Ico2 Headlice Essay

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ICO2 Headlice Explain how the following can be transmitted from one person to another Head Lice Head lice (pediculus humanus capitis) feed on blood, primarily on the heads of children. Infestation by head lice is called pediculosis. Fortunately, they do not transmit disease, although their presence can be very bothersome. These lice inject a saliva into their hosts as they feed to prevent the blood from clotting. This results in itching which at best is annoying and at worst can result in infection if scratched too vigorously. Anyone can become infested; the presence of head lice is not the result of unclean conditions. Adult head lice are about 1/8 inch long, greyish, flattened, and wingless. Their legs are claw-like, designed to hold onto hair. These lice excrete partially digested blood which can appear as 'black dandruff'. Lice eggs, commonly referred to as nits, are whitish, oval and the size of a pinhead (1/30 inch long). They are attached to hair near the scalp. Nits that are found further than 1/2 inch from the scalp nearly always have hatched or died. Head lice live in very close association with humans, especially on young children. They are found on heads where they take daily blood meals. Head lice cling to hair shafts near the scalp. Adult females glue eggs on hair shafts close to the scalp, usually behind the ears and on the nape of the neck. Eggs hatch after 5 to 10 days. Young head lice (called nymphs) are mobile and molt three times, developing into mature adults in about three weeks. Adults can live for about four weeks but do not lay eggs until after seven days. Head lice do not survive off a host for more than one or two days. Head lice do not jump or fly. They can however move from an infested person to another person during play or other close contact. Head lice may also spread when an infested child shares combs, brushes,

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