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]
Lebanon
Lebanon /ˈlɛbnən/ is the county seat of Wilson County, Tennessee, United States.[4]
The population was 26,190 at the 2010 census, 28,608 in 2013 and 32.372 following a special census conducted in 2016[5].
Lebanon is located in Middle Tennessee, approximately 25 miles (40 km) east of downtown Nashville. Lebanon is part of the Nashville Metropolitan Statistical Area.
The city was incorporated in 1801,[6] and was named after the biblical cedars of Lebanon.[7] Local residents have called Lebanon “Cedar City”, mostly a reference to the abundance of cedar trees in the area. The city is home to Cumberland University, a small, private four-year liberal arts institution.
As of the census[2] of 2000, there were 20,235 people, 7,987 households, and 5,319 families residing in the city. The population density was 692.0 people per square mile (267.2/km²). There were 8,693 housing units at an average density of 297.3 per square mile (114.8/km²). The racial makeup of the city was 82.89% White, 13.78% African American, 0.33% Native American, 0.82% Asian, 0.03% Pacific Islander, 1.00% from other races, and 1.15% from two or more races. Hispanic or Latino of any race were 2.26% of the population.
There were 7,987 households out of which 30.9% had children under the age of 18 living with them, 47.7% were married couples living together, 15.0% had a female householder with no husband present, and 33.4% were non-families. 28.5% of all households were made up of individuals and 11.1% had someone living alone who was 65 years of age or older. The average household size was 2.41 and the average family size was 2.94.