Barbiturate ingestion in three adult captive tigers (Panthera tigris) and concomitant fatal botulism of one : clinical communication

Abstract

Zoo animals, including tigers, have been reported to suffer from barbiturate intoxication, with pentabarbitone being most commonly recorded. Clinical signs range from mild ataxia to general anaesthesia with recovery over hours to days with several factors affecting hepatic barbiturate metabolism and tissue partitioning. Botulism is an often fatal intoxication in man, animals, birds and certain fish. The occurrence in carnivores is uncommon to rare, with only 2 reports found of botulism in felids. This report relates to 3 adult captive cohabiting tigers that simultaneously developed signs of abdominal discomfort, progressive ataxia, recumbency and comatose sleep resembling stage 2 anaesthesia, alternating with periods of distracted wakefulness and ataxic movements. These signs occurred 4 days after being fed the carcass of a horse that had ostensibly died of colic and not been euthanased. The male tiger that was the dominant animal in the feeding hierarchy was worst affected and had to be given intravenous fluids. The female that was lowest in hierarchy was unaffected. After 48-72 hours of treatment at the Onderstepoort Veterinary Academic Hospital the females could eat and made an uneventful recovery. The male tiger showed partial recovery but died during the night a few hours after drinking water on his return to the owner. Necropsy revealed severe oesophageal dilation and impaction with decaying grass; some of this material and water were present in the pharynx and trachea, and had been aspirated causing acute widespread bronchopneumonia. Colon content tested negative for common pesticides but, together with liver, tested positive for barbiturate. Serum taken on the day of admission had tested negative for barbiturate and the residual serum from the 3 animals later tested negative for botulinum toxin. Colon and oesophageal content from the male at necropsy were positive for Clostridium botulinum toxin type C by the mouse bioassay neutralisation test, confirming that this male had had concomitant barbiturate toxicity and botulism, and had succumbed to aspiration bronchopneumonia secondary to pharyngeal, laryngeal and oesophageal paralysis and oesophageal impaction

Gorilla gorilla gorilla gut: a potential reservoir of pathogenic bacteria as revealed using culturomics and molecular tools

“…Many opportunistic human pathogens were observed using culturomics, including 8 pathogens frequently associated with human disease (Table 1)1931. Among these, C. botulinum is also present in herbivore and carnivore hosts, including pigs, horses, cattle, giant pandas and tigers3233343536. In contrast, M. bolletii is an emerging pathogen for which no animal source is known31.…”

A review of secondary pentobarbital poisoning in scavenging wildlife, companion animals and captive carnivores

“…In 1990, a lioness (P. leo) died from pentobarbital poisoning, also having been poisoned but successfully treated 18 months before (Verster et al 1990). In 2011, three tigers (P. tigris) were reportedly poisoned at a zoo in South Africa (Williams et al 2011), and in 2015, at a wildlife sanctuary in Nevada (US) a tiger (and a wolf [Canis lupus]) died and a cheetah (A. jubatus) was intoxicated after they were accidentally fed meat from a pentobarbital-euthanized horse (Corona 2015). Private zoos, kennels and feeding stations for endangered red kite (M. milvus) also source carcass meat.…”

“…Unaware that the dead cow could harm the eagles, and therefore without malicious intent, the farmer simply intended to make them available to the birds as a food resource. Similarly, captive carnivores, including tigers (Panthera tigris), lions (Panthera leo), and cheetahs (Acinonyx jubatus), have unintentionally been poisoned at zoos across several continents after being fed the carcasses of animals euthanized using pentobarbital (AZA n.d., Verster et al 1990, Williams et al 2011. Companion animals (dogs and cats) face two main exposure scenarios: 1) by scavenging on the carcasses of euthanized animals while free-roaming outside (e.g., Kaiser et al 2010), or 2) by consuming tainted canned pet food containing by-products of animals euthanized with pentobarbital (e.g., Edgson andPayne 1967, FDA 2017) believed to have been made safer by the rendering process (AVMA 2013).…”