Browsing by Subject "disease ecology"
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Item Epidemiological Model and Weighted Edgelists of Contacts Among Cattle Herds in the Dry and Wet Season in Central Kenya(2017-07-13) VanderWaal, Kimberly; Gilbertson, Marie; Okanga, Sharon; Allan, Brian F.; Craft, Meggan E.; kvw@umn.edu; VanderWaal, KimberlyThis data consists of weighted edgelists representing the frequency with which mobile herds of cattle came into contact with one another in central Kenya. In addition, code is included that simulates the spread of a pathogen through the cattle network. This data can be used to better understand patterns of contact among cattle herds and its implication for the spread of pathogens.Item Host Diet and Pathogen Diversity: How Soil Nutrients Affect Plant Virus Interactions(2017-12) Kendig, AmyHuman activities and management choices can impact the spread and intensity of diseases in plant and animal populations. For example, high nutrient inputs to terrestrial and aquatic systems may enhance pathogen success or aid hosts in resisting and tolerating disease. Because nutrient supply rates and ratios mediate interactions among free-living species, they may also influence interactions between hosts and pathogens. Further, it is increasingly clear that infections involve multiple different kinds of pathogens, and their interactions may also be mediated by environmental nutrients. The goal of my dissertation research was to understand how soil nutrients affect interactions among plant viruses and the consequences of these interactions for disease dynamics. We used field-collected data to determine how nutrients, among other factors, affected spatial patterns of viruses in grasslands. We found that virus pairs frequently co-occurred, and phosphorus (P) addition promoted the aggregation of one pair. Then, we performed growth chamber experiments to evaluate how nitrogen (N) and P mediated within-host interactions between two viruses, disease severity, and transmission to new hosts. We found that pathogens coexisted within hosts and occasionally benefitted from increased N. Disease severity was not strongly influenced by soil nutrients, but modeling results indicated that this outcome depended on the mechanism behind virulence. Finally, we found that the viruses were likely to coexist at the host population scale, despite inhibition that occurred during transmission. These results indicate that soil N and P influence some aspects of the system, but are not the main drivers behind virus diversity. This research contributes to a growing body of knowledge about the mechanisms linking environmental nutrients to disease across systems.