PMID(sorted ascending)
antigenic activity in adult dipetalonema viteae in the indirect immunofluorescent test against sera from filariasis patients--the immunofluorescent histological search for "pure" antigen.using ifat, it has been shown that isolated egg-shells and uterine fluid of dipetalonema viteae are the most potent antigens in heterologous systems using human sera from patients infected with wuchereria bancrofti, onchocerca volvulus and loa loa, as well as in homologous systems using sera from animals infected with d. viteae. it is suggested that these antigens are unlikely to be highly species-specific, and that anatomical isolation of antigens is a necessary prerequisite to immunochemical a ...1979394410
the cryopreservation and in vitro cultivation of larval onchocerca volvulus.a system developed in our laboratory for the in vitro cultivation of larval onchocerca volvulus is being employed in a series of morphogenetic, physiologic, chemotherapeutic and immunologic investigations of this parasite. because of the need for a large and readily available supply of living worms for this work, cryogenic techniques are being used for the long-term preservation of larval parasites collected in various endemic areas of guatemala, c.a. to date, microfilariae have survived frozen ...1979507287
an evaluation of the bovine -- onchocerca gibsoni, onchocerca gutturosa model as a tertiary screen for drugs against onchocerca volvulus in this trial suramin, diethylcarbamazine, trichlorphon, levamisole, mebendazole, melarsonyl potassiu, hoechst 33258 and tinidazole were administered to cattle infected with o. gibsoni and o. gutturosa to determine the usefulness of this screen in predicting the effect of drugs in man against. o. volvulus except for melarsonyl potassium which was macrofilarticidal against o. gutturosa but not o. gibsoni when cattle were slaughtered 6 weeks after treatment. it was concluded that cattle infected w ...1979538819
sequential affinity chromatography for the purification of antigens extracted from onchocerca volvulus adult onchocerca volvulus worms were extracted sequentially with buffers of various ionic strengths. the extract was incubated with purified human onchocerciasis immunoglobulin-g (igg) convalently coupled to sepharose. antigens were then eluted with 8 m urea and 7.5 m guanidine-hcl. igg contained in the eluates was removed by incubating the eluates with rabbit anti-human igg covalently coupled to sepharose. as demonstrated by double immunodiffusion and "double" crossed immunoelectrophoresis at l ...1978644658
reactions to subconjunctival inoculation of onchocerca volvulus microfilariae in pre-immunized rabbits.rabbits, pre-immunized by intravenous inoculations of live, or of freeze-killed microfilariae of onchocerca volvulus, were later challenged by subconjunctival inoculation of live microfilariae. those pre-immunized with live microfilariae showed a marked chemotic conjunctivitis and reactions in the cornea (stromal keratitis and limbal abscesses), starting within one day of challenge. they were classed as sensitized. those pre-immunized with dead microfilariae produced minimal reactions also start ...19751216332
fundus lesions in the rabbit eye following inoculation of onchocerca volvulus microfilariae into the posterior segment. i. the clinical microfilariae of the cameroon forest and sudan-savanna strains of onchocerca volvulus were inoculated into the vitreous or into the subretinal layers of the eyes of rabbits. the lesions produced are described, and are compared with those seen in control animals, which had received inocula of microfilariae-free saline supernate introduced with a similar degree of operative trauma. control rabbits showed only minor pigment disturbance in the retina and choroid, near the healed operation scars ...19761258139
human onchocerciasis in the lower jos plateau, central nigeria: the prevalence, geographical distribution and epidemiology in akwanga and lafia local government investigation of human infection with onchocerca volvulus and the resulting clinical disease was carried out for the nigerian national onchocerciasis control programme between july and august 1989 [corrected]. the survey covered 10.6% of the rural population in 41 savanna villages of central nigeria. of the 8451 self-selected individuals examined, 900 (10.6%) had skin microfilariae (mf). there were differences between villages in both endemicity and intensity of infection, but in general the ...19921304706
identification of circulating parasite acetylcholinesterase in human and rodent the present study, the enzyme acetylcholinesterase (ache) from filarial parasites was identified in sera from humans infected with onchocerca volvulus as well as in mastomys natalensis infected with brugia pahangi. the enzyme was present in immune complexes precipitated with cold 4% polyethylene glycol. the infected sera showed 3-4 times more ache activity than did normal sera, and enzyme activity could be demonstrated in 5% polyacrylamide gels by specific staining. the enzyme from infected s ...19921480604
characterization of an hsp70 gene from the human filarial parasite, brugia malayi (nematoda).we have previously shown that an onchocerca volvulus cdna clone in lambda gt-11 designated ovg15, potentially encoding a peptide homologous to the 70-kda heat shock protein (hsp70), was recognized by sera of many individuals living in a zone endemic for lymphatic filariasis and most strikingly by sera from amicrofilaremic individuals including endemic normals, those with chronic symptoms and tpe patients. few asymptomatic microfilaremics recognized the hsp70. we have now used the insert from the ...19911775166
partial characterization of 2-beta-mercaptoethanol-soluble surface-associated antigens of onchocerca volvulus.antigens were extracted from the epicuticle/cuticle of intact female onchocerca volvulus using 2% 2-beta-mercaptoethanol and 1% sds. in western blot analysis a human infection serum selected for its high antibody titre against whole worm homogenates did not recognize any component solubilized by 1% sds. however, the same serum did bind at least 7 antigens among the material extracted with 2-beta-mercaptoethanol. these antigens have apparent molecular weights (mr) of: 15,000, 18,000, 28,000, 78,0 ...19911866191
observations and reflections on the immature stages of onchocerca volvulus in the human host.knowledge of the morphology, migrations and development rates of the l3, l4 and prepubertal l5 stages of onchocerca volvulus in the vertebrate host is an essential prerequisite to work vaccine development of chemoprophylaxis. after a brief review of the scanty literature available on this subject a description is given of two immature worms, one male and one female, found in an o. volvulus nodule from guatemala. the male, which measured 12 mm x 40 micron(s), had fine regular transverse cuticular ...19911888206
characterization of the autoantigen calreticulin.anti-ro/ss-a antibodies are commonly found in the sera of patients with sjögren's syndrome and sle. these antibodies also occur in the mothers of children with neonatal lupus and congenital heart block. ro/ss-a is a ribonucleoprotein complex whose cellular function remains unknown. to study its cellular function and to characterize its immunoreactivity, we have used an oligonucleotide designed after the published amino terminal sequence of a putative 60-kda ro/ss-a autoantigen to isolate its cdn ...19911919005
