This article is about the animal. For the disease known as crab lice, see Pediculosis pubis.
| Crab louse |
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| Scientific classification |
| Kingdom: |
Animalia |
| Phylum: |
Arthropoda |
| Class: |
Insecta |
| Order: |
Phthiraptera |
| Suborder: |
Anoplura |
| Family: |
Pthiridae |
| Genus: |
Pthirus |
| Species: |
P. pubis |
| Binomial name |
Pthirus pubis
(Linnaeus, 1758) |
| Synonyms |
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Pediculus pubis Linnaeus, 1758
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The crab louse (Pthirus pubis, frequently misspelled as Phthirus pubis), also known as the pubic louse, is an insect that is an obligate ectoparasite of humans.[1] It is typically found in pubic hair, but may also live on other areas with hair, including the eyelashes. They feed exclusively on blood. Humans are the only known hosts of this parasite, although a closely related species, Pthirus gorillae, infects gorilla populations. The species passed to humans 3.3 million years ago.[2]
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Contents
- 1 Description
- 2 Life cycle
- 3 Infestation of humans
- 4 Epidemiology
- 5 See also
- 6 References
- 7 External links
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Description
An adult crab louse is about 1.3–2 mm long (rather 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 back two pairs of legs of a crab louse are much thicker than the front legs and are equipped with large claws.[3]
Life cycle
The eggs of the crab louse are laid on the coarse hairs of the genital and perianal regions of the human body. Crab lice may also be found on other areas of the body that have coarse and relatively sparse coverings of hair, such as the beard, moustache, eyelashes, underneath the arms. They do not generally occur on the finer hair of the scalp. The eggs hatch after 6–8 days, and the three nymphal stages last for a total of 10–17 days. Adults can live up to 30 days.[3]
Infestation of humans
Infestations of crab lice are known as pediculosis pubis or phthiriasis pubis (which, unlike the generic name of the louse, is spelled with a phth). Infestation of the eyelashes is referred to as pediculosis ciliaris or phthiriasis palpebrarum.[4]
The main symptom of infestation with crab lice is itching, usually in the pubic-hair area, resulting from hypersensitivity to louse saliva, which can become stronger over two or more weeks following initial infestation. In some infestations, a characteristic grey-blue or slate coloration appears (maculae caeruleae) at the feeding site, which may last for days.
Epidemiology
Current worldwide prevalence has been estimated at 2% of two human populations, 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 personal physicians.[5]
Crab lice usually infect a new host only by close contact between individuals, usually through sexual intercourse. Parent-to-child infestations are more likely to occur through routes of shared towels, clothing, beds or closets. For this reason, infection in a young child or teenager is not necessarily indicative of sexual abuse, although this possibility should be kept in mind.[6][7] Adults are more frequently infested than children. As with most sexually transmitted pathogens, they can only survive a short time away from the warmth and humidity of the human body.
Pubic lice are primarily spread through sexual intercourse. Therefore, all partners with whom the patient has had sexual contact within the previous 30 days should be evaluated and treated, and sexual contact should be avoided until all partners have successfully completed treatment and are thought to be cured. Because of the strong association between the presence of pubic lice and classic sexually transmitted infections (STIs), patients diagnosed with pubic lice should undergo evaluation for other STIs.
See also
- Body louse
- Head louse
- Integrated Taxonomic Information System
- List of cutaneous conditions
- List of parasites (human)
- Pediculosis
- Treatment of human head lice
References
- ^ Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. ISBN 1-4160-2999-0.
- ^ Weiss RA (10 February 2009). "Apes, lice and prehistory". J Biol 8 (2): 20. doi:10.1186/jbiol114. PMC 2687769. PMID 19232074. //www.ncbi.nlm.nih.gov/pmc/articles/PMC2687769/.
- ^ a b Service, Mike (2008). Medical Entomology for Students (4th ed.). Cambridge: Cambridge University Press. ISBN 978-0-521-70928-6.
