How long do body lice live? - briefly
Adult body lice survive roughly one month, with most individuals dying within 30 – 40 days under normal conditions. Their life cycle—from egg to adult—completes in about ten days, after which the insect lives only a few weeks.
How long do body lice live? - in detail
Body lice (Pediculus humanus corporis) complete their development on a human host. The life cycle consists of three stages: egg (nit), nymph, and adult. Each stage has a defined duration under typical indoor conditions (20‑25 °C, 60‑70 % relative humidity).
- Egg: Females deposit 5‑10 eggs per day, attaching them to the seams of clothing fibers. Incubation lasts 7‑10 days before hatching.
- Nymph: Upon emergence, the immature insect passes through three molts. Each instar requires 3‑4 days, resulting in a total nymphal period of roughly 9‑12 days.
- Adult: After the final molt, the adult emerges. Adults can survive 30‑40 days on a host, feeding several times daily. Female adults lay eggs continuously throughout their lifespan.
Summing the stages, a single body louse may live approximately 45‑60 days from egg to death, assuming optimal temperature and regular blood meals. Survival without a host is limited; adults can endure up to 5 days away from clothing, while eggs remain viable for about 10 days in a dry environment. Temperature extremes shorten the cycle: higher temperatures accelerate development, whereas colder conditions extend each stage and reduce overall longevity. Poor hygiene and infrequent clothing changes increase the probability of sustained infestations, as the insects retain access to a stable habitat and continuous feeding opportunities.