identification of different radiolabelled antigens of the developmental stages of onchocerca using radioiodination methods which are thought to label preferentially the surface followed by sds-page and autoradiography, components of different developmental stages of o. volvulus have been identified. between 2 and 10 polypeptide antigens were revealed on infective larvae (l3), females, males, eggs, nodular and skin microfilariae by using immunoblotting assays with human onchocerciasis sera. antigen recognition did not vary with the density of skin microfilariae in the patients from wh ...19901978531
experimental ocular onchocerciasis in cynomolgus monkeys. iv. chorioretinitis elicited by onchocerca volvulus microfilariae.onchocerciasis is a major cause of blindness worldwide, and much of the blindness is caused by onchocercal chorioretinitis. in an experimental animal model for ocular onchocerciasis, intravitreal injections of 10,000 live onchocerca volvulus microfilariae isolated from infected humans into the eyes of cynomolgus monkeys (macaca fascicularis) resulted in patchy, progressive loss of retinal pigment with pigment clumping. areas of pigment loss were less extensive in animals that had been sensitized ...19912016131
guatemalan human onchocerciasis. ii. evidence for igg3 involvement in acquired immunity to onchocerca volvulus and identification of possible immune-associated isotypic differences in immune response to onchocerca volvulus ag were assessed for 778 long term residents of endemic guatemalan areas by quantitative elisa with 5-min incubation steps and immunoblot. the study population was separated into five groups based on clinical status: n+f+, n+f-, n-f+, n-f-h+, and n-f-h-, where n = o. volvulus adults (nodule), f = microfiladermia, and h = history of o. volvulus infection. a subset of 44 individuals with high exposure to onchocerciasis from ...19912033268
changes in antibody profile after treatment of human define the changes in antibody response to onchocerca volvulus antigens after treatment of patients with onchocerciasis, igg and ige antibodies were examined quantitatively and qualitatively in 21 patients and 3 control individuals before and sequentially for 14 days after treatment with diethylcarbamazine. the quantitative levels of ige and igg responses (both polyclonal and o. volvulus-specific) remained essentially unchanged for all patients, but 9 of the 21 patients showed intensified res ...19902197344
human onchocerciasis--an overview of the disease.the general characteristics of onchocerca volvulus infection and its transmission are outlined in this overview of human onchocerciasis. the pathogenic role of the microfilariae, producing lesions of the skin, lymphatic system, eye and deep organs, are described, along with the main clinical manifestations of the disease. the global prevalence and distribution of onchocerciasis are given. best estimates in 1985 gave 86 million persons at risk, 17.8 million infected, 336,400 blind and a like numb ...19902198761
cloning of specific diagnostic antigens of onchocerca volvulus.specific, serological diagnosis is one of the main goals in onchocerciasis research. to date this objective has been hampered by (a) scarcity of parasite material, and (b) antigenic cross-reaction between onchocerca volvulus and other nematode species. in order to obtain specific antigens, and in amounts suitable for study, molecular biological techniques have been adopted. a lambda gt11 cdna expression library prepared from o. volvulus adult female worms was screened using infected human sera f ...19902255840
molecular cloning, expression, and chromosome 19 localization of a human ro/ss-a antibodies are found in a number of human autoimmune disorders including sjogren's syndrome and several systemic lupus erythematosus-related disorders. these heterogeneous autoantibodies are known to recognize several distinct cellular antigens. with synthetic oligonucleotides corresponding to amino acid sequence information we have isolated a full-length cdna clone which encodes a human ro ribonucleoprotein autoantigen. the 1,890-base pair clone contains an open reading frame that encod ...19902332496
identification of antigens of onchocerca volvulus and onchocerca gibsoni for diagnostic use.adults of onchocerca volvulus and onchocerca gibsoni were identically fractionated into a surface-enriched fraction, a phosphate buffered saline (pbs) extract and a pbs insoluble-detergent soluble fraction. glycoproteins were prepared from these extracts and all fractions were examined by the western blot technique using sera from individuals infected with a variety of filarial and non-filarial nematode worms. using antisera to o. volvulus, a number of antigens were demonstrated in all of the ex ...19862429180
isolation of an antigenic fraction for diagnosis of onchocerciasis.a surface enriched fraction was prepared from adults of onchocerca volvulus by brief extraction of entire worms with detergent. this was then gel filtered to yield a low molecular weight fraction which functioned specifically in elisa analysis. an identical result was also obtained when the related cattle parasite, o. gibsoni, was similarly fractionated and tested. the low molecular weight fraction contained at least four antigenic components when examined by coprecipitation and immunoblotting s ...19872436130
phosphocholine epitopes on helminth and protozoal parasites and their presence in the circulation of infected human patients.antigens containing phosphocholine (pc) circulate in the blood during chronic filarial infection. because of the wide occurrence of such pc epitopes, we examined their specificity by evaluating 10 common parasites of humans for the presence of pc epitopes, and sera from patients infected with these parasites for circulating antigens containing pc. immunoblot analysis of extracts from various parasites using an anti-pc monoclonal antibody (ca101) demonstrated the presence of pc epitopes on the pr ...19892482559
the status of ivermectin in the treatment of human onchocerciasis.ivermectin is a macrocyclic lactone that has widespread antiparasitic activity. numerous clinical trials have shown that ivermectin is safe and effective in the treatment of human infection with onchocerca volvulus. although it is rapidly microfilaricidal, it does not cause a severe reaction, as is seen with diethylcarbamazine treatment. the drug temporarily interrupts production of microfilaria but has not known long-lasting effects on the adult worms. in patients with onchocerciasis, a single ...19892679172
a semi-automated system of intrathoracic injection for the large-scale production of onchocerca lienalis infective larvae.intrathoracic injection of onchocerca lienalis microfilariae (mf) into simulium ornatum sl. is a highly efficient procedure for routine production of infective stage larvae (l3). this bovine parasite provides a useful analogue of onchocerca volvulus from man, which presents far greater difficulties for l3 production outside endemic areas of onchocerciasis. using novel systems for the infection and caging of adult blackflies in the laboratory, mean yields of 10.1-38.6 l3 per fly have been regular ...19892740729
cloning and characterization of an onchocerca volvulus specific dna sequence.a cloned sequence, povs134, was isolated from a genomic library prepared from onchocerca volvulus of savanna origin in the plasmid puc9. povs134 hybridizes to all the geographic isolates of o. volvulus tested from both the new and the old world, but not to the species onchocerca gibsoni, onchocerca gutturosa, onchocerca ochengi, onchocerca cervicalis, the filarial parasites brugia malayi, or dirofilaria immitis, nor to human or simuliid dna. as little as 250 pg of dna can be detected on a dot bl ...19892811941
