George (1974) maps 63 species, three subspecies and two hybrids of subspecies from birds and mammals native to or domiciled in this country. Of these, 26 species and two subspecies have so far been recorded in Cornwall. One of these, Ornithopsylla laetitiae Rothschild, the Shearwater Flea, (which also occurs on the Puffin), is confined to Great Britain and Ireland. Apart from the Isles of Scilly, it is known from only five other sites in Wales, Scotland and southern Ireland. The Human Flea Pulex irritans Linnaeus and the Dog Flea Ctenocephalides canis (Curtis) are both decreasing whilst the Cat Flea Ctenocephalides felis Bouch‚ is increasing. The Rabbit Flea Spilopsyllus caniculi (Dale) is the vector of myxomatosis-causing virus, deliberately introduced from the continent.