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]
Huntingdon
Huntingdon is a borough in (and the county seat of) Huntingdon County, Pennsylvania, United States. It is located along the Juniata River, approximately 32 miles (51 km) east of Altoona and 98 miles (158 km) west of Harrisburg. It is the largest population center near Raystown Lake, a winding, 28 miles (45 km) long flood-control reservoir managed by the U. S. Army Corps of Engineers. The borough is located on the main line of the Norfolk Southern (formerly Pennsylvania) Railroad, in an agricultural and outdoor recreational region with extensive forests and scattered deposits of ganister rock, coal, fire clay, and limestone. Historically, the region surrounding Huntingdon was dotted with iron furnaces and forges, consuming limestone, iron ore and wood (for charcoal production) throughout the 19th century. Dairy farms dominate the local agriculture. The town is a regular stop for the Amtrak passenger service which connects Harrisburg with Pittsburgh.
Huntingdon is home to Juniata College, a private liberal arts college founded by members of the Church of the Brethren in 1876, and branch campuses of DuBois Business College and Penn Highlands Community College. In adjoining Smithfield Township (across the Juniata River) are the regional headquarters of the Pennsylvania Game Commission (Southcentral Division) and the Bureau of Forestry (Rothrock State Forest). State Game Lands 322 extends north from Huntingdon Borough in the direction of Petersburg. Public parks are the George N. Weaver Memorial Park (ball field and playground) at the end of 16th Street, Portstown Park along the Juniata River, and Blair Field bordering Standing Stone Creek. Historic Blair Park, directly across the same stream, is owned and managed by a nonprofit group; it contains a gazebo, and a level hiking and biking trail. A vintage chapel within the park is used by the congregation of Epiphany of Our Lord Orthodox Church.