scholarly journals Safety and Efficacy Profile of Commercial Veterinary Vaccines against Rift Valley Fever: A Review Study

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Moataz Alhaj
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Clinical Manifestations ◽  
Effective Vaccine ◽  
Published Data ◽  
Inactivated Vaccine ◽  
Significant Information ◽  
Valley Fever ◽  
Wide Range ◽  
Efficacy Profile

Rift Valley Fever (RVF) is an infectious illness with serious clinical manifestations and health consequences in humans as well as a wide range of domestic ruminants. This review provides significant information about the prevention options of RVF along with the safety-efficacy profile of commercial vaccines and some of RVF vaccination strategies. Information presented in this paper was obtained through a systematic investigation of published data about RVF vaccines. Like other viral diseases, the prevention of RVF relies heavily on immunization of susceptible herds with safe and cost-effective vaccine that is able to confer long-term protective immunity. Several strains of RVF vaccines have been developed and are available in commercial production including Formalin-Inactivated vaccine, live attenuated Smithburn vaccine, and the most recent Clone13. Although Formalin-Inactivated vaccine and live attenuated Smithburn vaccine are immunogenic and widely used in prevention programs, they proved to be accompanied by significant concerns. Despite Clone13 vaccine being suggested as safe in pregnant ewes and as highly immunogenic along with its potential for differentiating infected from vaccinated animals (DIVA), a recent study raised concerns about the safety of the vaccine during the first trimester of gestation. Accordingly, RVF vaccines that are currently available in the market to a significant extent do not fulfill the requirements of safety, potency, and DIVA. These adverse effects stressed the need for developing new vaccines with an excellent safety profile to bridge the gap in safety and immunity. Bringing RVF vaccine candidates to local markets besides the absence of validated serological test for DIVA remain the major challenges of RVF control.

scholarly journals The Nonstructural Protein NSs Induces a Variable Antibody Response in Domestic Ruminants Naturally Infected with Rift Valley Fever Virus

2011 ◽  
Vol 19 (1) ◽  
pp. 5-10 ◽  
Author(s):  
José-Carlos Fernandez ◽  
Agnès Billecocq ◽  
Jean Paul Durand ◽  
Catherine Cêtre-Sossah ◽  
Eric Cardinale ◽  
...  
Keyword(s):  
Antibody Response ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Nonstructural Protein ◽  
Rift Valley Fever Virus ◽  
High Rate ◽  
Antibody Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Valley Fever ◽  
Wide Range

ABSTRACTRift Valley fever (RVF) is an emerging zoonosis in Africa which has spread to Egypt, the Arabian Peninsula, Madagascar, and Comoros. RVF virus (RVFV) (Bunyaviridaefamily,Phlebovirusgenus) causes a wide range of symptoms in humans, from benign fever to fatal hemorrhagic fever. Ruminants are severely affected by the disease, which leads to a high rate of mortality in young animals and to abortions and teratogenesis in pregnant females. Diagnostic tests include virus isolation and genome or antibody detection. During RVFV infection, the nucleoprotein encapsidating the tripartite RNA genome is expressed in large amounts and raises a robust antibody response, while the envelope glycoproteins elicit neutralizing antibodies which play a major role in protection. Much less is known about the antigenicity/immunogenicity of the nonstructural protein NSs, which is a major virulence factor. Here we have developed a competitive enzyme-linked immunosorbent assay (ELISA) enabling detection of low levels of NSs-specific antibodies in naturally infected or vaccinated ruminants. Detection of the NSs antibodies was validated by Western blotting. Altogether, our data showed that the NSs antibodies were detected in only 55% of animals naturally infected by RVFV, indicating that NSs does not induce a consistently high immune response. These results are discussed in light of differentiation between infected and vaccinated animals (DIVA) tests distinguishing naturally infected animals and those vaccinated with NSs-defective vaccines.

scholarly journals Chitosan and chitosan nanoparticles as adjuvant in local Rift Valley Fever inactivated vaccine

3 Biotech ◽  
2020 ◽  
Vol 10 (3) ◽  
Author(s):  
Ashgan F. El-Sissi ◽  
Farida H. Mohamed ◽  
Nadia M. Danial ◽  
Ali Q. Gaballah ◽  
Korany A. Ali
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Chitosan Nanoparticles ◽  
Inactivated Vaccine ◽  
Valley Fever

Clinical Manifestations of Rift Valley Fever in Humans: Systematic Review and Meta-Analysis

