Platypus Envenomation :: Australian Animals Wildlife Essays

Platypus Envenomation Abstract The duck-billed platypus (Ornithorhynchus anatinus), order Monotrema, can be found throughout river systems in eastern Australia. The males have a retractable spur located on each of their hind legs. The spurs are attached to venom glands that produce a toxic cocktail of at least four different classes of peptides. These four compounds (Hyaluronidase, OvCNP-39, OvNGF, and defensin-like peptides) are highly selective enzymes and polypeptides that work together to inflict excruciating pain and edema that can last for months. The first compound identified, Hyaluronidase, lowers viscosity to allow for a deeper penetration of the venom into tissue. A C-type natriuretic peptide called OvCNP-39 contributes to edema. OvNGF is a nerve growth factor that is responsible for extreme sensitivity to heat and pressure. The role of Defensin-like proteins is not well known, but it is believed that they contribute the pain and edema associated with the venom. An unknown compound has been found to induce Ca++ dependent current in root ganglion cells, which may also contribute to the feeling of pain. Research is being done to identify the roles of these compounds and the possibility of them being used in medicine. Introduction The Platypus (Ornithorhynchus anatinus) is a unique animal that is found only in Australia. It is in the class Mammalia and the order Monotrema. Monotremes are phylogenetically the oldest of the mammals and can only be found naturally in Australia and in nearby New Guinea. They are quite different from placentals and marsupials and are believed to be the link between the reptiles and the other mammals. This is most noticeable though their means of reproduction and waste elimination. Montremes have a cloaca, which is a single opening for passage of solid and liquid waste, where the transfer of sperm takes place, and in females, the laying of eggs. This feature is shared only with birds and reptiles. Platypuses live solo, except during the breeding season. They feed on worms and freshwater crayfish (Cheerax destructor) in eastern Australian rivers (Sutherland, 1983). They have low average body temperature compared to other mammals, which further supports their reptilian evolution (Torres et al., 1999). They can live about 16 years and grow to be 40-50 cm long, with males being larger than females (Jackson, 2003). Venom: Production & Delivery A characteristic that helps add even more to the platypus ¡Ã‚ ¯ uniqueness is the males ¡Ã‚ ¯ ability to produce and deliver venom.