The infection is often transmitted through contact with a body louse.
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For example, the body louse (Pediculus humanus humanus) diverged from the head louse (Pediculus humanus capitis) around 100,000 years ago into a lifestyle associated with the origin of clothing.
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Subsequently, he served as the director and community coordinator of the Body Louse Genome Sequencing Consortium, a group of over 60 scientists that worked to develop an understanding of the annotation and interpretation of the body louse genome sequence and the genome of the obligate endosymbiont that lives in the body louse. The project was active from 2005 to 2010. The resultant paper was published in PNAS.
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Life cycle of Pediculus humanus capitis, which is similar to the body louse. The location of the body louse eggs are different from the head louse eggs. The head louse will lay their eggs on hair follicles, whereas a body louse will lay their eggs in articles of clothes. This picture represents the louse from egg to adult and the process of going through three molts to achieve adulthood.
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Pittendrigh was the lead author on the White Paper that was funded by NIH for the sequencing of the body louse genome.Pittendrigh, B.R., J. M. Clark, J. S. Johnston, S. H. Lee, J. Romero-Severson, and G. A. Dasch. 2006. Proposed sequencing of a new target genome: The human body louse, Pediculus humanus humanus. Journal of Medical Entomology. 43(6): 1103-1111.
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Borrelia recurrentis is a species of Borrelia, a spirochaete bacterium associated with relapsing fever. B. recurrentis is usually transmitted from person to person by the human body louse. Since the 1800s, the body louse has been known as its only known vector. B. recurrentis DNA was found in 23% of head lice from patients with louse-borne relapsing fever in Ethiopia.
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Other lice that infest humans are the body louse and the crab louse. The claws of these three species are adapted to attachment to specific hair diameters.
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First, gorilla lice host-switched to humans to found the species Crab louse. Second, the human louse duplicated into two forms, the Head louse and Body louse.
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The body louse diverged from the head louse at around 100,000 years ago, hinting at the time of the origin of clothing.Archive Body lice were first described by Carl Linnaeus in the 10th edition of Systema Naturae. The human body louse had its genome sequenced in 2010, and at that time it had the smallest known insect genome. Other lice that infest humans are the head louse and the crab louse.
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If an individual or a population of people are exposed to a long-term infestation, they may start to experience apathy, lethargy and fatigue. When feeding, the body lice resemble a mosquito feeding process. The body louse pierces the skin of the host and injects a salivary anticoagulant that helps the louse consume the hosts blood. Bites of the body louse can produce skin lesions that looks like a rash and in some cases, pruritus.
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They can feed up to five times a day and can live for about thirty days, but if they are separated from their host, they will die within a week. If the conditions are met, the body louse can reproduce rapidly in favoring conditions. The life cycle of the body louse consists of three stages: egg (also called a nit), nymph, and adult. # Nits are louse eggs that are laid in the folds of clothing and nowhere else.
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Epidemic typhus is a form of typhus so named because the disease often causes epidemics following wars and natural disasters. The causative organism is Rickettsia prowazekii, transmitted by the human body louse (Pediculus humanus corporis).
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They usually spend their whole life on a single host, cementing their eggs, called nits, to hairs or feathers. The eggs hatch into nymphs, which moult three times before becoming fully grown, a process that takes about four weeks. Humans host two species of louse—the head louse and the body louse are subspecies of Pediculus humanus; and the pubic louse, Pthirus pubis. The body louse has the smallest genome of any known insect; it has been used as a model organism and has been the subject of much research.
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Bartonella quintana is transmitted by contamination of a skin abrasion or louse-bite wound with the faeces of an infected body louse (Pediculus humanus corporis). There have also been reports of an infected louse bite passing on the infection.
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The sequencing of the genome of the body louse was first proposed in the mid-2000s and the annotated genome was published in 2010. An analysis of the body and head louse transcriptomes revealed these two organisms are extremely similar genetically.
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The strains differ in clinical symptoms and/or presentation as well as geographic distribution. Except for Borrelia recurrentis (which causes louse-borne relapsing fever and is transmitted by the human body louse), all known species are believed to be transmitted by ticks.
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When not attached to a human, they are unable to live beyond three days. Humans can also become infected with two other lice – the body louse and the crab louse. To make the diagnosis, live lice must be found. Using a comb can help with detection.
