Thesis
Transmission dynamics of genetically distinct strains of Anaplasma marginale following superinfection
Master of Science (MS), Washington State University
2008
Handle:
https://hdl.handle.net/2376/101510
Abstract
Strain superinfection occurs when a second pathogen strain infects a host already carrying a primary strain. Anaplasma marginale superinfection occurs when the second strain encodes a unique variant surface repertoire as compared to the primary strain and its epidemiologic consequences depend on the relative transmission efficiency of the two strains. Following strain superinfection in the reservoir host, we tested whether the presence of two strains that differed in transmission efficiency altered the transmission phenotypes as compared to single strain infections. Dermacentor andersoni males were fed on calves superinfected with the A. marginale ss centrale vaccine strain (low transmission efficiency) and the A. marginale St. Maries strain (high transmission efficiency). As expected, ticks most commonly acquired both strains (co-infection) although single infections with each strain were also detected. There was no significant difference in the percentage of ticks that acquired the St. Maries strain as compared to the A. centrale vaccine strain although most ticks developed higher levels of infection with the St. Maries strain. The St. Maries strain was transmitted to naïve calves by ticks fed either on superinfected calves or on calves solely infected with the St. Maries strain. In contrast, the A. centrale vaccine strain was not transmitted by either singly or co-infected ticks. These results suggest that the observed strain predominance in endemic regions can be mediated by the transmission efficiency of specific strains regardless of occurrence of superinfection.
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Details
- Title
- Transmission dynamics of genetically distinct strains of Anaplasma marginale following superinfection
- Creators
- Maria Fernanda Bandeira de Melo Galletti
- 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
- Identifiers
- 99900525013101842
- Language
- English
- Resource Type
- Thesis