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]
Valley Park
Valley Park is a city in St. Louis County, Missouri, United States. The population was 6,942 at the 2010 census.[6]
Descendants of the Mississippian culture still had a settlement along the Meramec River in the mid-18th century, until the Native Americans were pushed out by colonial French and German immigrant farmers in the 1760s.{{citation needed|date=May 2017}] The developing village over time was known as Nasby, Sulphur Springs, Quinette, Meramec, and finally Valley Park by around 1890. It had one of the first post offices established in St. Louis County. It developed as a railroad hub for the Missouri Pacific and St. Louis-San Francisco rail lines.
In 1894, the town became the site of the first lynching in St. Louis County. A black man named John Buckner was lynched when accused of raping a local black woman and a white teenager. He was taken from the authorities by several local residents and farmers and hanged from the main bridge in town overlooking the Meramec River. The lynchers were never prosecuted.