Current Status of Rift Valley Fever Vaccine Development

Abstract

Rift Valley Fever (RVF) is a mosquito-borne zoonotic disease that presents a substantial threat to human and public health. It is caused by Rift Valley fever phlebovirus (RVFV), which belongs to the genus Phlebovirus and the family Phenuiviridae within the order Bunyavirales. The wide distribution of competent vectors in non-endemic areas coupled with global climate change poses a significant threat of the transboundary spread of RVFV. In the last decade, an improved understanding of the molecular biology of RVFV has facilitated significant progress in the development of novel vaccines, including DIVA (differentiating infected from vaccinated animals) vaccines. Despite these advances, there is no fully licensed vaccine for veterinary or human use available in non-endemic countries, whereas in endemic countries, there is no clear policy or practice of routine/strategic livestock vaccinations as a preventive or mitigating strategy against potential RVF disease outbreaks. The purpose of this review was to provide an update on the status of RVF vaccine development and provide perspectives on the best strategies for disease control. Herein, we argue that the routine or strategic vaccination of livestock could be the best control approach for preventing the outbreak and spread of future disease.

Keywords: Rift Valley fever virus; livestock vaccination; vaccines.

Figure 1

Schematic illustration of RVFV genome organization. Left panel shows the virion containing small (S), medium (M), and large (L) RNA segments; the panel also shows the surface glycoproteins Gn and Gc incorporated into the envelope lipid bilayer. Left panel shows the schematic representation of the RNA segments and the coding strategy. L = L protein; NSm = non-structural protein M; glycoproteins Gn, Gc; N = nucleoprotein; NSs = non-structural protein S. The arrows indicate the coding strategy of the virus.