preliminary data on the genetic differentiation of onchocerca volvulus in africa (nematoda: filarioidea).data are reported on the genetic structure of three onchocerca volvulus populations, respectively from mali (savanna), ivory coast (forest), and zaire (forest gallery in savanna). electrophoretic analysis, carried out on 25 gene-enzyme systems, has shown a remarkable genetic heterogeneity existing within o.volvulus. zaire and west africa populations appear chiefly differentiated at mdh-1 and 6pgdh loci, their average nei's genetic distance being 0.11. in west africa nei's d found between the sav ...19852868636
the status of simulium oyapockense and s. limbatum as vectors of human onchocerciasis in brazilian an attempt to explain the current distribution of onchocerciasis in the forests of northern brazil (moraes et al., 1979, 1986), and its potential for dispersal to other areas, this study compares the vector status of simulium oyapockense floch and abonnenc, 1946 in both a hypoendemic and an onchocerciasis free area with that of s. limbatum knab, 1915 in the latter area. both species allowed the full development of onchocerca volvulus (leuckart) to the infective l3 stage after experimental inf ...19872979535
cloning and characterization of two onchocerca volvulus repeated dna sequences.two repeated sequences, plasmids pov8 and pov26, were cloned and characterized from the filarial parasite onchocerca volvulus. both clones can be used to distinguish o. volvulus dna from other onchocerca species or other nematodes by restriction fragment length polymorphisms, but neither clone can differentiate between dna from savanna (mali) or forest (ivory coast) o. volvulus isolates. dna from one o. volvulus infective larva can be detected by both clones in dot blot hybridization assays. nei ...19863024001
diagnosis and extirpation of nodules in human onchocerciasis.the clinical search for onchocercal nodules, and their preferred sites on the body in different geographic areas are described and illustrated. the differential diagnosis of onchocercomata is discussed and figures on the frequency of false diagnoses are reported. the prevalence of adult onchocerca volvulus in relation to the endemicity of infection, the age and sex of the patients, the localisation of nodules on the body, and the measures used to control onchocerciasis are discussed. recommendat ...19883067324
the vectoral role of several blackfly species (diptera: simuliidae) in relation to human onchocerciasis in the sierra parima and upper orinoco regions of venezuela.experimental and natural infections with onchocerca volvulus were studied in several anthropophilic blackfly species present in the endemic area of the upper orinoco region of venezuela. when fed on four different yanomami volunteers in the sierra parima, the total infection rate was 31.4% for simulium guianense in comparison with 7.5% for s. limbatum. the proportion of ingested microfilariae that entered the thorax during the first 24 hours and completed development to the infective stage was a ...19883256278
onchocerca antigens in protection, diagnosis and pathology.characterization of the immune response to onchocerca volvulus is important for the diagnosis, control and understanding of the disease it causes. the antibody response to surface, secreted and somatic antigens of the worm has therefore been examined at an individual immunoglobulin (ig) class level, by using a panel of different human sera. onchocerca-specific antigens tend to be of low molecular mass and preferentially recognized by igg4 and ige. there is considerable cross-reaction between o. ...19873297554
autoantibody induced by experimental onchocerca infection. effect of different routes of administration of microfilariae and of treatment with diethylcarbamazine citrate and ivermectin.hartley guinea pigs were injected with microfilariae (mf) of onchocerca lienalis as a model for acute inflammatory responses to mf in human onchocerca volvulus infection. igg autoantibody reactive with a 3 m kcl extract of guinea pig cornea was detected by elisa in the serum of guinea pigs injected with o. lienalis mf three or more times sub-conjunctivally, or two or more times subcutaneously. administration of the microfilaricides diethylcarbamazine citrate and ivermectin did not alter the prop ...19883366573
quantitative studies of onchocerciasis transmission by simulium yahense and simulium sanctipauli in the firestone rubber plantation at harbel, fly vectors of onchocerciasis from three ecologically different simuliid breeding habitats in the firestone rubber plantation at harbel, liberia, were surveyed by human-biting collections conducted at weekly intervals over a 13-month period. black flies were identified morphologically and the monthly and seasonal contribution of different vector species to the transmission of onchocerca volvulus at each site was determined. simulium yahense was identified as the predominant vector species ...19873578652
cell adherence to microfilariae of onchocerca volvulus: a comparative study.the conditions were examined for in vitro antibody-mediated adherence of granulocytes to microfilariae of onchocera volvulus and dirofilaria immitis. reactivity in human sera from patients in endemic foci in sudan was specific for o. volvulus and no reactions were observed with heterologous onchocerca species or with mansonella perstans. microfilariae from skin, nodules or adult female worms were satisfactory targets for cell adherence, and the cells involved were almost exclusively eosinophils. ...19873595320
ivermectin effect on microfilariae of onchocerca volvulus after a single oral dose in humans.ivermectin is a broad spectrum anti-helminthic agent which is currently being tested for use in human onchocerciasis. its activity is believed to result from its effect on gaba-mediated neurotransmission. we examined the effects of ivermectin on motility of microfilariae of o. volvulus following administration to humans. when ivermectin was given in dosages of 100, 150 and 200 mcg/kg on day 1 there was a clear reduction in motility of microfilariae obtained on day 3 when compared to microfilaria ...19873602843
polyamine metabolism in filarial worms.the human and animal filarial parasites onchocerca volvulus, dirofilaria immitis, brugia patei and litomosoides carinii contained low levels of putrescine but much higher levels of spermidine and spermine as estimated by ion-pair high pressure liquid chromatography; n-acetylated polyamines were present only in minute amounts. enzyme activities of ornithine decarboxylase (ec and arginine decarboxylase (ec, respectively, were not detectable. experiments carried out with o. volv ...19873627168
identification of non-cross-reacting antigens of onchocerca volvulus with lymphatic filariasis serum pools.onchocerca volvulus proteins labelled with 125i were immunoprecipitated with onchocerciasis and lymphatic filariasis human serum pools in order to differentiate between cross-reacting and non-cross-reacting antigens. analysis of the immunoprecipitates by two-dimensional gel electrophoresis revealed that all high molecular weight (mr) o. volvulus antigens cross-reacted with the lymphatic filariasis serum pools. we observed, however, that at least 8 o. volvulus antigens were specifically immunopre ...19863785977
successful application of the diffusion-in-gel-enzyme-linked immunosorbent assay (dig-elisa) in onchocerciasis.the recently described dig-elisa test was evaluated on 38 sera from patients with onchocerciasis, using a soluble, crude extract of onchocerca volvulus dissected out from glycerol-preserved nodules. results showed that the diameters of the orange-yellow antibody-antigen reaction zones obtained with infected sera were significantly greater than those obtained with normal human sera. a close correlation was observed between the diameters of the reaction zones and antibody concentration (expressed ...19853923666
