NOTES ON ANATOMY AND DISEASES OF PENGUINS
1. The trachea is normally bifurcated along most of its length.
2. The gizzard is thin walled and distensible, and may extend caudally to the region of the cloaca, filling a large portion of the abdominal cavity.
3. Excessive horny growth can occlude the nares if suitable objects for honing the bill are not provided, or if the diet lacks salt.
4. Penguins will frequently swallow sticks and/or feathers provided as nesting material, which can cause fatal perforations in the gastrointestinal tract. Feeding fish with large spines can also cause gastrointestinal perforations.
5. Aspergillosis is the major disease problem in captivity.
6. Avian malaria is also an important problem. Pulmonary congestion and edema (or overt pneumonia), and pericardial and thoracic effusions are generally the most prominent gross lesions.
7. Bumblefoot is a significant problem in some collections and can be fatal if bacteremia and septic embolization occurs. The feet should be examined carefully and samples of plantar skin taken for histopathology.
8. Bacterial enteritis can be a significant problem in chicks and juveniles. Gram negative enterics are most commonly implicated, but Clostridia may be involved in some cases of necrotizing enteritis.
9. Viral diseases have not been well documented in penguins, but hepatitis, nonsuppurative meningoencephalitis, and lymphoid necrosis of possible viral etiology have been seen by some pathologists.
10. Hyperplasia and cystic changes of the parathyroid glands has occurred in some Humboldt penguins, which could be due to inadequate calcium and/or vitamin D in the diet. Make certain that the parathyroids are collected for histopathology along with the thyroids.
HUMBOLDT PENGUIN EGG NECROPSY PROCEDURE
1. Refrigerate the egg if there will be a delay before necropsy (delays should be avoided since autolysis proceeds rapidly). Do not freeze eggs or embryos unless the primary goal is virus isolation or bacterial culture, rather than histologic evaluation.
2. Record all relevant historical information as indicated on the necropsy form. Much of this information could be provided in the form of a computer print-out (if available), but any additional historical information should be entered on the necropsy form.
3. Weigh and measure the egg as soon as possible after the embryo is confirmed dead.
a. Record weight in grams.
b. Measure length and greatest diameter of egg in centimeters.
4. Describe egg shell characteristics (abnormal shape, shell thickness, presence of cracks, degree of fecal staining, external calcium deposits, etc.).
5. Open the egg by carefully removing the shell overlying the aircell. This can be accomplished with a pair of sharp-blunt scissors, or by gently cracking the shell and removing fragments with forceps.
a. Examine the aircell membrane for integrity, thickenings, hemorrhages, etc.
6. For small (early stage) embryos, obtain separate swabs of yolk and albumen for culture and cytology. Skip to step 7 for larger embryos.
a. Peel back the aircell membrane and insert a swab to obtain the albumen culture. Note: if the fluid is watery, it is likely allantoic fluid rather than albumen.
b. The egg contents may have to be dumped out in order to obtain the yolk cultures.
c. A second swab of yolk (not a culture swab) may then be taken and rolled onto three microscope slides. The smears should be as thin as possible. NOTE: Avoid vigorous swabbing of the internal aspect of the yolk sac; hematopoietic cells which reside there may be dislodged and give a false impression that there is inflammation in the yolk sac. Recommended stains include Wright-Giemsa (or Diff-Quik) and gram. Save the third slide for additional stains, if needed.
7. For larger (late stage) embryos, remove enough egg shell to expose the embryo. Note the position of the head relative to other body parts, and in relation to the aircell. The normal position for embryos ready to pip is head under the right wing, with the tip of the beak pointing up toward the aircell.
a. If possible, photograph the position of the embryo if it is thought to be abnormal.
b. If the yolk sac is still external (has not retracted into the body cavity), and is accessible, puncture the wall with a sterile scalpel and obtain a culture. If the yolk sac is inaccessible, skip to step 8.
c. Obtain a second swab of yolk for cytology as described above.
d. Save the yolk sac (in formalin) for histopathology
e. Record the color and consistency (relative thickness or viscosity) of the yolk.
8. Remove the embryo and membranes from the shell by gently dumping the contents into a clean shallow container.
a. If swabs of yolk for culture and cytology have not yet been collected, obtain them now (as described under step 6). Record the color and consistency (relative thickness or viscosity) of the yolk.
b. Weigh the embryo with and without the yolk sac (if external).
c. Measure the length of the embryo and if possible estimate the stage of development using The Normal Stages of The Chick as a guideline.
d. Note any external abnormalities, such as musculoskeletal deformities, abnormal skin color, skin hemorrhages, edema, dryness, residual albumen, etc. If possible photograph any abnormalities.
e. Record the degree of internalization (retraction) of the yolk sac.
f. Examine the pipping muscle at the back of the neck for edema or hemorrhages.
g. Note the contents of the mouth, nares, and gizzard.
9. Small embryos may be immersed whole in formalin. The volume of formalin should be at least ten times the total volume of the tissues.
a. Save the yolk sac (in formalin) for histopathology along with the embryo and membranes.
10. If the embryo is large enough, conduct a mini-necropsy, retaining representative samples of all organs and tissues for histopathology.
a. Open the coelomic cavity by making a ventral midline incision with a scalpel or scissors, being careful to avoid tearing the yolk sac if it is internalized.
b. If the yolk sac is internal, proceed now with yolk sac cultures and cytology as described under steps 6 and 7 above.
c. Save the yolk sac (in formalin) for histopathology along with the embryo and membranes.
d. The volume of formalin should be at least ten times the total volume of the tissues.
11. Send a copy of the final pathology report and a recut set of H&E stained slides to Dr. Bruce A. Rideout, Pathology Department, San Diego Zoo, P.O. Box 551, San Diego, CA, 92112. Telephone (619) 231-1515, ext 4535. Pager (619) 982-7824.
