Wuchereriasis and Brug's filariasis

Wuchereriasis and Brug's filariasis - chronically proceeding helminthiases - characterised in an initial stage a fever, a lymphadenitis, a retrograde lymphangitis of extremities, an orchitis, a funiculitis and abscesses basically the allergic nature, and also development of an elephantiasis of extremities and thoracal glands, chylurias or the hydrocele.

Aetiology. Wuchereriasis originators - Wuchereria bancrofti, a Brug's filariasis - Brugia inalayi - helminths - the nematodes having the extended threadlike form with attenuations on the extremities. Length of parasites of 22-100 mm, width of 0,1-0,3 mm. Development of filarias descends to change of masters, definitive master Brugiainalayi - the human and some kinds of monkeys, mediate masters - various kinds of mosquitos of sorts Culex, Aedes, Mansonia, Anopheles. Puberal filarias parasitize in lymph nodes and pots.

Females of a helminth bear larvas - microfilarias which in a human body morphologicallies do not vary and do not grow. Microfilarias have length of 0,127-0,32 mm, width - 0,005-0,1 mm. They parasitize in vascular system. On the terminology accepted by Committee of experts on filariases a WHO, distinguish periodical and subperiodical strains of microfilarias. Microfilarias Wuchereria bancrofti the periodic strain (Microfilaria nocturna) are in pots of lungs in the afternoon, and move ahead in peripheric pots at night. Microfilarias Wuchereria bancrofti the subperiodical strain taped in region of Pacific ocean and consequently received name W. pacifica, are in peripheric blood round the clock, but in the afternoon their number considerably increases. Periodical strain Brugia inalayi is inherent only to the human while the subperiodical meets and at monkeys. Both strains Brugia inalayi are characterised by night peak of a microfilaremia which at the periodical strain meets much less often.

Adult filarias are capable to parasitize in a human body long time (to 12, and according to some information ѕ till 17 years), microfilarias - near 12 months.

Epidemiology. A wuchereriasis source is the sick human or a parasitifer, a Brug's filariasis source - the human and some monkeys. Immediate transmitting agents of an infection contamination are mosquitos.

The originator of wuchereriasis Wuchereria bancrofti is transferred by many kinds of mosquitos, is the most frequent Culex fatigans, C. pipiens, Aedes polynesiensis. The Brug's filariasis originator (Brugia malayi) is tolerated by various kinds of mosquitos of sorts Mansonia and Anopheles. Development of microfilarias in mosquitos proceeds 8-35 days depending on external environment temperature. At a mosquito puncture invasion forms of microfilarias get to a skin, activly take root into a vascular bed and by a blood flow are brought in a tissue. Metamorphosis of microfilarias into puberal forms descends later 3-18 months after their hit in a human body.

The wuchereriasis is precinctive for a number of the countries of Africa, Asia, meets in India, China, Japan, Central and the South America, on islands of Silent and Indian oceans.

The Brug's filariasis is extended in the countries of Asia: in India, on an island Ceylon, in Thailand, Vietnam, Laos, Cambodia, China, Japan, Indonesia, Malaysia.

Pathogenesis. At the heart of a wuchereriasis and Brug's filariasis pathogenesis toksiko-allergic reactions, mechanical influence of helminths to lymphatic system and a secondary bacteriemic infection contamination lay. As well as many other things helminthiases, a wuchereriasis and a Brug's filariasis in some cases can not give the expressed clinical picture. Sometimes there are in general no clinical implications of an invasion. The asymptomatic wuchereriasis or a Brug's filariasis take place when parasites do not cork absorbent vessels and do not cause inflammatory changes in surrounding tissues. Patients with such forms of an infection contamination are taped casually at detection at them microfilarias in peripheric blood.

Wuchererias and Bruges in absorbent vessels including in a thoracal duct, are weaved among themselves into balls which cause retardation of a lymph flow and a lymphostasis. Parasites cause inflammatory inspissation of sides of absorbent vessels, that, finally, conducts to an occlusion of pots as a result of a stenosis or a clottage. The thrombosed absorbent vessels burst often. Because of long lymphangites and lymphadenites in various parts of a body the elephantiasis (elephantiasis) can educe. The variated endothelium of absorbent vessels, the locuses of necrosises in lymph nodes and surrounding tissues are congenial places for development of a coccal infection contamination with formation of abscesses. As a result of vital activity of parasites and, especially at their disintegration materials which conduct to a sensibilization of an organism with aboriginal and general allergic responses - an eosinophilia, are formed by dermal rashes, etc.