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Bartonella quintana, originally known as Rochalimaea quintana, and "Rickettsia quintana", is a micro-organism transmitted by the human body louse. This microorganism is the causative agent of the well known trench fever. This bacterium caused outbreaks of trench fever affecting 1 million soldiers in Europe during World War I.
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In the United States, between 6 and 12 million children are infected a year. They occur more often in girls than boys. It has been suggested that historically, head lice infection were beneficial, as they protected against the more dangerous body louse. Infestations may cause stigmatization of the infected individual.
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An adult crab louse is about 1.3–2 mm long (slightly smaller than the body louse and head louse), and can be distinguished from those other species by its almost round body. Another distinguishing feature is that the rearmost two pairs of legs of a crab louse are much thicker than the front legs and have large claws.
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The claws of these three species are adapted to attachment to specific hair diameters. The body louse belongs to the phylum Arthropoda, class Insecta, order Phthiraptera and family Pediculidae. There has been roughly 5,000 species of lice described, 4,000 specialized to birds, 800 specialized to mammals and are seen all over the world in various habitats.
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Along with Rickettsia prowazekii and Bartonella quintana, Borrelia recurrentis is one of three pathogens of which the body louse (Pediculus humanus humanus) is a vector. Louse-borne relapsing fever is more severe than the tick-borne variety. Louse-borne relapsing fever occurs in epidemics amid poor living conditions, famine and war in the developing world. It is currently prevalent in Ethiopia and Sudan.
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The human body louse Pediculus humanus humanus has (2010) the smallest insect genome known. This louse can transmit certain diseases while the human head louse (P. h. capitis), to which it is closely related, cannot. With their simple life history and small genomes, the pair make ideal model organisms to study the molecular mechanisms behind the transmission of pathogens and vector competence.
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In animals, the mitochondrial genome is typically a single circular chromosome that is approximately 16 kb long and has 37 genes. The genes, while highly conserved, may vary in location. Curiously, this pattern is not found in the human body louse (Pediculus humanus). Instead, this mitochondrial genome is arranged in 18 minicircular chromosomes, each of which is 3–4 kb long and has one to three genes.
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Infection in cats is very common with a prevalence estimated between 40-60%, younger cats being more commonly infective. Cats usually become immune to the infection, while dogs may be very symptomatic. Humans may also acquire it through flea or tick bites from infected dogs, cats, coyotes, and foxes. Trench fever, produced by Bartonella quintana infection, is transmitted by the human body louse Pediculus humanus corporis.
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Menoponidae is a monophyletic family of lice in the suborder/order of chewing lice, Amblycera, often referred to as the chicken body louse family. They are ectoparasites of a wide range of birds including chickens, which makes them important to understand for veterinary science and for human health. However, Menoponidae are not exclusive to poultry and are common parasites for migratory birds, with more and more species being discovered every year.
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Dogs and sheep were among the first animals to be domesticated. Humans are involved in mutualisms with other species: their gut flora is essential for efficient digestion. Infestations of head lice might have been beneficial for humans by fostering an immune response that helps to reduce the threat of body louse borne lethal diseases. Some relationships between humans and domesticated animals and plants are to different degrees mutualistic.
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While at the Plague Research Laboratory he made what was probably his chief contribution to medicine, the discovery that the body louse, a blood-sucking insect, might serve as a vector for the transmission of relapsing fever. In August 1907 Mackie was sent to investigate an outbreak of relapsing fever that had broken out at a mission settlement in Nasik (now Nashik), in the state of Maharashtra. The boys and girls residing at the settlement were housed in separate, similar bungalows but many more of the boys than the girls were taken ill with the disease and Mackie's investigation pointed to the cause. The boys were found to be infested with body lice, while the girls were almost free of them. Confirmation of the body louse as vector came from microscopic examination of the lice, which showed they were carrying large numbers of the spirochetes characterizing the human disease and that they were multiplying within the insects’ stomachs.
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This condition is caused by body louse (Pediculus humanus humanus, sometimes called Pediculus humanus corporis), a louse which infests humans and is adapted to lay eggs in clothing, rather than at the base of hairs, and is thus of recent evolutionary origin. Pediculosis is a more serious threat due to possible contagion of diseases such as typhus. Epidemiology and treatment of human body lice is described in the article on body lice.
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The body louse (Pediculus humanus humanus, sometimes called Pediculus humanus corporis) is a hematophagic ectoparasite louse that infests humans. It is one of three such lice, the other two are the head louse, and the pubic louse. Despite the name, body lice do not directly live on the host. They lay their eggs in articles of clothing or bedding and only come into contact with the host whenever they need to feed.
