January 1997

We receive three types of exotic animal specimens for histopathologic examination; (1) biopsies for individual pets, (2) necropsy tissues from individual animals, and (3) necropsy material from a group situation. The biopsy sampling procedure is dictated by the disease process and the size of the lesion. Ideally, an excisional biopsy should be sent. Alternatively, one should collect as much tissue as possible, preferably from multiple sites. It is very important to sample underlying viable tissue from lesions covered by thick crusts; (therapeutically useful diagnoses rarely are mad~ from crusts.)

The type of necropsy specimen that is sent depends on the size of the animal, disease suspected, and the degree of autolysis. Do not send whole bodies fixed in formalin unless the animal is extremely small (less than 2 cm by 2 cm square). In the case of extremely small animals, open the body cavity to expose the internal organs to formalin. Aquarium fish are also submitted in this manner.

Ideally, necropsy specimens should be collected from every organ. As a minimum, the spleen, liver, and intestines are submitted from birds. If respiratory disease is suspected, also include sections from the air sacs and lungs. In young birds, it is essential to also submit the bursa of Fabricus. For reptiles, include at least the spleen, liver, intestines and kidneys. For a small mammal like a ferret, submit the liver, spleen, intestines, pancreas, adrenal glands, and lymph nodes. The intestines in all species should be opened before they are put in formalin.

In group situations, such as flock-wide disease, as many organs from an individual should be sampled as possible. If feasible, a very sick member of the group is sacrificed and samples are immediately placed in formalin. If this is not possible, a member of the group that has just died should be sampled.

Save tissues for bacterial culture and virus isolation. The preferred methods of preservation vary and you should contact the laboratory for instructions prior to the necropsy.

Biopsy and necropsy specimens should be placed in 10% neutral buffered formalin immediately after collection. Ideally, specimens should be no thicker than 1 cm and should be placed in 10 volumes formalin or greater per volume of tissue.

Accidentally frozen specimens may still yield information. To submit frozen tissue, take the tissue while still frozen and place it in formalin that has been cooled to refrigerator temperature. Place the sample container back into the refrigerator allowing the tissues to slowly thaw. The container and specimens are brought to room temperature after 24 hours of refrigeration and then submitted to the laboratory.

We occasionally receive feather biopsies from birds suspected of being infected with psittacine beak and feather disease (avian circovirus). The preferred method of diagnosing this disease is now a blood test. Where diagnosis of this disease requires examination of affected feathers, the most diagnostic samples to send are newly erupted, malformed blood feathers.

Antech has several pathologists with exotic animal pathology experience. Please feel free to ask for a consultation if you have additional questions about submission of specimens.

Dr. Jay Tappe is a board certified veterinary anatomic pathologist. He received his DVM from Iowa State University in 1981, and then went to the Animal Medical Center in New York City to complete a combined pathology residency at the AMC and Bronx Zoo. From 1984 to 1986, Dr. Tappe was the Chief of Pathology for the New York Zoological Society (Bronx Zoo). In 1986, Jay went to the National Animal Disease Center where he studied avian immunology and chlamydiosis, and in 1991 received his PhD. from Iowa State University. He moved to Dallas, Texas and worked at PAL Pathology from 1991 to 1996. Since 1996, Dr. Tappe has been promoted as the Central Region Pathology Director in Chicago, Illinois for Antech Diagnostics. His work at both the Bronx Zoo and the National Animal Disease Center has given him extensive experience in avian and exotic pathology. Jay is always available to assist Antech clients with any needs in this highly specialized field.