HUMBOLDT PENGUIN CHICK AND ADULT NECROPSY PROCEDURE
1. Refrigerate the body if there will be a delay before necropsy (delays should be avoided since autolysis proceeds rapidly). Do not freeze the body unless the primary goal is virus isolation or bacterial culture, rather than histologic evaluation.
2. Record all relevant historical information as indicated on the necropsy form.
3. Weigh the bird as soon as possible after death.
4. For chicks, note condition of the umbilicus or seal, particularly whether it dry and completely closed.
5. Note any musculoskeletal abnormalities, ectoparasites, evidence of trauma, proliferative skin lesions, etc.
6. Examine the feet carefully for evidence of pododermatitis (bumblefoot).
7. Examine body orifices for patency, exudates, fecal staining around cloaca, etc.
8. Make an evaluation of nutritional condition based on fat stores and relative muscle mass.
9. Make a ventral midline skin incision from the mandible to the cloaca with a sharp scalpel or scissors, being careful to avoid rupturing the yolk sac in young birds.
a. If the yolk sac ruptures, immediately obtain a yolk culture as the yolk spills out and prepare smears for cytology.
b. Note the size of the yolk sac and, if sufficient yolk remains, obtain separate swabs for culture and cytology.
10. Remove the keel to expose the thoracic organs.
a. Note any accumulations of fluid or exudate in the body cavity and obtain a swab for bacterial and/or fungal culture if appropriate.
11. Obtain blood for smears and bacterial culture by direct heart puncture using a 1 to 3 cc syringe with a 20 to 22 gauge needle.
a. Prepare at least two blood smears for hemoparasite screening (only a few drops of blood are needed).
b. If enough blood was obtained, bacterial cultures should be submitted on young birds to rule out septicemia.
c. If no blood can be obtained from the heart by syringe, smears can be prepared by dabbing the cut surface of the lung or liver onto two or three microscope slides.
12. Collect the thyroids (with parathyroids), thymus, and spleen for histopathology.
a. Determine gender by examining the gonads prior to removal.
13. Remove the internal organs and examine each systematically.
a. Obtain samples for histopathology using the tissue list below as a guide. Save samples of all lesions.
b. Note especially the quantity and nature of the ingesta throughout the GI tract.
c. The bursa of Fabricius lies dorsal to the cloaca, close to the cloacal orifice (vent). Make sure the bursa does not remain attached to the body when the GI tract is removed.
HUMBOLDT PENGUIN TISSUE CHECKLIST
All of the following tissues may be placed together in a single container of 10% neutral buffered formalin. THE VOLUME OF FORMALIN SHOULD BE 10 TIMES THE VOLUME OF ALL TISSUES COLLECTED. The tissues should be no thicker than 0.5cm to ensure proper fixation.
Skin Muscle (pectoral and thigh) Sciatic nerve (with thigh muscle) Tongue Esophagus Crop Proventriculus Gizzard Duodenum Jejunum Ileum Cecum Colon Cloaca with Bursa of Fabricius Liver with gallbladder Pancreas Spleen Kidney with Gonad Oviduct Adrenal (with kidney) Thyroid and Parathyroid Thymus Trachea Lung Heart Aorta Pituitary Eye Brain Femoral Bone Marrow
FREEZE PORTIONS OF THE FOLLOWING:
Freeze each tissue separately by wrapping in foil and placing in separate plastic bags (at least 10 grams of each tissue if large enough):
Liver Spleen Lung Brain Heart Skeletal Muscle
These tissues can be valuable for ancillary diagnostics. They may be discarded after a definitive diagnosis is established, but if possible, should be saved for future research purposes.
11. Send a copy of the pathology report and a recut set of H&E slides to Dr. Bruce A. Rideout, Pathology Department, San Diego Zoo, P.O. Box 551, San Diego, CA, 92112. Telephone (619) 231-1515, ext 4535. Pager (619) 982-7824.
HUMBOLDT PENGUIN EGG NECROPSY REPORT
|DATE OF DEATH:
||TIME OF DEATH:
|DATE OF NECROPSY:
||TIME OF NECROPSY:
|EXPECTED HATCH DATE:
|CIRCLE ONE IF: PARENT INCUBATED ARTIFICIALLY INCUBATED:
|DATE PULLED FOR ARTIFICIAL INCUBATION:
|% EGG WT LOSS DURING INCUBATION
|EXPECTED % WT LOSS:
|PREVIOUS REPRODUCTIVE FAILURE/SUCCESS:
ADDITIONAL HISTORY (candling notes, developmental progress, status of clutchmates, etc.):
POSTMORTEM EGG WEIGHT: EGG DIMENSIONS:
NECROPSY FINDINGS (egg shell quality, integrity of membranes, positioning of embryo, stage of development, presence of edema, hemorrhages, deformities, degree of yolk sac retraction, etc):
HUMBOLDT PENGUIN CHICK AND ADULT NECROPSY REPORT
IDENTIFICATION NUMBER: PATHOLOGY #:
DATE OF DEATH: TIME OF DEATH:
DATE OF NECROPSY: TIME OF NECROPSY:
AGE: SEX: BODY WEIGHT: ENCLOSURE I.D.: INDOOR: OUTDOOR:
WEATHER/INDOOR CLIMATE (hot, cold, rainy, etc):
CHECK IF: PARENT REARED: HAND REARED:
MOVEMENTS or RELOCATIONS: DATE:
HUMBOLDT PENGUIN CHICK AND ADULT NECROPSY REPORT
NECROPSY FINDINGS (Describe lesions in detail and indicate which organs, if any, were not examined):
TISSUES SUBMITTED FOR HISTOPATHOLOGY: