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PubMed1986

[Wuchereria bancrofti: value of the diethylcarbamazine provocation test for the diurnal detection of microfilaria carriers].

Sixty-nine of 83 (83%) patients with circulating microfilariae of nocturnally periodic Wuchereria bancrofti were detected in daytime blood films following the one-time administration of diethylcarbamazine at a dose per patient of 1 +/- .25 mg/kg of body weight. This method of detecting microfilaria carriers in Haiti is recommended as a reasonably sensitive alternative when circumstances make it impossible to conduct a nighttime blood survey.

Adolescent↗
PubMed1987

Identification and partial characterization of a parasite antigen in sera from humans infected with Wuchereria bancrofti.

The purpose of this study was to identify and characterize soluble parasite antigens present in sera from humans infected with the filarial nematode Wuchereria bancrofti. Affinity chromatography and immunoblot methods were used to demonstrate a 200,000 m.w. circulating parasite antigen in sera from infected humans which corresponded to an antigen released by adult W. bancrofti during in vitro culture. Two monoclonal antibodies were produced to this antigen by immunizing mice with antigens from Dirofilaria immitis, a filarial parasite that is closely related to W. bancrofti, and screening cell fusion supernatants by enzyme immunoassay and counterimmunoelectrophoresis inhibition. The antibodies bound to a single repeated epitope (not phosphorylcholine) that was resistant to heat, acid, and protease treatments but sensitive to periodate oxidation. Immunoperoxidase studies showed that the epitope was concentrated in the cuticle and reproductive organs in D. immitis, and it was released in relatively large amounts by adult female D. immitis in vitro. The epitope is also present in antigens of other species of filarial and nonfilarial nematodes, but on the basis of preliminary studies, its presence in human serum appears to be specific for W. bancrofti infection.

Antibodies, Monoclonal↗
PubMed1986

Attempt to culture Wuchereria bancrofti in vitro.

Third-stage larvae of Wuchereria bancrofti recovered from laboratory raised Aedes togoi and Anopheles maculatus fed on a human volunteer were recovered by mass dissection methods and introduced into in vitro culture. LLC-MK2 cells were used as feeder cells, and the culture medium consisted of RPMI-1640 buffered with Hepes and sodium bicarbonate and supplemented with human AB serum. The third-stage larvae molted as early as 12 days and those surviving had all molted by 16 days. The fourth-stage parasites averaged in length from 1.4 mm to a maximum of 1.8 mm. Some larvae remained alive in culture as long as 40 days and while the worms were distorted in fixation, possible primodial cells of a spicule could be visualized in the rectal region. The cuticle also appeared to be separating in the posterior end. Although complete development was not achieved, it seems that with a continuing effort, success could be obtained using this culture system with feeder cells.

Aedes↗
PubMed1978

Ultrastructure of the anterior alimentary tract of infective-stage Wuchereria bancrofti (Nematoda: Filarioidea).

The anterior alimentary tract of infective-stage Wuchereria bancrofti is divided into the following segments: stoma or buccal capsule, muscular esophagus, glandular esophagus, esophageal-intestinal valve, and intestine. Invaginated external cuticle lines only the anterior stoma. External cuticle and esophageal lining are not continuous and are ultrastructurally distinct; the latter is compared morphologically to the amorphous component of elastin. The glandular esophagus is a composite structure of a stellate contractile epithelial core, surrounded by a sleeve of secretory epithelium. The glandular cytoplasm shows evidence of formation and release of dense secretory granules. At least 2 nerve cell bodies lie within the esophagus approximately 15 micrometer anterior to the esophageal-intestinal valve and their associated processes pass forward and backward through the contractile epithelium. Materials interpreted as ingested flight muscle mitochondria of the mosquito vector appear in various stages of degeneration within the intestinal lumen. It is suggested that, although simple by comparison to some other nematodes, the anterior alimentary tract of infective-stage W. bancrofti functions in the ingestion and breakdown of nutrient materials. The ultrastructure of the excretory cell likewise suggests a functional capability.

Aedes↗
PubMed1978

Abortive development of Wuchereria bancrofti in a West African strain of Culex pipiens fatigans.

The detailed morphology of the larvae of Wuchereria bancrofti developing in a refractory strain of Culex pipiens fatigans from Liberia, West Africa, has been described. The abortive development of the parasite in the thoracic muscles of the mosquito was characterized mainly by: (i) retardation or complete failure of initial division of the G-cell, (ii) partial or complete encapsulation of developing larvae, especially at the anal and excretory vesicle areas of late first-stage, (iii) breakdown of the forming internal structures with formation of clusters of DNA-and RNA-positive material, and (iv) anomalous development of some larvae in which extra-corporeal growth of internal tissues took place.

Africa, Western↗
PubMed1979

Ultrastructure of the rectum of infective-stage Wuchereria bancrofti (Nematoda: Filarioidea).

The authors have examined the ultrastructure of the rectum of infective-stage Wuchereria bancrofti by transmission electron microscopy. Our observations show that the rectum is divided into anterior and posterior segments. The cells of the anterior rectum appear to be derived from the microfilarial R (rectal) cells described by other authors. In both stages, these cells show voluminous nuclei, abundant mitochondria, and small cytoplasmic processes which contain fibrillar components. Amorphous material associated with these processes appears throughout the larval rectum and may protrude from the anus as the rectal plug. In the specimens examined, a patent lumen could not be traced completely through the anterior rectum. The posterior rectum has no counterpart in published accounts of microfilarial ultrastructure and probably arises during larval morphogenesis; it is lined with invaginated body cuticle, overlaid by a single layer of epithelial cells which may be of hypodermal origin.

Animals↗
PubMed1985

Electron microscope study on the developmental stages of Wuchereria bancrofti in the intermediate host: structure of the digestive tract.

The digestive tract and its development from undifferentiated primordia of first, second and third stage larvae of Wuchereria bancrofti are described at the ultrastructural level. In the young first stage larva the future oesophageal cells form a long column surrounding the cuticularized pharyngeal thread. In the midbody region, a small number of cells associated with the inner body represent the intestinal precursor. The large R-cells around the anal vesicle are fully differentiated.--The late first stage larva shows numerous, small oesophageal cells aligned around the pharyngeal thread. The few intestinal cells have greatly enlarged and start to form small lumina between their central membranes. The anal vesicle has increased and is divided in an inner and an outer portion.--In the second stage larva the oesephageal cells gradually differentiate into an inner muscular core around the triradiate cuticularized lumen, and an outer glandular sleeve. The intestinal cells start to form small microvilli at their luminal sides. Large amounts of particulate matter fill the lumina of oesophagus and intestine at this larval stage. The R-cells are still located between the posterior end of the intestine and the inner portion of the anal vesicle. Small, undifferentiated cells around the outer portion of the anal vesicle start to form the rectal tube.--The third stage larva has a fully differentiated digestive tract. The glandular portion of the oesophagus contains an abundance of secretory granules and vacuoles, the intestinal cells show lipid inclusions and long, tightly packed microvilli. The narrow rectal tube opens to the exterior.

Animals↗
PubMed1979

Attempts to infect Meriones unguiculatus and Mastomys natalensis with Wuchereria bancrofti from West Africa.

44 male and female Meriones unguiculatus and 13 male Mastomys natalensis were inoculated with infective stage larvae of Wuchereria bancrofti from West Africa and dissected between 16 and 360 days after inoculation. Fourth stage larvae of W. bancrofti were recovered in Meriones until the 90th day p.i. and in Mastomys until the 175th day p.i. The longest larva obtained from Meriones measured 9.5 mm and from Mastomys 6.5 mm.

Animals↗
PubMedDate not supplied

Cytologic detection of Wuchereria bancrofti microfilariae in urine collected during a routine workup for hematuria.

A 23-year-old Guyanese man experienced intermittent, total, painless, gross hematuria for a month for which he sought medical attention at the Kings County Hospital Center in Brooklyn. Hematuria was accompanied by weakness but not by frequency of urination or burning on urination. Catheterized urine at the time of cystoscopy and each of two subsequent voided specimens examined cytologically contained sheathed microfilariae. Distinguishing features of the microfilariae were well demonstrated with the Papanicolaou stain. The well-stained nuclei, which did not extend into the clear zone, and the distinct, pale-stained sheath led to the positive identification of the microfilariae as Wuchereria bancrofti. The Papanicolaou stain may well be the stain of choice for the identification of microfilariae in the blood. The excellent detail obtained with this routine cytologic stain is as good as that with Giemsa, which does not stain the sheath.

