Filariose de Bancroft

The lymphatic filariose is a Tropical disease, infectious and more precisely parasitic caused by parasitic worms of the telegraphic kind, Wuchereria bancrofti, Brugia malayi, and Brugia timori, all transmitted by the Moustique S. It is an extremely rare affection in the Western countries. leasing leasing is another human telegraphic parasite, transmitted by the flies.

The most spectacular symptom of the lymphatic filariose is the elephantiasis which causes a thickening of the skin and fabrics under cutaneous. It was the first disease transmitted by insects to being discovered. Elephantiasis occurs when the parasites invade the lymphatic Système.

History

In 1866, Otto Wucherer proved the presence of Microfilaire S or telegraphic Larves, in the Urine. In 1871, Timoth Lewis discovered the presence of microfilaires in peripheral blood; later, in 1876, Joseph Bancroft discovers the adult shape of the parasite. Finally in 1878, Patrick Manson observes the development of W.bancrofti in the mosquitos.

Cycle parasite

W.bancrofti carries out its parasitic cycle at two host S. the beings the Human ones play the part of final hosts and the intermediate mosquitos that of hosts. At the adulthood the parasites resident in the vessels Lymphatique S. They are Vivipares. The larvae of the first stage are known under the name of Microfilaire S. the microfilaires are present in the circulatory Système. The microfilaires migrate between major circulation and peripheral circulation. During the day they are in the deep veins and during the night they migrate towards peripheral circulation. Then, the worm is transferred in a vector. the most common vectors are species of mosquito: Culex , anophèles , Aedes and Mansonia . Inside their second host, it matures to become a mobile Larve. When its usual host nourishes himself, and it is projected in the blood current of its new human host. The larvae move towards the ganglia of the system Lymphatique, mainly in the lower extremities and the genitals, and transform themselves into adult worm at the end of one year. At this time, an adult female will be able to give itself birth to microfilaires.

W.bancrofti presents a great difference in size between the male and female. This differentiation is known under the name of sexual Dimorphisme. The adult male worm is long and thin and measures between four and five centimetres length, a tenth centimetre in diameter, and has a curved tail. The female, on the other hand, is long from six to ten centimetres, and has a diameter three times larger than the male. This difference in size can be explained by the great number of microfilaires why the female eliminates each day.

Geographical distribution

The filariose is endemic in the tropical areas of Asia, of Africa, Central America and South America with 120 million infected people.

In certain endemic areas of the world (for example, Malaipea in Indonesia), up to 54% of the population can have microfilaires in their blood.

Clinical signs

The beginning of the symptoms is progressive, but the effects are very apparent at the end of several years. During the initial inflammatory stage, a host can present edema, wounds, and circulatory troubles. Then, the lymphatic ganglia are inflated and dilated. are hardened and blocked by fibrous fabric, and that prevents the lymphatic system from functioning correctly. The microfilaires also cause swelling, thickening, and the discoloration of the Peau. Without suitable drainage of the blood fluids and lymph, the affected fabric will inflate and it will result from it a elephantiasis, a monstrous dilation of the body which can sometimes lead to death.

Elephantiasis affects mainly the lower ends, whereas the Oreille S and the Muqueuse S are seldom affected; however, that depends on the species on telegraphic. W.bancrofti can touch the legs, the arms, the vulva, the centres, whereas Brugia timori seldom reaches the genitals. The infection by Onchocerca volvulus and the migration of its microfilaires through the Cornée are a frequent cause of blindness (Onchocercose).

Diagnosis

The diagnosis is made by identifying the microfliaires on a thick drop of blood after coloring of Giemsa. Blood must be taken the night, since the microfilaires circulate the night, when their vector, the mosquito, is most likely to prick.

There are also analyzes by PCR available for the diagnosis.

Treatment

The drugs used to treat the lymphatic filariose are more effective when they are used shortly after infection, but they have toxic side effects. Moreover, it is difficult to detect the disease at an early stage. Consequently, it is necessary to improve the treatments and the tests of laboratory.

The serious symptoms caused by the parasite can be avoided by the use of certain molecules. The Diéthylcarbamazine and the Caparsolate of sodium are used to kill the worms and their microfilaires. Diéthylcarbamazine is generally the product more used and is managed by oral way. Protection is comparable with that which is conferred for other diseases transmitted by the mosquitos; one can use at the same time physical barriers (Moustiquaire S) and chemical (Répulsif S).

Anecdotic

Joseph Merrick, " The Elephant Man " , was not reached by a parasitic worm, but by the Syndrome of Protée.

Refer

Oetinger, David. " Filaria." The World Book Encyclopedia. Chicago: World Book Inc. 2000.
" Elephantiasis." Human Diseases and Conditions. New York: Charles Scribner' S Sounds. 2000.
David F. Oetinger, " Filaria." World Book Online Refers Center. http://www.worldbookonline.com/ar?/na/ar/co/ar196440.htm, November 28,2003.
" Lymphatic filariasis." World Health Organization. http://www.who.int/ctd/filariasis/home/, November 28,2003.

External bonds

lymphatic courses filarioses
WHO Document of popularization
WHO Information memorandum
WHO Report/ratio filarioses

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