Rift Valley fever virus (RVFV) is an RNA virus that is transmitted among domesticated ruminants by mosquito vectors. Pregnant ewes and newborn lambs are most susceptible to disease. Infection of these animals results in high abortion and mortality rates, respectively. Mortality rates among young goats and calves can also be considerable. Humans are also susceptible to disease. Human infections are generally asymptomatic or manifest as a benign and self-resolving illness, although severe complications occur in ~1% of symptomatic individuals. The most severe complications are encephalitis and hemorrhagic fever, which may have a fatal outcome. In endemic areas (Africa and the Arabian Peninsula), the virus is spread by mosquitoes of the Aedes and Culex genera. The mosquito species that is most common in The Netherlands, Culex pipiens, was associated with the largest RVF outbreak in history (Egypt '77). Earlier research at CVI has demonstrated that Dutch Culex pipiens mosquitoes can be infected with the virus and that ~10% of infected mosquitoes contains virus in their saliva, 3 weeks after blood feeding. These experiments were, however, performed with a high virus dose and at high environmental temperature. In the present project, we will initially investigate the effect of virus dose and temperature on vector competence by in vitro experiments. We will subsequently study how efficiently the virus is transmitted from a viremic lamb to mosquitoes during blood feeding. The knowledge that results from this project will provide new insight into the epidemiology of the disease and can be used to improve transmission models of RVFV spreading in The Netherlands.
|Effective start/end date||1/01/16 → 31/12/16|