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Rickettsia – typhus-causing bacteria Typhus-spreading body louse The development of the typhus vaccine involved several stages. First, the lice larvae had to be bred and then fed on human blood. Once they matured, they were removed from the feeders, held down in a clamp machine especially designed by Weigl, and anally injected with the strain of the typhus bacteria. At that point the infected louse had to be fed human blood for about five more days.
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B. quintana is a fastidious, aerobic, Gram-negative(-), pole rod-shaped (bacillus) bacterium. The infection caused by this microorganism, trench fever, was first documented in soldiers during World War I, but has now been seen Europe, Asia, and North Africa. Its primary vector is known to be Pediculus humanus variety corporis, also known as the human body louse. It was first known to be isolated in axenic culture by J.W. Vinson in 1960, from a patient in Mexico City.
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Some conditions that are needed is the weather, humidity and lack of hygiene. Diseases like typhus are reported mainly in the winter/spring months, during these months, individuals have to wear multiple articles of clothing, which serves as a great place for the body louse to live and breed. All of these diseases negatively impact human health, but can now be treated. If they go without treatment, two of the diseases have a high fatality rate.
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At least three species or subspecies of Anoplura are parasites of humans; the human condition of being infested with sucking lice is called pediculosis. Pediculus humanus is divided into two subspecies, Pediculus humanus humanus, or the human body louse, sometimes nicknamed "the seam squirrel" for its habit of laying of eggs in the seams of clothing, and Pediculus humanus capitis, or the human head louse. Pthirus pubis (the human pubic louse) is the cause of the condition known as crabs.
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Pediculus humanus humanus (the body louse) is indistinguishable in appearance from Pediculus humanus capitis (the head louse) but will interbreed only under laboratory conditions. In their natural state, they occupy different habitats and do not usually meet. Compared to the other two related lice species (head and pubic lice), body lice do not directly live on the host. They lay their eggs in articles of clothing or bedding and only come into contact with the host whenever they need to feed.
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The mitochondrial genome of the human species of the body louse (Pediculus humanus humanus), the head louse (Pediculus humanus capitis) and the pubic louse (Pthirus pubis) fragmented into a number of minichromosomes, at least seven million years ago. Analysis of mitochondrial DNA in human body and hair lice reveals that greater genetic diversity existed in African than in non-African lice. Human lice can also shed light on human migratory patterns in prehistory. The dominating theory of anthropologists regarding human migration is the Out of Africa Hypothesis.
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Lice differ from other hematophagic ectoparasites such as fleas in spending their entire lifecycle on a host. Head lice cannot fly, and their short, stumpy legs render them incapable of jumping, or even walking efficiently on flat surfaces. 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.
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Outbreaks have been documented, for example, in Seattle and Baltimore in the United States among injection drug users and in Marseille, France, and Burundi. Trench fever is also called Wolhynia fever, shin bone fever, Meuse fever, His disease and His–Werner disease or Werner-His disease (after Wilhelm His Jr. and Heinrich Werner). The disease is caused by the bacterium Bartonella quintana (older names: Rochalimea quintana, Rickettsia quintana), found in the stomach walls of the body louse. Bartonella quintana is closely related to Bartonella henselae, the agent of cat scratch fever and bacillary angiomatosis.
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Genetic analysis suggests that the human body louse, which lives in clothing, may only have diverged from the head louse some 170,000 years ago, which supports evidence that humans began wearing clothing at around this time. These estimates predate the first known human exodus from Africa, although other hominid species who may have worn clothes – and shared these louse infestations – appear to have migrated earlier. Sewing needles have been dated to at least 50,000 years ago (Denisova Cave, Siberia) – and uniquely associated with a human species other than modern humans, i.e. H. Denisova/H. Altai.
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Rickettsia prowazekii is a species of gram-negative, alphaproteobacteria, obligate intracellular parasitic, aerobic bacillus bacteria that is the etiologic agent of epidemic typhus, transmitted in the feces of lice. In North America, the main reservoir for R. prowazekii is the flying squirrel. R. prowazekii is often surrounded by a protein microcapsular layer and slime layer; the natural life cycle of the bacterium generally involves a vertebrate and an invertebrate host, usually an arthropod, typically the human body louse. A form of R. prowazekii that exists in the feces of arthropods remains stably infective for months.
