How do pubic lice attach to a person? - briefly
Pubic lice grasp hair shafts with specialized claws and produce a glue‑like secretion that bonds their eggs to the strands, ensuring firm attachment. They stay attached until they molt or are mechanically removed.
How do pubic lice attach to a person? - in detail
Pubic lice (Pthirus pubis) remain on a host by clinging to hair shafts and feeding on blood. The attachment process involves several distinct mechanisms.
The louse’s anatomy includes robust claws at the end of each leg. These claws interlock with the cuticle of coarse hair found in the pubic region, as well as in axillary, facial, and chest hair. The grip is reinforced by the insect’s ability to contract its leg muscles, creating a firm hold that resists displacement during movement or washing.
Feeding behavior further secures the parasite. After locating a suitable hair, the louse inserts its piercing‑sucking mouthparts into the epidermis. Saliva containing anticoagulant compounds is released, keeping the blood flow steady. Continuous ingestion of blood supplies the louse with nutrients and maintains its position because the mouthparts remain embedded until the next feeding cycle.
Reproductive activity contributes to attachment stability. Female lice lay eggs (nits) on the hair shaft, cementing each egg with a proteinaceous glue. This adhesive not only secures the egg but also adds additional friction to the surrounding hair, making it harder for the host’s grooming actions to dislodge the insects.
Key factors that enhance adherence:
- Claw morphology: curved, sharp tarsi that match hair diameter.
- Mouthpart insertion: permanent puncture sites that anchor the insect.
- Salivary anticoagulants: prevent clotting, ensuring uninterrupted feeding.
- Egg cement: protein glue that binds nits tightly to hair.
Environmental conditions such as humidity and temperature affect the strength of the grip, with moderate humidity improving claw adhesion. Mechanical removal (e.g., shaving, combing) disrupts the attachment by eliminating the hair substrate, while chemical treatments (permethrin, pyrethrins) impair the louse’s muscular control, reducing its ability to maintain hold.