Wuchereria bancrofti

Revision as of 21:16, 30 July 2015 by Gerald Chi- (talk | contribs)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to navigation Jump to search
Wuchereria bancrofti
Microfilaria of Wuchereria bancrofti, from a patient seen in Haiti. Thick blood smears stained with hematoxylin.
Microfilaria of Wuchereria bancrofti, from a patient seen in Haiti. Thick blood smears stained with hematoxylin.
Scientific classification
Kingdom: Animalia
Phylum: Nematoda
Class: Secernentea
Order: Spirurida
Suborder: Spirurina
Family: Filarioidea
Genus: Wuchereria
This page is about microbiologic aspects of the organism(s).  For clinical aspects of the disease, see Filariasis.

WikiDoc Resources for Wuchereria bancrofti

Articles

Most recent articles on Wuchereria bancrofti

Most cited articles on Wuchereria bancrofti

Review articles on Wuchereria bancrofti

Articles on Wuchereria bancrofti in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Wuchereria bancrofti

Images of Wuchereria bancrofti

Photos of Wuchereria bancrofti

Podcasts & MP3s on Wuchereria bancrofti

Videos on Wuchereria bancrofti

Evidence Based Medicine

Cochrane Collaboration on Wuchereria bancrofti

Bandolier on Wuchereria bancrofti

TRIP on Wuchereria bancrofti

Clinical Trials

Ongoing Trials on Wuchereria bancrofti at Clinical Trials.gov

Trial results on Wuchereria bancrofti

Clinical Trials on Wuchereria bancrofti at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Wuchereria bancrofti

NICE Guidance on Wuchereria bancrofti

NHS PRODIGY Guidance

FDA on Wuchereria bancrofti

CDC on Wuchereria bancrofti

Books

Books on Wuchereria bancrofti

News

Wuchereria bancrofti in the news

Be alerted to news on Wuchereria bancrofti

News trends on Wuchereria bancrofti

Commentary

Blogs on Wuchereria bancrofti

Definitions

Definitions of Wuchereria bancrofti

Patient Resources / Community

Patient resources on Wuchereria bancrofti

Discussion groups on Wuchereria bancrofti

Patient Handouts on Wuchereria bancrofti

Directions to Hospitals Treating Wuchereria bancrofti

Risk calculators and risk factors for Wuchereria bancrofti

Healthcare Provider Resources

Symptoms of Wuchereria bancrofti

Causes & Risk Factors for Wuchereria bancrofti

Diagnostic studies for Wuchereria bancrofti

Treatment of Wuchereria bancrofti

Continuing Medical Education (CME)

CME Programs on Wuchereria bancrofti

International

Wuchereria bancrofti en Espanol

Wuchereria bancrofti en Francais

Business

Wuchereria bancrofti in the Marketplace

Patents on Wuchereria bancrofti

Experimental / Informatics

List of terms related to Wuchereria bancrofti

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Wuchereria bancrofti is a parasitic filarial nematode worm spread by a mosquito vector. It is one of the three parasites that cause lymphatic filariasis. Named for Otto Wucherer and Joseph Bancroft, it affects over 120 million people, primarily in Africa, South America, and other tropical and sub-tropical countries. Elephantiasis can result if the infection is left untreated. Limited treatment modalities exist and no vaccines have been developed.

File:Filariasis 01.png
Life cycle of Wuchereria bancrofti
File:Armigeres subalbatus mosquito.jpg
An Armigeres subalbatus mosquito ingesting a blood meal from a human finger

W. bancrofti carry out their life cycle in two hosts. Human beings serve as the definitive host and mosquitoes as their intermediate hosts. The adult parasites reside in the lymphatics. They are viviparous. The first stage larvae are known as microfilariae. The microfilaria are present in the circulation. The microfilaria migrate between the deep and the peripheral circulation. During the day they are present in the deep veins and during the night the migrate to the peripheral circulation. Next, the worm is transferred into a vector; the most common vectors are the mosquito species: Culex, Anopheles, Aedes, and Mansonia. Inside their second host, it matures into motile larvae. When its current host feeds, and it is egested into the blood stream of its new human host. The larvae moves to the lymph nodes, predominantly in the legs and genital area, and develops into adult worm over the course of a year. By this time, an adult female can produce microfilariae itself.

W. bancrofti displays a large size gap between the male and female—a difference known as sexual dimorphism. The adult male worm is long and slender, between four and five centimeters in length, a tenth of a centimeter in diameter, and features a curved tail. The female, in contrast, is six to ten centimeters long, and three times larger in diameter than the male. This size deviation can be attributed to the vast numbers of microfilariae that the female produces each day.

The onset of symptoms is slow, but the effects are very apparent after several years. During the initial inflammatory stage, a host can exhibit swelling, granulation lesions, and impaired circulation. Following, the lymph nodes are enlarged and dilated. They become hardened and clogged with fibrous tissue, and this prevents the lymphatic system from operating correctly. The microfilariae also cause swelling, thickening, and discolouration of the skin. Without the proper drainage of fluids, the affected tissue will expand and elephantiasis, a gross expansion of body, will result, followed sometimes by death.

The parasite's severe symptoms can be avoided by the use of therapeutic drugs. Both diethylcarbamazine and sodium caparsolate are used to kill the worms and their microfilariae. Diethylcarbamazine is most commonly used and is administered orally. Protection is similar to that of other mosquito spread illnesses; one can use barriers both physical (a mosquito net) and chemical (insect repellent).

Trivia

References

References