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]
Sioux Falls
Sioux Falls (/ˌsuː ˈfɔːlz/) (Lakota: Íŋyaŋ Okábleča Otȟúŋwahe;[8] “Stone Shatter City”) is the largest city in the U.S. state of South Dakota. It is the county seat of Minnehaha County,[9] and also extends into Lincoln County to the south. It is the 47th fastest-growing city in the United States[10] and the fastest-growing metro area in South Dakota, with a population increase of 22% between 2000 and 2010.[11]
As of 2016, Sioux Falls had an estimated population of 178,500. The metropolitan population of 251,854 accounts for 29% of South Dakota’s population. It is also the primary city of the Sioux Falls-Sioux City Designated Market Area (DMA), a larger media market region that covers parts of four states and has a population of 1,043,450.[12] Chartered in 1856 on the banks of the Big Sioux River, the city is situated in the rolling hills on the western edge of the Midwest at the junction of Interstate 90 and Interstate 29.
The history of Sioux Falls revolves around the cascades of the Big Sioux River. The falls were created about 14,000 years ago during the last ice age. The lure of the falls has been a powerful influence. Ho-Chunk, Ioway, Otoe, Missouri, Omaha (and Ponca at the time), Quapaw, Kansa, Osage, Arikira, Dakota, Nakota and Cheyenne people inhabited and settled the region previous to Europeans and European descendants. Numerousburial mounds still exist on the high bluffs near the river and are spread throughout the general vicinity. Indigenous people maintained an agricultural society with fortified villages, and the later arrivals rebuilt on many of the same sites that were previously settled. Lakotapopulate urban and reservation communities in the contemporary state and many Lakota, Dakota, Nakota, and numerous other Indigenous Americans reside in Sioux Falls today.[13]