The increasing threat of Rift Valley fever virus globalization: strategic guidance for protection and preparation

Authors: Gibson, Seth; NORONHA, LEELA - US Department Of Agriculture (USDA); TUBBS, HEIDI - Oak Ridge National Laboratory; COHNSTAEDT, LEE - US Department Of Agriculture (USDA); WILSON, WILLIAM - US Department Of Agriculture (USDA); MIRE, CHAD - US Department Of Agriculture (USDA); MITZEL, DANA - US Department Of Agriculture (USDA); ANYAMBA, ASSAF - Oak Ridge National Laboratory; ROSTAL, MELINDA - Ecohealth Alliance; Linthicum, Kenneth - Ken

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/2023
Publication Date: 10/20/2023
Citation: Gibson, S., Noronha, L., Tubbs, H., Cohnstaedt, L., Wilson, W., Mire, C., Mitzel, D., Anyamba, A., Rostal, M., Linthicum, K. 2023. The increasing threat of Rift Valley fever virus globalization: strategic guidance for protection and preparation. Journal of Medical Entomology. 60(6):1197-1213. https://doi.org/10.1093/jme/tjad113.
DOI: https://doi.org/10.1093/jme/tjad113

Interpretive Summary: Rift Valley fever virus (RVFV) is the causative agent of a prominent disease that is a global threat to people and agriculture. Changing climates, increased movement of goods and people, and poor mosquito and pathogen surveillance have increased the risk of virus introduction to the United States and other areas worldwide. RVFV is endemic to the African continent with large outbreaks observed at the decadal scale since the early 20th century. However a spread to the Arabian Peninsula and shows increasing patterns of outbreaks on an annual scale. This virus can be transmitted by mosquitoes as well as though direct contact with infected tissues and can cause sporadic as well as widespread morbidity and mortality in domestic livestock as well as humans. High virus levels in infected livestock moved for legal and illegal trade as well as in infected humans traveling from RVFV-endemic regions can spread this virus to the US, southern Europe, and other regions worldwide where permissive ecological infrastructure could support rapid establishment. With global commerce, it is likely RVFV will be introduced to new areas with suitable hosts, mosquito vector species, and environments. We discuss how tools can be developed to investigate factors affecting virus and mosquito vector surveillance need to be developed and maintained to detect and mitigate a virus introduction to a new geographic area. Only a rapid and coordinated response will prevent permanent establishment of the virus resulting in long-term recurring problems.

Technical Abstract: Rift Valley fever virus (RVFV) is a prominent vector-borne zoonotic foreign animal disease threat to global agriculture and public health. Risks of introduction into the United States and other areas are closely tied to changing climate regimes and other dynamic environmental factors that are becoming more prevalent by the year, as well as virus evolutionary factors and human movement. RVFV is endemic to the African continent with large epizootics observed at the decadal scale since the early 20th century but has spread to the Arabian Peninsula and shows increasing patterns of interepizootic transmission on the annual scale. This virus can be transmitted by mosquitoes as well as though direct contact with infected tissues and can cause sporadic as well as widespread morbidity and mortality in domestic ungulate livestock as well as humans. High viremias in infected livestock moved for legal and illegal trade as well as in infected humans traveling from RVFV-endemic regions can spread this virus to the US, southern Europe, and other regions worldwide where permissive ecological infrastructure could support rapid establishment. With global commerce, it is likely RVFV will be introduced to new areashave with suitable hosts, mosquito vector species, and environments. We discuss how animal and mosquito models, as well as molecular tools such as reverse genetic systems and next generation sequencing for virus population genetics, have been developed to investigate factors affecting evolution of RVFV replication, pathogenicity, and transmission. The strong mosquito component of RVFV epidemiology combined with these molecular parameters create opportunities to develop strategies to leverage models of connectivity among potential source and emerging regions to target surveillance and mitigation activities to reduce the risk of RVFV introduction, or contain the virus should it be introduced, into the US and elsewhere.