Lice are very small insects with larger abdomens and smaller bodies. Lice have six legs arranged in pairs. They are pale grayish to buff to white colored and difficult to spot unless there has been a significant infestation. However, in humans, a lice infestation can cause significant itching. You can then see the infestation in the form of very small, moving insects crawling amongst the hair follicles. Lice also lay eggs, called nits, that can also be seen in the hair if they are in a high enough concentration.
Though there are several thousand species of lice in the world, only three of those species are pathogen carriers for humans. While there are several species that are free of lice infestation, lice feed off of very nearly every species of bird or mammal on the planet. Most species of lice are specific to their host animals, as avian lice will not infest mammals and vice versa. Lice are more commonly female than male, and some species have no males at all and reproduce via parthenogenis or asexual reproduction.
Signs of Infestation
The most obvious sign of a lice infestation is, of course, by sighting them present on their host. Other signs are the presence of itching in almost all species that are capable of being infested by lice. With humans, the infestation and itching generally occur in the hair of the head. It is far more common in children than in adults. Nits are attached by saliva on mammalian species infested by lice and avian species typically lay their eggs in areas where the birds cannot reach them to preen. In pet species, a lice infestation is generally rare in pet species, but it has been found that dogs can get human head lice.
Lice typically enjoy an environment that leaves them as undisturbed as possible. Lice that feed on humans specifically cannot hop, jump or fly and only transfer from one animal to another through contact with a source of infestation. It is a myth that lice prefer to infest dirty hair, and in fact actually prefer to infest clean hair because the lighter follicles are more prone to fly-aways that can be latched onto by the adult lice. Lice are not restricted to children and can be caught by any age of adult. This is generally true for all species of hosts and their lice. Lice will not leave their host species to strike out on their own in search of new hosts unless there is actual physical contact between hosts.
Lice feed in two ways: on the skin and bits of detritus found on the host’s body and also on the fluids and blood of the host. Lice that feed on bits of skin generally feed using moving mouth-parts, however those species that feed on blood and other bodily fluids have evolved piercing mouth-parts and search out veins close to the surface of the skin. Once these veins have been identified, the blood feeding louse will pierce the skin and draw up blood with two pumps in it’s head. The louse will then turn a darker color because of the translucence of the louses’ body.
Treatment and Prevention
The best way to treat lice, in humans, is a special chemical shampoo and the use of a specialized comb to remove the nits and lice from the hair once they have been killed. It can take several treatments to completely remove the lice infestation. This can be difficult, especially if the infested member of the household is either a small child or a pet. Prevention is more difficult, as there is not real way to prevent a lice infestation other than not sharing grooming implements.