Some species of ants possess a sting and venom gland in their tails, as well as powerful jaws. The ant bites with its jaws, then doubles up to inject venom via the sting. This usually results in local pain or itch with a weal or swelling at the injection site. Although only local problems typically result from envenomation, patients allergic to the venom may suffer life-threatening reactions. Stinging ants of the genus Myrmecia (jumper ants and bull ants) represent a hazard to humans in the southern states of Australia due to the relatively high proportion of the population (3-4% estimated from one study) with significant allergy to their venom. Purified venom for desensitization is currently unavailable, except for certain individuals in Tasmania treated at the Royal Hobart Hospital. Fire ants have become established in Brisbane so may also become a problem in Australia.