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USGS, National Wildlife Health Center
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1. General necropsy preparation

(file size: 128 Kbytes)

2. Carcass labelling and preparation

(file size: 277 Kbytes)

3. Reflecting the skin of the carcass

(file size: 214 Kbytes)

4. Lifting the sternum and opening the body to expose viscera (heart, liver etc.)

(file size: 219 Kbytes)

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5. Reflecting the gizzard, further examining organs and removing spleen

(file size: 426 Kbytes)

6. Lifting viscera and cutting mesentery, examining gonads and bursa, and removing kidney

(file size: 627 Kbytes)

7. Removing brain

(file size: 677 Kbytes)

8. Disposing of carcass and cleaning necropsy area

(file size: 216 Kbytes)


SPECIES IDENTIFICATION: The image below provides a comparison of black corvids (Corvidae: the crow family) likely to be submitted in the USA for WNV surveillance

Click image for full screen view

OBJECTIVE: To record the species, sex and age of wildlife carcasses and to remove the spleen, one kidney and the brain (in some cases) for virology test in a manner that precludes cross-carcass contamination.

  1. Remove the carcass from the plastic bag used to contain and ship the carcass and record pertinent information provided about the date, location, carcass condition and other circumstances of the collection.

  2. Wash the carcass with a disinfectant (Unicide); this is wet the plumage to prevent interference from feathers.

  3. Examine the heart. If white areas are seen, potentially areas of necrosis are present and the carcass may be infected with West Nile Virus. If possible, the carcass should be given a thorough necropsy.

  4. Lift and rotate the gizzard and remove the spleen beneath it with sterile instruments. If the spleen is enlarged (to 40 or 50mm in length in the American crow), the carcass may be infected with West Nile Virus. It may be convenient for a second person to remove the spleen. Place spleen in labelled plastic bag or other sterile container.

  5. Record the Post-mortem state.

  6. Lift viscera, and examine the gonads and record sex.

  7. Lift mesentery, lay viscera to the side and examine the cloaca for bursa and record age.

  8. Remove one kidney with sterile instruments. It may be convenient for a second person to remove the kidney. Place kidney in labelled plastic bag or other sterile container.

  9. If the brain is to be tested, remove the whole brain with sterile instruments; incise skin over cranium, separate skin away from skull, incise muscle on back of skull, cut the skull with sharp instrument such as pair of scissors and remove the excised piece of skull to expose and collect the brain. Place brain in labelled plastic bag or other sterile container. The cerebellum and or brain stem are the most important portions of the brain to be tested for west Nile Virus.

  10. Discard the carcass and dispose of it safely with appropriate safety procedures.


1. Information to be recorded:

  • Species
  • Sex, based on gonad
  • Age, based on bursa
  • Post-mortem state

2. Thorough necropsy would include the examination, description and preservation in formalin of:

  • Heart
  • Liver
  • Spleen
  • Duodenum
  • Kidney
  • Lung
  • Brain

3. Instrumentation requirements include:

  • Enough multiple basic instruments sets should be used to ensure that each set soaks in disinfectant for at least 30 minutes between uses
  • A separate supply of forceps will be available for use with #11 disposable scalpels for collecting tissues.

4. Unicide 256 is produced by Brulin & Company Inc. (P.O. Box 270, Indianapolis, IN 46206 - 0270, telephone (317) 923-3211) and contains:

  • Alkyl dimethyl benzyl ammonium chloride
  • Octyl decyl dimethyl ammonium chloride
  • Didecyl dimethyl ammonium chloride
  • Dioctyl dimethyl ammonium chloride

Video clips and protocol prepared by the USGS, National Wildlife Health Center
6006 Schroeder Road
Wisconsin 53711

Tel: (608) 270-2400

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