Antivenom
Antivenoms are purified antibodies which act as a kind of molecular sponge to soak up venoms or venom components (toxins). The most commonly used animal in the production of Australian antivenoms is the horse. Sheep, rabbits and dogs are also currently used in Australia. Venom is obtained in a number of different ways. Snakes and funnel web spiders are milked for their venom. Stonefish, redback spider and box jellyfish venoms are extracted from dissected glands and tissues. This can be a dangerous process.
Today there are 12 commercially available antivenoms in Australia.
| Australian snake antivenoms | Produced in: | Other Australian antivenoms | Produced in: |
| Tiger snake | Horses | Funnel web spider | Rabbits |
| Brown snake | Horses | Redback spider | Horses |
| Taipan | Horses | Australian paralysis tick | Dogs |
| Black snake | Horses | Box jellyfish | Sheep |
| Death adder | Horses | Stonefish | Horses |
| Sea snake | Horses | ||
| Polyvalent snake | Horses |
Producing Antivenoms Small doses of venom or venom components are injected into the host animal. The venom dose is gradually increased as the animal builds up tolerance or resistance to the toxins in the venom. In response to the introduced venom the animal produces antibodies against this foreign substance. The larger the venom doses injected, the greater the amount of antibody produced.
Samples of the host animal's blood are taken and the antibodies are separated out. They are then fragmented and purified by a series of digestion and processing steps. When injected into a patient, specific sites (binding sites) on the antibody fragments bind to the venom or venom components which circulate through the blood stream. This binding neutralizes the activity of the venoms and prevents further complications in the patient.
Antivenoms have been made since the 1890s. Australia was one of the first countries in the world to experiment with snake antivenoms; in New South Wales in 1898 Frank Tidswell commenced immunization of a former ambulance horse with tiger snake (N. scutatus) venom.
CSL Ltd is the sole manufacturer of antivenoms for human use in Australia. Australian antivenoms are amongst the best in the world, in terms of purity and low adverse reaction rate. It also developed a number of antivenoms for veterinary use in Australia (tiger/brown snake and paralysis tick antivenoms). Although these are now sold by Pfizer, they are still manufactured by CSL.