 The bubonic and septicaemic plagues are the most probable form of the plague that would spread as a result of a bioterrorism attack that used fleas as a vector.The banker Charles Rothschild devoted much of his time to entomology, creating a large collection of fleas now in the Rothschild Collection at the Natural History Museum, London.He discovered and named the plague vector flea, "Xenopsylla cheopis", also known as the oriental rat flea, in 1903.