Clone 13-infected Aedes aegypti salivary components inhibit Rift Valley fever virus pathogenicity

Rift Valley fever virus (RVFV) continues to cause large outbreaks among humans and domestic animals in Africa. RVFV Clone 13, a naturally attenuated clone, is a promising vaccine which was used during the 2009-2010 outbreak in South Africa and played a key role in the control of the disease. In this work, we infected Aedes aegypti mosquitoes with RVFV Clone 13 and prepared salivary gland extracts (SGE). C57BL/6-NRJ male mice were infected with a mixture of SGE infected by Clone 13 and the ZH548 RVFV strain. With the injection of increasing doses of Clone 13-infected SGE, all mice were protected. Our results suggest Clone 13 infected SGE contain unique antiviral components able to counteract the replication of RVFV when injected into vertebrates.