[filariae of rodents useful for the experimental study of human onchocerciasis].in order to obtain skin and ocular lesions comparable to those which are found in human onchocerciasis, it is not necessary to use members of the genus onchocerca which are found in large animals and difficult to use. other filariae with biological features comparable to onchocerca volvulus can be used in which microfilariae are localized in capillaries and can escape from the walls and produce lesions similar to those in onchocerciasis. the life cycles of several filariae of rodents have been w ...19853937568
pathologic changes of human onchocerciasis: implications for future research.onchocerciasis--infection by onchocerca volvulus--has four cardinal manifestations: dermatitis, subcutaneous nodules, sclerosing lymphadenitis, and eye disease. the first three are discussed here. the dermatitis begins when microfilariae degenerate in the dermis. this process is accompanied by inflammation, with degranulation of eosinophils and deposition of the major basic protein of the eosinophil granules on the cuticle of the microfilariae. so far as is known, the chronic effects of onchocer ...19854070919
daytime variation in the density of onchocerca volvulus microfilariae in human aim of this study was to determine whether a corneal-scleral punch biopsy instrument provides skin specimens of sufficiently uniform size so as to eliminate the need to weigh or measure the specimens in order to provide a reproducible index of the density of onchocerca volvulus microfilariae in the skin. a second aim was to determine whether the density of microfilariae in the skin varies with the time of day. the reports of others on the latter are contradictory. duplicate skin specimens we ...19734547174
observations on adult onchocerca volvulus maintained in onchocerca volvulus were enzymatically isolated with collagenase from excised nodules and kept in tc medium 199 with hank's salts supplemented with various sera. male and female worms survived in the culture medium and 10% human serum on average for about 11 days (maximum 28 days) and 14.5 days (maximum 42 days). up to 4,000 microfilariae were expelled by each female per day, but the production of new oocytes or development of embryos could not be observed in vitro.19846087508
attempts to establish onchocerca volvulus infection in primates and small laboratory animals.attempts were made to transmit o. volvulus infection to small laboratory animals and several species of primates to identify a practical laboratory host for human onchocerciasis. infective larvae of o. volvulus of guatemalan origin were inoculated into the following animals: rhesus monkeys, bonnet monkeys, golden spider monkeys, black spider monkeys, galagos, opossums, jirds, newborn and adult swiss mice, kinkajou, cebus monkey, normal and splenectomized multimammate rats, and a calf. the animal ...19826131591
the major radioiodinated cuticular antigens of onchocerca gibsoni microfilariae are neither species nor onchocerca specific.the possible role of microfilarial surface (cuticular) antigens in immuno-diagnosis of human filarial infections has been assessed using microfilariae (mf) of the cattle parasite onchocerca gibsoni. a triton x-100 extract of 125i-labeled o. gibsoni mf was reacted with a panel of sera from humans infected with onchocerca volvulus, wuchereria bancrofti and schistosoma japonicum as well as sera from uninfected controls. results of these immunoprecipitations indicated that sera from humans infected ...19816171154
induction of non-specific human suppressor cells in vitro by defined onchocerca volvulus the present study the activity of onchocerca volvulus total antigens (ova) on the proliferative response of human lymphocytes from healthy donors was investigated. normal human lymphocytes were cultured for 72 h with polyclonal activators, phytohaemagglutinin (pha) or pokeweed mitogen (pwm), together with ova, and thymidine uptake was measured. the proliferation of normal lymphocytes was markedly inhibited by the parasite antigens. the inhibition was not attributable to a cytotoxic effect of ...19836225576
onchocerciasis in the benue state of nigeria. iv. the prevalence of the disease among the population in manor.between january and december 1981, parasitological and symptomatological methods of diagnosis were used to survey the prevalence of onchocerciasis among the human population in the manor area of the benue state of nigeria. hospital records of different health establishment all over the state were also examined to assess the status of the disease in the state. 911 or 69.8% of the 1306 persons examined were positive for microfilariae of onchocerca volvulus; 135 or 10.3% had visual impairment inclu ...19836642907
the action of diethylcarbamazine on the skin-dwelling microfilariae of monanema globulosa (nematoda: filarioidea) in rodents.diethylcarbamazine (dec) administered orally to jirds and striped mice (300 mg/kg for five days) was effective against the microfilariae of monanema globulosa in experimental infections. based on the small numbers of animals used in this trial, it is questionable whether the drug had significant activity against the adult worms in pulmonary arteries. densities of microfilariae in the ears (mf/mg) fell by 80-100% of pretreatment levels over a four week period following treatment. there was no app ...19846710601
filariasis in amerindians of western guyana with observations on transmission of mansonella ozzardi by a simulium species of the amazonicum order to conduct experimental infection studies of mansonella ozzardi in local haematophagous diptera, volunteers infected with this parasite were identified during a microfilaria survey in four amerindian villages in the pakaraima mountains of western guyana, near the brazilian border. m. ozzardi microfilariae were detected in thick blood smears from 8-21% of persons examined. they were also found in skin snips from 8/73 persons all of whom were positive by blood smear examination. no onchoc ...19826761913
detection of circulating antigens in onchocerciasis.this report describes the presence of circulating onchocerca volvulus antigens (coa) in sera of patients with onchocerciasis. by using a double diffusion immunoelectrophoresis method, coa could be detected in 24 of 77 sera analyzed (31%). in contrast, when more sensitive assays such as the radioimmunoprecipitation-peg assay or sandwich radioimmunoassay were used to detect coa, about 75% of the sera from o. volvulus-infected patients were found positive; moreover, a highly significant correlation ...19816798890
[serodiagnosis of onchocerciasis using micro-elisa. study of 450 sera and comparison with indirect immunofluorescence].the microtest elisa has been used for human onchocerciasis serological study. the antigens employed were adult onchocerca volvulus extracts, collected from dissected nodules, delipidized and cleared from human proteins by affinity chromatography. under the circumstances, the positivity limit of the test seems excellent (maximum )d: 0,23) defined with 171 negative sera, 66 of them taken from africans. specificity controls were studied with 56 heterologous sera; cross-reactions occurred with hydat ...19807006842
