Rift Valley Fever

Dungu, Baptiste; Bouloy, Michèle

doi:10.1002/9781119506287.ch19

Cited by 3 publications

(3 citation statements)

References 64 publications

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“…It is endemic in large parts of Africa, occurring as epizootics/epidemics at irregular intervals [ 25 , 34 , 35 ]. An effective way to establish solid herd immunity is through regular vaccination, but this is not widely practiced due to irregular and long intervals between epizootic/epidemic periods [ 36 , 37 , 38 ]. The lack of a visible impact and associated costs during inter-epizootic/epidemic periods is a deterrent in implementing RVF vaccination, exposing highly susceptible animals when outbreaks emerge [ 16 , 39 , 40 ].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a Combined Live Attenuated Vaccine against Lumpy Skin Disease, Contagious Bovine Pleuropneumonia and Rift Valley Fever

Bamouh,

Elarkam,

Elmejdoub

et al. 2024

Vaccines

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The use of effective vaccines is among the most important strategies for the prevention and progressive control of transboundary infectious animal diseases. However, the use of vaccine is often impeded by the cost, a lack of cold chains and other factors. In resource-limited countries in Africa, one approach to improve coverage and reduce cost is to vaccinate against multiple diseases using combined vaccines. Therefore, the objective of this study was to evaluate a combined vaccine for the prevention and control of Lumpy Skin Disease (LSD), Contagious Bovine Pleuropneumonia (CBPP) and Rift Valley fever (RVF). The LSD and CBPP were formulated as a combined vaccine, and the RVF was formulated separately as live attenuated vaccines. These consisted of a Mycoplasma MmmSC T1/44 strain that was propagated in Hayflick-modified medium, RVF virus vaccine, C13T strain prepared in African green monkey cells (Vero), and the LSDV Neethling vaccine strain prepared in primary testis cells. The vaccines were tested for safety via the subcutaneous route in both young calves and pregnant heifers with no side effect, abortion or teratogenicity. The vaccination of calves induced seroconversions for all three vaccines starting from day 7 post-vaccination (PV), with rates of 50% for LSD, 70% for CBPP and 100% for RVF, or rates similar to those obtained with monovalent vaccines. The challenge of cattle vaccinated with the LSD/CBPP and the RVF vaccine afforded full protection against virulent strains of LSDV and RVFV. A satisfactory level of protection against a CBPP challenge was observed, with 50% of protection at 6 months and 81% at 13 months PV. A mass vaccination trial was performed in four regions of Burkina Faso that confirmed safety and specific antibody responses induced by the vaccines. The multivalent LSD/CBPP+RVF vaccine provides a novel and beneficial approach to the control of the three diseases through one intervention and, therefore, reduces the cost and improves vaccination coverage.

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Section: Introductionmentioning

confidence: 99%

Evaluation of a Combined Live Attenuated Vaccine against Lumpy Skin Disease, Contagious Bovine Pleuropneumonia and Rift Valley Fever

Bamouh,

Elarkam,

Elmejdoub

et al. 2024

Vaccines

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“…Humans near affected flocks may become infected by fomites or through bites of mosquitoes previously fed from viremic animals. Most infected humans usually develop flu-like symptoms, but more severe complications can develop in a low percentage of the infected population, leading to encephalitis or to a, usually fatal, haemorrhagic disease ( Dungu and Bouloy, 2021 ). All these features make RVF a paradigm of disease for the One Health concept.…”

Section: Introductionmentioning

confidence: 99%

“…Both live-attenuated and inactivated vaccines are available in Africa for veterinary use. While inactivated vaccines need booster doses, vaccines based on live-attenuated RVFV allow more successful immunization programs, but their use is usually limited because of risks associated to their residual virulence, especially for immune compromised hosts, or in pregnant sheep ( Makoschey et al., 2016 ; Dungu et al., 2018 ; Dungu and Bouloy, 2021 ). On the other hand, a licensed human vaccine is not yet available in endemic countries, not even for high-risk groups exposed to RVFV infection during RVF outbreaks.…”

Section: Introductionmentioning

confidence: 99%

Identification of Single Amino Acid Changes in the Rift Valley Fever Virus Polymerase Core Domain Contributing to Virus Attenuation In Vivo

Borrego

Moreno

López-Valiñas

et al. 2022

Front. Cell. Infect. Microbiol.

