How long can lice survive without food and at what temperature? - briefly
Lice can endure up to about two days without a blood meal when held at moderate room temperature («20‑25 °C»). Exposure to temperatures above «30 °C» or below «10 °C» shortens survival to less than 24 hours, and extreme heat (≥«40 °C») or cold (≤«5 °C») is rapidly lethal.
How long can lice survive without food and at what temperature? - in detail
Lice require regular blood meals to maintain metabolic activity. When deprived of a host, an unfed nymph can survive for up to five days, while adult individuals may endure slightly longer, typically six to seven days. Under optimal humidity (70‑80 %) and temperature (approximately 30 °C), survival without nourishment can extend to nine or ten days, after which physiological reserves are exhausted.
Temperature strongly influences mortality rates. At temperatures above 45 °C, lethal effects appear within minutes; exposure to 50 °C results in death in less than one minute. Conversely, low temperatures slow metabolic processes. At 4 °C, lice remain viable for several days, and at freezing temperatures (0 °C or lower) mortality occurs within a few hours. Room‑temperature conditions (20‑25 °C) allow a maximum survival period of about two weeks without a blood source, provided humidity remains adequate.
Key survival parameters:
- Optimal range: 28‑32 °C, 70‑80 % relative humidity – up to 10 days without feeding.
- Moderate range: 20‑25 °C, 50‑70 % humidity – up to 14 days, gradual decline in activity.
- High temperature: >45 °C – death in <5 minutes; >50 °C – death in <1 minute.
- Low temperature: 0‑4 °C – death in 2‑6 hours; below 0 °C – rapid fatality within hours.
The combination of insufficient food and unfavorable temperature conditions determines the upper limit of lice viability, with extreme heat providing the fastest eradication, while moderate ambient conditions permit the longest survival interval.