Page 397 - The Veterinary Laboratory and Field Manual 3rd Edition

366 Susan C. Cork

Brief guidelines for sample collection ParaSItoLoGy
Collect representative faecal samples (10 g) and
SaMPLES For HIStoPatHoLoGy any whole parasites and store in 70% alcohol
Collect samples (1 × 1 × 1 cm) representative of or 10% formal saline in labelled jars or sealed
the normal and diseased tissue in an organ and plastic bags. Smears can be prepared from the
store in a labelled bottle in ten times the sample mucosal lining of the intestine especially around
volume of 10% buffered formalin. For intestinal the ileocaecal valve (for Mycobacteria) and the
sections, it may be necessary to attach the tissue caecum and ileum (for crytposporidia and coccidia).
to a piece of cardboard with a note outlining the
area of the gut the section was taken from (for HaEMatoLoGy
example, ileum, jejunum, caecum, colon and so Impression smears and blood smears can be
on). This is because the location of lesions can prepared from the spleen, lymph nodes, bone
be important. For brain examination, the whole marrow (iliac crest/rib) and heart blood to look
brain should be fixed in a bucket of formalin. for blood parasites and to examine the morphol-
This is to allow a more comprehensive examina- ogy of red and white blood cells.
tion of different parts of the brain tissue. DO
NOT FREEZE tissues for histopathology (HP). toxIcoLoGy
Tissues taken from carcasses of animals Unless a specific toxin is suspected it is hard
which have been dead for > 12 h will show a to confirm poisoning as a cause of death. Even
lot of secondary changes and may therefore not where comprehensive toxicology facilities are
be suitable for HP examination so this should be available it is not always possible to confirm
noted on the submission form along with details the presence of the toxin in tissues as the active
of any gross findings. ingredient may already have been metabolized
prior to death. However, as a general rule, to
MIcrobIoLoGy investigate such deaths collect routine samples
Collect representative tissue sections, body flu- for HP (liver, spleen, heart, lung, kidney/ureter/
ids or discharges using sterile forceps, a swab, bladder wall, and a bone marrow smear for cytol-
or a needle and syringe, and store in sterile well ogy). Fresh liver and stomach contents should
labelled containers. Collect such samples before also be submitted along with a detailed report
opening the gut to avoid contamination with gut of the clinical signs prior to death and any gross
bacteria and other contaminants. Make a note of findings. If plant toxins are suspected also send
what disease is suspected in order to assist the a sample of the plant. If contaminated feed is
laboratory to choose the correct growth media implicated as a cause of death it is important to
for culturing the causative agent(s). Impression take 1 kg from the suspect batch for analysis and
smears taken from the freshly cut surface of to record the feed batch number (see Chapter 7).
organs such as the liver and spleen may be pre-
pared and fixed in the field using ethanol or, if a
flame is available, heat fix. Smears should be pre- Procedure for post-mortem
pared in duplicate for staining and examination examinations
at the laboratory. Collect urine using a sterile
catheter or a needle and syringe. Faecal samples The approach must be systematic to allow thor-
for microbiology can be collected from the gut ough examination of each of the main body
into sterile containers using a clean spatula after systems (gastrointestinal, respiratory, cardiovas-
other samples have been collected. cular, urogenital, lymphoreticular, integumentary

Vet Lab.indb 366 26/03/2019 10:26