Untangling the Intangible: The Folds of β-Amyloid

The intersection of art and science is an ambiguous, yet fertile space that holds endless potential for creative exploration. Of the infinite number of biological topics that exist on every imaginable physical scale, there also exists an analytical and interpretive gradient, ranging from factual science to imaginative and emotional art. Finding the interesting points along this theoretical spectrum is one of the greatest challenges that I have realized throughout the course of my honors thesis. My journey has followed a pathway generating pieces that range dramatically in scientific, emotional, and visual content, and I have experimented with new techniques and media at every step. I have been challenged by both content and process, growing immensely in my approach to art-making throughout the course of this thesis. Here, I trace my journey and explain my most intensive artistic endeavor to date.Bachelor of Scienc

High-Throughput Sequencing for Understanding the Ecology of Emerging Infectious Diseases at the Wildlife-Human Interface

Rising rates of emerging infectious diseases (EIDs) demand creative, efficient, and integrative investigations to understand their transmission, ecological contingencies, and dynamics at wildlife-human interfaces. High-throughput sequencing (HTS) methodologies provide enormous potential to unravel these contingencies to improve our understanding, but their potential is only just starting to be realized. While recent work has largely focused on novel pathogen discovery at likely interfaces, high-throughput methods can also allow disease ecologists to better explore the critical effects of climate, seasonality, and land-use changes on EIDs. HTS can facilitate the creation of entire host-pathogen networks, integrate important microbiome and co-infection data, and even pinpoint important exposure routes at interfaces through environmental media. Here we highlight studies at the frontier of HTS and disease ecology research, identify current limitations, and outline promising future applications for EIDs

More than mimicry? Evaluating scope for flicker-fusion as a defensive strategy in coral snake mimics

Coral snakes and their mimics often have brightly colored banded patterns, generally associated with warning coloration or mimicry. However, such color patterns have also been hypothesized to aid snakes in escaping predators through a “flicker-fusion” effect. According to this hypothesis, banded color patterns confuse potential predators when a snake transitions from resting to moving because its bands blur together to form a different color. To produce this motion blur, a moving snake’s bands must transition faster than the critical flicker-fusion rate at which a predator’s photoreceptors can refresh. It is unknown if coral snakes or their mimics meet this requirement. We tested this hypothesis by measuring the movement speed and color patterns of two coral snake mimics, Lampropeltis triangulum campbelli and L. elapsoides, and comparing the frequency of color transitions to the photoreceptor activity of the avian eye. We found that snakes often produced a motion blur, but moving snakes created a blurring effect more often in darker conditions, such as sunrise, sunset, and nighttime when these snakes are often active. Thus, at least two species of coral snake mimics are capable of achieving flicker-fiision, indicating that their color patterns may confer an additional defense aside from mimicry

Large-herbivore nemabiomes: patterns of parasite diversity and sharing

Amidst global shifts in the distribution and abundance of wildlife and livestock, we have only a rudimentary understanding of ungulate parasite communities and parasite-sharing patterns. We used qPCR and DNA metabarcoding of fecal samples to characterize gastrointestinal nematode (Strongylida) community composition and sharing among 17 sympatric species of wild and domestic large mammalian herbivore in central Kenya. We tested a suite of hypothesis-driven predictions about the role of host traits and phylogenetic relatedness in describing parasite infections. Host species identity explained 27 – 53% of individual variation in parasite prevalence, richness, community composition and phylogenetic diversity. Host and parasite phylogenies were congruent, host gut morphology predicted parasite community composition and prevalence, and hosts with low evolutionary distinctiveness were centrally positioned in the parasite- sharing network. We found no evidence that host body size, social-group size or feeding height were correlated with parasite composition. Our results highlight the interwoven evolutionary and ecological histories of large herbivores and their gastrointestinal nematodes and suggest that host identity, phylogeny and gut architecture — a phylogenetically conserved trait related to parasite habitat — are the overriding influences on parasite communities. These findings have implications for wildlife management and conservation as wild herbivores are increasingly replaced by livestock

The role of watering holes as hotspots of disease transmission in changing climates

Humans impact the globe in numerous ways that have important yet variable effects on human and animal diseases. Anthropogenic changes may be particularly consequential where landscape resources increase transmission opportunities; however, these spatial hotspots of human and animal activity are a relatively understudied aspect of disease dynamics. Watering holes are an ideal system for studying such transmission hotspots amid accelerating global changes, as they draw together wildlife, domestic animals, and humans in arid climates that are increasingly impacted by climate change. In this dissertation, I used observational and experimental data to investigate plants, herbivores, and gastrointestinal parasites at these important ecological resources in a semi-arid savanna system in central Kenya.I first examined how watering holes and associated herbivore aggregations shape plant communities that form the transmission substrate for many fecal-oral parasites. I found that herbivore aggregation near water was associated with decreased plant cover but opposing plant diversity patterns, depending on soil and rainfall. This was driven by changes in grass and tree cover and dominance shifts of two globally important grass species. I then used a two-year water manipulation experiment and observational study to examine the extent to which herbivores and their gastrointestinal parasites aggregated near water sources under different gradients of water availability: aridity, recent rainfall, and distance from surface water. I found marked differences in dung and parasite aggregation at water by herbivore species, with elephants and cattle congregating strongly in arid conditions. However, all animals displayed some degree of increased watering hole use with at least one metric of decreased water availability, suggesting that drying environments may contribute to increased parasite concentration at these hotspots across species.I then investigated gastrointestinal parasite communities in 18 sympatric and globally threatened herbivore species using DNA metabarcoding I found that host phylogeny and gut type were central in determining parasitic nematode sharing. I linked data on parasite spatial aggregation and sharing to data from an 8000-volunteer citizen science project measuring herbivore activity from camera traps to estimate parasite transmission near water relative to dry sites. I found that due to their abundance, degree of aggregation around water, and ability to share parasites, cattle were strong potential drivers of gastrointestinal parasite transmission for other herbivore species at watering holes. Together, these findings demonstrate predictable patterns of parasite transmission in resource-limited areas and have implications for understanding and predicting disease dynamics in humans, wildlife, and domesticated animals that live in increasingly dry landscapes

