I'm sure we now know more about the little beasties than before this thread was posted, e.g:
Wiki:
The human body louse Pediculus humanus humanus has the smallest insect genome known. This louse can transmit certain diseases while the human head louse (P. h. capitis), to which it is closely related, cannot.
Genetic evidence suggests that our human ancestors acquired pubic lice from gorillas approximately 3-4 million years ago.
Well, there's a little skeleton in the family cupboard but, TBH, perpetrated by a brave man
