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At least 19 recordsLinked to original sources
PubMed1992

Characterization of a muscle-associated antigen from Wuchereria bancrofti.

A recombinant clone, WbN1, isolated from a genomic expression library of Wuchereria bancrofti and showing restricted specificity at the DNA level (Southern and PCR analyses) for Wuchereria bancrofti and Brugia malayi has been previously described. Sequence analysis of WbN1 indicated that it had notable similarity to myosin. Further characterization using in situ hybridization has localized the mRNA in the muscle of the adult parasite and in the microfilariae. Rabbit polyclonal antiserum, raised against the recombinant WbN1 fused to the maltose-binding protein, recognized a 200-kDa polypeptide in immunoblots containing B. malayi antigen extracts. The same antibody also recognized myosin extracted from Brugia pahangi, Onchocerca volvulus, and Caenorhabditis elegans. Localization using the rabbit antiserum revealed the presence of the antigen in the adult muscle tissue and in the microfilariae; the same antibody inhibited the binding of a monoclonal antibody 28.2 (directed toward MHC B of C. elegans myosin) to the recombinant WbN1 antigen and also to purified C. elegans myosin. Based on homology data, structural location, competitive ELISA, and immunoblot we conclude that WbN1 is related to myosin or a similar myofibrillar protein.

Amino Acid Sequence↗
PubMedDate not supplied

Wuchereria bancrofti infection in human and mosquito populations of a Polynesian village ten years after interruption of mass chemoprophylaxis with diethylcarbamazine.

In 1991, a study on Wuchereria bancrofti microfilariae (mf) and infection rates was carried out in the human and mosquito populations of a Polynesian village where, 10 years before, the mf prevalence rate was 6.4% and twice-yearly mass treatment with 3 mg/kg of diethylcarbamazine (DEC) was interrupted. Venous blood samples were collected from 575 (97%) individuals aged 15 years or more, of whom 122 (21.4%) were mf positive. The mf carrier prevalence rate was 27.4% in males, significantly higher than that of 14% in females; it increased from 7-12% in the youngest age group (15-19 years) to 40-50% in the oldest (> or = 60 years) for both males and females. 387 mosquito collections were performed and 1748 female Aedes polynesiensis were dissected, of which 1176 were parous. Among the latter, 114 (9.7%) were infected with Wuchereria bancrofti larvae at L1, L2 or L3 stages. The mean number of larvae per mosquito was 2.46 (range 1-15). Of the 114 infected mosquitoes, 30 harboured L3 larvae, giving a 2.55% infective rate; the mean number of L3 larvae per mosquito was 1.15 (range 1-2). Such findings indicate that the interruption of systematic twice-yearly mass treatment with DEC (3 mg/kg) has resulted, after 10 years, in a substantial increase of microfilarial prevalence in humans, and in high infection rates in mosquitoes.

Adolescent↗
PubMed1976

Studies on quantitative aspects of the transmission of Wuchereria bancrofti.

Feeding experiments with Anopheles gambiae and Culex fatigans infected with Wuchereria bancrofti showed that the mosquito females were losing about 20% of their worm burden when they were feeding on a blood chamber as well as on the guinea pig. 6.6% of all mature larvae found in the mosquitoes succeeded in entering the final host. A striking high infection rate was observed in those mosquitoes which refused to feed on a guinea pig. These mosquitoes have also to be considered when the loss of filarial larvae is calculated. Furthermore the experiments showed, that only very few larvae of Wuchereria bancrofti get lost when the mosquitoes are feeding only on sugar water solution.

Animals↗
PubMed1975

[On the migration of the third stage larvae of Wuchereria bancrofti in Anopheles gambiae (author's tranls)].

The migratory pattern of the third stage larvae of Wuchereria bancrofti from the thorax into the head of Anopheles gambiae has been studied. A total of 1269 infected mosquitoes were dissected and examined from the 7th through the 19th day after the blood meal. The filarial worms migrated from the thorax through the abdomen before they reached the head of the mosquito. Third stage larvae first appeared in the abdomen on the 9th day after infection, where their number increased progressively up to the 13th day and then decreased steadily thereafter. In contrast, mature larvae were first found in the head on the 11th day, and a concentration of larvae could be observed in this region only from the 14th day onwards.

Abdomen↗
PubMed1990

Rapid diagnosis of Brugia malayi and Wuchereria bancrofti filariasis by an acridine orange/microhematocrit tube technique.