associations in filarial infections in man in the savanna zones of mali and upper 14 villages located in the west african savanna belt, 1,305 people were examined for microfilariae in blood and skin. the results indicate that the associations between filariae in infected patients are not the result of chance alone. the frequency of associations between wuchereria bancrofti and tetrapetalonema perstans was highly significant, whereas onchocerca volvulus appeared to be associated with w. bancrofti only in the absence of t. perstans.19817020450
anthropophily of simulium damnosum s.l. and its rôle as a vector of human onchocerciasis in the yemen arab republic.immature stages of simulium damnosum s.l. were collected in four of the main wadis (surdud, zabid, rasyan, ghayl) which drain westward to the red sea. the species was absent from the wadi tuban which flows to the south-east, but other black-fly species were found herein. for the first time it was shown that s. damnosum s.l. in the yemen bites man, may ingest microfilariae of onchocerca volvulus and can harbour filarial infections. out of 303 flies which were caught on human bait in the wadi rasy ...19827135475
ige antibodies are more species-specific than igg antibodies in human onchocerciasis and lymphatic explore the relative species specificities of the ige and igg antibody responses to helminth infections in man, we studied four pools of sera from patients infected with wuchereria bancrofti, brugia malayi, onchocerca volvulus or ascaris lumbricoides and ten individual sera from patients with onchocerciasis. ige antibodies were detected by radioallergosorbent test (rast) analysis and igg antibodies by a staphylococcus protein a radioimmunoassay (staph a-ria). analysis of the binding curves wi ...19827199027
analysis of the anticomplementary activity in sera of three african patients with parasitic and bacteriological infections.the sera of three different patients from togo, africa were investigated with respect to their complement profile. the three patients were suffering from parasitic (onchocerca volvulus) and bacteriological (treponema pertenue) diseases. the total hemolytic activity (50% hemolytic complement) was markedly depressed. the analysis of the individual complement components revealed the the titers of c1, c2, c3, and c4 were lowered up to 90%, indicating an activation of the classical pathway of complem ...19807358423
an abundant, trans-spliced mrna from toxocara canis infective larvae encodes a 26-kda protein with homology to phosphatidylethanolamine-binding proteins.a full-length mrna encoding a secreted 26-kda antigen of infective larvae of the ascarid nematode parasite toxocara canis has been identified. this was characterized as a 1,082-base pair clone highly abundant (0.8-1.9%) in cdna prepared from infective stage larvae but absent from cdna from adult male worms. sequence analysis revealed an open reading frame corresponding to a hydrophilic 263-amino acid residue polypeptide with a 20-residue n-terminal signal peptide, indicating that it is secreted. ...19957629180
characterization of genes encoding members of the nuclear hormone receptor superfamily from onchocerca volvulus.several lines of evidence suggest that molting in parasitic nematodes is controlled through the action of steroid molting hormones, or ecdysones. in other organisms, the central mediator of steroid hormone action is the hormone receptor. these receptor molecules are members of a superfamily of proteins called the nuclear hormone receptor family. using an oligonucleotide derived from the amino-acid sequence of the drosophila melanogaster ecdysone receptor, genes encoding homologues of the nuclear ...19957637701
onchocerciasis and human immunodeficiency virus in western uganda: prevalences and treatment with ivermectin.epidemiologic investigations were made to assess the interaction between onchocerciasis and human immunodeficiency (hiv) type 1 infection and the efficacy of ivermectin treatment. among 1,910 onchocerca volvulus carriers in a hyperendemic focus, 73 (3.8%) were concurrently infected with hiv and 20 (7.2%) of 276 persons without microfilariae (mf) were hiv-seropositive. a stratified analysis showed no epidemiologic association between onchocerciasis and hiv infection. consistently, a microfilaria ...19957677220
immunological studies on an onchocerca volvulus intermediate-filament protein.we report the complete sequence of the cdna encoding an intermediate filament (if) protein from onchocerca volvulus. the ovif cdna encodes a protein of 613 amino acid residues, which has a predicted molecular weight of approximately 70 kd. the size of the protein encoded by the ovif cdna corresponds well with estimates obtained in western blotting experiments, but these same experiments suggest that onchocerca sp. may contain at least two if proteins. to identify the domain(s) of the ovif protei ...19957761109
human autoantibody to defensin: disease association with hyperreactive onchocerciasis (sowda).chronic hyperreactive onchodermatitis (sowda) is a severe form of onchocerciasis observed in a subset of individuals infected with the filarial nematode onchocerca volvulus. sds-page and immunoblot analyses of o. volvulus adult worm extracts were used to characterize the antigens of the marked antibody response of sowda patients. one 2.5-kd antigen was recognized by sera from all 35(100%) sowda patients that were studied. in comparison, only 7 of 44 (16%) patients with generalized onchocerciasis ...19957790822
a 16mer peptide of the human autoantigen calreticulin is a most prominent hla-dr4dw4-associated self-peptide.the human ca(2+)-binding (storage) protein calreticulin, located in the lumen of the endoplasmic reticulum, is proposed to play a role as autoantigen: anticalreticulin autoantibodies occur in the sera of patients with sle and patients with onchocerciasis (calreticulin shows a high sequence homology to the onchocerca volvulus antigen ral-1). here we present sequencing data of a hla-dr4dw4-associated calreticulin peptide fragment, cal(295-310), purified from a dr4dw4 self-peptide pool. cal(295-310 ...19947836063
a novel type of glutathione s-transferase in onchocerca volvulus.onchocerca volvulus is a pathogenic human filarial parasite which, like other helminth parasites, is capable of evading the host's immune responses by a variety of defense mechanisms which are likely to include the detoxification and repair mechanisms of the enzyme glutathione s-transferase (gst). in this study, we show that one of the previously described gsts from o. volvulus appears to possess the characteristics of a secreted enzyme. when the complete o. volvulus gst1 (ovgst1) sequence prese ...19947927752
[onchocerciasis control program in west africa: socioeconomic development and risk of recrudescence of transmission. 2. experimental study of the transmission of onchocerca volvulus strains from southwestern sierra leone by simulium yahense and simulium squamosum].the movements of human populations towards the mining wealth of the northern parts of sierra leone are favorable to a high contact rate between onchocerciasis patients coming from the south-western area of this country and the vector species simulium yahense and simulium squamosum which assume the essential of onchocerciasis transmission in the above-mentioned mining area. in fact, the onchocerca volvulus strains concerned by this contact seem to be more pathogenic than those locally transmitted ...19947944649