- ^ Manjunatha NP, Jayamanne GR, Desai SP, Moss TR, Lalik J, Woodland A. Pediculosis pubis: presentation to ophthalmologist as phthriasis palpebrarum associated with corneal epithelial keratitis. Int. J. STD AIDS 2006; 17: 424-426
- ^ Anderson AL, Chaney E (February 2009). "Pubic lice (Pthirus pubis): history, biology and treatment vs. knowledge and beliefs of US college students". Int J Environ Res Public Health 6 (2): 592–600. doi:10.3390/ijerph6020592. PMC 2672365. PMID 19440402. //www.ncbi.nlm.nih.gov/pmc/articles/PMC2672365/.
- ^ Klaus S, Shvil Y, Mumcuoglu KY (March 1994). "Generalized infestation of a 3½-year-old girl with the pubic louse". Pediatr Dermatol 11 (1): 26–8. doi:10.1111/j.1525-1470.1994.tb00068.x. PMID 8170844.
- ^ Varela JA, Otero L, Espinosa E, Sánchez C, Junquera ML, Vázquez F (April 2003). "Phthirus pubis in a sexually transmitted diseases unit: a study of 14 years". Sex Transm Dis 30 (4): 292–6. doi:10.1097/00007435-200304000-00004. PMID 12671547. http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0148-5717&volume=30&issue=4&spage=292.
External links
- MedlinePlus Encyclopedia Pubic lice
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Sexually transmitted diseases and infections (STD/STI) (primarily A50–A64, 090–099)
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| Bacterial |
- Chancroid (Haemophilus ducreyi)
- Chlamydia/Lymphogranuloma venereum (Chlamydia trachomatis)
- Donovanosis or Granuloma Inguinale (Klebsiella granulomatis)
- Gonorrhea (Neisseria gonorrhoeae)
- Syphilis (Treponema pallidum)
- Ureaplasma infection (Ureaplasma urealyticum)
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| Protozoal |
- Trichomoniasis (Trichomonas vaginalis)
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| Parasitic |
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| Viral |
- AIDS (HIV-1/HIV-2)
- Cervical cancer, vulvar cancer & Genital warts (condyloma), Penile cancer, Anal cancer (Human papillomavirus (HPV))
- Hepatitis B (Hepatitis B virus)
- Herpes simplex (HSV1/HSV2)
- Molluscum contagiosum (MCV)
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General
inflammation |
- female
- Cervicitis
- Pelvic inflammatory disease (PID)
- male
- Epididymitis
- Prostatitis
- either
- Proctitis
- Urethritis/Non-gonococcal urethritis (NGU)
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noco/cong/npls, sysi/epon
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proc/asst, drug (G1/G2B/G3CD)
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noco/cong/tumr, sysi/epon
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Human lice and pediculosis
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| Species |
- Head louse
- Crab louse
- Body louse
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| Infestation |
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| Treatment |
- Nitpicking
- Pediculicide
- Lindane
- Permethrin
- Phenothrin
- Delphinium
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| Other terms of interest |
- Cooties
- Sucking louse
- Louse
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Infectious diseases – Parasitic disease: ectoparasitic infestation / arthropod (B85–B89, 132–134)
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| Insecta |
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Phthiraptera
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- Pediculus humanus corporis / Pediculus humanus capitis
- Pediculosis
- Head-louse infestation
- Pediculosis corporis
- Phthirus pubis
- Phthiriasis
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Hemiptera
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Diptera
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- Dermatobia hominis / Cordylobia anthropophaga (Myiasis)
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Siphonaptera
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- Tunga penetrans
- Tungiasis
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| Arachnida |
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Acariasis / mange mites)
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- Trombidiformes: Trombicula
- Trombiculosis
- Chigger bite
- Demodex brevis / Demodex folliculorum
- Demodicosis
- Demodex mite bite
- Pyemotes herfsi
- Cheyletiella
- Cheyletiellosis
- Sarcoptiformes: Sarcoptes scabiei
- Scabies
- Dermanyssus gallinae
- Liponyssoides sanguineus
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Ticks
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| Crustacea |
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Pentastomida
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- Linguatula serrata
- Linguatulosis
- Porocephalus crotali / Armillifer armillatus
- Porocephaliasis
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