Cutaneous infestations and insect bites

The geographical segregation of human lice preceded that of Pediculus humanus capitis and Pediculus humanus humanus

“…Our data support the divergence of body and head lice to be the result of two distinct events, whereas it was thought that this was a single split [21]. This observation contradicts the current classification into either two species or subspecies, namely Pediculus humanus corporis and Pediculus humanus capitis.…”

“…The current taxonomic position of human lice is unclear, as their description and phylogenetic classification have mostly been based on morphological criteria [41][42][43]. Subtle differences in color and size of different body parts have been reported: head lice were described as being smaller and more heavily pigmented than body lice [3] and as having a shorter femur size [21]. Some authors have reported that the color of head lice may vary according to their hosts and have suggested that it could be the genotypic result of coevolution with different human races [3,22,23], whereas others have proposed that this phenomenon to be only phenotypic, i.e.…”

“…Whether modern human pediculidae evolved from a single ancestor associated with early hominidae and spread with major expansions of human populations [20] is likely but not demonstrated. It has been suggested that the head louse is the ancestor form that subsequently invaded clothing [21]. Anatomic differences characterize head or body lice [21] and some authors have also suggested that different strains of head lice evolved in different parts of the world following geographical isolation [3] that are closely associated with hosts of particular racial origin [22,23].…”

“…It has been suggested that the head louse is the ancestor form that subsequently invaded clothing [21]. Anatomic differences characterize head or body lice [21] and some authors have also suggested that different strains of head lice evolved in different parts of the world following geographical isolation [3] that are closely associated with hosts of particular racial origin [22,23]. However, other authors have proposed that these differences were due to distortion of exoskeleton during the mounting of specimens [24].…”