The paralysis tick, Ixodes holocyclus, is one of about 75 species of Australian tick fauna and is considered the most medically important. It is found in a 20-kilometre band that follows the eastern coastline of Australia. As this is where most people live, incidences of tick bites on people, pets and livestock are relatively common. Although most cases of tick bite are uneventful in humans, some can result in fatal illnesses including paralysis, tick typhus and severe allergic reactions. The tick's paralysing toxin has been estimated to affect as many as 100,000 domestic animals annually, with up to 10,000 companion animals being referred to veterinary surgeons for treatment. Up to 1989, 20 fatal cases have been reported in Australia.