Phthirus pubis

Commonly know as "Crab Louse"

This insect is parasitic, using humans as their primary host, attaching to the host's thick pubic hairs perianal region, chest, abdomen and axillae. The insect's size ranges from 0.8-1.2 mm in length, with the first pair of legs much smaller and more slender than the second and third pairs, which resemble the pinchers of a common crab. The abdomen of Phthirus pubis is much shorter compared to that of the head and body louse (Wentworth 1988). This parasite is transmitted via venereal contact; once infected, the host develops painless blue-grey macules from the feeding of the lice. The lice and eggs are macroscopic and may cause discomfort via burning or itching. Rarely, the insect can be transmitted to a new host via a toilet seat.


Start by learning about Classification.

This website is a part of a growing project called Multiple Organisms.