[subcutaneous nodules and cutaneous lesions caused by different onchocerca in african cattle].subcutaneous nodules and skin biopsy specimens obtained from the umbilical area of 6 onchocercal bos indicus were collected in cameroon and subjected to a histological examination. the nodules containing onchocerca ochengi and onchocerca dukei showed the same structure as onchocerca volvulus nodules in man; they consisted of inflammatory pseudo-cysts often containing a female filaria. these pseudo-cysts were classified as "young", "active" and "old" depending on the inflammatory cellular compone ...19947991898
[nematode larva migrans. on two cases of filarial infection].with rapid air travel, so-called parasitic infections are becoming more important in northern hemisphere and temperate climates. parasitic disease is usually taken to imply infections caused by protozoa and helminths. the most important helminthic infections in man and with world-wide incidence are schistosomiasis, hookworm, and filariasis. we report the clinico-pathological findings of two patients with filarial infection of soft tissue and lymphatic nodes.19948072951
biosynthetic radiolabelling of excretions-secretions of adult male onchocerca gibsoni.maintenance of adult male worms of the bovine filarial parasite onchocerca gibsoni in vitro, in the presence of radioactive precursors, resulted in the time-dependent excretion-secretion of radiolabelled parasite macromolecules (es). molecules labelled with amino acids ([35s] methionine, [3h] leucine) covered a wide range of molecular weights, whereas labelling with [3h] glucosamine produced predominantly molecules of high molecular weight. many of the products were recognized by antibodies in t ...19948082984
characterization of a recombinant t cell and b cell reactive polypeptide of onchocerca identify potentially protective ag of the filarial nematode onchocerca volvulus on the molecular level we screened a cdna library of o. volvulus with a human serum raised against radiation-attenuated infective larvae of o. volvulus. a cdna clone of 218 bp (ovl3-1) was selected for further studies. it was expressed in escherichia coli and affinity purified recombinant polypeptide was tested for its ability to stimulate in vitro pbmc from african onchocerciasis patients and pbmc from chimpanzee ...19938454865
concurrent parasitic infections in onchocerciasis and the occurrence of adverse reactions after ivermectin treatment.ivermectin is a safe, effective, and relatively well-tolerated drug for the treatment of human onchocerciasis. however, due to side effects of the drug, large-scale ivermectin distribution without medical supervision is not recommended. the mechanisms involved in the pathogenesis of ivermectin-induced adverse reactions are not yet known. since onchocerciasis patients are likely to have concurrent parasitic infections, we investigated whether side effects that occur after ivermectin treatment cou ...19938517484
identification of onchocerca volvulus collagen as an antigen mainly recognized by antibodies in chronic hyper-reactive onchodermatitis (sowda).an onchocerca volvulus expression library was differentially screened to identify a molecular marker distinguishing sowda (lichenified onchodermatitis) from other onchocerciasis forms. one clone, pg3, was recognized by pooled sera from patients with sowda, but not by pooled sera from patients with generalized onchocerciasis; it was not recognized by sera from patients with lymphatic filariasis or other helminth infections. the dna of pg3 hybridized strongly with o. volvulus eco ri-digested dna, ...19968644904
filariasis in the kaiyamba chiefdom, moyamba district sierra leone: an epidemiological and clinical a cross-sectional epidemiological and clinical study of human filariasis, 630 individuals were examined for onchocerca volvulus, wuchereria bancrofti and mansonella perstans infections in five communities in the kaiyamba chiefdom, moyamba district, sierra leone. the overall prevalence of o. volvulus infection in males 144(39.1%) and females 94(35.9%) was not significantly different and the sex prevalence rate between communities was also not significant (g = 3, d.f. = 4, p > 0.05). prevalence ...19968668763
immunoglobulin kappa chain allotypes (km) in and km allotypes, powerful tools for genetic characterization of human populations, have been shown to play an important role in genetic predisposition to some infectious diseases. two diverse racial groups--afro-ecuadorians and amerindians--living in a single restricted geographical area of ecuador, appear to have different risk factors for acquisition and clinical expression of onchocerciasis, a disease caused by the filarial parasite onchocerca volvulus. in this study, gm and km allotypes ...19958675641
human onchocerciasis in nigeria: isotypic responses and antigen recognition in individuals with defined cutaneous pathology.antigen (ag)-specific isotype responses to onchocerca volvulus ag (ovag) were assessed by enzyme-linked immunosorbent assay and immunoblot in 123 residents of a mesoendemic area in northern nigeria and 16 nigerians from a nonendemic area. individuals from an endemic area were divided into six groups on the basis of cutaneous onchocercal pathology: acute papular onchodermatitis (apod), chronic papular onchodermatitis (cpod), lichenified onchodermatitis (lod), atrophy (atr), depigmentation (dpm) a ...19968686779
the putatively protective onchocerca volvulus neuronal protein e1 is a member of the death domain protein we show that e1, an ankyrin-related, potentially protective, neuronal protein of the human filarial nematode onchocerca volvulus contains a death domain (dd), most similar to that of human mort1/fadd (39% identity). in addition, sequence comparison of e1 to its homologue from litomosoides sigmodontis and to caenorhabditis elegans ankyrin defines two further putative functional domains. one represents the end of the spectrin-binding domain of ankyrins, the other an unique domain, most highly ...19968706821
structural characteristics of the ascaris allergen, aba-1.the structure of the ascaris allergen, aba-1 was characterized at several levels. purified allergen monomers eluted from reducing page were found to reassociate into dimers in phosphate buffered saline containing 0.9 mm ca2+. this association may involve the formation of disulfide bonds between monomers. the primary amino acid sequence was used to predict secondary structure and compare the allergen to other known proteins sequences. aba-1 appears to be highly helical protein of two domains. seq ...19959137643
onchocerciasis hyperendemic in the unturán mountains: an extension of the endemic region in southern venezuela.a new region with human onchocerciasis is reported in the unturán mountains, south venezuela, affecting yanomamö populations not surveyed in previous studies conducted in the venezuelan-brazilian border area. its distribution probably extends towards the upper toototobi endemic area in brazil. the age-standardized prevalence of onchocerca volvulus microfilariae (mf) (67%), the prevalence of infection in those aged > or = 20 years (86%), and the community microfilarial load (cmfl) (24 mf/mg), are ...19979196753
human infection with onchocerca volvulus does not affect the t helper cell phenotype of the cellular immune response to mycobacterial order to determine whether infection with onchocerca volvulus might modify the immune response to mycobacterial antigen, the proliferative and cytokine responses of peripheral blood mononuclear cells from 117 persons infected with o. volvulus and 36 non-endemic control subjects were compared. tuberculin-stimulated cellular proliferative responses and production of th1-type cytokines (interferon gamma) were reduced in persons infected with o. volvulus compared to controls. however, there was n ...19979231215
