Head louse (or Human louse)

Human hair and scalp

Obligate ectoparasite that feeds exclusively on human blood multiple times a day

Crawls along hair shafts near the scalp using specialized claws; attaches eggs (nits) firmly to the base of hair shafts near the skin for warmth

Causes intense itching (pruritus) and skin irritation on the scalp; can lead to secondary bacterial infections from scratching. It does not transmit disease vectors, but causes social and physical discomfort.