Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff

Although protected for nearly a century, California’s sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile and Escherichia coli O157:H7), and pathogens endemic to the marine environment (Vibrio cholerae, V. parahaemolyticus and Plesiomonas shigelloides). We evaluated statistical associations between detection of these pathogens in otter feces and demographic or environmental risk factors for otter exposure, and found that dead otters were more likely to test positive for C. perfringens, Campylobacter and V. parahaemolyticus than were live otters. Otters from more urbanized coastlines and areas with high freshwater runoff (near outflows of rivers or streams) were more likely to test positive for one or more of these bacterial pathogens. Other risk factors for bacterial detection in otters included male gender and fecal samples collected during the rainy season when surface runoff is maximal. Similar risk factors were reported in prior studies of pathogen exposure for California otters and their invertebrate prey, suggesting that land-sea transfer and/or facilitation of pathogen survival in degraded coastal marine habitat may be impacting sea otter recovery. Because otters and humans share many of the same foods, our findings may also have implications for human health

Ocean acidification and disease: How will a changing climate impact Vibrio tubiashii growth and pathogenicity to Pacific oyster larvae?

Thesis (Master's)--University of Washington, 2012Vibrio tubiashii (Vt) is a causative agent of vibriosis in molluscan bivalves. Recent re-emergence of vibriosis in economically valuable shellfish, such as the Pacific oyster (Crassostrea gigas) in Washington State, has increased the urgency to understand the ecology of this pathogen. It is currently unknown how predicted environmental changes associated with ocean acidification, such as elevated surface seawater temperature, increased partial pressure of CO2 (pCO2), and Vt abundance will impact marine organismal health and disease susceptibility. This study investigates how environmental cues predicted with ocean acidification influence physiological changes and pathogenicity in Vt. Using laboratory experiments to manipulate temperature and pCO2, we examined how these environmental factors influenced pathogen growth. Larval susceptibility to vibriosis was determined by exposing C. gigas larvae to a combination of elevated pCO2 and Vt concentrations. These experiments provide insight into the environmental parameters that may drive pathogenicity or influence proliferation of the bacterium. Investigation of single and multivariate parameters such as temperature, pCO2, and pathogen levels will help assess how predicted shifts in ocean conditions can impact shellfish survival and disease resistance

Vibrio tubiashii ATCC19106 virulence associated contiguous sequences

<p><em>V. tubiashii</em> sequences matched to GO identifiers with putative bacterial virulence.</p> <p>Results limited to sequences with top BLAST hit e-values of less than or equal to 1e-05 and greater than 20x coverage.</p

Contiguous sequences from Vibrio tubiashii ATCC19106 assembly

<p>Contiguous sequences from <em>de novo</em> assembly of <em>V. tubiashii</em> strain ATCC19106.</p

Vibrio tubiashii ATCC19106 annotated contiguous sequences

<p><em>V. tubiashii</em> sequences matched to UniProt/SwissProt identifiers using the BLASTx algorithm. Results limited to sequences with top BLAST hit e-values of less than or equal to 1e-05 and greater than 20x coverage.</p

Contiguous sequences from Vibrio tubiashii RE22 assembly

<p>Contiguous sequences from <em>de novo</em> assembly of <em>V. tubiashii,</em> strain RE22. </p

Identifying Stressor Risk to Biological Health in Streams and Small Rivers of Western Washington

An essential step in watershed management is the identification of key natural and anthropogenic stressors influencing important biological indicators of watershed health, such as the benthic index of biotic integrity, or B-IBI. Relative risk analysis provides quantifiable associations between biological response and stressors of concern, making this a useful tool to identify potential risks to aquatic biota. For this project, water quality, sediment chemistry, and physical habitat data (146 sites) from the Washington State Department of Ecology’s Status and Trends Monitoring for Watershed Health and Salmon Recovery Program were used to determine the relative importance and strength of relationship between benthic macroinvertebrate metrics and environmental stressors in western Washington streams and small rivers. The results presented here provide essential information needed to protect sites in excellent biological health and identify potential sources of impairment, which complement monitoring programs and support watershed management decisions