Lice (singular: louse)
3 species in humans:
Pubic [Crab louse]
The Order of lice (Phthiraptera) is divided taxonomically into sucking lice (Anoplura) and chewing lice (Mallophaga), but there are alternative taxonomic classifications. Anoplura only parasitize mammals. Only three species of Anoplura are of regular direct medical importance to humans.
These wingless insects are cosmopolitan, obligate haematophages and strictly adapted to their host (there is no animal reservoir).
Polyplax spinulosa (Anoplura) is the sucking louse of rats and acts as an occasional vector of murine typhus.
Only a single species of Mallophaga (Trichodectes canis) is known to have medical significance. T. canis is the chewing louse of dogs and acts as one of the larval hosts of the dog tapeworm Dipylidium caninum. This insect cannot live on man.