Louse

Human scalp and hair; they cling to hair shafts near the warmth of the scalp.

Obligate parasites that feed exclusively on human blood several times a day.

They cannot jump or fly; they crawl from head to head via direct contact. Females lay eggs (nits) and glue them to hair shafts.

Causes intense itching and scalp irritation. Not known to spread disease, but scratching can lead to secondary bacterial skin infections.