Reston virus (family Filoviridae) is unique among the viruses of the Ebolavirus genus in that it is considered non-pathogenic in humans, in contrast to the other members which are highly virulent. The virus has however, been associated with several outbreaks of highly lethal hemorrhagic
fever in non-human primates (NHPs), specifically cynomolgus monkeys (Macaca fascicularis) originating in the Philippines. In addition,
Reston virus has been isolated from domestic pigs in the Philippines. To better understand virus spillover events and potential adaption to new hosts, the whole genome sequences of representative
Reston virus isolates were obtained using a next generation sequencing (NGS) approach and comparative genomic analysis and virus fitness analyses were performed. Nine virus genome sequences were completed for novel and previously described isolates obtained from a variety of hosts including a human case, non-human primates and pigs. Results of phylogenetic analysis of the sequence differences are consistent with multiple independent introductions of RESTV from a still unknown natural reservoir into non-human primates and swine farming operations. No consistent virus
genetic markers were found specific for viruses associated with primate or pig
infections, but similar to what had been seen with some Ebola viruses detected in the large Western Africa outbreak in 2014-2016, a truncated version of VP30 was identified in a subgroup of
Reston viruses obtained from an outbreak in pigs 2008-2009. Finally, the genetic comparison of two closely related viruses, one isolated from a human case and one from an NHP, showed
amino acid differences in the viral polymerase and detectable differences were found in competitive growth assays on human and NHP cell lines.