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25
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Introduction
Claire Couch is currently a research associate at Oregon State University. She studies fish and wildlife disease ecology, with particular interest in the connections between disease, microbiomes, and host health. She was previously a PhD student at Oregon State University and a postbac at the National Institutes of Health.
Skills and Expertise
Publications
Publications (25)
Objective
Premature mortality of adult female Chinook Salmon Oncorhynchus tshawytscha is a major barrier to population recovery. The Willamette River basin, Oregon, typifies the problems that are faced by fishery managers in the Pacific Northwest (USA). Adult salmon are trapped and transported upstream of dams to access historical spawning grounds,...
Ectotherms have peculiar relationships with microorganisms. For instance, bacteria are recovered from the blood and internal organs of healthy teleosts. However, the presence of microbial communities in the healthy teleost brain has not been proposed. Here, we report a living bacterial community in the brain of healthy salmonids with bacterial load...
Zebrafish ( Danio rerio ) is now the second most used animal model in biomedical research. As with other vertebrate models, underlying diseases and infections often impact research. Beyond mortality and morbidity, these conditions can compromise research end points by producing nonprotocol induced variation within experiments. Pseudoloma neurophili...
Bighorn sheep (Ovis canadensis) are herbivorous ungulates that live in forage-poor areas of the American west. The trace minerals that herbivores derive from forage are important for immune function. Therefore, identifying trace minerals that affect immune function in bighorn sheep could provide important insights into disease susceptibility and po...
Objective
Dams and reservoirs can alter juvenile growth and survival of migratory salmonids through several physical and biological mechanisms. Juvenile Chinook Salmon Oncorhynchus tshawytscha that are produced upstream of large hydropower dams may have associated passage mortality, but the reservoirs created by these dams can support rapid growth....
Ectotherms have long been known to have peculiar relationships with microorganisms. For instance, bacteria can be recovered from blood and internal organs of healthy teleost fish. However, until now, the presence of a microbial community in the healthy teleost brain has not been proposed. Here we report a living bacterial community in the brain of...
In species where offspring survival is highly variable relative to adult survival, such as bighorn sheep (Ovis canadensis), physiological indicators of maternal investment could clarify the functional mechanisms of life history trade-offs and serve as important predictors of population dynamics. From a management perspective, simple predictors of j...
Pacific salmon experience prolonged elevation in corticosteroid hormones during important life history events including migration, reproduction, and senescence. These periods of elevated corticosteroids correspond with changes to immunity and energy metabolism; therefore, fish may be particularly vulnerable to mortality at these times. Recent studi...
In semelparous Pacific salmon, increased cortisol levels accompany sexual maturation and may be related to the rapid senescence and death that occur after spawning. In fish with extremely high cortisol, pre-spawning mortality is more likely. This may be because elevated cortisol is accompanied by energy depletion and reduces the immune capacity of...
There have been several significant new findings regarding Microsporidia of fishes over the last decade. Here we provide an update on new taxa, new hosts and new diseases in captive and wild fishes since 2013. The importance of microsporidiosis continues to increase with the rapid growth of finfish aquaculture and the dramatic increase in the use o...
Arctic species are likely to experience rapid shifts in prey availability under climate change, which may alter their exposure to microbes and parasites. Here, we describe fecal bacterial and macroparasite communities and assess correlations with diet trophic level in Pacific walruses harvested during subsistence hunts by members of the Native Vill...
Measuring inflammatory markers is critical to evaluating both recent infection status and overall human and animal health; however, there are relatively few techniques that do not require specialized equipment or personnel for detecting inflammation among wildlife. Such techniques are useful in that they help determine individual and population-lev...
A novel Enterocytozoon infection was identified in the intestines of sexually mature Chinook salmon. While microsporidian parasites are common across a diverse range of animal hosts, this novel species is remarkable because it demonstrates biological, pathological, and genetic similarity with Enterocytozoon bieneusi, the most common causative agent...
In recent years, emerging sequencing technologies and computational tools have driven a tidal wave of research on host-associated microbiomes, particularly the gut microbiome. These studies demonstrate numerous connections between the gut microbiome and vital host functions, primarily in humans, model organisms, and domestic animals. As the adaptiv...
Objectives
Methylmercury metabolism was investigated in Pacific walruses ( Odobenus rosmarus divergens ) from St. Lawrence Island, Alaska, United States.
Methods
Total mercury and methylmercury concentrations were measured in fecal samples and paired colon samples ( n = 16 walruses). Gut microbiota composition and diversity were determined using 1...
Studies in humans and laboratory animals link stable gut microbiome “enterotypes” with long-term diet and host health. Understanding how this paradigm manifests in wild herbivores could provide a mechanistic explanation of the relationships between microbiome dynamics, changes in dietary resources, and outcomes for host health. We identify two puta...
Supplemental feeding of wildlife is a common practice often undertaken for recreational or management purposes, but it may have unintended consequences for animal health. Understanding cryptic effects of diet supplementation on the gut microbiomes of wild mammals is important to inform conservation and management strategies. Multiple laboratory stu...
Chlamydia trachomatis can cause persistent infection that drives damaging inflammatory responses resulting in infertility and blindness. Little is known about chlamydial genes that cause persistence or factors that drive damaging pathology. In this work, we show that the C. trachomatis plasmid protein gene 3 (Pgp3) is the essential virulence factor...
Studies in laboratory animals demonstrate important relationships between environment, host traits, and microbiome composition. However, host-microbiome relationships in natural systems are understudied. Here, we investigate metapopulation-scale microbiome variation in a wild mammalian host, the desert bighorn sheep (Ovis canadensis nelsoni). We so...
Serum biochemical parameters can be utilized to evaluate the physiological status of an animal, and relate it to the animal’s health. In order to accurately interpret individual animal biochemical results, species-specific reference intervals (RI) must be established. Reference intervals for biochemical parameters differ between species, and physio...
Chlamydia trachomatis is an obligate intracellular pathogen characterized by a unique biphasic developmental cycle that alternates between infectious and non-infectious organisms. Chlamydial ChxR is a transcriptional activator that has been implicated in the regulation of the development cycle. We used a reverse genetics approach to generate three...
Questions
Question (1)
I am comparing the differences in microbiome community composition between animals according to three different dietary regimes: hay, green vegetation, and restricted feed. Looking at a PCoA plot, the centroid and dispersion of the restricted feed group is obviously different from the two others, and comparing bray-curtis distances with the vegan::adonis() function yields a high R squared and a significant p-value. The green vegetation and hay groups appear the same, but running an adonis test comparing these two groups yields a significant p-value (albeit a very low r squared value of 0.02). Must I reject the null hypothesis that the hay fed group and the green vegetation groups are homogeneous, despite the low r-squared value and the disagreement with the PCoA plot results?