Necropsy or Post – mortem examination means systemic examination of
animal after death which is conducted by Veterinarian or Veterinary
Pathologists to ascertain the cause and nature of disease in fatal cases of
disease. The term autopsy is preferred in human medicine for PM examination and
necropsy in Veterinary Medicine.
Autopsy means seeing with ones own eyes.
Necropsy means seeing a corpse.
Autopsist is one who conducts the PM examination.
Objectives of the P.M.
Examination
1) To know the cause of death
of animals.
2) It is done in the
veterolegal/ insurance aspects.
3) To study the epidemiology
status of various diseases in the particular area/region.
4) To know change in the disease
scenario of a particular disease in an area.
TYPES OF NECROPSY
a. Where no necropsy is
conducted.
If the blood smear from ear
vein (cattle, sheep and goat ) or smear from edematous fluid from throat or
abdominal region ( pigs, horse) reveals anthrax bacilli no PM should be
conducted on the carcass since the organisms are aerobic spore formers. The
spores survive as long as 18 years.
S. No. Particulars Anthrax bacilli Anthracoids
1. Organism Bacillus
anthracis Other than B anthracis
2. Capsule Predominantly pink
stain Less predominant
3. Spores Absent Present
4. Length of chain
Short-usually 2 to 3 organism Long chains
5. End of bacilli Truncated
Rounded
b. Partial necropsy
In case of rabies only the
brain of the carcass is examined for diagnosis. Here only a part of the body (
head ) is opened for the purpose. Other parts of the body are not opened.
c. Complete necropsy
All parts of the body are
thoroughly examined o arrive at a etiological diagnosis.
d. Cosmetic necropsy
Examination of the carcass is
done with very less mutilation. Cuttings and incisions are sewed together and
the body is washed to appear as nearly intact as possible. It is done in case
of pet and wild animals.
PRECAUTIONS
1. Obtain permission of the
owner in writing before PME.
2. Request from local police is
must in Vetro-legal cases.
3. Conduct PM as early as
possible to avoid putrefaction.
4. Examine the smear from
peripheral blood to rule out anthrax. Besides anthrax bacilli examination of
blood smear may reveal blood parasites, other bacteria and or PM invaders.
5. PME should be done in day
time to appreciate the accurate changes in the colour of the tissues. This is
not possible with artificial light.
6. Conduct PM far away from
animal houses and preferably in a Government land to avoid litigation.
7. Obtain history, symptoms and
treatment done etc,
8. Wear gloves, masks, apron and gum boots to avoid contact with Zoonotic agents.
9.
Record the PM findings immediately.
10. Burry the carcass in deep ditches layered with lime.
Carcasses can be burnt to ashes if incinerator is available.
Small and large scissors with either pointed or rounded ends,
chisel and hammer,
curved scissors,
small and large knives,
scalpel and blades,
bone cutters and saw ( small and large),
small and large forceps,
toothed forceps,
hand lens, rubber or latex hand gloves,
masks, Bunsen burner or spirit lamp or stoves,
spatula, syringe and needles (Tuberculin syringe),
sterilizer, autoclave, spirit or alcohol,
cotton and cotton swabs sterilized,
sterilized vials, Petri dishes and test tubes,
Pasteur pipettes and rubber bulbs,
tissue fixatives 10 % formalin,
formal saline, buffered neutral formalin,
small or large stainless steel trays, monocular / binocular microscope.
Clean glass slides and cover slips,
normal saline and glycerine- saline,
different staining solutions,
Ziehl Neelsen, Giemsa and Wrights and Leishman stain,
match boxes, rubber apron,
disinfectants including dettol, savlon, phenyl, iodophore etc,
fly repellents, bowl for cold water, water container, small screw – top, water tight jars,
blotting paper, staining rack, sticker labels, marking pen,
glass marking pencils, slide tray, monopan balance, physical balance / Jeweler’s balance,
kitchen balance max 5 kg with weight,
measuring tape cm / inches,
aluminum foil, adhesive tapes, towel soaps,
measuring cylinder, centrifuge,
record, ice box / flask,
transport media for bacteria,
transport media for virus,
antibiotics solutions (penicillin, streptomycin, gentamycin and mycostatin),
polypropylene bags,
mask disposable, thread,
gum boots, camera with film,
postmortem stainless steel top table,
rexin /rubber sheets,
vials with anticoagulants.
STEPS IN NECROPSY
1. Record the kind of animal and to whom it belongs.
2. Write the precise of the case.
3. Carry the external examination of the carcass. Then proceed to internal examination.
4. Secure the carcass on its back.
5. Make incision in the midventral line from chin to anus going round about the external genatalia in male and the incision is also make to medial aspect of all legs and flay the skin.
6. Examine the subcutaneous tissue.
7. Open the cavities of the body. Look for exudates or transudes etc.
8. Examine the position of the organs.
9. Separate lungs from heart and palpate for any abnormalities. Incise and examine the lungs.
10. Examine the pericardial sac. Open the pericardium, examine the nature of contents.
11. Cut through heart and the vessels. Examine the wall and chambers for the nature of contents, valves and the lumen of vessels.
12. Examine the diaphragm.
13. Examine the abdominal visceral organs – liver, spleen, kidneys, adrenals, pancreas before and after incising the organs.
14. Open the bile ducts and gall bladder and examine them.
15. Divide the kidney symmetrically by longitudinal incision. Remove the capsule, examine the cortex, medulla and pelvis.
16. Open the mouth to examine the gum, tooth, tongue and buccal cavity. Then open and examine oesophagus.
17. Open the nasal cavity and examine. Examine the pharynx, larynx, trachea and bronchi.
18. Open the stomach / fore stomach and abomasums ( ruminants) and examine the nature of contents and the wall.
19. Open the intestine. Examine the contents and the wall.
20. Open and examine the urinary bladder for the nature of contents and the wall.
21. Examine the generative organs.
22. Open the skull and vertebral column to examine the brain and spinal cord.
23. Examine the skeleton and musculature.
24. Record the findings.
25. Summarize the appearance found.
26. Collect suitable material for microbiological, histopathological, parasitological and chemical examination as required.
27. Arrive at an etiological diagnosis based on the PM finding and the results of the material examined.
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