генома, а их экологии, включая географические диапазоны, предпочтительные виды переносчиков и носители, существенно различаются. В отличие от других вирусов амбисенсы, где структуры шпильки RNA, используемые в качестве сигналов прекращения транскрипции, часто выделяют противоположные открытые рамы счи

Совпадение в аннотации оригинала
The Phlebovirus genus (family Bunyaviridae) is composed of a diverse group of arboviruses that cause disease syndromes ranging from mild feb … nscription termination signal for the N, NSs, and GPC mRNAs in three diverse phleboviruses, namely, Rift Valley fever, sandfly Sicilian, and Toscana viruses. The exact termination of nascent virus mRNA molecules was determined by 3' rapid amplification of cDNA ends. Surprisingly, analysis of the termini of mRNAs from both S and M segments of these three viruses rev …

In Vitro and In Vivo Models for Drug Development Against Two Hemorrhagic Hareavirales: Rift Valley Fever and Crimean Congo Hemorrhagic Fever Viruses.

Rift Valley fever virus (RVFV) and Crimean-Congo hemorrhagic fever virus (CCHFV) are designated by the World Health Organization as priority pathogens due to their epidemic potential, zoonotic transmission, and the absence of licensed therapeutics or vaccines. The development of effective antivirals critically relies on robust in vitro and in vivo models; however, progress is limited by the requirement for high-containment facilities. In this review, we provide a comprehensive overview of the experimental models currently available for RVFV and CCHFV, ranging from cell-based assays to animal m…

Seroprevalence and Co-Circulation of Rift Valley Fever Virus and West Nile Fever Virus in Livestock Population of Afar Region, Northeast Ethiopia.

The distribution, epidemiology, and socioeconomic impact of Rift Valley fever (RVF) and West Nile (WN) viruses are poorly known in areas of sub-Saharan countries like Ethiopian pastoral region. The human and livestock density in the area has increased greatly in recent years, but little work has been done on arboviral diseases and their potential impact on human and livestock health. The aim of this study was to detect the circulation of zoonotic arboviruses such as Rift Valley fever virus and West Nile viruses in the livestock population and to estimate seroprevalence in Afar pastoral area no…

Seroprevalence of Crimean-Congo Hemorrhagic Fever Virus and Rift Valley Fever Virus in human population in Senegal from October to November 2020.

OBJECTIVES: Rift Valley Fever and Crimean-Congo Hemorrhagic Fever are two infections classified among the emerging diseases to be monitored with highest priority. Studies undertaken in human and animals have shown endemicity of these two arboviruses in several African countries. However, most of the investigations were carried out on domestic cattle and the studies conducted on human populations are either outdated or limited to a small number of well-known endemic areas. It is then critical to better evaluate the burden of these viruses in Senegal at a national scale. METHODS: This work reli…

Transboundary Animal Diseases (TADs) affecting domestic and wild African ungulates: African swine fever, foot and mouth disease, Rift Valley fever (1996-2018).

Transboundary Animal Diseases (TADs) affecting ungulates are potentially epidemic diseases that are contagious or transmissible, and a concern for humans worldwide. While globalization has led to increased containment efforts at a global scale, additional local attention is needed as well for vulnerable pastoralist communities that are in close proximity to livestock. We reviewed and then summarized outbreaks, cases, and deaths for 3 TADs (African Swine Fever (ASF), Foot and Mouth Disease (FMD), and Rift Valley Fever (RVF)) affecting domestic and wild ungulates for all African countries from 1…

Immunogenicity of combination DNA vaccines for Rift Valley fever virus, tick-borne encephalitis virus, Hantaan virus, and Crimean Congo hemorrhagic fever virus.

DNA vaccines for Rift Valley fever virus (RVFV), Crimean Congo hemorrhagic fever virus (CCHFV), tick-borne encephalitis virus (TBEV), and Hantaan virus (HTNV), were tested in mice alone or in various combinations. The bunyavirus vaccines (RVFV, CCHFV, and HTNV) expressed Gn and Gc genes, and the flavivirus vaccine (TBEV) expressed the preM and E genes. All vaccines were delivered by gene gun. The TBEV DNA vaccine and the RVFV DNA vaccine elicited similar levels of antibodies and protected mice from challenge when delivered alone or in combination with other DNAs. Although in general, the HTNV …