Body Louse (or Head Louse) - Nymph Stage
Scientific Name: Pediculus humanus humanus (or Pediculus humanus capitis)
Order & Family: Order: Phthiraptera, Family: Pediculidae
Size: Nymphs are 1-2 mm (approx. size of a pinhead), Adults are 2-3 mm (approx. size of a sesame seed)
Natural Habitat
Exclusively on human hosts; Body lice live in clothing and bedding and move to skin to feed, while head lice live on the scalp and hair.
Diet & Feeding
Hematophagous (feeds exclusively on human blood)
Behavior Patterns
They are parasitic insects that cling to hair or clothing fibers. They undergo simple metamorphosis (egg/nit, nymph, adult). They spread through close personal contact or sharing contaminated items.
Risks & Benefits
Risks: Cause intense itching (pruritus) and skin irritation. Body lice can transmit serious diseases like typhus, trench fever, and relapsing fever. Head lice do not transmit disease but are a nuisance and cause secondary infections from scratching. No ecosystem benefits as they are obligate parasites.
Identified on: 2/19/2026