extermination of the flies by insecticides. Clothes should be washed thoroughly, preferably in hot water, dried away from flies, and ironed thoroughly. The heat of the iron kills the eggs of myiasis-causing flies. Treatment This applies once an infestation is established. In many circles the first response to cutaneous myiasis once the breathing hole has formed, is to cover the air hole thickly with petroleum jelly. Lack of oxygen then forces the larva to the surface, where it can more easily be dealt with. In a clinical or veterinary setting there may not be time for such tentative approaches, and the treatment of choice might be more direct, with or without an incision. First the larva must be eliminated through pressure around the lesion and the use of forceps. Secondly the wound must be cleaned and disinfected. Further control is necessary to avoid further reinfestation. Livestock may be treated prophylactically with slow-release boluses containing ivermectin, which can provide long-term protection against the development of the larvae. Sheep also may be dipped, a process that involves drenching the animals in persistent insecticide to poison the larvae before they develop into a problem. Epidemiology The most common infected animal worldwide is the domestic sheep, for more information see fly strike in sheep. This condition is caused by the blowfly (particularly Lucilia sericata and its sister species L. cuprina), especially where the weather is often hot and wet. Blowfly strike accounts for over A$170 million a year in losses in the Australian sheep industry, the largest such losses in the world. Given the seriousness of the risk, Australian sheep farmers commonly perform preventive measures such as mulesing designed to remove the most common targets for the flies. The docking of lambs' tails (another frequently-soiled area that flies target) is also commonly practiced by sheep farmers worldwide. Maggots also occasionally infest the vulvar area, causing the condition called vulvar myiasis. Such problems are not peculiar to Australia and New Zealand; they occur worldwide, especially in countries where livestock, particularly sheep, are kept under hot, wet, conditions, including most of Africa and the Americas, ranging from the cold temperate regions in the north, to corresponding latitudes in the south. Myiasis is also not restricted to sheep; screwworm flies (Cochliomyia hominivorax in particular) regularly cause upwards of US$100 million in annual damages to domestic cows and goats, though the impact has been heavily mitigated in recent