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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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 goatsnpj Vaccines 4 (2019)1. - ISSN 2059-0105
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.
Mutation of adjacent cysteine residues in the NSs protein of Rift Valley fever virus results in loss of virulence in miceVirus Research 249 (2018). - ISSN 0168-1702 - p. 31 - 44.
Transmission of Rift Valley fever virus from European-breed lambs to Culex pipiens mosquitoesPLoS Neglected Tropical Diseases 11 (2017)12. - ISSN 1935-2727
A novel highly sensitive, rapid and safe Rift Valley fever virus neutralization testJournal of Virological Methods 248 (2017). - ISSN 0166-0934 - p. 26 - 30.
Four-segmented Rift Valley fever virus-based vaccines can be applied safely in ewes during pregnancyVaccine 35 (2017)23. - ISSN 0264-410X - p. 3123 - 3128.
Single-Molecule FISH Reveals Non-selective Packaging of Rift Valley Fever Virus Genome SegmentsPLoS Pathogens 12 (2016)8. - ISSN 1553-7366
Companion Animals as a Source of Viruses for Human Beings and Food Production AnimalsJournal of Comparative Pathology 155 (2016)1. - ISSN 0021-9975 - p. S41 - S53.