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.
Wageningen Bioveterinary Research is developing a vaccine to prevent and control future outbreaks.
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.
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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Reproducing the Rift Valley fever virus mosquito-lamb-mosquito transmission cycleScientific 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 ewesnpj Vaccines 6 (2021)1. - ISSN 2059-0105
Safety and efficacy of four-segmented Rift Valley fever virus in young sheep, goats and cattleVaccines 5 (2020)1. - ISSN 2076-393X
Early pathogenesis of wesselsbron disease in pregnant ewesPathogens 9 (2020)5. - ISSN 2076-0817
Multimeric single-domain antibody complexes protect against bunyavirus infectionseLife 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 ProfileVaccine: X 5 (2020). - ISSN 2590-1362
Rift Valley fever virus targets the maternal-foetal interface in ovine and human placentasPLoS Neglected Tropical Diseases 14 (2020)1. - ISSN 1935-2727
Safety and efficacy of ChAdOx1 RVF vaccine against Rift Valley fever in pregnant sheep and goatsVaccines 4 (2019)1. - ISSN 2076-393X
NSs Filament Formation Is Important but Not Sufficient for RVFV Virulence In VivoViruses 11 (2019)9. - ISSN 1999-4915
Rift Valley fever: biology and epidemiologyJournal of General Virology 100 (2019)8. - ISSN 0022-1317 - p. 1187 - 1199.