Location: Arthropod-borne Animal Diseases ResearchTitle: Efficacy of a recombinant Rift Valley fever virus MP-12 with NSm deletion as a vaccine candidate in sheep) Author
Submitted to: Vaccine
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/18/2013
Publication Date: 4/25/2014
Citation: Weingartl, H.M., Nfon, C.K., Zhang, S., Marszal, P., Wilson, W.C., Morrill, J.C., Bettinger, G.E., Peters, C.J. 2014. Efficacy of a recombinant Rift Valley fever virus MP-12 with NSm deletion as a vaccine candidate in sheep. Vaccine. 32(20):2345-9. doi: 10.1016/j.vaccine.2013.12.064 Interpretive Summary: The mosquito-borne virus Rift Valley fever causes severe to lethal disease in domestic ruminants and man. The disease is endemic is Sub-Saharan Africa and could be accidentally introduced into non-endemic countries. Current vaccines are effective but have limitations that prevent their use in non-endemic countries. This paper describes the evaluation of a new safer vaccine candidate for this important viral disease.
Technical Abstract: Rift Valley fever virus (RVFV), a mosquito-borne virus in the Bunyaviridae family and Phlebovirus genus, causes RVF, a disease of ruminants and man, endemic in Sub-Saharan African countries. However, outbreaks in Yemen and Saudi Arabia demonstrate the ability for RVFV to spread into virgin territory and thus the need exists to develop safe and efficacious vaccines that can be used outside the endemic zones. Commercial RVFV vaccines are available but have limitations that prevent their use in disease-free countries. Consequently, there are ongoing efforts to develop and/or improve RVFV vaccines with global acceptability. In this study a previously developed MP-12-derived vaccine candidate with a large deletion of the NSm gene in the pre Gn region of the M segment (arMP-12-'NSm21/384) developed by T. Ikegami, that was already shown to be safe in pregnant sheep causing neither abortion nor fetal malformation was further evaluated. This vaccine was tested for protection of sheep from viremia and fever following challenge with virulent RVFV ZH501 strain. A single vaccination with arMP-12-'NSm21/384 fully protected sheep when challenged four weeks post vaccination, thereby demonstrating that this vaccine is efficacious in protecting these animals from RVFV infection.