The platypus, a monotreme, is one of only a few venomous mammals in the world, and the first to have its genome sequenced. The project involved Professor Wes Warren’s team at the University of Washington Genome Centre in Missouri, which coordinated the Platypus Genome Project, Associate Professor Kathy Belov’s molecular genetics group at the University of Sydney’s Faculty of Veterinary Sciences at Camperdown, in NSW, and Dr Anthony Papenfuss of the Walter and Eliza Hall Medical Research Institute’s Bioinformatics Division. That was the pharmacologically intriguing question that a joint US-Australian project set out to answer early in 2010, using DNA sequence data from the recently completed Platypus Genome Project.
The persistence of severe pain in the presence of analgesics and hypnotics with well-characterised actions upon specific nerve-cell receptors implied that components of platypus venom acted upon unidentified pain-sensing systems against novel receptors. What kind of brew of proteins and non-peptide agents causes systemic pain that almost nothing from the medicine cabinet of modern analgesics, nor even morphine, can assuage? The Medical Journal of Australia describes the patient’s suffering: "Pain was immediate, sustained, and devastating traditional first aid analgesic methods were ineffective… Significant functional impairment of the hand persisted for three months, the cause of which is uncertain… produces savage local pain… No antivenom is available." For a 57-year old angler stung when he handled a platypus in the Broken River near Mackay in 1991, only a nerve-blocking agent directly injected in the elbow’s 'funny bone' nerve ganglion dulled his agony.
Nobody has died from a platypus sting, but in lucid moments during a three-day delirium of excruciating agony, rare victims of platypus envenomtion have probably wished they had. If not picked up safely by the tail, a male platypus can suddenly wrap its rear legs around an arm or a leg and thrust its spurs downward into the flesh of its incautious handler. Ornithorhynchus anatinus males pack a venomous punch – or puncture – in two sharp spurs that project from the rear legs. The duck-billed platypus is the strangest of beasts, down to its deepest evolutionary roots. This feature appeared in the May/June 2011 issue of Australian Life Scientist.
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