Antiviral activity of primary human trophoblast conditioned media against rift valley fever virus.

Rift Valley Fever Virus (RVFV) is a Phlebovirus that is found across most of Africa with the majority of cases coming from eastern Africa near Egypt to as far south as South Africa and is a significant public health concern. Aedes mosquitos are the primary vectors of the disease, and as a consequence of this cases are more common after heavy rainfall or flooding. RVFV primarily infects domesticated ruminants, and epidemics are characterized by abortion storms among livestock. During these epidemics, people inevitably come into contact with infected tissues and these people are at the highest risk for zoonosis. Domestic ruminants are not the only animals at risk for spontaneous abortion or juvenile death; wild ruminants and other animals also develop similar outcomes. RVFV is known to cause extensive fetal loss in animals but a similar outcome in cases of human infections is not well documented. Two published case reports exist which suggest vertical transmission events could occur in humans. Currently there are only speculative in vitro models investigating the potential for the vertical transmission of RVFV have been demonstrated. Primary Human Trophoblasts (PHT) cells isolated from human placentas could serve as a good model for a vertical transmission event because these cells serve as a physical barrier to the placenta and have also been shown to be resistant to viral infection. PHT cells express a very unique cluster of miRNA’s located on chromosome 19 and the expression of these miRNA’s is specific to pregnancy with expression dropping off shortly after birth. The viral resistance seen in PHT cells can also be conferred to other cell types. One possible way that viral resistance can be conferred to other cell types is via exosome. Since RVFV is of public health concern and potentially associated with fetal infections in humans, we will test the ability of primary human trophoblast conditioned media (PHTCM) to confer viral resistance to other cell types against RVFV