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]
Midland
Midland is a city in the U.S. state of Michigan in the Tri-Cities region of Central Michigan. It is the county seat of Midland County.[7] The city’s population was 41,863 as of the 2010 census. It is the principal city of the Midland Micropolitan Statistical Area, part of the larger Saginaw-Midland-Bay City Combined Statistical Area. In 2010, Midland was named the no. 4 Best Small City to raise a family in by Forbes magazine.[8]
By the late 1820s, Midland was established as a fur trading post of the American Fur Company supervised by the post at Saginaw. Here agents purchased furs from Ojibwe trappers. The Campau family of Detroit operated an independent trading post at this location in the late 1820s.[9]
The Dow Chemical Company was founded in Midland in 1897, and its world headquarters are still located there. Through the influence of a Dow Chemical plant opening in Handa, Aichi, Japan, Midland and Handa have become sister cities.[10] The Dow Corning Corporation and Chemical Bank are also headquartered in Midland.
In 1969 the city unilaterally defined a Midland Urban Growth Area (MUGA), which at the time was a territory two-miles around the city limits of Midland in an attempt to control urban sprawl. [11] The central policy was that as the only capable supplier of drinking water, the city would provide water services to commnities outside the MUGA such as the nearby village of Sanford, but would not provide to water services to the area within the MUGA without annexation to the city of Midland thus controlling most of the growth in the county. Since 1991 however, the policy has since been revised with a series of Urban Cooperation Act Agreements with surrounding townships which has allowed case-by-case redrawings of the MUGA line to allow Midland to sell water to the surrounding townships without annexation.[11]