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Background. Human infection by orthopoxviruses is being reported with increasing frequency, attributed in part to the cessation of smallpox vaccination and concomitant waning of population-level immunity. In July 2015, a female resident of interior Alaska presented to an urgent care clinic with a dermal lesion consistent with poxvirus infection. Laboratory testing of a virus isolated from the lesion confirmed infection by an Orthopoxvirus. Methods. The virus isolate was characterized by using electron microscopy and nucleic acid sequencing. An epidemiologic investigation that included patient interviews, contact tracing, and serum testing, as well as environmental and small-mammal sampling, was conducted to identify the infection source and possible additional cases. Results. Neither signs of active infection nor evidence of recent prior infection were observed in any of the 4 patient contacts identified. The patient's infection source was not definitively identified. Potential routes of exposure included imported fomites from Azerbaijan via the patient's cohabiting partner or wild small mammals in or around the patient's residence. Phylogenetic analyses demonstrated that the virus represents a distinct and previously undescribed genetic lineage of Orthopoxvirus, which is most closely related to the Old World orthopoxviruses. Conclusions. Investigation findings point to infection of the patient after exposure in or near Fairbanks. This conclusion raises questions about the geographic origins (Old World vs North American) of the genus Orthopoxvirus. Clinicians should remain vigilant for signs of poxvirus infection and alert public health officials when cases are suspected.

Background: Cowpox virus (CPXV), a rodent-borne Orthopoxvirus (OPV) that is indigenous to Eurasia can infect humans, cattle, felidae and other animals. Molecular characterization of CPXVs isolated from different geographic locations is important for the understanding of their biology, geographic distribution, classification and evolution. Our aim was to characterize CPXVs isolated from Fennoscandia on the basis of A-type inclusion (ATI) phenotype, restriction fragment length polymorphism (RFLP) profiles of atip gene fragment amplicon, and phylogenetic tree topology in conjunction with the patristic and genetic distances based on full length DNA sequence of the atip and p4c genes. Methods: ATI phenotypes were determined by transmission electron microcopy and RFLP profiles were obtained by restriction enzyme digestion of the atip gene fragment PCR product. A 6.2 kbp region spanning the entire atip and p4c genes of Fennoscandian CPXV isolates was amplified and sequenced. The phylogenetic affinity of Fennoscandian CPXV isolates to OPVs isolated from other geographic regions was determined on the basis of the atip and p4c genes. Results: Fennoscandian CPXV isolates encoded full length atip and p4c genes. They produce wild type V+ ATI except for CPXV-No-H2. CPXVs were resolved into six and seven species clusters based on the phylogeny of the atip and p4c genes respectively. The CPXVs isolated from Fennoscandia were grouped into three distinct clusters that corresponded to isolates from Norway, Sweden and Finland. Conclusion: CPXV is a polyphyletic assemblage of six or seven distinct clusters and the current classification in which CPXVs are united as one single species should be re-considered. Our results are of significance to the classification and evolution of OPVs.

The mechanisms of infection development in intraperitoneal inoculation of mice by ectromelia virus strain K-1 and cowpox strain EP-2 were studied. Ultrastructural parameters of virus assembly and maturation are described. Differences in the types of cells replicating the viruses and in the type of visceral injuries were detected. The studies showed a local type of strain EP-2 cowpox infection and dissemination of ectromelia strain K-1.

BeAn 58058 virus (BAV) was isolated from an Oryzomis rodent in Brazil. BAV was shown to be antigenically related to another poxvirus also isolated in Brazil, the Cotia virus, but it remained ungrouped. Electron microscopy revealed that BAV has a typical poxvirus morphology. The Hind III DNA profile of BAV genome was similar with that of VV WR and Lister, but some differences in the profile were detected. We have also detected the presence of genes homologous to vaccinia virus (VV WR) genes in the genome of BAV. Genes related to vaccinia thymidine kinase (TK) gene and vaccinia growth factor (VGF) gene were found. The patterns of TK and VGF mRNA transcripts described for vaccinia virus infected cells were observed in BAV infected cells. Nucleotide sequence of BAV VGF homologous gene was similar to VV WR VGF sequences. This similarity was further seen when cross-hybridization of total genomes of BAV and VV was done. Polypeptide synthesis of BAV and vaccinia in infected cells also showed similar profiles. The genetic data was used to construct a phylogenetic tree where BAV and VV were placed at the same cluster. Based on our findings we propose that BAV is a vaccinia virus variant.