Head lice / louse
The head louse (Pediculus humanus capitis) is an obligate ectoparasite of humans that causes head lice infestation (pediculosis capitis).[1]
Head lice are wingless insects spending their entire lives on the human scalp and feeding exclusively on human blood.[1] Humans are the only known hosts of this specific parasite, while chimpanzees host a closely related species, Pediculus schaeffi. Other species of lice infest most orders of mammals and all orders of birds,[1] as well as other parts of the human body.
Lice differ from other hematophagic ectoparasites such as fleas in spending their entire lifecycle on a host.[2] Head lice cannot fly, and their short, stumpy legs render them incapable of jumping, or even walking efficiently on flat surfaces.[2]
The non-disease-carrying head louse differs from the related disease-carrying body louse (Pediculus humanus humanus) in preferring to attach eggs to scalp hair rather than to clothing. The two subspecies are morphologically almost identical, but do not normally interbreed, although they will do so in laboratory conditions. From genetic studies, they are thought to have diverged as subspecies about 30,000–110,000 years ago, when many humans began to wear a significant amount of clothing.[3][4] A much more distantly related species of hair-clinging louse, the pubic or crab louse (Pthirus pubis), also infests humans. It is visually different from the other two species and is much closer in appearance to the lice which infest other primates.[5] Lice infestation of any part of the body is known as pediculosis.[6]
Head lice (especially in children) have been, and still are, subject to various eradication campaigns. Unlike body lice, head lice are not the vectors of any known diseases. Except for rare secondary infections that result from scratching at bites, head lice are harmless, and they have been regarded by some as essentially a cosmetic rather than a medical problem. Head lice infestations might be beneficial in helping to foster a natural immune response against lice which helps humans in defense against the far more dangerous body louse, which is capable of transmission of dangerous diseases.[7]
Odessa
Odessa /ˌoʊˈdɛsə/ is a city in and the county seat of Ector County, Texas, United States. It is located primarily in Ector County, although a small portion of the city extends into Midland County.[3] Odessa’s population was 118,918 at the 2010 census making it the 29th-most populous city in Texas; estimates as of July 2015 indicate a population of 159,436 in the city.[4] It is the principal city of the Odessa Metropolitan Statistical Area, which includes all of Ector County. The metropolitan area is also a component of the larger Midland–Odessa combined statistical area, which had a 2010 census population of 278,801; a recent report from the United States Census Bureau estimates that the combined population as of July 2015 is 320,513.[4][5] In 2014, Forbes magazine ranked Odessa as the third fastest-growing small city in the United States.[6]
Odessa was founded in 1881 as a water stop and cattle-shipping point on the Texas and Pacific Railway. The first post office opened in 1885. Odessa became the county seat of Ector County in 1891 when the county was first organized. It was incorporated as a city in 1927, after oil was discovered in Ector County on the Connell Ranch southwest of Odessa.[8]