Molecular Investigation of Wildlife Herpesvirus and Parapoxvirus: Benefits and Limitations of Genetic Characterization of dsDNA Viruses from Tissues
Date
2019-12-18
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Abstract
Wildlife populations can be reservoirs or victims of pathogens shared with humans and/or domestic animals. Most diseases at the wildlife-livestock interface are caused by viruses. Herpesviridae and Parapoxviridae are families of important double-stranded DNA (dsDNA) viruses that have been implicated in diseases of wildlife, domestic animals, and humans resulting from spill-over or zoonotic transmission, yet still little is known about viruses circulating in wildlife. Wildlife health surveillance is a primary tool for the management of zoonotic diseases, the control of diseases of domestic animals, and the preservation of wildlife populations. Studies herein conduct molecular surveillance of herpesviruses (HV) and orf virus (a parapoxvirus) through diagnostic polymerase-chain reactions (PCR), sequencing, and phylogenetic analysis using tissues of various wildlife animal species in Canada. The viral DNA polymerase (DPOL) gene is an effective target for the detection and characterization of HV present in infected animals. Previously uncharacterized HV were characterized in marten across Canada, and Reindeer gamma-HV 1 was characterized in caribou from different herds. Phylogenetic analysis suggests HV have coevolved with their wildlife host at a species level. Detection of orf virus was most successful when targeting the viral immunodominant envelope protein gene: B2L. Orf virus was detected in muskoxen on Victoria Island in areas managed by the Northwest Territories (NT) and Nunavut (NU), and on the adjacent mainland of NU, Canada. Orf virus was present in males and females, from calf to adulthood, indicating this virus represents a disease threat for muskoxen. Next-generation sequencing was performed directly on the DNA extracted from tissues of four clinically infected, geographically distant muskoxen in our study area. Phylogenetic analysis revealed Muskox orf virus (MxOV), to be unique from known orf viruses. This thesis documents the diversity of HV circulating in wildlife, increases our awareness of limitations when using tissues for molecular surveillance, increases our understanding of orf virus infection in muskoxen, and highlight areas of much-needed research. Methodologies herein can be adapted for the surveillance of other dsDNA viruses, while the data directly contribute to the database of HV and orf virus sequences in Canadian wildlife that provide context for new or emerging pathogens.
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Keywords
Herpesvirus, Orf virus, Virology, Molecular surveillance, Genome, PCR, Muskox, Caribou, Marten
Citation
Dalton, C. S. (2019). Molecular Investigation of Wildlife Herpesvirus and Parapoxvirus: Benefits and Limitations of Genetic Characterization of dsDNA Viruses from Tissues (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.