Adult↗
PubMed1981

The mechanisms which affect the periodic cycle of Pacific Wuchereria bancrofti microfilariae.

1. Investigations were made of the effect of various procedures in raising or lowering the microfilaria count of Pacific type Wuchereria bancrofti in the peripheral blood. 2. Raising the body temperature in the early morning was followed by a moderate fall in the counts. Breathing increased oxygen, or reduced oxygen (hypoxia) or increased carbon dioxide, or the ingestion of sodium bicarbonate produced no consistent and significant change in the count. Ingestion of glucose (in one volunteer) was followed by a small rise in the count. Muscular exercise was followed by a fall in the count, which is interpreted as probably being a response to a lower concentration of oxygen in the venous blood returning to the lung. 3. It has not been possible to identify the physiological components on the circadian rhythm of the human body which entrain the cycle of these microfilariae. Attempts to obtain evidence incriminating the stimuli described above have been unsuccessful.

Adult↗
PubMedDate not supplied

Microfilariae of Wuchereria bancrofti in cytologic smears.

Microfilariae of Wuchereria bancrofti were observed in cytologic material in 35 cases. The material included cervicovaginal smears (17 cases), effusions (14), urine (2), bronchial washings (1) and ovarian cyst fluid (1). The initial diagnosis was made from the cytologic smear in all cases; none had clinical filariasis. Symptomatic vaginal bleeding in 9 of the 17 cases with microfilaria-positive cervicovaginal smears was reflected in the large numbers of red blood cells found in the smear. Blood eosinophilia was present in 11 of 19 cases investigated. Eosinophils were seen in the smears in 20 cases. In the majority of the cases of effusions with microfilariae the effusions were malignant. Significant adherence of inflammatory cells and macrophages to microfilariae was present in 7 of the 35 cases. The significance of these findings is discussed.

Adhesiveness↗
PubMed1984

Electron microscope study on the developmental stages of Wuchereria bancrofti in the intermediate host: structure of the body wall.

The cuticle, hypodermis and musculature of first, second and third stage larvae of Wuchereria bancrofti from the mosquito vector were studied by transmission electron microscopy. The young first stage larva is characterized by a thick cuticle with distinct layers demonstrating oriented fibrils. The muscle cells are well developed while the hypodermis has undifferentiated cytoplasm. - The late first stage larva (sausage-stage) still has a thick cuticle but the fibrils are no longer discernible. The volume of the hypodermal cells increases considerably, their plasma shows an abundance of organelles. The muscle sectors are shifted apart from each other by the growth of the hypodermis. The muscle cells are small, they start to multiply. - The cuticle of the second stage larva consists of three thin laminae only. The number of the hypodermal cells increases. They form the characteristic hypodermal chords. The four muscle sectors contain poorly developed muscle cells which multiply until the onset of the second moult. - The third stage larva shows a thick, multilayered cuticle with fibrous sublayers. Hypodermis and musculature are well differentiated. The hypodermal chords protrude into the centre of the worm. The muscle cells have grown considerably and their outer fibrillar portions show beginning septation.

Animals↗
PubMed1984

Field evaluation of ELISA using Wuchereria bancrofti mf ES antigen for bancroftian filariasis.

An enzyme-linked immunosorbent assay using Wuchereria bancrofti microfilarial excretory-secretory antigen was used in field studies to screen blood samples collected on filter-paper from persons residing in areas endemic for bancroftian filariasis. This assay system, when compared with examination of night wet blood smears for microfilariae, gave a relative sensitivity of 98% and a relative specificity of 86%. Daytime blood samples can also be used in this test, which can thus replace tedious examination of night blood samples in field surveys in endemic areas.

Antigens, Helminth↗
PubMed1982

Immune complexes in Wuchereria bancrofti infection in man.

The levels of immune complexes in the sera of patients with Wuchereria bancrofti infection were determined by enzyme-linked immunosorbent assay, using a rabbit antibody to the adult Setaria digitata antigens SD2-4, and by the Clq-binding assay. Approximately 3-7% of microfilaraemic subjects and 30-40% of amicrofilaraemic symptomatic patients had levels of immune complexes that were significantly higher than the levels observed in non-filarial control subjects. The antigen in the polyethylene glycol-precipitated immune complexes was isolated. This W. bancrofti antigen was found to be similar to the S. digitata antigen SD2-4. Both antigens had the properties of an acidic glycoprotein of isoelectric point around pH 3.

