How long do lice survive in clothing? - briefly
Lice can remain alive on fabrics for up to 24 hours, occasionally extending to 48 hours under optimal humidity and temperature. After this period, they typically die from dehydration.
How long do lice survive in clothing? - in detail
Lice that detach from a host remain viable only for a limited period, and the length of survival depends on environmental conditions. The two common species, the head louse and the body louse, share similar off‑host requirements: moisture, moderate temperature, and darkness.
At typical indoor temperatures (20 °C–25 °C) with relative humidity around 50 %–70 %, adult lice can survive up to 48 hours. Lower temperatures slow metabolism, extending viability to 72 hours or slightly longer when humidity remains high. Exposure to temperatures above 30 °C combined with low humidity reduces survival to less than 24 hours, as dehydration occurs rapidly. Direct sunlight accelerates desiccation, often killing insects within a few hours.
Key factors influencing longevity:
- Moisture – humid environments prevent rapid water loss.
- Temperature – moderate warmth supports metabolic activity; extreme heat or cold is lethal.
- Light – ultraviolet radiation and heat from sunlight increase mortality.
- Substrate – fabrics that retain moisture (e.g., wool, synthetic blends) provide a more favorable microhabitat than dry cotton.
Practical measures for contaminated garments:
- Wash items in hot water (minimum 55 °C) for at least 10 minutes; heat denatures proteins and kills lice and eggs.
- Dry at high heat (≥60 °C) for 30 minutes; thermal exposure eliminates residual stages.
- Seal unwashed clothing in airtight plastic bags for 2 weeks; prolonged deprivation of food and moisture leads to death.
- Freeze items at –20 °C for 24 hours; low temperature halts metabolism and ensures mortality.
- Avoid storing clothing in dark, humid closets without treatment; such conditions extend viability.
Understanding these parameters allows effective interruption of transmission cycles and ensures that clothing no longer poses a risk after appropriate processing.