PROCEDURES FOR COLLECTION AND SUBMISSION OF SPECIMENS

General Information | Pre-necropsy | Preparation for the Necropsy
What to Remember about Collecting Specimens | Necropsy Procedure | Post-necropsy

General InformationThe list of specimens in the TABLE OF SPECIMEN COLLECTION is a guide for the type of specimens required. In some cases, specific instructions are given for the specimens listed for the respective diseases. However, all cases of an exotic disease do not always run a typical course or have classical lesions. In addition, insidious disease forms may enter a susceptible population and spread without notice because they do not show the expected clinical picture. Therefore, a comprehensive collection of specimens based on species will be the most useful in providing a diagnosis.These instructions are intended to supply the field diagnostician with lists of specimens based on species, as well as recommended necropsy and shipping procedures. The specimen listings are minimum recommended lists and are not intended to replace the field diagnostician's judgment concerning the collection of additional specimens.The following items were given consideration in compiling the lists:a. Each species specimen list lends itself to diagnostic confirmation of FADs for the species.b. The specimen lists include adequate specimens for differential diagnosis of domestic animal diseases that might be confused with a foreign animal disease.c. These lists represent a minimum of specimens necessary for basic diagnostic testing; additional specimens are left to the field diagnostician's discretion.

d. For vesicular disease specimens, consult the TABLE OF SPECIMEN COLLECTION.

Pre-necropsy

a. Obtain and record the animal and/or herd history.

b. Do not approach the examination with a preconceived diagnosis.

c. Make sure appropriate disinfectant is available and be familiar with its use.

d. Observe and collect samples from clinically normal animals first, if applicable (i.e., multiple pens with one pen containing clinically ill animals).

e. Conduct the examination of live animals with precautions needed to protect attendants, yourself, and other animals from infection or injury. Always be aware of rabies and other diseases transmissible to man or highly contagious to other animals.

f. Examine and collect specimens from live animals not intended for necropsy. Select animals in various stages of disease. Obtain permission from the owner to conduct the necropsy. Be aware of the owner's wishes, and use safeguards necessary for proper disposal of the carcass.

g. If possible, select several animals in various stages of disease for necropsy.

Preparation for the Necropsy

a. Remove from the kit only what is needed, so that unused equipment will not be contaminated.

b. Do not conduct necropsies while wearing street clothes. Wear rubber boots, gloves, and coveralls. A mask and goggles may be used at your discretion.

c. Check the TABLE OF SPECIMEN COLLECTION to see what samples are required, but remember, this is a minimum recommended list. In addition to the listed specimens, samples of all lesions should be collected for histopathologic examination.

d. Prelabel specimen containers to ensure all recommended specimens will be collected.

(1) Use a method of labeling which cannot be lost or easily destroyed. For example, adhesive tape should go entirely around the vial so that it will not be dislodged by moisture.

(2) Writing should be with pencil or waterproof ink.

(3) Use plastic screw-cap containers instead of glass containers where practical. Electrical tape should be wound around the cap in the same direction as the screw cap is applied.

(4) Use disposable equipment such as cardboard trays and disposable syringes.

What to Remember about Collecting Specimens

a. Fresh tissue for microbiological examination:

Each tissue to be preserved in a refrigerated or frozen state should be placed in a separate container.

b. Preserved tissue for histologic examination:

The recommended preservative is 10% buffered neutral formalin. All tissues can be placed in one container, but allow a ratio of ten volumes of formalin to one volume of tissue (10:1). To provide adequate fixation, cut the tissue into slices no more than 3-6 mm thick. Cut lesions so that a normal area of tissue or organ is included in the section. Lymph nodes or organs with capsules should be incised. The whole brain or half brain should remain intact for fixation without making multiple cross-sections in the brain substance. See specific instructions for BSE Surveillance, page 14.

c. The initial piece of each organ will be collected aseptically for microbiological examination. Flame the instruments before collecting each specimen, or use separate sterile instruments. Samples from the gut or intestine should be collected last.

d. Swabs should be placed in transport medium, swirled, and then discarded. For bacteriology investigations, it is critical that the swabs remain in the transport medium until they reach the NVSL.

Necropsy Procedure

a. If the animal is presented for euthanasia, collect blood samples before euthanatizing. If the animal is presented dead, collect the blood or serum samples from the heart. Make blood smears, air dry, and fix in methanol.

b. Cattle, sheep, goats, and pigs are best positioned on their left side. Horses should be positioned on their right side.

c. Make an external examination and collect ectoparasites (place in 70% alcohol).

d. Collect nasal swabs and skin lesions or swabs, if indicated. Place in transport or growth nutrient media, and refrigerate.

e. To prevent contamination, disinfect the skin or use clean instruments to open body cavities. Open the abdominal and thoracic cavities carefully so as to prevent contamination from the outside or from a cut organ.

f. Observe, but do not disturb, organ placement (note any abnormalities).

g. With a syringe, aseptically collect a specimen of any abnormal body fluid.

h. Aseptically collect specimens of liver, kidney, spleen, and lymph nodes (gastrohepatic node for swine).

i. Aseptically collect specimens of lung and heart.

j. Remove the tongue, open the pharynx, and collect the tonsil (swine).

k. Remove the trachea, lung, and heart. Collect tracheal and bronchial swabs if appropriate. Examine the respiratory tract and heart.

l. Tie off and remove a 3" section of ileum just anterior to the ileocecal valve. Double ligate to prevent spillage of intestinal contents. Do not tie off intestinal segments to be placed in formalin because the fixative should infiltrate the lumen of the organ.

m. Complete the examination of the abdominal cavity. The entire digestive tract should be opened.

n. Decapitate the animal, remove the brain and collect specimens (note any abnormalities).

Post-necropsy

a. Decontaminate instruments before cleaning them.

b. Clean and disinfect all work surfaces.

c. Decontaminate self, e.g., disinfect and remove boots, gloves, and coveralls.

d. Record the necropsy findings.