What causes lice? - briefly
Lice infestations arise when Pediculus humanus capitis is transferred via direct head‑to‑head contact or shared personal items such as combs, hats, or bedding. The insects thrive in warm, humid conditions that support their development and reproduction.
What causes lice? - in detail
Lice infestations arise from several biological and environmental factors that facilitate the transfer and survival of the parasites.
The primary mechanisms include:
- Direct head‑to‑head contact, which allows adult lice to move from one scalp to another during close physical interaction.
- Sharing personal items such as combs, hats, hair accessories, helmets, or pillows, which can harbor live insects or their eggs.
- Crowded living conditions, where a high density of individuals increases the probability of accidental contact.
- Insufficient hygiene practices, not because lice are attracted to dirt, but because infrequent washing of hair and bedding reduces the chance of removing existing insects.
- Seasonal peaks, typically in late summer and early autumn, when school sessions resume and children spend more time together.
Secondary contributors involve:
- Presence of untreated infestations within a household or community, providing a persistent source of parasites.
- Lack of regular inspection, especially among children who may not report itching or discomfort.
- Use of ineffective over‑the‑counter treatments that fail to eradicate both adult lice and their eggs, allowing re‑infestation.
Understanding these factors helps target preventive measures, such as avoiding the exchange of headgear, conducting routine scalp checks, and applying proven eradication products when needed.