Post Mortems at ZSL
Post mortems are very important to ZSL as a way of investigating causes of death, and tracking patterns of disease in order to prevent future deaths and improve the health and welfare of our animals. ZSL is one of the few zoological institutes in the world that employs a dedicated pathologist.
Giant Fregate Beetles Animals in captivity die of old age or, when sick, may die despite the best efforts of our veterinary and animal care teams. Sometimes it is necessary to euthanase animals if they are suffering due to illness or injury.
Where possible, all animals are examined post mortem; ranging in size from Partula snails to elephants. ZSL carries out over 1,200 necropsies each year over its two collections, covering a large variety of animals. This may sound a lot, but considering that the London Zoo and Whipsnade Zoo hold over 23,000 individuals of more than 800 species, and that many small animals only live for a few years, this number is not excessive.
Stained smear of a Bali Starling spleen, showing protozoal parasites During the necropsy the animals are dissected in a systematic manner so that nothing is missed. In some cases the main cause of death is obvious, but most of the time closer examination and testing is needed. Radiographs may be taken if there are suspected fractures or, in the case of some wild animals, to determine if they have been shot. Samples are taken from many of the organs. These are either sent through to our resident microbiologist for immediate microscopic examination and bacteriological culturing, or sent to specialist laboratories for further tests. Histopathology is particularly useful; thin slices of tissue are placed on slides and stained to show individual cells. Trained histopathologists examine these tissues under a microscope, noting subtle cellular changes which indicate what disease processes were occurring.
After the post mortem the body is usually cremated, but sometimes the skeleton or carcass may go to a museum for display and research. All fixed and frozen tissue samples are kept in our archives; one of the largest and most important collections of samples in the world. These samples are vital for research on causes of death and the occurrence of specific disease-producing organisms. Information collected can be used to compile lists of significant diseases that are specific to groups of animals, which help improve the welfare of captive populations and pinpoint areas for future research. Our findings are shared across all zoos so that endangered species in captive breeding programmes can be managed effectively.
The pathologist finalises the post mortem report and all details are placed on a database. Information is sent to all the clinical vets, keepers and curators, and if necessary the results are discussed so that plans can be put in place to prevent future problems.