characterization of human immune responses to the cytosolic superoxide dismutase and glutathione s-transferase from onchocerca onchocerciasis patients and in o. volvulus-exposed individuals without signs of onchocericiasis, t- and b-cell responses to two recombinantly expressed o. volvulus enzymes were analysed and compared to responses to total protein extract of adult parasites. the cytosolic enzymes cu/zn superoxide dismutase 1 (ovsod1) and glutathione s-transferase 2 (ovgst2) represent 2 detoxifying molecules which may play an important role in parasite defense against host-induced oxidative stress. the t-cell re ...19979294549
identification of an epitope of a recombinant onchocerca volvulus protein that induces corneal pathology.ocular onchocerciasis results from immune recognition of parasite proteins released into the eye by degenerating microfilariae. previous studies have shown that pathology similar to human ocular onchocerciasis can be induced in sensitized mice by intracorneal injection with onchocerca volvulus antigens. in the current study, we used this murine model to map the segments of o. volvulus protein disulfide isomerase (ovpdi) associated with the development of corneal pathology. subclones of ovpdi wer ...19979297706
immunohistological studies on macrophages in lymph nodes of onchocerciasis patients after treatment with ivermectin.the role of macrophages in the killing and elimination of microfilariae (mf) was studied immunohistologically in 14 lymph nodes from 10 patients with generalized onchocerciasis 20-68 h after treatment with a single oral dose of 150 microg/kg ivermectin. mf with signs of damage at light microscopical level were surrounded by a cellular infiltrate comprising macrophages, eosinophils and neutrophils, whereas light microscopically intact mf mostly showed no cellular reaction. resident mature macroph ...19979438472
identification of a novel family of non-lysosomal aspartic proteases in nematodes.a protein encoded by cdnas from the human parasite onchocerca volvulus and its homologs from caenorhabditis elegans and ancyclostoma caninum define a family of aspartic proteases that are most closely related to cathepsins d, but differ from them in lacking the n-glycosylation site known to be required for lysosomal targeting. the nematode proteins have a potential n-glycosylation site at the same position as mammalian cathepsins e and in common with these have atypically long n-terminal extensi ...19989507052
[onchocerca volvulus--a rare cause of a mass in children].the parasite onchocerca volvulus is well-known in its endemic areas in south and central america and west africa. it is transmitted to man by simulium flies and causes systemic infection with skin, lymphatic and ophthalmic manifestations and can cause blindness (river blindness). treatment with ivermectin is effective but sometimes there is need for surgical intervention to prevent or treat complications. we describe an 11-year-old girl, a new immigrant from ethiopia, who had a firm mass in her ...19989517276
human occult loiasis: field evaluation of a nested polymerase chain reaction assay for the detection of occult infection.a nested polymerase chain reaction (nested pcr) assay, targeted on the repeat 3 region (15r3) of the gene coding for a loa loa 15 kd polyprotein, was developed to detect l. loa infection. the assay has a sensitivity of 95% and is 100% specific with regard to sympatric filarial parasites: mansonella perstans, onchocerca volvulus and wuchereria bancrofti. in this field study in a mixed filarial (l. loa and m. perstans) endemic region of gabon, 157 l. loa amicrofilaraemic blood samples (amf; diagno ...19989657514
[excretion-secretion antigens from adult dirofilaria immitis in the diagnosis of human filariasis by solid phase immunoenzyme assay].the solid phase enzymatic immuno-assay (elisa) was normalized for detecting antibodies against. filaria using excretion-secretion antigens (esa) from dirofilaria immitis adults in a group of asymptomatic and microfilaraemic patients infected by different species of filariae (loa loa, wuchereria bancrofti, onchocerca volvulus, mansonella ozzardi and mansonella perstans), and in another group of symptomatic and aminorofilaraemic patients, temporary residents in an area with endemic loiasis. the es ...19919768181
determination of sample sizes for the estimation of onchocerca volvulus (filarioidea: onchocercidae) infection rates in biting populations of simulium ochraceum s.l. (diptera: simuliidae) and its application to ivermectin control programs.monthly samples of biting simulium ochraceum s.l. walker were collected before and after ivermectin treatment in southern mexico and analyzed for onchocerca volvulus leuckart infection rates, infection intensity, and the characteristics of larval distribution among parous flies. the variance over mean ratio (vmr) indicated that in all cases this distribution departed from poisson and was strongly aggregated (vmr > 1). the negative binomial was found to be an adequate model with a small value of ...19989775604
impaired tetanus-specific cellular and humoral responses following tetanus vaccination in human onchocerciasis: a possible role for interleukin-10.onchocerca volvulus infection has been associated with impaired cellular responses to parasite antigens, an impairment that may also extend to nonparasite antigens. to investigate the mechanism of this impaired immune response, the effect of concurrent o. volvulus infection on the immune response to tetanus toxoid (tt) following tetanus vaccination was studied. the proliferative, cytokine, and antibody response to tt of o. volvulus-infected subjects (n = 19) and comparable noninfected controls ( ...19989806045
population biology of human onchocerciasis.human onchocerciasis (river blindness) is the filarial infection caused by onchocerca volvulus and transmitted among people through the bites of the simulium vector. some 86 million people around the world are at risk of acquiring the nematode, with 18 million people infected and 600,000 visually impaired, half of them partially or totally blind. 99% of cases occur in tropical africa; scattered foci exist in latin america. until recently control programmes, in operation since 1975, have consiste ...199910365406
[deep onchocerciasis of the left thigh. an unusual case].commonly onchocercoma has been presented as superficial and multiple nodules. when it's unique and deeply situated, its clinical diagnosis is difficult. an uncommon form of onchocercoma is reported.199910392419
structural studies of n-glycans of filarial parasites. conservation of phosphorylcholine-substituted glycans among species and discovery of novel chito-oligomers.n-type glycans containing phosphorylcholine (pc-glycans), unusual structures found in the important human pathogens filarial nematodes, represent a novel target for chemotherapy. previous work in our laboratories produced compositional information on the pc-glycan of es-62, a secreted protein of the rodent parasite acanthocheilonema viteae. in particular, we established using fast atom bombardment mass spectrometry (ms) analysis that pc was attached to a glycan with a trimannosyl core, with and ...199910409642
discovery of a new focus of human onchocerciasis in central autochthonous case of human onchocerciasis was reported 13 years ago in the town of minaçu, northern goiás (brazil), but a subsequent survey of the population using the traditional technique of examining skin biopsies with the light microscope failed to detect other cases. recent surveys using more sensitive diagnostic techniques (serodiagnosis, dna probes, mazzotti test) that are detailed in this paper revealed the presence of other cases of the disease in minaçu, the nearby town of formoso ...199910492748
