Thesis
Anaplasma marginale superinfection attributable to pathogen strains with distinct genomic backgrounds
Washington State University
Master of Science (MS), Washington State University
2014
Handle:
https://hdl.handle.net/2376/102406
Abstract
Microbial strain structure is dynamic over space and time; shifts in pathogen strain structure results in changing patterns of disease. The scale of change in space and time differs markedly among pathogens depending on multiple factors including pathogenspecific mechanisms of genetic change and the strength of the selective pressure. In endemic regions with high prevalence of infection, broad population immunity develops against Anaplasma marginale, a highly antigenically variant rickettsial pathogen, and creates strong selective pressure for emergence of and superinfection with strains that differ in their Msp2 variant repertoire. The strains may emerge either by msp2 locus duplication and allelic divergence on an existing genomic background or by introduction of a strain with a different msp2 allelic repertoire on a distinct genomic background. To answer this question, we developed a multi-locus typing assay, based on high throughput sequencing of non-msp2 target loci, to distinguish among strains on different genomic backgrounds. The technical error level was statistically defined based on the percentage of perfect match sequences of clones of each target locus and validated using experimental single strains and strain pairs. Testing of A. marginale positive samples from endemic tropical regions identified individual infections that contained unique alleles for all five targeted loci. The data revealed a highly significant difference in the number of strains per animal in the tropical regions as compared to infections in temperate regions and strongly supported the hypothesis that transmission of genomically distinct A. marginale strains predominates in high prevalence endemic areas.
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Details
- Title
- Anaplasma marginale superinfection attributable to pathogen strains with distinct genomic backgrounds
- Creators
- Eduardo Vallejo Exquerra
- Contributors
- Guy Palmer (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Veterinary Medicine, College of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525143801842
- Language
- English
- Resource Type
- Thesis