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Lice
Louse (: lice) is the common name for any member of the infraorder Phthiraptera, which contains nearly 5,000 species of wingless parasitic insects. Phthiraptera was previously recognized as an order, until a 2021 genetic study determined that they are a highly modified lineage of the order Psocodea, whose members are commonly known as booklice, barklice or barkflies. Lice are obligate parasites, living externally on warm-blooded hosts, which include every species of bird and mammal, except for monotremes, pangolins, and bats. Chewing lice live among the hairs or feathers of their host and feed on skin and debris, whereas sucking lice pierce the host's skin and feed on blood and other secretions. 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 lou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Head Louse
The head louse (''Pediculus humanus capitis'') is an obligate parasite, obligate parasitism, ectoparasite of humans. Head lice are wingless insects that spend their entire lives on the human scalp and feed exclusively on human blood. Humans are the only known host (biology), hosts of this specific parasite, while Common chimpanzee, chimpanzees and bonobos host a closely related species, ''Pediculus schaeffi''. Other species of lice infest most orders of mammals and all orders of birds. 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 norm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anoplura
Sucking lice (known scientifically as Anoplura) are a parvorder of around 550 species of lice. All sucking lice are blood-feeding ectoparasites of mammals. They can cause localized skin irritations and are vectors of several blood-borne diseases. 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. Classification Sucking lice are classified as a parvorder called Anoplura, named by Leach in 1815. Anoplura belongs to the infraorder Phthiraptera, which contains all lice, and is part of the larger order Psocodea, which also con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Louse
The body louse (''Pediculus humanus humanus'', also known as ''Pediculus humanus corporis'') or the cootie is a hematophagic ectoparasite louse that infests humans. It is one of three lice which infest humans, the other two being the head louse, and the crab louse or pubic louse. Body lice may lay eggs on the host's hairs and clothing, but clothing is where the majority of eggs are usually secured. Since body lice cannot jump or fly, they spread by direct contact with another person or more rarely by contact with clothing or bed sheets that are infested. Body lice are disease vectors and can transmit pathogens that cause human diseases such as epidemic typhus, trench fever, and relapsing fever. In developed countries, infestations are only a problem in areas of poverty where there is poor body hygiene, crowded living conditions, and a lack of access to clean clothing. Outbreaks can also occur in situations where large groups of people are forced to live in unsanitary c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pubic Louse
The crab louse or pubic louse (''Pthirus pubis'') is an insect that is an obligate ectoparasite of humans, feeding exclusively on blood. The crab louse usually is found in the person's pubic hair. Although the louse cannot jump, it can also live in other areas of the body that are covered with coarse hair, such as the perianal area, the general body hair, and the eyelashes (in children). Humans are the only known hosts of the crab louse, although a closely related species, '' Pthirus gorillae'', infects gorillas. The human parasite is thought to have diverged from ''Pthirus gorillae'' approximately 3.3 million years ago. It is more distantly related to the genus '' Pediculus'', which contains the human head and body lice and lice that affect chimpanzees and bonobos. Description 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 distinguishi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ischnocera
Ischnocera is a large parvorder of lice from the infraorder Phthiraptera. The parvorder consists of Mallophaga, chewing lice, which feed on the feathers and skin debris of birds. Many species of Ischnocera have evolved an elongated body shape. This allows them to conceal themselves within plumage to avoid being dislodged during preening or flight. Species in Ischnocera spend their entire lives living on a host, and attach themselves to Hippoboscidae, hippoboscid flies to help move across individual birds. Ischnocera contains the large family (biology), family Philopteridae, along with a few other minor families. Ischnocera are distributed globally, with around 3,800 species identified. The lice are very host-specific, and each species rarely parasitizes outside of their preferred bird species. Birds infested by Ischnocera's species can experience discomfort and damage to reproductive systems. Classification Ischnocera previously included the mammalian parasitic lice Trichodectera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amblycera
