関: Onchocerciasis

-回旋糸状虫

WordNet

abnormal twisting of the intestines (usually in the area of the ileum or sigmoid colon) resulting in intestinal obstruction

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/04/22 20:58:08」(JST)

wiki en

[Wiki en表示]

Onchocerca volvulus is a nematode that causes onchocerciasis or "river blindness" mostly in Africa. Long-term corneal inflammation, or keratitis, leads to thickening of the corneal stroma which ultimately leads to blindness. Humans are the only definitive host for O. volvulus. The intermediate host or vector is the black fly (Simulium).

O. volvulus, along with most filarial nematodes, share an endosymbiotic relationship with the bacterium Wolbachia. In the absence of Wolbachia, larval development of the O. volvulus is disrupted or ceased.

The life cycle of O. volvulus

The life cycle of O. volvulus begins when a parasitised female black fly of the genus Simulium takes a blood meal. The microfilariae form of the parasite found in the dermis of the host is ingested by the black fly. Here the microfilariae then penetrates the gut and migrates to thoracic flight muscles of the black fly, entering its first larval phase (J₁). After maturing into J₂, the second larval phase, it migrates to the proboscis where it can be found in the saliva. Saliva containing stage three (J_3S) O. volvulus larvae passes into the blood of the host. From here the larvae migrate to the subcutaneous tissue where they form nodules and then mature into adult worms over a period of six to twelve months. After maturation, the smaller adult males migrate from nodules to subcutaneous tissue where they mate with the larger adult females, which then produce between 1,000 and 3,000 microfilariae per day. The normal adult worm lifespan is up to fifteen years. The eggs mature internally to form stage one microfilariae, which are released from the female's body one at a time and remain in the subcutaneous tissue.

These stage one microfilariae are taken up by black flies upon a blood meal, in which they mature over the course of one to three weeks to stage three larvae, thereby completing the life cycle.

The normal microfilariae lifespan is 1–2 years; however, their presence in the bloodstream causes little or no immune response until death or degradation of the microfilariae or adult worms.

O. volvulus has been proposed as the causative agent of nodding syndrome, a condition that affects children aged 5 to 15 and is currently only observed in South Sudan, Tanzania and northern Uganda. Although the cause of the disease is unknown, O. volvulus is being increasingly studied as a possible cause due to its ubiquity in areas where the disease is found.^[1] Nodding syndrome causes children to nod violently while eating; it has been described as an unusual form of epilepsy.

References

Saint André Av, Blackwell NM, Hall LR; et al. (March 2002). "The role of endosymbiotic Wolbachia bacteria in the pathogenesis of river blindness". Science 295 (5561): 1892–5. doi:10.1126/science.1068732. PMID 11884755.

^ Abraham, Curtis. "Mysterious nodding syndrome spreading through Uganda". New Scientist. Retrieved 2016-03-29.

External links

"Onchocerca volvulus". NCBI Taxonomy Browser. 6282.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. オンコセルカ症 onchocerciasis
2. 中央アフリカへの旅行によって感染する可能性のある疾患 diseases potentially acquired by travel to central africa
3. Acquired hypopigmentation disorders other than vitiligo
4. ロア糸状虫症（ロア糸状虫感染） loiasis loa loa infection
5. リンパ管フィラリア症の診断、治療、および予防 diagnosis treatment and prevention of lymphatic filariasis

English Journal

Modelling Neglected Tropical Diseases diagnostics: the sensitivity of skin snips for Onchocerca volvulus in near elimination and surveillance settings.

Bottomley C1, Isham V2, Vivas-Martínez S3, Kuesel AC4, Attah SK5, Opoku NO6, Lustigman S7, Walker M8, Basáñez MG8.
Parasites & vectors.Parasit Vectors.2016 Jun 14;9(1):343. doi: 10.1186/s13071-016-1605-3.
BACKGROUND: The African Programme for Onchocerciasis Control has proposed provisional thresholds for the prevalence of microfilariae in humans and of L3 larvae in blackflies, below which mass drug administration (MDA) with ivermectin can be stopped and surveillance started. Skin snips are currently
PMID 27301567

Analysis of age-dependent trends in Ov16 IgG4 seroprevalence to onchocerciasis.

Golden A1, Faulx D1, Kalnoky M1, Stevens E1, Yokobe L1, Peck R1, Karabou P2, Banla M3, Rao R4, Adade K2, Gantin RG3, Komlan K3, Soboslay PT3,5, de Los Santos T1, Domingo GJ6.
Parasites & vectors.Parasit Vectors.2016 Jun 13;9(1):338. doi: 10.1186/s13071-016-1623-1.
BACKGROUND: Diagnostics provide a means to measure progress toward disease elimination. Many countries in Africa are approaching elimination of onchocerciasis after successful implementation of mass drug administration programs as well as vector control. An understanding of how markers for infection
PMID 27296630

Does Increasing Treatment Frequency Address Suboptimal Responses to Ivermectin for the Control and Elimination of River Blindness?

Frempong KK1, Walker M2, Cheke RA3, Tetevi EJ4, Gyan ET4, Owusu EO5, Wilson MD1, Boakye DA1, Taylor MJ6, Biritwum NK7, Osei-Atweneboana M4, Basáñez MG2.
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.Clin Infect Dis.2016 Jun 1;62(11):1338-47. doi: 10.1093/cid/ciw144. Epub 2016 Mar 21.
BACKGROUND: Several African countries have adopted a biannual ivermectin distribution strategy in some foci to control and eliminate onchocerciasis. In 2010, the Ghana Health Service started biannual distribution to combat transmission hotspots and suboptimal responses to treatment. We assessed the
PMID 27001801

Japanese Journal

Analysis of Wuchereria bancrofti infections in a village community in northern Nigeria: Increased prevalence in individuals infected with Onchocerca volvulus

ENGELBRECHT Fred,OETTL Tobias,HERTER Ursula,LINK Claudia,PHILIPP Diana,EDEGHERE Henry,KALIRAJ P,ENWEZOR Felicia
Parasitology international : official journal of the Japanese Society of Parasitology 52(1), 13-20, 2003-03-01
NAID 50000738987

Molecular cloning of an alpha-enolase from the human filarial parasite Onchocerca volvulus that binds human plasminogen

JOLODAR A
Biochim. Biophys. Acta 1627, 111-120, 2003
NAID 80016042467

Development of a recombinant antigen vaccine against infection with the filarial worm Onchocerca volvulus

ABRAHAM D.
Infect. Immun. 69, 262-270, 2001
NAID 30020828862

Related Pictures

★リンクテーブル★

リンク元	「O. volvulus」
関連記事	「Onchocerca」「volvulus」

「O. volvulus」

Onchocerca volvulus
	O. volvulus, the causative agent of river blindness
Scientific classification
Kingdom:	Animalia
Phylum:	Nematoda
Class:	Secernentea
Order:	Spirurida
Family:	Onchocercidae
Genus:	Onchocerca
Species:	O. volvulus
Binomial name
	Onchocerca volvulus; Bickel, 1982

　　[★]

回旋糸状虫

関: Onchocerca volvulus

「Onchocerca」

　　[★]

回旋糸状虫類、オンコセルカ、ンコセルカ属、Onchocerca属

「volvulus」

　　[★] 腸軸捻転

latin volvere 'to roll'

[1] Abraham, Curtis. "Mysterious nodding syndrome spreading through Uganda". New Scientist. Retrieved 2016-03-29.

匿名

検索

案内

案内

Onchocerca volvulus