Page 558 - The Veterinary Laboratory and Field Manual 3rd Edition

Necropsy guidelines 495

A2.2 reasons for carrying out • Surveillance: Surveillance encompasses the
necropsy-based disease aggregation of disease investigation and
investigation diagnostic testing data to create a picture of
animal disease in a particular area. In many
• Sudden unexplained death of a single or group areas, this is based on active surveillance pro-
of animals: This is a very common scenario grammes which use molecular tests to look
with which a pathologist may be presented. directly for a limited number of economically
In these cases, historical information is usu- important diseases. While molecular testing
ally limited and this necessitates an even has rapid throughput, high sensitivity and
more thorough and methodical approach to specificity they have a narrow focus and will
necropsy so important details are not over- only detect what is tested for. This approach
looked. The sudden unexpected nature of the is good for collating information about known
death often causes the owner to jump to the disease syndromes; however, will invariably
conclusion that the animal or animals have miss the presence of new or emerging disease.
been poisoned. While this is a consideration it Basing surveillance programmes on necropsy
is relatively rare, and the disease investigation examination and analysis of routine diagnos-
should be approached with an open mind. tic specimens is much more likely to provide
• Epidemic disease outbreak: This may include information on these conditions which may
epidemic disease with high mortality or a dis- be of significant importance.
ease outbreak with high morbidity and low
mortality with implications for production
efficiency and animal welfare. In either case A2.3 Equipment and safety
necropsy protocol may be adapted to focus
on the organ or system of interest suggested Equipment required:
by clinical signs and history. In these cases,
it is very useful to examine several animals Complete necropsy examination and sample col-
who have succumbed to disease along with lection can be performed in the field with very
several morbid animals at various stages of minimal equipment.
the clinical course euthanized specifically for Personal protective equipment (PPE):
necropsy examination. Limiting investigation
to animals that have died naturally may mean • coveralls
that acute lesions with the most diagnostic • rubber gloves
utility are overlooked or have been masked • cut-resistant gloves/arm sleeves
by secondary changes. • rubber boots
• Research: Many live animal experiments will • protective eyewear
be terminal and require necropsy examination • container for waste sharps.
to evaluate outcomes and collect samples for Tools:
further testing. In addition, any unexpected • knife: with fixed handle, that is, not a fold-
mortalities should be fully investigated both ing knife
to rule out an unexpected outcome with the • scissors
experimental model and to investigate the • scalpel blades and handle
possibility of concurrent disease which may • forceps
jeopardize the validity of results or negatively • rib cutters (long-handled gardening shears
impact welfare of experimental animals. are ideal)

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