The Role of Watering Holes as Hotspots of Disease Transmission in Changing Climates

Humans impact the globe in numerous ways that have important yet variable effects on human and animal diseases. Anthropogenic changes may be particularly consequential where landscape resources increase transmission opportunities; however, these spatial hotspots of human and animal activity are a relatively understudied aspect of disease dynamics. Watering holes are an ideal system for studying such transmission hotspots amid accelerating global changes, as they draw together wildlife, domestic animals, and humans in arid climates that are increasingly impacted by climate change. In this dissertation, I used observational and experimental data to investigate plants, herbivores, and gastrointestinal parasites at these important ecological resources in a semi-arid savanna system in central Kenya. I first examined how watering holes and associated herbivore aggregations shape plant communities that form the transmission substrate for many fecal-oral parasites. I found that herbivore aggregation near water was associated with decreased plant cover but opposing plant diversity patterns, depending on soil and rainfall. This was driven by changes in grass and tree cover and dominance shifts of two globally important grass species. I then used a two-year water manipulation experiment and observational study to examine the extent to which herbivores and their gastrointestinal parasites aggregated near water sources under different gradients of water availability: aridity, recent rainfall, and distance from surface water. I found marked differences in dung and parasite aggregation at water by herbivore species, with elephants and cattle congregating strongly in arid conditions. However, all animals displayed some degree of increased watering hole use with at least one metric of decreased water availability, suggesting that drying environments may contribute to increased parasite concentration at these hotspots across species. I then investigated gastrointestinal parasite communities in 18 sympatric and globally threatened herbivore species using DNA metabarcoding I found that host phylogeny and gut type were central in determining parasitic nematode sharing. I linked data on parasite spatial aggregation and sharing to data from an 8000-volunteer citizen science project measuring herbivore activity from camera traps to estimate parasite transmission near water relative to dry sites. I found that due to their abundance, degree of aggregation around water, and ability to share parasites, cattle were strong potential drivers of gastrointestinal parasite transmission for other herbivore species at watering holes. Together, these findings demonstrate predictable patterns of parasite transmission in resource-limited areas and have implications for understanding and predicting disease dynamics in humans, wildlife, and domesticated animals that live in increasingly dry landscapes

Conservation of biodiversity as a strategy for improving human health and well-being

The Earth's ecosystems have been altered by anthropogenic processes, including land use, harvesting populations, species introductions and climate change. These anthropogenic processes greatly alter plant and animal communities, thereby changing transmission of the zoonotic pathogens they carry. Biodiversity conservation may be a potential win-win strategy for maintaining ecosystem health and protecting public health, yet the causal evidence to support this strategy is limited. Evaluating conservation as a viable public health intervention requires answering four questions: (i) Is there a general and causal relationship between biodiversity and pathogen transmission, and if so, which direction is it in? (ii) Does increased pathogen diversity with increased host biodiversity result in an increase in total disease burden? (iii) Do the net benefits of biodiversity conservation to human well-being outweigh the benefits that biodiversity-degrading activities, such as agriculture and resource utilization, provide? (iv) Are biodiversity conservation interventions cost-effective when compared to other options employed in standard public health approaches? Here, we summarize current knowledge on biodiversity-zoonotic disease relationships and outline a research plan to address the gaps in our understanding for each of these four questions. Developing practical and self-sustaining biodiversity conservation interventions will require significant investment in disease ecology research to determine when and where they will be effective.This article is part of the themed issue 'Conservation, biodiversity and infectious disease: scientific evidence and policy implications'

Dataset for: Cattle aggregations at shared resources create potential parasite exposure hotspots for wildlife

<p>Globally rising livestock populations and declining wildlife numbers are likely to dramatically change disease risk for wildlife and livestock, especially at resources where they congregate. However, limited understanding of interspecific transmission dynamics at these hotspots hinders disease prediction or mitigation. In this study, we combined gastrointestinal nematode density and host foraging activity measurements from our prior work in this system with three estimates of parasite-sharing capacity to investigate how interspecific exposures alter the relative riskiness of an important resource – water – among cattle and five dominant herbivore species in an East African tropical savanna. </p> <p>We found that due to their high parasite output, water dependence, and parasite-sharing capacity, cattle greatly increased potential parasite exposures at water sources for wild ruminants. When untreated for parasites, cattle accounted for over two-thirds of total potential exposures around water for wild ruminants, driving 2–23-fold increases in relative exposure levels at water sources. Simulated changes in wildlife and cattle ratios showed that water sources become increasingly important hotspots of interspecific transmission for wild ruminants when the relative abundance of cattle parasites increases. These results emphasize that livestock have significant potential to alter the level and distribution of parasite exposures across the landscape for wild ruminants.</p><p>Funding provided by: National Science Foundation<br>Crossref Funder Registry ID: https://ror.org/021nxhr62<br>Award Number: 1556786</p><p>Funding provided by: National Geographic Society<br>Crossref Funder Registry ID: https://ror.org/04bqh5m06<br>Award Number: EC-33R-18</p><p>Funding provided by: National Science Foundation<br>Crossref Funder Registry ID: https://ror.org/021nxhr62<br>Award Number: 1650114</p&gt