A microhematocrit tube technique for diagnosis of human filariasis has been previously described. A system incorporating heparin, EDTA, and acridine orange into a microhematocrit tube (Quantitative Blood Count, QBC) has been commercially developed for the quantitation of blood counts and has been used for the diagnosis of malaria. We evaluated this test for its usefulness in the diagnosis of filariasis. Upon centrifugation, the parasites were concentrated in the area of the buffy coat and could be observed through the wall of the tube. The parasites were concentrated further by a plastic float that expands the buffy coat and confines the parasites to the periphery of the tube. Acridine orange stains the DNA of the parasite, and morphologic characteristics can be examined by fluorescence microscopy. The terminal and subterminal nuclei and long cephalic space of Brugia malayi, as well as the short cephalic space and caudal nuclei of Wuchereria bancrofti, were easily recognized and differentiated from each other. Microfilariae were detected in samples diluted to a level of approximately 50/ml.

Acridine Orange↗
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↗
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↗
PubMed1978

Failure of diethylcarbamazine as a provocative test in subperiodic Wuchereria bancrofti filariasis.

The effect of diethylcarbamazine (DEC) on levels of microfilaraemia in 70 patients with subperiodic, Pacific-variant Wuchereria bancrofti infection was studied one hour after oral administration of 5 mg/kg of drug. In contrast to the immediate DEC-induced increase in microfilaraemia which had been previously described in patients with nocturnally periodic filariasis, diethylcarbamazine failed to elicit such a response in patients with subperiodic bancrofti infection. Indeed, one hour after oral DEC the number of circulating microfilariae was reduced to about 8% of pre-treatment values.

Adolescent↗
PubMed1979

Studies on human filariasis in Malaysia: immunoglobulin and complement levels in persons infected with Brugia malayi and Wuchereria bancrofti.

Levels of immunoglobulins G, A, M and E as well as complement components C3c and C4 have been determined in populations in various endemic areas in Peninsular Malaysia and also in filariasis patients. High immunoglobulin levels were seen. In the microfilarial-negative group IgG was 2009 mg% while IgE was 3967 I.U./ml. In the filariasis group, Wuchereria bancrofti patients had significantly higher levels of IgG, IgM and IgE, namely, 3314 mg%, 804 mg% and 18400 I.U./ml respectively. The significance of these levels is discussed.

Adolescent↗
PubMedDate not supplied

A quantitative approach to the relationship between Wuchereria bancrofti microfilaria counts by venous blood filtration and finger-prick blood films.

Counts of nocturnally periodic Wuchereria bancrofti microfilariae (mf) in 20 mm3 finger-prick blood films were compared with membrane counts after filtration of 1 ml of venous blood for their efficacy in determining the prevalence of Bancroftian filariasis. The technique used for spreading and staining the blood films was critically important to the sensitivity of this screening procedure. There was good agreement between the 2 methods. Four statistical approaches were used to measure the correlation between the 2 sampling methods: 2 linear regression methods using untransformed and transformed data, and 2 non-parametric rank correlation methods. Based on the statistical analyses, this study strongly supports the general observation that finger-prick blood samples tend to contain more mf than equivalent volumes of venous blood, at mf densities high enough to be detectable by the finger-prick technique. It also demonstrates that finger-prick samples provide good estimates of mf densities and prevalence of infection except in areas of very low mf densities, where the membrane filtration method would provide a more accurate estimate of prevalence. Regression analyses using untransformed and transformed data, and the rank correlation tests, demonstrated a strong statistically significant correlation (P less than 0.001) between venous and finger-prick mf counts.

Adolescent↗
PubMedDate not supplied

Factors affecting transmission of Wuchereria bancrofti by anopheline mosquitoes. 4. Facilitation, limitation, proportionality and their epidemiological significance.

Quantitative understanding of the transmission dynamics of lymphatic filarial parasites is essential for the rational planning of control strategies. One of the most important determinants of transmission dynamics is the relationship between parasite yield, the success rate of ingested microfilariae (mf) becoming infective larvae in a mosquito vector, and mf density in the source of the human blood meal. Three types of relationship have been recognized in human filaria/mosquito couples--limitation, facilitation and proportionality; facilitation has hitherto been observed only in the couple Wuchereria bancrofti/Anopheles gambiae in Burkina Faso, in experimental studies on a high density mf carrier. The present paper demonstrates facilitation in W. bancrofti/An. gambiae and W. bancrofti/An. arabiensis in lower mf density carriers in The Gambia and Tanzania, and in W. bancrofti/An. funestus in Tanzania. Facilitation was not found in An. melas in The Gambia nor in An. merus in Tanzania. Analysis of published data shows limitation at low level mf densities in W. bancrofti/Culex quinquefasciatus in Sri Lanka, and in the same couple in India. Limitation also occurs in Brugia malayi/Aedes togoi in experimental cats; proportionality occurs in B. malayi/Mansonia bonneae in Malaysia. The epidemiological significance of these host/parasite relationships is discussed, and supporting evidence for its validity is presented from the published results of large-scale control programmes.