Symptoms and flow. Allergic implications can educe approximately in 3 months after a becoming infected. Microfilarias are taped in blood not earlier than in 9 months. Disease begins with various allergic implications. On a skin, especially on arms, there are painful elements of a type of an exudative erythema, lymph nodes in inguinal ranges are enlarged, on a neck and in axillary recesses, often there are painful lymphangites, a funiculitis, an orchiepididymitis, a synovitis with an outcome in a false ankylosis, at women - a mastitis. At long relapsing flow of a funiculitis and an orchiepididymitis there is a hydrocele. The fever is characteristic, the bronchial asthma and a bronchopneumonia quite often educe. In 2-7 years after infestation disease enters the second stage which is characterised basically by lesions of dermal and deep absorbent vessels with development of varicose dilating, lymph flow disturbance, breakages of these pots. There are painful lymphangites with a regional lymphadenitis. At this time within several days at the patient the expressed phenomena of the general intoxication against a heat of a body and strong headaches become perceptible. Vomiting is often observed, the delirious condition sometimes educes. The attack usually comes to an end with an abundant diaphoresis. As a result of breakages of absorbent vessels the efflux of a lymph and reduction of intensity of a lymphadenitis is observed.

Phases of relative well-being are periodically replaced by the next exacerbations of disease. On a place of lymphangites there are the dense bands, the struck lymph nodes also are exposed to fibrous inspissation. The augmentation of inguinal and femoral lymph nodes Initial swelling of lymph nodes of a pain is characteristic does not cause, however at the subsequent development of lymphangites there are strong pains in ganglions. The lesion can be one-or bilateral, the dimensions of ganglions from small to 5-7 sm in diameter. Often in parallel educe a so-called lymphoscrotum (a chyle impregnation tunica vaginalis) and a chyluria. The lymphoscrotum clinically shows scrotum augmentation. At a palpation of a skin of a scrotum amplate absorbent vessels are easily defined. At breakages of these pots the considerable quantity of quickly coagulated lymph follows. The efflux of a lymph from damaged pots can proceed some hours.

In the countries of the North Africa, India and China at sick the chyluria or a lymphuria meets a wuchereriasis or a Brug's filariasis often. The patient notices, that urine has got a milky-white shade. In some cases urine becomes pink or even red, sometimes it happens white in the morning and red in the evening or on the contrary. Presence at blood urine along with a lymph speaks, obviously, breakages of fine vascular amplate absorbent vessels. Microfilarias are taped in urine only at night. Sometimes it is preceded by small pains over a pubis or in inguinal ranges. The ischuria owing to coagulation of a lymph and formation of flakes in urinary pathes is characteristic. At a lymphuria in urine there is an admixing of a lymph, a protein in a significant amount, the blood admixing is possible, but there are no Adeps traces. In an urocheras lymphocytes are found.

Bodies of the lost filarias usually completely resolve or calcine. However in some cases the lost parasites are the cause of development of abscesses which lead to serious complications, such as an empyema, a peritonitis, a purulent inflammation of genitals.

In connection with damage of sides of absorbent vessels at a wuchereriasis microbes can get to surrounding tissues and in blood that can lead to sepsis development. In blood of such patients the hemolitic streptococcus is often found.

The third (obstructive) stage of disease is characterised by an elephantiasis. In 95 % of cases the elephantiasis of the inferior extremities educes, is a little bit rarer the-top extremities, the generative organs, separate fields of a trunk and is very rare persons. Clinically the elephantiasis shows quickly progressing lymphangitis with apposition of a dermatitis, a cellulitis in a combination to a fever which can serve in some cases as the basic symptom of disease and is a consequence of apposition of a bacteriemic infection contamination. The skin becomes covered in due course by warty and papillomatous growths, there are fields an eczema of similar change of a skin, not healing ulcers. Feet can reach the huge dimensions, they take a form of shapeless blocks with thick cross-section cords of the struck skin. The scrotum weight usually compounds 4-9 kg, and on occasion to 20 kg, the case when the weight of a scrotum at the patient has reached 102 kg is described. In case of an elephantiasis of the person the upper eyelid is more often amazed. At a Brug's filariasis the elephantiasis arises usually only on extremities, a lesion more often secund, the skin remains smooth.

The diagnosis and the differential diagnosis of a wuchereriasis and Brug's filariasis is based on epidemiological data and a characteristic clinical picture of disease (allergic implications in an early stage of disease, a lesion of lymphatic system and, at last, elephantiasis development in the third stage of disease).

Diagnosis final confirmation is detection of microfilarias in blood. For analysis it is necessary to take blood at the night. At suspicion on invasion W. pacifica blood for analysis is better to take in the afternoon (diurnal peak filariemia). At viewing under cover glass of a fresh drop of blood at small augmentation of a microscope mobile microfilarias are easily taped. For an establishment of a kind of microfilarias blood preparations (smears or drops), imbued on Romanovsky are investigated. In the third stage of disease concentration of microfilarias in blood is insignificant. In these cases resort to enrichment methods (Bell's to filtration or concentration). One ml of a venous blood is led in 9 ml of solution of formalin by of 2 % on the distilled water, centrifuge 3-5 mines and the received deposit investigate an admixture under a microscope. More complex enrichment methods are used also. At a microfilaria chyluria sometimes it is possible to tap in urine. Intradermal allergy test with an antigen from Dirofilariaimitis (filariates dogs), the reaction of binding complement and an agglutination test with the adsorbed antigens are not strictly specific.