Animals↗
PubMed1980

Antigen of Setaria digitata: cross-reaction with surface antigens of Wuchereria bancrofti microfilariae and serum antibodies of W. bancrofti-infected subjects.

Extracts of Setaria digitata have been fractionated by DEAE-Sephadex A50 chromatography and the fractions obtained were used in the inhibition of indirect immunofluorescence of Wuchereria bancrofti microfilariae. The fractions were also tested by an enzyme-linked immunosorbent assay (ELISA) technique for reactivity against antibodies in the serum of patients with W. bancrofti infections. The results indicate that S. digitata contains several antigenic fractions that show cross-reactivity against filariasis sera; two of these fractions cross-reacted with surface antigens of W. bancrofti microfilariae but, when tested by the ELISA technique, these antigens did not show the highest reactivity against serum antibodies.

Animals↗
PubMed1980

Scanning electron microscope study on larvae of Wuchereria bancrofti from the vector and from experimental rodent hosts.

The surface structures of larvae of Wuchereria bancrofti from Liberia were examined by scanning electron microscopy. For this study microfilariae from man, first-stage, second-stage, and third-stage larvae from the vector Aedes aegypti, and fourth-stage larvae from the experimental rodent hosts Mastomys natalensis and Meriones unguiculatus were available. From these larvae the structure of the anterior ends, the cuticle in the midbody regions, and the posterior ends are presented. As an obvious structure at the anterior end of the microfilaria and the first-stage larva there is a cephalic cap with a hook on its left side. Three spines are found on the right side close behind the border of the cap. The amphidial openings are found immediately beside the cephalic cap. A simply formed oval mouth is found in the second-stage larva. A small elevation is situated on each side of the mouth. On the anterior end of the third-stage larva there are eight papillae. The four outer papillae are round, the four inner papillae are cone-shaped. The caudal extremity of this larva carries three characteristic bubble like papillae. The mouth of the fourth-stage larva from the experimental rodent host is surrounded by an oral field. The cephalic papillae are indented and the amphidial openings are associated with papillary protuberances. The cuticle of these larvae is regularly annulated. On the caudal extremity, the dorsal papilla is reduced.

Aedes↗
PubMed1980

The susceptibility of Liberian Culex quinquefasciatus to Wuchereria bancrofti in Sri Lanka.

Strains of Culex quinquefasciatus collected in Liberia showed low susceptibility to Wuchereria bancrofti from Liberian donors. However, when the same mosquito strains were fed on W. bancrofti donors from Sri Lanka they showed equally high susceptibility as Sri Lankan C. quinquefasciatus simultaneously fed on the same donors. A Liberian strain did not respond to selection for refractoriness. Thus the strains of W. bancrofti from Liberia and Sri Lanka differ in their ability to infect specific mosquito strains and it is concluded that Liberian C. quinquefasciatus could not provide genes for use in the construction of a refractory strain intended for the replacement of Sri Lankan vector populations.

Animals↗
PubMed1981

Further studies on the development of Wuchereria bancrofti in laboratory animals.

In an attempt to obtain a small animal laboratory model for Wuchereria bancrofti Mongolian gerbils and hamsters were infected with third-stage larvae of strains of the parasite from Indonesia and China. Gerbils were necropsied at 7 to 591 days and larvae recovered up to 219 days. The third molt occurred on or before 10 days and worms found after 14 days were in the fourth stage. More worms were recovered early in the infection (7 to 30 days) than in older infections. The worms were usually recovered from the testes, pelt and carcass and heart and lungs. An adult male worm was recovered on one occasion from the lung of a gerbil at 92 days. The parasite was also found to develop in hamsters with results similar to those in gerbils. Gerbils and hamsters were given antithymocyte sera before and after infection and more worms were recovered and the worms larger in size in some treated animals. Continued studies with geographic strains of W. bancrofti in various animals should be encouraged in order to find a small laboratory animal model for the parasite.

Animals↗