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]
Spokane
Spokane (
i/spoʊˈkæn/ spoh-kan)[7] is a city in the state of Washington, in the northwestern United States. It is the seat of Spokane County, and the economic and cultural center of the Spokane Metropolitan Area, the Greater Spokane Area, and the Inland Northwest. It is located along the Spokane River west of the Rocky Mountain foothills in eastern Washington, 92 miles (148 km) south of the Canada–US border, approximately 20 miles (30 km) from the Washington–Idaho border, and 280 miles (450 km) east of Seattle along Interstate 90. The city, along with the whole Inland Northwest, is served by Spokane International Airport, 5 miles (8 km) west of downtown Spokane. According to the 2010 Census, Spokane had a population of 208,916, making it the second largest city in Washington and the 102nd largest city in the United States.
The first humans to live in the area, the Spokane people (their name meaning “children of the sun” in Salishan), arrived between 13,000 and 8,000 years ago, living off plentiful game. Known as the birthplace of Father’s Day, Spokane is officially nicknamed the “Lilac City”. David Thompson explored the area with the westward expansion and establishment of the North West Company‘s Spokane House in 1810. This trading post was the first long-term European settlement in Washington. Completion of the Northern Pacific Railway in 1881 brought settlers to the Spokane area, and that same year it was officially incorporated as a city with the name of “Spokan Falls”. In the late 19th century, gold and silver were discovered in the Inland Northwest. The local economy depended on mining, timber, and agriculture until the 1980s. Spokane hosted the first environmentally themed World’s Fair at Expo ’74.