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Typhus is a group of infectious bacterial diseases often spread through lice, fleas, and mites. Typhus fever, spread by the body louse, had ravaged both the military and civilian populations of Eastern Europe throughout WWI and continued to plague the European populace. While no typhus vaccine was available at the beginning of WWII, there had been promising research by the United States Public Health Service and the Harvard School of Public Health. At Connaught Laboratories, James Craigie launched a federally supported research program in July 1940 seeking to build on these findings.
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Despite this, the modern view is that only the body louse can transmit the disease. Detail showing delousing from Jan Siberechts' painting Cour de ferme ("Farmyard"), 1662 Soldiers in the trenches of the First World War suffered severely from lice, and the typhus they carried. The Germans boasted that they had lice under effective control, but themselves suffered badly from lice in the Second World War on the Eastern Front, especially in the Battle of Stalingrad. "Delousing" became a euphemism for the extermination of Jews in concentration camps such as Auschwitz under the Nazi regime.
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The nymph will molt three times after hatching and after the third molt, it has developed into an adult louse. The nymph developing into an adult louse usually takes 9-12 days after hatching. # The adult body louse is about the size of a sesame seed (2.5–3.5 mm), has six legs, wingless and is tan to grayish-white. After the final molt, female and male lice can mate immediately and since the louse typically lives for 20 days before dying, mating is crucial in order to increase their population size.
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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 may 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.
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However, it turned out that the human pubic louse does not descend from the ancestral human louse, but from the gorilla louse, diverging 3.3 million years ago. This suggests that humans had lost body hair (but retained head hair) and developed thick pubic hair prior to this date, were living in or close to the forest where gorillas lived, and acquired pubic lice from butchering gorillas or sleeping in their nests. The evolution of the body louse from the head louse, on the other hand, places the date of clothing much later, some 100,000 years ago. The soft, fine hair found on many nonhuman mammals is typically called fur.
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B. recurrentis, a common species underlying relapsing fever, is transmitted by the human body louse; no other animal reservoir of B. recurrentis is known. B. recurrentis infects the person via mucous membranes and then invades the bloodstream. Other tick-borne relapsing infections are acquired from other species, such as B. hermsii, B. parkeri, or B. miyamotoi, which can be spread from rodents, and serve as a reservoir for the infection, via a tick vector. B. hermsii and B. recurrentis cause very similar diseases, although the disease associated with B. hermsii has more relapses and is responsible for more fatalities, while the disease caused by B. recurrentis has longer febrile and afebrile intervals and a longer incubation period.
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After the war, he retired with the title of Generaloberst, practicing medicine in Berlin as a specialist of infectious diseases. Werner is remembered for his description of trench fever during an outbreak of the disease in World War I. The disorder is sometimes referred to as "Werner–His disease", named in conjunction with Swiss anatomist Wilhelm His, Jr., who also described the malady.Medicine Online: Werner–His diseaseWilhelm His Jr. at Who Named It The disease is caused by the parasite Rickettsia quintana, and transmitted to humans by the body louse Pediculus humanus corporis.Werner–His disease at Who Named It During his career, Werner published a number of articles on tropical and parasitic diseases.
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Indirect evidence of tailoring by Neanderthals includes the ability to manufacture string, which could indicate weaving ability, and a naturally-pointed horse metatarsal bone from Cueva de los Aviones, Spain, which was speculated to have been used as an awl, perforating dyed hides, based on the presence of orange pigments. Whatever the case, Neanderthals would have needed to cover up most of their body, and contemporary humans would have covered 80–90%. Since human/Neanderthal admixture is known to have occurred in the Middle East, and no modern body louse species descends from their Neanderthal counterparts (body lice only inhabit clothed individuals), it is possible Neanderthals (and/or humans) in hotter climates did not wear clothes, or Neanderthal lice were highly specialised.
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In some infestations, a characteristic grey-blue or slate coloration appears (maculae caeruleae) at the feeding site, which may last for several days. Crab louse egg on human body hair Current worldwide prevalence has been estimated at 2% of the human population, but accurate numbers are difficult to gauge because crab lice infestations are not considered a reportable condition by many governments, and many cases are self-treated or treated discreetly by primary physicians. It has been suggested that an increasing percentage of humans removing their pubic hair has led to reduced crab louse populations in some parts of the world.Bloomberg: Brazilian bikini waxes make crab lice endangered species, published 13 January 2013, retrieved 14 January 2013 Other lice that infest humans are the body louse and the head louse.
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