Publications

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 ...	1985	4070919
[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 ...	1985	3937568
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 ...	1985	3923666
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 ...	1986	3785977
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 4.1.1.17) and arginine decarboxylase (ec 4.1.1.19), respectively, were not detectable. experiments carried out with o. volv ...	1987	3627168
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 ...	1987	3602843
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. ...	1987	3595320
quantitative studies of onchocerciasis transmission by simulium yahense and simulium sanctipauli in the firestone rubber plantation at harbel, liberia.	black 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 ...	1987	3578652
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 ...	1988	3366573
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. ...	1987	3297554
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 ...	1988	3256278
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 ...	1988	3067324
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 ...	1986	3024001
the status of simulium oyapockense and s. limbatum as vectors of human onchocerciasis in brazilian amazonia.	in 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 ...	1987	2979535
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 ...	1985	2868636
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 ...	1989	2811941
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 ...	1989	2740729
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 ...	1989	2679172
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 ...	1989	2482559
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 ...	1987	2436130
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 ...	1986	2429180
molecular cloning, expression, and chromosome 19 localization of a human ro/ss-a autoantigen.	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 ...	1990	2332496
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 ...	1990	2255840
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 ...	1990	2198761
changes in antibody profile after treatment of human onchocerciasis.	to 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 ...	1990	2197344
guatemalan human onchocerciasis. ii. evidence for igg3 involvement in acquired immunity to onchocerca volvulus and identification of possible immune-associated antigens.	ag-specific 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 ...	1991	2033268
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 ...	1991	2016131
identification of different radiolabelled antigens of the developmental stages of onchocerca volvulus.	by 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 ...	1990	1978531
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 ...	1991	1919005
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 ...	1991	1888206
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 ...	1991	1866191
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 ...	1991	1775166
identification of circulating parasite acetylcholinesterase in human and rodent filariasis.	in 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 ...	1992	1480604
human onchocerciasis in the lower jos plateau, central nigeria: the prevalence, geographical distribution and epidemiology in akwanga and lafia local government areas.	an 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 ...	1992	1304706
fundus lesions in the rabbit eye following inoculation of onchocerca volvulus microfilariae into the posterior segment. i. the clinical picture.	live 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 ...	1976	1258139
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 ...	1975	1216332
sequential affinity chromatography for the purification of antigens extracted from onchocerca volvulus adult worms.	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 ...	1978	644658
an evaluation of the bovine -- onchocerca gibsoni, onchocerca gutturosa model as a tertiary screen for drugs against onchocerca volvulus in man.	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 ...	1979	538819
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 ...	1979	507287
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 ...	1979	394410