Subfamily: Chordopoxvirinae

Genus: Vespertilionpoxvirus


Distinguishing features

The Vespertilionpoxvirus genus includes a single virus species, Eptesipox virus, including eptesipox virus, which was isolated from the synovial tissue of a big brown bat from North America that had been treated at a wildlife rehabilitation centre due to joint swellings and an inability to fly (Tu et al., 2017). Five other bats were similarly affected. It is not known whetherthe big brown bat serves as the reservoir species for the virus or if there is another host. Equally, the significance of the virus in the wild is unknown. Although both eptesipox virus and pteropox virus (genus Pteropopoxvirus), have been found in bats (Chiroptera), their respective hosts are from different sub-orders of microbats and megabats respectively and from different continents. These two viruses are different from the unclassified chordopoxvirus hypsugopoxvirus, found in an insectivorous bat from northern Italy. There is no evidence that eptesipox virus is zoonotic.


The virion of eptesipox virus is typical of orthopoxviruses being brick-shaped with a surface structure of irregularly arranged filaments and a dumbbell-shaped core. It measures approximately 190 nm × 270 nm. Nothing is known about the ether-sensitivity of infection.

Genome organization and replication

The dsDNA genome is approximately 177 kbp, encoding a predicted 191 genes; the G + C content is approximately 33%. The central core of the genome is conserved in gene content and co-linearity, containing the 90 essential genes found in the majority of mammalian chordopoxviruses. Phylogenetic analysis using the predicted amino acid sequences of 7 conserved proteins places eptesipox virus on a discrete branch between the orthopoxviruses and a clade including members of the genera Capripoxvirus, Suipoxvirus, Yatapoxvirus, Leporipoxvirus and Cervidpoxvirus (the CSYLC poxvirus clade). This positioning is supported by the presence of 7 genes that appear only to have homologues with CSYLC clade viruses as well as the genome locations of a further two genes that are syntenic only with their positions in members of the CSYLC clade. Equally, eptesipox virus, possesses 5 genes that are otherwise considered to be orthopoxvirus-specific. Eleven predicted proteins appear to be unique to eptesipox virus, with their biological functions remaining obscure due to the lack of significant homology to any sequences in current databases (Tu et al., 2017). There appear to be no genes shared between eptesipox virus and pteropox virus that would hint at a common virulence mechanism in bat hosts.

For replication please see discussion under family description.

Species demarcation criteria

There is only one species in the genus and therefore criteria have not been defined.