Molecular aspects of Rift Valley fever virus and the emergence of reassortants

Abstract

Rift Valley fever phlebovirus (RVFV) is a mosquito-transmitted pathogen endemic to sub-Saharan Africa and the Arabian Peninsula. RVFV is a threat to both animal and human health and has costly economic consequences mainly related to livestock production and trade. Competent hosts and vectors for RVFV are widespread, existing outside of endemic countries including the USA. Thus, the possibility of RVFV spreading to the USA or other countries worldwide is of significant concern. RVFV (genus Phlebovirus) is comprised of an enveloped virion containing a three-segmented, negative-stranded RNA genome that is able to undergo genetic reassortment. Reassortment has the potential to produce viruses that are more pathogenic, easily transmissible, and that have wider vector or host range. This is especially concerning because of the wide use of live attenuated vaccine strains throughout endemic countries. This review focuses on the molecular aspects of RVFV, genetic diversity of RVFV strains, and RVFV reassortment.

The Emergence of Rift Valley Fever in Gedaref State Urges the Need for a Cross-Border One Health Strategy and Enforcement of the International Health Regulations

“…The disease is caused by the arthropod-borne virus (arbovirus) RVF phlebovirus (RVFV), which is a member of the Phenuiviridae viral family [ 1 ]. RVFV was first isolated and characterized following a large-scale epizootic in Kenya in 1931 [ 2 ]. Several mosquito species are competent vectors of RVFV, differently contributing in the virus transmission in both the enzootic cycle among sylvatic animals and the epizootic/epidemic transmission cycle among domestic animals and people [ 2 ].…”

“…RVFV was first isolated and characterized following a large-scale epizootic in Kenya in 1931 [ 2 ]. Several mosquito species are competent vectors of RVFV, differently contributing in the virus transmission in both the enzootic cycle among sylvatic animals and the epizootic/epidemic transmission cycle among domestic animals and people [ 2 ]. Additionally, RVFV infection can be acquired through close contact with infected animals, and through contact with the raw milk or meat from infected animals [ 3 ].…”

Structure of a functional cap-binding domain in Rift Valley fever virus L protein

“…The virus infects ruminants and pseudoruminants leading to abortions in pregnant animals and high mortality among young animals. The virus can also be transmitted to humans causing febrile illness with the possibility for severe disease even with fatal outcome [1, 2]. Due to the high economical burden of RVFV outbreaks among livestock, the possibility of severe human disease without effective antiviral treatment options and the epidemic potential RVFV is listed on the WHO R&D Blueprint.…”

Phylogenetic Analysis of Massilia phlebovirus in Portugal

“…In these viruses, reassortment has seemingly occurred both between distant (intertypic) and closely-related (intratypic) lineages [ 41 , 42 ]. As in the population biology of other viruses (e.g., Influenza A), reassortment is a mechanism of diversification and adaptation [ 43 ], with potential implications for fitness, pathogenicity and host-range [ 44 ]. In general, reassortants pose challenges to the current definition of species as per the ICTV criteria, highlighting the possibility that more general considerations may be required for deciding under what conditions particular reassortants should be considered as members of an existing or new species.…”