This 2006 photograph depicted a lateral view of a female body louse, Pediculus humanus
, as it was obtaining a blood-meal from a human host, who in this case, happened to be the photographer. Note its elongated abdominal region without any processes, and three pairs of legs, which are all equal in length and width, features displayed by Pediculus
Body lice are parasitic insects that live on the body, and in the clothing or bedding of infested humans. Infestation is common, found worldwide, and affects people of all races. Body lice infestations spread rapidly under crowded conditions where hygiene is poor, and there is frequent contact among people. Note the sensorial setae, or hairs that cover the louses body, which pick up, and transmit information to the insect about changes in its environment such as temperature, and chemical queues. The dark mass inside the abdomen is a previously ingested blood meal.