trehalose-6-phosphate-potent anti-onchocerciatic agent.onchocerciasis is a disease that engages the attention of most researchers. presently, there is not an ideal onchocerciatic agent, hence the search must continues. consequently alpha, alpha-trehalose-6-phosphate was synthesised and assessed for onchocerciatic activity against o. volvulus; using diethylcarbamizine citrate as the control drug. results from this study showed that alpha, alpha-trehalose-6-phosphate is a glucose analogue with effective micro and macro-filaricidal agent, better than t ...199810497654
identification and stage-specific expression of two putative p-glycoprotein coding genes in onchocerca volvulus.the potential for the development of ivermectin (ivm) resistance in microfilariae of onchocerca volvulus and the existence of ivm tolerance in adult worms of this human pathogen are major concerns for the effective control of onchocerciasis. p-glycoprotein (p-gp), an atp-binding transporter protein associated with multidrug resistance in mammals, protozoa and the nematode, haemonchus contortus, might play important roles in the development of ivm resistance and/or in the tolerance of adult o. vo ...199910498183
human onchocerciasis and tetanus vaccination: impact on the postvaccination antitetanus antibody investigate whether helminth infections may affect the efficacy of vaccines by impairing the immune response to nonparasite vaccine antigens, we compared the antibody responses to tetanus toxoid (tt) after tetanus vaccination in 193 subjects with onchocerca volvulus infection with 85 comparable noninfected controls. after vaccination, the proportions of subjects in each group attaining protective levels of antitetanus antibodies were similar (96.9% infected versus 97.6% noninfected). postvacc ...199910531253
prenatal immune priming with helminth infections: parasite-specific cellular reactivity and th1 and th2 cytokine responses in neonates.the present investigation aimed to determine to what extent maternal helminth infection primes parasite-specific cellular responsiveness in neonates. umbilical cord mononuclear blood cells (ucbc) and peripheral blood mononuclear cells (pbmc) from mothers proliferated in response to mitogenic stimulation with concanavalin a, as well as to bacterial streptococcus pyogenes-derived (streptolysin o) and helminth-specific antigens of necator americanus and onchocerca volvulus. cellular responses to ec ...200010955699
biting behaviour and potential vector status of anthropophilic blackflies in a new focus of human onchocerciasis at minaçu, central brazil.monthly collections were made of man-biting female blackflies: simulium auripellitum enderlein, s. guianense wise, s. minusculum lutz and s. nigrimanum macquart (diptera: simuliidae) from four catching stations in the newly discovered focus of human onchocerciasis at minaçu (13 degrees 35 minutes s 48 degrees 18 minutes w), 300 km north of brasília in goiás state. these provided baseline data on biting habits, population density and seasonal prevalence during the year before completion of the se ...200111297099
early human infection with onchocerca volvulus is associated with an enhanced parasite-specific cellular immune response.the immune response after early exposure to or infection with onchocerca volvulus was investigated in an autochthonous focus caused by the migration of infected persons to a previously unaffected area in ecuador. peripheral blood mononuclear cell (pbmc) proliferative and cytokine responses (interferon [ifn]-gamma and interleukin [il]-5) to filarial antigens were measured in 14 subjects with serologic evidence of exposure and in 7 subjects with evidence of dermal microfilarial dna and were compar ...200111343216
neutrophil accumulation around onchocerca worms and chemotaxis of neutrophils are dependent on wolbachia endobacteria.unlike in many other helminth infections, neutrophilic granulocytes are major cellular components in the hosts immune response against filarial worms. the pathways that drive the immune response involving neutrophils are unclear. this study shows that wolbachia endobacteria (detectable by polyclonal antibodies against endobacterial heat shock protein 60 and catalase and by polymerase chain reaction being sensitive to doxycycline treatment) are direct and indirect sources of signals accounting fo ...200111377205
a stochastic model for the aggregation of onchocerca volvulus in nodules.a model is presented which describes the aggregation of female onchocerca volvulus in nodules and their distribution in the human population. the basic model is based on a single parameter, the formation probability q, which represents the probability with which incoming larvae form a new nodule. this parameter describes parasite behaviour which cannot easily be recognized in available data without modelling. the estimate for the average formation probability of muq = 0.39 suggests an attraction ...200111510685
combined benefits of annual mass treatment with ivermectin and cattle zooprophylaxis on the severity of human onchocerciasis in northern cameroon.we studied the effect of 10 annual distributions of ivermectin for control of human onchocerciasis on the reduction of onchocerca volvulus transmission by simulium vector flies. prevalence and infection load in the human population decreased, whilst the annual biting rates (abr) of the vector remained unchanged. the annual transmission potential of infective larvae of o. volvulus fell to 40% of the pre-intervention level, but was still sufficient to maintain endemicity. however, recent immigrati ...200111555439
gene structure of the extracellular glutathione s-transferase from onchocerca volvulus and its overexpression and promoter analysis in transgenic caenorhabditis elegans.two highly similar genes encoding unique extracellular, glycosylated glutathione s-transferases (gsts) of the human-pathogenic nematode, onchocerca volvulus (ov-gst1a and ov-gst1b), have been isolated and characterised. the genes are approximately 3 kb in length and consist of seven exons interrupted by introns of approximately 100 bp in length, with the exception of intron ii, which is approximately 1.6 kb in length. interestingly, exon i and ii encode a signal peptide and an n-terminal extensi ...200111606224
misidentification of onchocerca volvulus as guinea worm.over the past 10 years, the status of human infection with guinea worm (dracunculus medinensis) in the central african republic (car) has been difficult to ascertain. it is unclear if indigenous cases are occurring and whether cases are migrating into the car from surrounding countries. a team of investigators visited the car in july-august 2000, to attempt to ascertain the presence of indigenous transmission. no cases of true guinea-worm infection (i.e. dracunculiasis) were detected, but three ...200111784436
the variant arg110gln of human il-13 is associated with an immunologically hyper-reactive form of onchocerciasis (sowda).onchocerca volvulus infection usually results in a predominantly immunopermissive reaction called generalized onchocerciasis and characterized by high microfilarial burden and immunological tolerance to the worms. rarely, however, infection leads to the sowda form of the disease displaying low microfilarial numbers, i.e. microfilarial control, and a t helper 2 (th2)-type immune response including high immunoglobulin (ig)e levels, and interleukin (il)-13 being one of the key cytokines. the aim of ...200211825773
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