Quantification of blood intake of the head louse: Pediculus humanus capitis

Abstract

Although head lice, Pediculus humanus capitis, are globally prevalent blood-sucking ectoparasites, the amount of blood imbibed by head lice has not been determined. This study investigated this parameter, as regular loss of a small quantity of blood may lead to an iron deficiency and anaemia. Adult female lice (66), adult males (46), and nymphs (152) were weighed before and after feeding in groups of 17-109 lice. The average amounts of blood imbibed at a single feed were: adult female louse (0.0001579 ml), adult male (0.0000657 ml) and nymph (0.0000387 ml). Assuming three feeds per day by an average infection of 30 lice (10 females, 10 males, and 10 nymphs), the average child with active pediculosis would loose 0.008 ml of blood per day. This amount of blood loss is of no clinical significance even in iron-deficient children. The most heavily infected child observed with 2657 lice could be expected to loose 0.7 ml/day or 20.8 ml/month, which may be of clinical importance in a child on an adequate diet, and would be significant in an iron-deficient child. However, if head lice feed more often than three times a day, a heavy infestation would have a greater potential to lead to iron deficiency. The frequency of feeding of head lice on the head of the human host needs to be determined.

Anemia, leukocytosis and eosinophilia in a resource-poor population with helmintho-ectoparasitic coinfection

“…Comparable to intensity of infestation with intestinal helminths, Speare et al (2006) showed that only an infestation with head lice is unlikely to significantly contribute to anemia, only at extremely high parasite loads (more than 2500 head lice per individual) [12]. To what extent ectoparasitc infestation contributes to eosinophilia is difficult to correlate, since in impoverished communities coinfection with ectoparasites is common [14].…”

“…Furthermore, ectoparasitic infestations may also cause hematological alterations such as leukocytosis or eosinophilia [6][7][8][9][10][11][12]. In addition, in severe cases, persistent pediculosis may contribute to anemia [12].…”

Contact and fumigant toxicity of hexane flower bud extract of Syzygium aromaticum and its compounds against Pediculus humanus capitis (Phthiraptera: Pediculidae)

“…Symptoms associated with infestation are constant itching and scalp irritation. When the ectoparasites are associated with poor social conditions and inadequate iron in the diet, the infestation may even lead to anemia (Linardi et al 1988;Speare et al 2006). It has been suggested that transmission of P. humanus capitis is caused by shared combs, hairbrushes, mats, hats, bed linen, and clothes (Burkhart 2003).…”

Severe Iron Deficiency Anemia and Lice Infestation

“…A single study conducted by Speare and associates attempted to quantitate the amount of blood a single head louse ingests during a single feed (13). The value ranged from 0.0000387 mL to 0.0000657 mL in female and male lice, respectively (13). Although never studied, the body louse, generally larger than P. humanus capitis, might be expected to ingest a somewhat larger amount.…”

“…Pediculus humanus capitis is the cause of head lice, Pediculus humanus corporis the cause of body lice, and Phthiris pubis the cause of pubic infestation. A single study conducted by Speare and associates attempted to quantitate the amount of blood a single head louse ingests during a single feed (13). The value ranged from 0.0000387 mL to 0.0000657 mL in female and male lice, respectively (13).…”