Images

Nested polymerase chain reaction (nPCR) for the detection of Renibacterium salmoninarum. Agarose gel electrophoresis is used for size separation and visualization of amplified DNA sequences.

Nested polymerase chain reaction (nPCR) for the detection of Renibacterium salmoninarum. Following two rounds of PCR amplification, samples are pipetted into an agarose gel for electrophoresis.

Nested polymerase chain reaction (nPCR) for the detection of Renibacterium salmoninarum. Agarose gel electrophoresis is used for size separation and visualization of amplified DNA sequences.

Spread plate procedure for quantitative culture Renibacterium salmoninarum from fish tissue or ovarian fluid.

Tissue sections are mounted on glass slides, stained and examined with a microscope that magnifies cellular details up to 2,000 times with brightfield or fluorescence imaging. Microscopes are used in our research to understand the pathological changes caused by infectious agents such as bacteria, fungi, parasites and viruses.

Quantitative Polymerase Chain Reaction (qPCR) assay for the detection of Renibacterium salmoninarum DNA. A nucleic acid sequence detection system is shown.

Quantitative polymerase chain reaction (qPCR) assay for the detection of Renibacterium salmoninarum DNA. Observation of qPCR results on the screen of a sequence detection system.

Direct fluorescent antibody test (DFAT) for the detection of Renibacterium salmoninarum in tissues. Fluorescing R. salmoninarum cells are visible on a slide.

Fish health principle investigators, students, post-docs, and technicians from different research groups work together as a fish processing team on days when large numbers of fish require sampling.  They are collecting multiple tissues from each fish for testing virus infection and host immune response.

Nucleospora (Enterocytozoon) salmonis infected fingerling steelhead kidney imprint. Note parasitized lymphoblasts containing spherical, light colored, nondescript, nuclear inclusions (arrows). L-G stain. X1000. (Courtesy of B. MacConnell)

Connie McKibben and Carla Conway (USGS) taking kidney samples from adult female Chinook salmon for detection and quantification of Renibacterium salmoninarum (Rs) in the fish, while Joy Evered observes.  Dr. Evered is a USFWS Veterinary Medical Officer and the USFWS Project Officer for this research project.

Dr. Wendy Olson, USFWS biologist (orange rain pants) records data for female spring Chinook salmon being spawned at the hatchery. Among the data recorded are fin clips designating treatment groups for the research project (erythromycin treatment, tulathromycin treatment, or no treatment).

Graduate student Daniel Hernandez, from the University of Washington School of Aquatic and Fishery Sciences, measures virus for a Chinook salmon infection experiment in the WFRC wet lab.  Doug McKenney, USGS volunteer is assisting.

Graduate student Daniel Hernandez, measures virus for a Chinook salmon infection experiment in the WFRC wetlab.

Underwater image of Pacific herring bait ball in Puget Sound. Herring aggregate in schools for protection.

Typical clinical signs of SVC disease, exopthalmia and abdominal distension with hemorrhaging seen in a virus-exposed fathead minnow.

Figure 1. Appearance of descaling site exposed to fast green FCF dye six hours after intentional descaling injury, showing loss of scales and presence of fast green staining. Areas of unintentional integumental injury are also stained (arrows).

Related image Figure 2.

Figure 2. Scanning electron micrograph of descaling area delimited by box in Figure 1 showing epidermal disruption, empty scale pockets and an exposed scale with visible concentric ridges (upper right). Scale bar = 500 µm.

Figure 3. Appearance of descaling site exposed to fast green FCF dye 96 hours after intentional descaling injury, showing lack of scales, presence of fast green staining in areas of epidermal disruption and absence of staining in areas where migrating epidermal cells have closed the wound.

Figure 4.  Scanning electron micrograph of descaling area delimited by box in Figure 3 showing epidermal disruption (arrows), empty scale pockets and restoration of epidermal integrity (asterisk). An exposed scale with visible concentric ridges is visible at the lower center. Scale bar = 500 µm.

Typical clinical signs of disease, pop eye, dermal hemorrhages, abdominal distension, and hemorrhages at the base of fins, displayed in koi infected with spring viremia of carp virus (SVCV).