Detection of fowlpox virus carrying distinct genome segments of reticuloendotheliosis virus

Authors: JOSHI, LOK - South Dakota State University; BAUERMANN, FERNANDO - South Dakota State University; HAIN, KYLE - South Dakota State University; KUTISH, GERALD - University Of Connecticut; ARMIEN, ANIBAL - University Of Minnesota; LEHMAN, CHAD - South Dakota Game, Fish And Parks; NEIGER, REG - South Dakota State University; Afonso, Claudio; TRIPATHY, DEOKI - University Of Illinois; DIEGO, DIEL - South Dakota State University

Submitted to: Archives of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/21/2018
Publication Date: 10/22/2018
Publication URL: https://handle.nal.usda.gov/10113/6195913
Citation: Joshi, L.R., Bauermann, F.V., Hain, K.S., Kutish, G.F., Armien, A.G., Lehman, C.P., Neiger, R., Afonso, C.L., Tripathy, D.N., Diego, D.G. 2018. Detection of fowlpox virus carrying distinct genome segments of reticuloendotheliosis virus. Archives of Virology. 260:53-59. https://doi.org/10.1016/j.virusres.2018.10.017.
DOI: https://doi.org/10.1016/j.virusres.2018.10.017

Interpretive Summary: Avipox viruses comprise a broad group of poxviruses that are known to infect multiple avian species, including domestic poultry and wild birds. Several types of avipox have been described, with Fowlpox virus as the virus causing diseases in domestic poultry (chickens and turkeys) and wild turkeys. Fowlpox virus infections can lead to significant economic losses to the poultry industry. Although significant mortality rates has been observed during outbreaks of fowlpox, mortality is also associated with secondary bacterial infections. The samples studied here correspond to viruses circulating the US, thus these represent a risk to the poultry industry. Here the genetic composition of these viruses is described. This information will be used to better understand the epidemiology and diagnostic of the disease.

Technical Abstract: Fowlpox virus (FWPV), the type species of the genus Avipoxvirus family Poxviridae, is a large double-stranded DNA virus that causes fowlpox in chickens and turkeys. Notably, sequences of the avian retrovirus reticuloendotheliosis virus (REV) are frequently found integrated into the genome of FWPV. While some FWPV strains carry remnants of the REV long terminal repeats (LTRs), other strains have been shown to contain insertions of nearly the full-length REV provirus in their genome. In the present study we detected heterogeneous FWPV populations carrying the REV LTR or the near full-length REV provirus genome in a Merriam’s wild turkey (Meleagris gallopavo merriami). The bird presented papules distributed throughout the non-feathered areas of the head. Avipoxvirus-like virions were observed in the lesions by transmission electron microscopy and the presence of FWPV was confirmed by DNA sequencing. Metagenomic sequencing performed on nucleic acid extracted from the skin lesions revealed two FWPV genome populations carrying either a 197-nt remnant of the REV LTR or a 7939-nt long fragment corresponding to the full-length REV provirus. Notably, PCR amplification using primers targeting FWPV sequences flanking the REV insertion site, confirmed the natural occurrence of the heterogeneous FWPV genome populations in one additional clinical sample from another turkey affected by fowlpox. Additionally, sequencing of a historical FWPV isolate obtained from chickens in the US in 2000 also revealed the presence of the two FWPV-REV genome populations. Results here demonstrate distinct FWPV populations containing variable segments of REV genome integrated into their genome. These distinct genome populations are likely a result of homologous recombination events that take place during FWPV replication.