Facts about disease vectors
Fleas (Siphonaptera)
Fleas can transmit plague (caused by Yersinia pestis), murine typhus (caused by Rickettsia typhi), flea-borne spotted fever (Rickettsia felis), and cat scratch disease (Bartonella henselae).
Lice (Phthiraptera)
Lice (Phthiraptera) are a very diverse group of insects, exclusively adapted to parasitism. Several thousand species have been described to date.