2021 ◽  
Author(s):  
Zacchaeus Anywaine ◽  
Swaib A. Lule ◽  
Christian Holm Hansen ◽  
George Warimwe ◽  
Alison Eliott
Keyword(s):  
Systematic Review ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Meta Analysis ◽  
Clinical Manifestations ◽  
Valley Fever

scholarly journals Insights into the Pathogenesis of Viral Haemorrhagic Fever Based on Virus Tropism and Tissue Lesions of Natural Rift Valley Fever

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 709
Author(s):  
Lieza Odendaal ◽  
A Sally Davis ◽  
Estelle H Venter
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Multiorgan Failure ◽  
Current Understanding ◽  
Coagulation System ◽  
Future Research ◽  
Type I ◽  
Haemorrhagic Fever ◽  
Valley Fever ◽  
Wide Range

Rift Valley fever phlebovirus (RVFV) infects humans and a wide range of ungulates and historically has caused devastating epidemics in Africa and the Arabian Peninsula. Lesions of naturally infected cases of Rift Valley fever (RVF) have only been described in detail in sheep with a few reports concerning cattle and humans. The most frequently observed lesion in both ruminants and humans is randomly distributed necrosis, particularly in the liver. Lesions supportive of vascular endothelial injury are also present and include mild hydropericardium, hydrothorax and ascites; marked pulmonary congestion and oedema; lymph node congestion and oedema; and haemorrhages in many tissues. Although a complete understanding of RVF pathogenesis is still lacking, antigen-presenting cells in the skin are likely the early targets of the virus. Following suppression of type I IFN production and necrosis of dermal cells, RVFV spreads systemically, resulting in infection and necrosis of other cells in a variety of organs. Failure of both the innate and adaptive immune responses to control infection is exacerbated by apoptosis of lymphocytes. An excessive pro-inflammatory cytokine and chemokine response leads to microcirculatory dysfunction. Additionally, impairment of the coagulation system results in widespread haemorrhages. Fatal outcomes result from multiorgan failure, oedema in many organs (including the lungs and brain), hypotension, and circulatory shock. Here, we summarize current understanding of RVF cellular tropism as informed by lesions caused by natural infections. We specifically examine how extant knowledge informs current understanding regarding pathogenesis of the haemorrhagic fever form of RVF, identifying opportunities for future research.

scholarly journals Tilorone-Dihydrochloride Protects against Rift Valley Fever Virus Infection and Disease in the Mouse Model

2021 ◽  
Vol 10 (1) ◽  
pp. 92
Author(s):  
Kendra N. Johnson ◽  
Birte Kalveram ◽  
Jennifer K. Smith ◽  
Lihong Zhang ◽  
Terry Juelich ◽  
...  
Keyword(s):  
Mouse Model ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Lethal Dose ◽  
Fever Virus ◽  
Post Exposure Prophylaxis ◽  
Valley Fever ◽  
Wide Range

Rift Valley fever (RVF) is a mosquito-borne zoonotic disease endemic to Africa and the Middle East that can affect humans and ruminant livestock. Currently, there are no approved vaccines or therapeutics for the treatment of severe RVF disease in humans. Tilorone-dihydrochloride (Tilorone) is a broad-spectrum antiviral candidate that has previously shown efficacy against a wide range of DNA and RNA viruses, and which is clinically utilized for the treatment of respiratory infections in Russia and other Eastern European countries. Here, we evaluated the antiviral activity of Tilorone against Rift Valley fever virus (RVFV). In vitro, Tilorone inhibited both vaccine (MP-12) and virulent (ZH501) strains of RVFV at low micromolar concentrations. In the mouse model, treatment with Tilorone significantly improved survival outcomes in BALB/c mice challenged with a lethal dose of RVFV ZH501. Treatment with 30 mg/kg/day resulted in 80% survival when administered immediately after infection. In post-exposure prophylaxis, Tilorone resulted in 30% survival at one day after infection when administered at 45 mg/kg/day. These findings demonstrate that Tilorone has potent antiviral efficacy against RVFV infection in vitro and in vivo and supports further development of Tilorone as a potential antiviral therapeutic for treatment of RVFV infection.

scholarly journals TRANSFER OF DANGEROUS VIRAL INFECTIONS IN THE NON-ENDEMIC AREA

2017 ◽  
pp. 91-100
Author(s):  
V. A. Markin ◽  
D. E. Chifanov
Keyword(s):  
Rift Valley ◽  
Influenza A ◽  
Rift Valley Fever ◽  
Endemic Area ◽  
Viral Infections ◽  
Clinical Manifestations ◽  
Hemorrhagic Fever ◽  
Climatic Conditions ◽  
Valley Fever

