Exposure to pathogens can play an important role in fish ecology and population health. For example, pathogens are regarded as a major cause of mortality in juvenile salmonids that migrate through the Pacific Northwest of North America and infections have been correlated with salmonid smolt mortality during their migration to the ocean.

Environmental diseases (field work related) – Dr. Segarra evaluate potential pathogens infections in Delta Smelt and juvenile Chinook Salmon (Oncorhynchus tshawytscha) deployed at key sites along a major migration corridor. The primary objective is to determine the consequences of pathogenic infection on fish performance and fitness, using a combination of indicators at multiple levels of biological organization. We hypothesize that pathogenic infection would elicit immune responses detectable at the molecular level (gene expression), which would also result in reduced growth and energy reserves and reduced tolerance to thermal and hypoxic stress.

Fish health and experimental infection – Segarra Lab study synergetic effect of pesticide and pathogen infection on fish health. We hypothesis that 1) Pesticide or bacteria may affect mucus gill characteristics and increase fish metabolic rate to support the cost of the detoxification and 2) Pesticide exposure can affect Immune defenses from pathogens. To address these hypothesis we evaluate gill lessions, mucus secretion, microbiota dysbiosis, metabolic rate, growth and mortality.

Here Salmon were preliminary exposed to an insecticide (Bifenthrin) followed by an bacterial challenge using Flavobacterieum columnare in the Aquatic Pathology Lab at the Center for Aquatic Biology and Aquaculture (CABA) (collaboration with Dr. Soto).

Previous research was focusing on evaluating mucosal immunity and microbial homeostasis in healthy and diseased bivalves on oysters (Crassostrea gigas and C. virginica) and clams (Mercenaria mercenaria) using proteomic and metagenomic approaches (in collaboration with the MADL, Stony Brook University).

C. virginica prior a bacterial injection in the adductor muscle using recombinant Vibrio parahaemolyticus, pathogen for human.

GFP and RFP recombinant Vibrio parahaemolyticus incubated at 37C