Graduation Date

Fall 2023

Document Type



Master of Science degree with a major in Biology

Committee Chair Name

Karen Kiemnec-Tyburczy

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

John Reiss

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Sharyn Marks

Third Committee Member Affiliation

HSU Faculty or Staff

Fourth Committee Member Name

Adam Cummings

Fourth Committee Member Affiliation

Community Member or Outside Professional


Northern California, Ranavirus, Bsal, Bd, Chytrid, Rhyacotriton variegatus, Pathogen, Batrachochytrium, Viral load, Prevalence

Subject Categories



Amphibian population declines around the world have been attributed in part to the emergence of deadly pathogens. However, the severity of the effects of pathogens on amphibian communities can vary by species and location. This study focuses on assessing the prevalence of Batrachochytrium dendrobatidis (Bd), Batrachochytrium salamandrivorans (Bsal), and ranaviruses in populations of southern torrent salamanders (Rhyacotriton variegatus). I also tested for association between environmental factors and the prevalence and viral load of the three pathogens in Northern California. A total of 309 skin swab samples were collected from salamanders in nine sites in Del Norte and Humboldt Counties. A quantitative PCR diagnostic assay was used to detect the presence of pathogen DNA in each sample. Approximately 16% of all R. variegatus swab samples contained ranavirus DNA, but neither Bd nor Bsal were detected. Ranavirus prevalence varied widely across sites (from 0-40%). The water temperature of the salamander’s microhabitat significantly influenced an individual’s ranavirus load. Additionally, ranavirus prevalence was significantly different across seasons. Ranavirus prevalence was highest in the winter, but viral load was highest in the spring. This study provides the first evidence of ranavirus presence in R. variegatus.

Citation Style


Included in

Biology Commons


Thesis/Project Location


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