Geology topics

Jolene A. Glenn

Publications and source records attributed to Jolene A. Glenn.

3 recordsLinked to original sources

USGS2023

Susceptibility of Pallid Sturgeon to viral hemorrhagic septicemia virus genotype IVb

Objective Viral hemorrhagic septicemia virus (VHSV) is an aquatic rhabdovirus causing severe disease in freshwater and saltwater fish species. The susceptibility of endangered Pallid Sturgeon Scaphirhynchus albus to VHSV genotype IVb (VHSV-IVb) infection was investigated. Methods An in vitro assessment using two Pallid Sturgeon cell lines derived from skin and spleen tissue and in vivo evaluation of juvenile Pallid Sturgeon after exposure to VHSV-IVb were performed. Result Plaque assay and RT-PCR results confirmed VHSV-IVb replication in Pallid Sturgeon cell lines. Sturgeon were also susceptible to VHSV-IVb infection after immersion and injection exposures during laboratory experiments. However, after widespread mortality occurred in all treatment groups, including negative control fish, it was determined that the Pallid Sturgeon stock fish were infected with Missouri River sturgeon iridovirus (MRSIV) prior to experimental challenge. Nevertheless, mortalities were equal or higher among VHSV-exposed fish than among negative controls (MRSIV infected), and histopathological assessments indicated reduced hematopoietic cells in spleen and kidney tissues and hemorrhage in the gastrointestinal organs only in fish from the VHSV treatment. Conclusion These results indicate that Pallid Sturgeon is a susceptible host for VHSV-IVb, but the degree of pathogenicity was confounded by the underlying MRSIV infection. Research comparing susceptibility of specific pathogen-free and MRSIV-infected fish to VHSV-IVb is needed to accurately assess the vulnerability of Pallid Sturgeon to VHSV-IVb.

Journal of Aquatic Animal Health↗

USGS2014

Molecular identification of erythrocytic necrosis virus (ENV) from the blood of Pacific herring ( Clupea pallasii )

Viral erythrocytic necrosis (VEN) is a condition affecting the red blood cells of more than 20 species of marine and anadromous fishes in the North Atlantic and North Pacific Oceans. Among populations of Pacific herring ( Clupea pallasii ) on the west coast of North America the disease causes anemia and elevated mortality in periodic epizootics. Presently, VEN is diagnosed by observation of typical cytoplasmic inclusion bodies in stained blood smears from infected fish. The causative agent, erythrocytic necrosis virus (ENV), is unculturable and a presumed iridovirus by electron microscopy. In vivo amplification of the virus in pathogen-free laboratory stocks of Pacific herring with subsequent virus concentration, purification, DNA extraction, and high-throughput sequencing were used to obtain genomic ENV sequences. Fragments with the highest sequence identity to the family Iridoviridae were used to design four sets of ENV-specific polymerase chain reaction (PCR) primers. Testing of blood and tissue samples from experimentally and wild infected Pacific herring as well as DNA extracted from other amphibian and piscine iridoviruses verified the assays were specific to ENV with a limit of detection of 0.0003 ng. Preliminary phylogenetic analyses of a 1448 bp fragment of the putative DNA polymerase gene supported inclusion of ENV in a proposed sixth genus of the family Iridoviridae that contains other erythrocytic viruses from ectothermic hosts. This study provides the first molecular evidence of ENV's inclusion within the Iridoviridae family and offers conventional PCR assays as a means of rapidly surveying the ENV-status of wild and propagated Pacific herring stocks.

Veterinary Microbiology↗

USGS2012

Kinetics of viral load and erythrocytic inclusion body formation in pacific herring artificially infected with erythrocytic necrosis virus

Viral erythrocytic necrosis (VEN) is a condition that affects marine and anadromous fish species, including herrings and salmonids, in the Atlantic and Pacific oceans. Infection is frequently associated with severe anemia and causes episodic mortality among wild and hatchery fish when accompanied by additional stressors; VEN can be presumptively diagnosed by (1) light microscopic identification of a single characteristic—a round, magenta-colored, 0.8-μm-diameter inclusion body (IB) within the cytoplasm of erythrocytes and their precursors on Giemsa-stained blood films; or (2) observation (via transmission electron microscopy [TEM]) of the causative iridovirus, erythrocytic necrosis virus (ENV), within erythrocytes or their precursors. To better understand the kinetics of VEN, specific-pathogen-free Pacific herring Clupea pallasii were infected with ENV by intraperitoneal injection. At 1, 4, 7, 10, 14, 21, and 28 d postexposure, samples of blood, spleen, and kidney were collected and assessed (1) via light microscopy for the number of intracytoplasmic IBs in blood smears and (2) via TEM for the number of virions within erythrocytes. The mean prevalence of intracytoplasmic IBs in the blood cells increased from 0% at 0–4 d postexposure to 94% at 28 d postexposure. Viral load within circulating red blood cells peaked at 7 d postexposure, fell slightly, and then reached a plateau. However, blood cells observed within the kidney and spleen tissues demonstrated high levels of ENV between 14 and 28 d postexposure. The results indicate that the viral load within erythrocytes does not correlate well with IB prevalence and that the virus can persist in infected fish for more than 28 d.

Journal of Aquatic Animal Health↗