päänästä

Päänästi, scientifically known as Pediculus humanus capitis, is an insect that infests the hair of humans. It is a common ectoparasite, meaning it lives on the outside of its host. The päänästi is wingless and measures about 2-3 millimeters in length. It has a grayish-white or translucent body and six legs, each equipped with claws that help it cling to hair shafts.

These parasites feed exclusively on human blood, biting the scalp and drawing blood through their proboscis. The bites can cause itching, which is the primary symptom of an infestation. Scratching due to itching can lead to secondary skin infections. Päänästits do not transmit diseases.

The päänästi lifecycle includes three stages: egg (nit), nymph, and adult. Nits are tiny, oval-shaped eggs that are cemented to hair shafts, usually close to the scalp. They are difficult to remove and can be mistaken for dandruff. Nymphs hatch from the nits and resemble smaller versions of adult lice. They mature into adults within about two weeks.

Transmission of päänästits occurs through direct head-to-head contact with an infested person. They can also spread through shared personal items like combs, brushes, hats, and bedding, although this is less common. Päänästits cannot jump or fly, and they die quickly if separated from a human host.

Diagnosis is typically made by visual inspection of the hair and scalp for live lice or nits. Treatment usually involves over-the-counter or prescription medicated shampoos, lotions, and conditioners designed to kill lice. Thorough combing of the hair with a fine-toothed nit comb is also an essential part of treatment to remove nits and dead lice. Environmental cleaning, such as washing bedding and clothing in hot water, is also recommended.