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Rift Valley fever (RVF) is an arboviral zoonotic disease affecting many African countries with the potential to spread to other geographical areas. RVF affects sheep, goats, cattle and camels, causing a high rate of abortions and death of newborn lambs. Also, humans can be infected, developing a usually self-limiting disease that can turn into a more severe illness in a low percentage of cases. Although different veterinary vaccines are available in endemic areas in Africa, to date no human vaccine has been licensed. In previous works, we described the selection and characterization of a favipiravir-mutagenized RVFV variant, termed 40Fp8, with potential as a RVF vaccine candidate due to the strong attenuation shown in immunocompromised animal models. Compared to the parental South African 56/74 viral strain, 40Fp8 displayed 7 amino acid substitutions in the L-protein, three of them located in the central region corresponding to the catalytic core of the RNA-dependent RNA polymerase (RdRp). In this work, by means of a reverse genetics system, we have analyzed the effect on virulence of these amino acid changes, alone or combined, both in vitro and in vivo. We found that the simultaneous introduction of two changes (G924S and A1303T) in the heterologous ZH548-RVFV Egyptian strain conferred attenuated phenotypes to the rescued viruses as shown in infected mice without affecting virus immunogenicity. Our results suggest that both changes induce resistance to favipiravir likely associated to some fitness cost that could be the basis for the observed attenuation in vivo. Conversely, the third change, I1050V, appears to be a compensatory mutation increasing viral fitness. Altogether, these results provide relevant information for the safety improvement of novel live attenuated RVFV vaccines.

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

Megenas,

Dadi,

Mekonnen

et al. 2024

Veterinary Medicine International

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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 northeast Ethiopia. Cross‐sectional serological survey was carried out in 736 serum samples from which cattle (224), camel (155), goats (121), sheep (144), and donkeys (92) were tested for the presence of anti‐RVFV and anti‐WNV IgG using a competitive enzyme‐linked immunosorbent assay (c‐ELISA) in two purposively selected districts of the Afar region. The present study revealed a 9.1% (95% CI = 8.86–9.29) seroprevalence of co‐circulation of RVF and WNV. High 32/155 (20.7%) seroprevalence of co‐circulation was seen in camels, followed by goat 14/121 (11.6%), cattle 16/224 (7.14%), and sheep 5/144 (3.5%), respectively, and higher 41/421 (9.7%) seroprevalence of co‐circulation was observed in Amibara district than Haruka district. Camels were seven times (OR: 7.016, 95% CI = 2.639–18.653) more likely to be seropositive for the co‐circulation than sheep (p ≤ 0.001). Livestock herds found in Amibara district were 1.2 times (OR: 1.165, 95% CI = 0.680–1.996) more likely to be seropositive for RVFV infection than those in Haruka areas. Given the co‐occurrence of RVFV and WNV circulations, along with often suboptimal human and animal health surveillance in many similar areas’ attention should be given. Investigation of the potential socioeconomic and health impacts of zoonotic arbovirus infections in such areas is crucial. Since both RVFV and WNFV are transmitted through a mosquito vector, avoiding mosquito bites is the primary method of prevention.

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Rift Valley Fever

Cited by 3 publications

References 64 publications

Evaluation of a Combined Live Attenuated Vaccine against Lumpy Skin Disease, Contagious Bovine Pleuropneumonia and Rift Valley Fever

Evaluation of a Combined Live Attenuated Vaccine against Lumpy Skin Disease, Contagious Bovine Pleuropneumonia and Rift Valley Fever

Identification of Single Amino Acid Changes in the Rift Valley Fever Virus Polymerase Core Domain Contributing to Virus Attenuation In Vivo

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

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