What do pubic lice feed on? - briefly
Pubic lice (crab lice) survive by extracting blood from the human host’s skin, especially in the genital and adjacent areas. Their mouthparts pierce the epidermis to access capillary blood.
What do pubic lice feed on? - in detail
Pubic lice, also known as Pthirus pubis, are obligate ectoparasites that survive exclusively on human blood. Their mouthparts are adapted to pierce the thin epidermis of hair‑bearing skin, allowing direct access to capillary blood. Each feeding episode involves the insertion of a stylet, the release of anticoagulant saliva, and the ingestion of a small volume of blood, typically less than 0.5 µL.
Both adult insects and their immature nymphal stages require blood meals. Nymphs must feed at least three times before each molt, while adult females obtain blood several times daily to support egg production. Males feed less frequently but still depend on regular blood intake for sustenance.
Feeding sites are confined to regions where coarse hair is present: the pubic area, perianal region, axillae, chest, abdomen, and, in some cases, facial hair. The lice anchor themselves to a single hair shaft with their claws and remain motionless while feeding, which can last from a few minutes to half an hour per bout.
Saliva contains enzymes that prevent clotting and cause a localized inflammatory response. The host’s immune reaction manifests as itching, erythema, and sometimes secondary bacterial infection. Continuous blood extraction does not produce significant anemia in the host, but the irritation can lead to discomfort and psychosocial distress.
Control measures target the parasite’s reliance on blood. Insecticidal shampoos, lotions, or oral ivermectin disrupt feeding by either killing the lice or impairing their ability to locate blood vessels. Mechanical removal of infested hair, combined with thorough washing of bedding and clothing at temperatures above 50 °C, eliminates residual blood sources and reduces re‑infestation risk.
In summary, pubic lice subsist on human blood obtained from hair‑covered skin, employing specialized mouthparts and anticoagulant saliva to extract minute quantities of plasma repeatedly throughout their life cycle. Their feeding behavior underlies the clinical signs of infestation and guides effective treatment strategies.