On whom do lice live? - briefly
Lice are obligate ectoparasites that inhabit the bodies of warm‑blooded vertebrates, chiefly humans, other mammals, and birds. They feed on blood, skin debris, or feathers and complete their entire life cycle on the host’s skin or plumage.
On whom do lice live? - in detail
Lice are obligate ectoparasites that survive exclusively on the bodies of warm‑blooded vertebrates. Each species of louse has evolved a narrow range of suitable hosts, and successful colonisation depends on direct contact with the appropriate animal.
Human beings host three distinct types: the head louse (Pediculus humanus capitis) inhabits scalp hair, the body louse (Pediculus humanus corporis) lives in clothing and feeds on skin, and the pubic louse (Pthirus pubis) occupies the genital region. These insects cannot complete their life cycle on other mammals because they require specific temperature, humidity, and hair or feather structures found on humans.
Birds support a large diversity of lice, collectively called avian chewing lice (order Phthiraptera, suborder Amblycera and Ischnocera). These parasites cling to feathers, feeding on skin debris and blood. Species such as Menacanthus stramineus infest domestic chickens, while Philopterus spp. are common on passerines. Avian lice are rarely found on mammals, reflecting strict host fidelity.
Mammalian hosts other than humans include:
- Dogs and cats – infested by Trichodectes canis and Felicola subrostratus, respectively.
- Cattle – harbor Haematopinus eurysternus (cattle biting louse) and Linognathus vituli (cattle chewing louse).
- Horses – host Haematopinus asini (horse biting louse) and Solenopotes capillatus (horse biting louse).
- Pigs – affected by Haematopinus suis.
- Rodents – carry Polyplax serrata and other species of the genus Polyplax.
The life cycle of a louse comprises egg (nit), three nymphal stages, and adult. All stages remain on the host; lice cannot survive long off the body, typically less than 24 hours. Transmission occurs through direct physical contact, shared bedding, or, for body lice, contaminated clothing.
Ecologically, host specificity limits the spread of lice across taxonomic groups. Cross‑species infestations are rare and usually result from close human‑animal interaction, such as pet ownership or agricultural practices. Control measures therefore target the host environment—regular grooming, washing of clothing and bedding at temperatures above 50 °C, and, where necessary, topical or systemic insecticides.