BIOLOGY

Lice, true insects with three pairs of legs, cling to hair using clawlike legs as they lack wings or powerful jumping abilities. While head lice primarily reside on the scalp, they can move to other body parts. They feed every four to six hours and require close contact with a host. Lice cannot survive off humans for more than 24 hours, so they do not thrive in items like rugs, carpets, furniture, or school buses.

Lice eggs, or nits, are oval, tan, and about 0.5-1.0 mm long. Usually, the female louse glues them near the scalp's base, often behind the ears or along the nape of the neck. Eggs hatch in 7-10 days, and the newly hatched lice must feed quickly. Immature lice undergo three molts and feed on blood before becoming sexually mature adults. It takes around 10-12 days for a newly hatched louse to reach adulthood, measuring about 1.8-3.3 mm in length.

A female louse has the capacity to lay six to seven eggs (nits) daily, amounting to a potential total of 140 eggs during her lifespan. Without a blood meal, adults cannot survive for more than approximately 24 hours. Both nymphs and adults possess piercing-sucking mouthparts that penetrate the skin to extract blood.

Individuals' reactions to louse bites can vary significantly. Those who have not been previously exposed to lice typically experience minimal irritation from the initial bite. However, over a short period, ranging from a few days to a few weeks, individuals may develop sensitization to the bites, resulting in a general allergic reaction characterized by skin reddening, itching, and inflammation. In subsequent infestations, itching and redness usually manifest within 24 to 48 hours. It's important to note that some individuals may never exhibit any symptoms.