The ASPCA Animal Poison Control Center estimates that intentional poisonings account for about 1% of all exposures; however, the true incidence is likely higher. Dogs account for 75% of cases and cats approximately 15%, with the remaining animals being wildlife or farm animals. Little is known about the psychology of people intentionally poisoning animals. What is known is people tend to use products they know (eg, ethylene glycol) and multiple poisons may be involved. There is no "magic toxicology" screen and the toxicologist will need to base diagnostic testing on as many history and physical examination findings as can be provided. Several factors should raise suspicions: sudden rapid death in an otherwise healthy animal; multiple animals showing similar signs; history of threats; unexpected presence of food or empty containers in an animal pen; or identification of food or other items foreign to the animal's environment in vomitus, stomach contents, or feces. If there is strong suspicion of intentional poisoning, the authorities should be notified and a careful chain of evidence established. Definitive diagnosis is difficult and requires a thorough history of events, especially those in the last 24 hours prior to presentation or death. The environment of the animal should be carefully examined and any abnormal items sampled; in addition, samples of the animal's food and water should be taken. It is best to take as many and as much of each sample as possible. In cases involving live animals, blood, serum or plasma, stomach contents/vomitus, urine, feces, and hair should be collected. Postmortem samples should include the liver, kidney, brain, fat, skin and subcutaneous tissue around injection sites, blood from heart, stomach and intestinal contents, urine, and vitreous humor or the entire eyeball. Collect samples in glass and avoid plastics, which can leach out contaminants and interfere with tests. Do not use syringes as they can cause leaching of contaminants and pose a risk to personnel in the laboratory. Whole blood can be shipped refrigerated but plasma, serum, and urine should be frozen. Stomach contents, vomitus, carrion, feces, and perishable feed should also be shipped frozen. Airtight containers can be used for hair, hay, and mushrooms.
COMMENTARY: The issue of cruelty to animals is one of personal significance to me, having lost 3 of my own cats to intentional cruelty by neighbors. As noted in this article, a variety of motivations and methods exist for the perpetration of animal abuse, with malicious poisoning being one method occasionally seen by small animal practitioners. This article contains a wealth of useful information regarding history-taking, physical examination, sample collection, and related forensics for suspected cases of poisoning. As advocates for animal victims of crime, veterinarians must remember to include toxicoses on their differential diagnosis list whenever presenting clinical signs are sudden in onset and severe in nature.
Forensic toxicology: Intentional poisoning of animals. Gwaltney-Brant S. NAVC PROC 2009, pp 697-701.