The Australian paralysis or 'scrub' tick, Ixodes holocyclus, is responsible for the deaths of many pets and livestock in the wetter areas of eastern coastal Australia. This parasite may also attack man, causing a range of reactions from hypersensitivity - a heightened or accelerated response to salivary antigens - to paralysis and even death. It is the most consistently virulent paralysis tick in the world, secreting a toxin that causes muscular paralysis in victims. This leads to acute breathing difficulties, often complicated by cardiovascular problems and pneumonia.