SUCKING LOUSE

any small, wingless, flat insect of the suborder Anoplura, with more than 400 described species and worldwide distribution. The sucking louse has piercing and sucking mouthparts and lives on blood and tissue fluids of mammals as an ectoparasite (external parasite). The adult sucking louse, or true louse, glues her eggs, or nits, to the host's hair. The young, which resemble adults when they hatch, become sexually mature after several molts. The sucking louse ranges in colour from whitish to yellow and shows distinct host specificity. The presence of related lice on related groups of hosts may evidence parallel evolution of parasites and hosts. The sucking louse Pediculus humanus infests the human race wherever hygienic practices are not maintained. In heavy infestations this insect, which is known as the human louse (q.v.), may cause serious skin irritations, but far more serious is its role as a vector of diseases such as typhus, relapsing fever, and trench fever. The pubic louse (q.v.) is found in the hair of the armpits, in the eyebrows and beard, and in the pubic region. The more important sucking lice that attack domestic animals belong to the genera Haematopinus and Linognathuse.g., the hog louse, H. suis; the short-nosed cattle louse, H. eurysternus; the horse louse, H. asini; the long-nosed cattle louse, L. vituli; and the dog louse, L. setosus. Lindane is an effective lice insecticide, but because it has neurotoxic effects, it must be used with caution. Pyrethrin and its synthetic derivative permethrin are newer treatments that are considered safer and more effective. Poisonous gases, chemical solutions, and heat sterilization are used to delouse clothing. Chemical dips or sprays are used on infested domestic animals. Predatory mites also help to control lice populations.