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There are many published sources
for laboratory procedures used in the diagnosis of finfish diseases. The National
Wild Fish Health Survey (NWFHS) – Laboratory Procedure Manual is not
intended to be comprehensive in its treatment of this large subject area.
Many of the major fish diseases that occur within the United States and throughout
the world have not been documented in wild fish populations. Consequently,
the NWFHS (Survey) has targeted major fish pathogens that are considered a
risk to both natural and artificially produced fish populations. The NWFHS
Laboratory Procedure Manual (Manual) contains protocols for these major pathogens,
and also provides a general scheme of approach to allow detection of new or
exotic agents through the disciplines of virology, bacteriology, parasitology
and histology.
Pathogens of Regional Importance (PRI) are included for informational purposes,
however specific protocols have not been included, in most cases, for these
pathogens.
The Survey includes methodologies
that provide the highest sensitivity for detection of fish pathogens in subclinical
wild fish populations. For this reason, Polymerase Chain Reaction1 (PCR) technology
is included in the Survey as an additional tool to corroborate detection of
specific diseases (Whirling Disease, Bacterial Kidney Disease, Ceratomyxosis,
and viral agents such as IHNV and VHSV). In this application of PCR as a “corroborative
method”, it is not the intent of the Survey to imply that PCR should
replace “gold standard” methodologies for detecting or confirming
a specific fish pathogen. Rather, PCR is being utilized as a secondary detection
tool to corroborate the presence of a pathogen that has been detected by standard
methods. The intent of the Survey is to test the PCR technique along side
standard detection methods such as Pepsin-Trypsin Digest, ELISA, and virology.
This information and field-testing will add information to our knowledge of
both fish diseases and the performance of molecular tools as detection methodologies.
Traditional confirmation tests such as histology (for Whirling Disease and
ceratomyxosis), and serum neutralization for viral agents are also included
for the Survey. Furthermore, the data collected from PCR testing will be evaluated
annually to determine the appropriate use of this tool and its place in the
Survey as methodologies evolve. The foremost purpose of this Manual
is to provide a working document of very detailed information for the U.S.
Fish and Wildlife Service - Fish Health Center staff and clients regarding
the daily procedures in which we conduct the National Wild Fish Health Survey.
Where appropriate, the methods herein follow those described in Suggested
Procedures for the Detection and Identification of Certain Finfish and Shellfish
Pathogens, 1994, 4th edition. American Fisheries Society, Fish Health Section,
Bethesda, Maryland, commonly referred to as the AFS Blue Book. Additional
protocols are included for the Enzyme Linked Immunosorbent Assay (ELISA) and
Polymerase Chain Reaction (PCR) techniques. In several instances protocols
cited from other investigators in the published literature have been referenced
as well. As with most laboratory manuals, this document will be updated as
new and improved procedures become available.
1The PCR Process is covered by Patents owned by Hoffman-LaRoche, Inc. |
