In the Necropsy lab, samples are being taken from a fish to be tested for pathogens and
viruses of concern.
First, a gill clip is taken and placed in a bottle of fixative.
Then the abdominal cavity is opened up to gain access to the fish’s internal organs.
Different parts are retrieved from the fish sample for a series of lab tests.
First the pyloric caeca are removed – that is the part of the fish that secretes digestive
enzymes for nutrient absorption.
Other tissue samples are then removed including the liver, stomach and kidney.
The kidney sample is placed in a vial and the other tissues are placed in a sample bag
to prepare them for tests to help detect viruses.
One method of preparing the samples is to use manual pressure and a bottle
to homogenize the tissues.
Another method to homogenize the samples involves the use of a machine called the “Stomacher”.
It breaks up the tissues for further diagnostic testing.
Here we see a process called virus isolation in cell culture.
A plate is used that has multiple wells of cultured tissue growing on the bottom.
This cultured tissue is susceptible to live virus particles.
The processed fish sample is added to each well using a pipette.
Specific changes in the culture tissue will allow us to determine if live virus is present
in our fish sample.
The kidney sample from our fish necropsy is being processed.
The sample is being prepared for RNA extraction.
Because viruses are made up of RNA, all RNA needs to be removed from the tissue samples
to prepare them for RT qPCR testing.
A solution is added to the tissue along with microbeads to help break down the tissue.
Vials are placed in a tray then into a machine called a TissueLyser and shaken until they’re pulverized.
Using a multichannel pipetter can help speed things up, delivering multiple samples at one time.
Using a 96-well plate allows several tests to be run at the same time.
In this lab, molecular tests called RT qPCR are being run.
Samples from the Molecular lab are loaded into the RT qPCR machine that will produce
data to indicate if the viral RNA is present in our sample.
Science staff analyse the results from the RT qPCR tests.
They are examining amplification curves that will tell them if a particular virus is present
in the tissue from the fish sample.
This information is critical for identifying the cause of death and helps with decision-making
for mitigation.
Every step of this process in the lab involves highly trained individuals.
The science advice that comes from their work provides the evidence needed for managers
and regulators to make informed decisions that directly impact Canada’s aquatic resources
…resources that Canadians depend on for healthy aquatic ecosystems and sustainable fisheries.