Thesis
The effects of aquatic community members on the persistence of an amphibian Ranavirus
Washington State University
Master of Science (MS), Washington State University
2013
Handle:
https://hdl.handle.net/2376/105495
Abstract
Community interactions can strongly influence disease dynamics in myriad ways, particularly for pathogens that persist while unprotected by their host for a portion of their life cycles. Ranaviruses--often-lethal viruses of cold-blooded vertebrate hosts transmitted by direct contact, and via water, sediment, and fomites--offer an interesting system for understanding these community influences. It is unclear how long ranaviruses remain infectious in the aquatic environment. Previous research suggests persistence times of days to years, depending on the specific conditions used in the study. Viral interactions with the biotic community may explain some of these discrepancies as studies in which virions were held in sterile conditions had much longer persistence times than those where virions were unprotected. To address the role of the biotic community and particulate matter on ranavirus persistence we experimentally inoculated filter-sterilized, UV-treated, and unmanipulated pond water with an FV3-like Ranavirus and took samples over 78 days, quantifying viral titers with real-time quantitative PCR and plaque assays. Viral counts dropped quickly in all pond water treatments; by an average of an order of magnitude in less than one day in unmanipulated pond water and eight days in filter-sterilized pond water. In a second experiment we measured viral titers over 24 hours in virus-spiked spring water with 0, 1, 2, 5, or 10 Daphnia pulex at two different food concentrations. Presence of D. pulex resulted in a reductions of active ranavirus concentrations by approximately an order of magnitude in 24 hours, although concentrations of viral DNA were largely unchanged. Daphnia themselves did not accumulate the virus. We conclude from these experiments that both microbial and zooplanktonic communities can play an important role in ranavirus epidemiology, rapidly inactivating aquatic concentrations of these viruses and thereby minimizing environmental transmission. We suspect that interactions with the biotic community will be important for most pathogens with environmental resting or transmission stages.
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Details
- Title
- The effects of aquatic community members on the persistence of an amphibian Ranavirus
- Creators
- Angela Johnson
- Contributors
- Jesse L. Brunner (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Sciences, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525003501842
- Language
- English
- Resource Type
- Thesis