Wageningen Bioveterinary Research (WBVR) has demonstrated that the most common species of mosquito in the Netherlands, Culex (Cx.) pipiens, known as the common mosquito, is able to spread Rift Valley fever virus (RVFV). Previous research showed that lambs in the Netherlands are extremely susceptible to this virus.
Spread of RVFV
In initial experiments, the virus was added to blood that was then artificially fed to the mosquitoes. These experiments revealed that the mosquitoes are able to take in the virus, facilitate propagation, and pass it on in their saliva.
Research was subsequently conducted into whether the mosquitoes can become infected when feeding on lambs infected with RVFV. Virus transmission from lamb to mosquito turned out to be astonishingly efficient, even if it appeared to be restricted to the period when the virus count in the blood was at a maximum.
In addition, raised virus replication in the skin was observed, which was associated with a local inflammatory response caused by the mosquito bites. More detailed research will be conducted this year in order to confirm this last conclusion and to study thoroughly the entire cycle of virus transmission between lambs and mosquitoes.
Rift Valley fever virus
Rift Valley fever virus (RVFV) is a virus that is spread by mosquitoes. The virus can cause serious illness in farm animals. Infection of new-born lambs results in death and infection of gestating ewes results in abortion. RVFV infection in humans usually leads to flu-like symptoms, but may cause extremely serious illness in a small percentage of cases which may even result in death. The virus currently occurs primarily on the African continent and the Arabian Peninsula, but there is a risk that it will spread further, much like the West Nile, Chikungunya and Zika viruses.