in many cases, where it would otherwise have been impossible. However, current disease surveillance systems, for human diseases and zoonoses alike, fail to make adequate use of diagnostic pathology.
Veterinary pathologists are highly attuned to zoonotic diseases, because most of the diseases that threaten humans—brucellosis, Q-fever, leptospirosis, tularemia, rabies, and many more—are diseases that go hand in hand with being a veterinarian. Nor is this a one-way street: some diseases of humans can be passed to animals.
This animal–human link is particularly critical for veterinary pathologists who work in zoos. These individuals regularly work with a number of high-risk species, such as macaques, which can transmit herpes B virus that can be fatal to humans. In addition, zoos typically are located in urban areas, which have their own forms of indigenous wildlife that present a constant threat of introducing diseases to the zoo’s collection. These introduced diseases hold potential to spread rapidly throughout an entire herd or flock, and from there to the veterinary staff, the keeper staff, and, in the worst-case scenario, to the public. Yet only six zoos nationwide have a full-time pathologist on staff. Thus, zoo pathologists lack the generations of information, as well as the arsenal of drugs and vaccines, that other veterinarians take for granted. As a result, zoo and wildlife pathology is still very much a frontier.
This means veterinary pathologists always must expect the unexpected. In today’s changing world, with unknown disease threats, this is perhaps a good model for other fields to follow. At the Bronx Zoo, this philosophy of expecting the unexpected leads us to perform a necropsy on every animal that dies and to use a variety of techniques to study tissue samples. Before making a final diagnosis, we consider all known possibilities, including diseases in both domestic animals and wildlife, as well as the chance that an unknown agent may be responsible. When our analyses are complete— with, it is hoped, a definitive diagnosis—we “bank” microscope slides of representative sections of every organ. The zoo has accumulated a massive library of samples, some dating to the 1930s, and we now are incorporating the slides on CD-ROM. We also are computerizing a variety of other data from as far back as 1895. In this way, members of the larger veterinarian community will be able to readily share these valuable, often unique, resources.
By taking all of the above steps, every time and in an ordered fashion, we greatly improve our ability to reach a definitive diagnosis of etiology. This approach also adds to the scientific community’s knowledge base; enables zoo staff members—and, with the new database, other researchers as well—to carry out powerful retrospective studies; increases the zoological community’s ability to detect disease trends; and enables researchers to