Record Details

Strain differentiation and detection of infectious hematopoietic necrosis virus

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Field Value
Title Strain differentiation and detection of infectious hematopoietic necrosis virus
Names LaPatra, Scott Edward (creator)
Fryer, John L. (advisor)
Date Issued 1989-05-05 (iso8601)
Note Graduation date: 1989
Abstract The virulence of selected isolants of infectious hematopoietic
necrosis virus (IHNV) were differentiated and correlated with
electrophoretic mobilities of virion structural proteins by sodium
dodecylsulfate polyacrylamide gel electrophoresis. A type 1
electropherotype of IHNV was more virulent for kokanee salmon
(Oncorhynchus nerka) and a type 2 strain more virulent for rainbow
trout (Oncorhynchus mykiss). Viruses from the Columbia River basin
(electropherotypes 2 and 3) were more virulent for steelhead trout
(Oncorhynchus mykiss) and IHNV electropherotypes from southern
Oregon and California (type 3) were most virulent for chinook salmon
(Oncorhynchus tshawytscha). Microscopic pathology induced by type 1
and 3 strains of IHNV in rainbow trout was less severe and involved
fewer tissues than that caused by a type 2 providing further
evidence that type 2 strains are more pathogenic for rainbow trout.
A fluorescent antibody test (FAT) was developed for the rapid
detection of IHNV. The FAT was used for the detection of IHNV in
blood smears and organ imprints from clinically infected juveniles
and IHNV-infected cells in ovarian fluid from adult carriers. The
test was equal in sensitivity to the plaque assay method and
required less time to obtain a definitive diagnosis. Other sources
of virus examined included cells contained in the ovarian fluid (OF)
of sexually mature steelhead trout. Ovarian fluid collected from
spawning steelhead trout determined to be virus-free tested viruspositive
when reexamined post-spawning. Results indicated that
cells free in OF allowed replication of IHNV and could be used in
diagnostic tests to detect this delayed virus expression.
Infectious hematopoietic necrosis virus was also detected in mucus
obtained from naturally infected juvenile and adult salmonids. In
adult chinook and kokanee salmon, a higher prevalence of virus was
detected in mucus collected from the external surface of fish than
observed in OF, seminal fluid, or spleen tissue homogenates.
Experimental infection of juvenile rainbow trout suggested IHNV
detected in mucus was a result of the normal progression of disease
and that the integument may have been a site of virus replication
and a possible portal of entry.
Genre Thesis/Dissertation
Topic Rhabdoviruses
Identifier http://hdl.handle.net/1957/41766

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