
Rift Valley fever virus (RVFV)
Rift Valley fever (RVF) is a viral zoonosis that primarily affects animals but also has the capacity to infect humans. Wageningen Bioveterinary Research conducts research on this disease.
Infection with Rift Valley fever virus
Most human RVFV infections manifest as a transient, flu-like illness. However, a small percentage of humans develop encephalitis or hemorrhagic fever, which may be fatal. In animals the virus causes severe disease in ruminants like sheep, cattle, goats and camels. Sheep are the most susceptible target species. Age has also been shown to be a significant factor in the animal's susceptibility to the severe form of the disease: over 90 percent of lambs younger than three weeks of age may succumb to the infection.
The rate of abortion among pregnant infected ewes is almost 100 percent. The incubation period is approximately 2 days and is followed by an abrupt onset of fever and general malaise.
Vaccine development
Wageningen Bioveterinary Research is developing a vaccine to prevent and control future outbreaks.
The virus
RVFV is a member of the family Phenuiviridae (genus Phlebovirus, order Bunyavirales). The virus was shown to be transmitted by 48 different mosquito species under laboratory conditions. Importantly, the mosquito species most prevalent in the Netherlands, Culex pipiens (the Northern house mosquito), was shown to be capable of transmitting the virus after feeding on infected sheep.
Outbreaks
The disease was for the first time described after a large outbreak that occurred on a sheep farm in the Rift Valley in Kenya in 1930. Since that time, large outbreaks have occurred across Africa and the Arabian Peninsula. The most recent outbreaks occurred in 2018 in South Africa, Uganda, Rwanda and Kenya resulting in both animal and human fatalities.
Animation: the spread of RVF (1930-2018)
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Publications
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Reproducing the Rift Valley fever virus mosquito-lamb-mosquito transmission cycle
Scientific Reports 11 (2021)1. - ISSN 2045-2322 -
A single vaccination with four-segmented rift valley fever virus prevents vertical transmission of the wild-type virus in pregnant ewes
npj Vaccines 6 (2021)1. - ISSN 2059-0105 -
Safety and efficacy of four-segmented Rift Valley fever virus in young sheep, goats and cattle
Vaccines 5 (2020)1. - ISSN 2076-393X -
Early pathogenesis of wesselsbron disease in pregnant ewes
Pathogens 9 (2020)5. - ISSN 2076-0817 -
Multimeric single-domain antibody complexes protect against bunyavirus infections
eLife 9 (2020). - ISSN 2050-084X -
Theoretical risk of genetic reassortment should not impede development of live, attenuated Rift Valley fever (RVF) vaccines commentary on the draft WHO RVF Target Product Profile
Vaccine: X 5 (2020). - ISSN 2590-1362 -
Rift Valley fever virus targets the maternal-foetal interface in ovine and human placentas
PLoS Neglected Tropical Diseases 14 (2020)1. - ISSN 1935-2727 -
Safety and efficacy of ChAdOx1 RVF vaccine against Rift Valley fever in pregnant sheep and goats
Vaccines 4 (2019)1. - ISSN 2076-393X -
NSs Filament Formation Is Important but Not Sufficient for RVFV Virulence In Vivo
Viruses 11 (2019)9. - ISSN 1999-4915 -
Rift Valley fever: biology and epidemiology
Journal of General Virology 100 (2019)8. - ISSN 0022-1317 - p. 1187 - 1199.