Epidemic data are presented, possible causes analyzed and the dangers of observed in recent years expansion of existing areas of viral infections, including the introduction of the agent to the non-endemic area, evaluated. At the present time there is a significant expansion of the ranges of some zooantroponozes pathogens, particular filovirus Ebola and arboviruses - Rift Valley fever, Zika, Chikungunya. When extending the boundaries of epidemic foci in the new territory for the pathogen, can occur aggravating of clinical manifestations of the disease and increase mortality among the indigenous population. Extremely hazardous exotic viral hemorrhagic fever (Ebola, Marburg, Lassa) when transfer with sick people in some cases, can cause contamination of the contact persons. Rift Valley fever - one of the most aggressive arboviruses, in the case of importation can form stable epidemic foci. Transfer of Zika fever in the territory of the Russian Federation has not represent substantial epidemiological value. Epidemiological factors, essential for the formation of new areas of pathogens may include the presence of permissive candidates in natural hosts and vectors, the climatic conditions. Role of socio-economic factors is significant. Among of environmental factors is the important role of some trace elements, including selenium, involved in the regulation of homeostasis and which faults occur in the upward virulence virus mutating. In parts of Africa and Asia, with soils poor in selenium, were first introduced pathogens or highly virulent strains of influenza A, SARS, Ebola and of SIV, and drifts on these and similar areas have led to an increase in the virulence of viruses.

Predictability of the Normalized Difference Vegetation Index in Kenya and Potential Applications as an Indicator of Rift Valley Fever Outbreaks in the Greater Horn of Africa

2006 ◽  
Vol 19 (9) ◽  
pp. 1673-1687 ◽  
Author(s):  
Matayo Indeje ◽  
M. Neil Ward ◽  
Laban J. Ogallo ◽  
Glyn Davies ◽  
Maxx Dilley ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Horn Of Africa ◽  
Valley Fever ◽  
Wide Range ◽  
Potential Applications ◽  
Greater Horn Of Africa

Abstract In this paper the progress made in producing predictions of the Normalized Difference Vegetation Index (NDVI) over Kenya in the Greater Horn of Africa (GHA) for the October–December (OND) season is discussed. Several studies have identified a statistically significant relationship between rainfall and NDVI in the region. Predictability of seasonal rainfall by global climate models (GCMs) during the OND season over the GHA has also been established as being among the best in the world. Information was extracted from GCM seasonal prediction output using statistical transformations. The extracted information was then used in the prediction of NDVI. NDVI is a key variable for management of various climate-sensitive problems. For example, it has been shown to have the potential to predict environmental conditions associated with Rift Valley Fever (RVF) viral activity and this is referred to throughout the paper as a motivation for the study. RVF affects humans and livestock and is particularly economically important in the GHA. The establishment of predictability for NDVI in this paper is therefore part of a methodology that could ultimately generate information useful for managing RVF in livestock in the GHA. It has been shown that NDVI can be predicted skillfully over the GHA with a 2–3-month lead time. Such information is crucial for tailoring forecast information to support RVF monitoring and prediction over the region, as well as many other potential applications (e.g., livestock forage estimation). More generally, the Famine Early Warning System (FEWS), a project of the U.S. Agency for International Development (USAID) and the National Aeronautics and Space Administration (NASA) and other specialized technical centers routinely use NDVI images to monitor environmental conditions worldwide. The high predictability for NDVI established in this paper could therefore supplement the routine monitoring of environmental conditions for a wide range of applications.

scholarly journals Observations on the epidemiology of Rift Valley fever in Kenya

1975 ◽  
Vol 75 (2) ◽  
pp. 219-230 ◽  
Author(s):  
F. G. Davies
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Virus Isolation ◽  
Forest Edge ◽  
Serological Survey ◽  
Valley Fever ◽  
Wide Range ◽  
Maintenance Cycle

SUMMARYThe epizootic range of Rift Valley fever in Kenya is defined from the results of virus isolations during epizootics, and from an extensive serological survey of cattle which were exposed during an epizootic. A study of the sera from a wide range of wild bovidae sampled immediately after the epizootic, showed that they did not act as reservoir or amplifying hosts for RVF.Virus isolation attempts from a variety of rodents proved negative. Rift Valley fever did not persist between epizootics by producing symptomless abortions in cattle in areas within its epizootic range. A sentinel herd sampled annually after an epizootic in 1968 revealed not one single seroconversion from 1969 to 1974. Certain forest and forest edge situations were postulated as enzootic for Rift Valley fever, and a small percentage of seroconversions were detected in cattle in these areas, born four years after the last epizootic. This has been the only evidence for the persistence of the virus in Kenya since 1968, and may be a part of the interepizootic maintenance cycle for Rift Valley fever in Kenya, which otherwise remains unknown.

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