Amblycera is a parvorder of chewing lice from the infraorder Phthiraptera. The lice are ectoparasites and spend their entire lives parasitizing their hosts. Amblycera tend to mostly feed on birds, and have specialized anatomy to assist in feeding. The lice undergo a three part process of metamorphosis and survive around thirty days after moulting into an adult. They rely on a combination of skin debris and blood for nutrients to sustain themselves. Amblycera are distributed globally, and are very host–specific. Classification Amblycera is currently classified as a parvorder, and it was named by Kellogg in 1896. Amblycera belongs to the infraorder Phthiraptera, which contains all lice, and is part of the larger order Psocodea, which also contains booklice, barklice and barkflies. Around 30% of all bird lice belong to Amblycera. A cladogram showing the position of Amblycera within Phthiraptera and Psocodea is shown below: Characteristics Like all chewing lice, Amblycera are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psocodea
Psocodea is a taxonomic group of insects comprising the bark lice, book lice and parasitic lice. It was formerly considered a superorder, but is now generally considered by entomologists as an order. Despite the greatly differing appearance of parasitic lice (Phthiraptera), they are believed to have evolved from within the former order Psocoptera, which contained the bark lice and book lice, now found to be paraphyletic. They are often regarded as the most primitive of the hemipteroids. Psocodea contains around 11,000 species, divided among four suborders and more than 70 families. They range in size from 1–10 millimetres (0.04–0.4 in) in length. The species known as booklice received their common name because they are commonly found amongst old books—they feed upon the paste used in binding. The barklice are found on trees, feeding on algae and lichen. Anatomy and biology Psocids are small, scavenging insects with a relatively generalized body plan. They feed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasitic
Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson characterised parasites' way of feeding as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the broomrapes. There are six major parasitic strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), trophicallytransmitted parasitism (by being eaten), vector-transmitted parasitism, parasitoidism, and micropredation. One major axis of classification concerns invasiveness: an endopar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Typhus
Typhus, also known as typhus fever, is a group of infectious diseases that include epidemic typhus, scrub typhus, and murine typhus. Common symptoms include fever, headache, and a rash. Typically these begin one to two weeks after exposure. The diseases are caused by specific types of bacterial infection. Epidemic typhus is caused by '' Rickettsia prowazekii'' spread by body lice, scrub typhus is caused by '' Orientia tsutsugamushi'' spread by chiggers, and murine typhus is caused by '' Rickettsia typhi'' spread by fleas. Vaccines have been developed, but none is commercially available. Prevention is achieved by reducing exposure to the organisms that spread the disease. Treatment is with the antibiotic doxycycline. Epidemic typhus generally occurs in outbreaks when poor sanitary conditions and crowding are present. While once common, it is now rare. Scrub typhus occurs in Southeast Asia, Japan, and northern Australia. Murine typhus occurs in tropical and subtropi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhynchophthirina
The genus ''Haematomyzus'' includes three species of lice that differ so markedly from all other lice that the genus is placed in its own family Haematomyzidae, itself monotypic within the parvorder Rhynchophthirina (previously ranked as a superfamily). These unusual lice are ectoparasites of elephants and warthogs. Their mouthparts are elongated to form a drill-like structure that allows them to penetrate the thick skin of their host. Taxonomy The three species, '' Haematomyzus elephantis'' (elephant louse), '' Haematomyzus hopkinsi'' (warthog louse) and '' Haematomyzus porci'' ( red river hog louse) belong to a single family, the Haematomyzidae, itself the only family within Rhynchophthirina. Rhychophthirina is a parvorder within the infraorder Phthiraptera. A molecular phylogenetic study using subunit rRNA sequences suggests a placement of the Rhychophthirina as a sister group of the Anoplura. Below is a cladogram showing the position of Rhychophthirina within Phthiraptera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insect
Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, Thorax (insect anatomy), thorax and abdomen (insect anatomy), abdomen), three pairs of jointed Arthropod leg, legs, compound eyes, and a pair of antenna (biology), antennae. Insects are the most diverse group of animals, with more than a million described species; they represent more than half of all animal species. The insect nervous system consists of a insect brain, brain and a ventral nerve cord. Most insects reproduce Oviparous, by laying eggs. Insects Respiratory system of insects, breathe air through a system of Spiracle (arthropods), paired openings along their sides, connected to Trachea#Invertebrates, small tubes that take air directly to the tissues. The blood therefore does not carry oxygen; it is only partly contained in ves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