Animals↗
PubMedDate not supplied

Mass chemoprophylaxis of lymphatic filariasis with a single dose of ivermectin in a Polynesian community with a high Wuchereria bancrofti infection rate.

In April 1991 supervised mass prophylaxis of lymphatic filariasis with a single dose of ivermectin, 100 micrograms/kg, was carried out in a Polynesian village with a high infection rate of Wuchereria bancrofti in humans and active transmission by the vector mosquito, Aedes polynesiensis. Of 876 inhabitants aged 3 years or more (pregnant women excluded), 864 (98.6%) were treated. Simultaneously, venous blood samples were collected from 577 (97.5%) of the 595 inhabitants aged 15 years or more, of whom 122 (21.4%) were found to be microfilaria (mf) carriers (86 males and 36 females). The geometric mean microfilariae (GMM) count was 358.7 mf/ml for the whole group, 387 mf/ml for males (range 1-8160 mf/ml) and 280 mf/ml for females (range 1-7769 mf/ml). Following treatment, 33 (3.8%) of the 864 persons treated experienced some adverse reactions (21 with grade 1 and 12 with grade 2). Of the 33 with reactions, 29 were among the 122 (23.8%) mf carriers and 4 among the 831 (0.5%) non-microfilaraemic persons. Six months later, 123 (21.1%) of 584 inhabitants sampled were microfilaraemic: the GMM count for the whole group was 106 mf/ml (1-8177), with 29 mf/ml (1-3740) in 35 female and 177 mf/ml (1-8177) in 88 male carriers. Of these 123, 15 (whose GMM count was 4.5 mf/ml; range 1-204) were amicrofilaraemic 6 months before, and 19 had a microfilaraemia level higher than that 6 months earlier, before treatment. 117 of the 122 carriers identified in April were resampled: comparison of their GMM counts before and 6 months after mass treatment indicated that treatment with a single dose of 100 micrograms/kg ivermectin resulted in a reduction of microfilaraemia by 69%.

Adolescent↗
PubMed1991

Detection of amplified Wuchereria bancrofti DNA in mosquitoes with a nonradioactive probe.

A technique to identify Wuchereria bancrofti larvae in mosquito vectors with an enzyme-labeled DNA probe is described. To overcome the low sensitivity of nonradioactive detection methods, analyte DNA was amplified by polymerase chain reaction (PCR). Oligonucleotide primers were used to amplify W. bancrofti-specific DNA fragments of 380 and 650 bp, respectively. Parasite DNA in mosquito extracts was isolated free of inhibitors of the PCR by hybridization to a biotinylated DNA fragment (IWb 67), which hybridizes to DNA from most filarial species, followed by absorption of the resulting DNA hybrids onto avidin-coated acrylic beads. PCR-amplified DNA was detected with a biotin-labeled W. bancrofti-specific repeat DNA (IWb 35) coupled to avidin-alkaline phosphatase and the chemiluminescent substrate, AMPPD. The DNA equivalent of less than one larva can be detected by this method in mosquito extracts. The sensitivity of detection was comparable to that of radioactive probes and the assay is suitable for field application in endemic countries.

Animals↗
PubMed1992

A cloned antigen for serological diagnosis of Wuchereria bancrofti microfilaremia with daytime blood samples.

By differentially screening an adult Brugia malayi cDNA library with sera from microfilaremic and amicrofilaremic donors infected with Wuchereria bancrofti, we have identified a novel parasite antigen denoted SXP-1. Recombinant SXP-1 filarial antigen is preferentially recognized by sera from microfilaremic persons with bancroftian filariasis and from skin snip-positive patients with onchocerciasis. Antibodies to SXP-1 are restricted to the IgG4 subclass and gradually decline after treatment with diethylcarbamazine. These findings indicate that it may be possible to replace microscopic examination of night blood films with a serological test designed to detect antibodies to a mix of SXP-1 and other suitable antigens for the diagnosis of microfilaremia due to bancroftian filariasis.

Amino Acid Sequence↗
PubMed1976

Diagnosis of Wuchereria bancrofti filariasis by immunofluorescence using microfilariae as antigen.

A new technique for the diagnosis of wuchereriasis is described. Microfilariae treated with proteolytic enzyme were used as antigen for the immunofluorescent reaction. The specificity of the reaction is demonstrated in sera from persons who have a microfilariaemia, individuals with clinical symptoms of the disease but no microfilariaemia, those who have no clinical symptoms, but harbour other parasites, and in persons living in France, where the Wuchereria bancrofti filariasis is absent.

Antigens↗