| onchocerca ochengi: epidemiological evidence of cross-protection against onchocerca volvulus in man. | in north cameroon, the vector of onchocerca volvulus (causative agent of human onchocerciasis) also transmits 2 filariae of animals: o. ochengi from cattle and o. ramachandrini from wart hogs. in order to assess the qualitative and quantitative roles of these 'animal filariae' in the epidemiology of o. volvulus, the transmission of the 3 parasites was measured in 2 villages and related to the endemicity of human onchocerciasis. in galim, a cattle-farming guinea savanna village where wild animals ... | 1998 | 9585937 |
| in vitro production and characterization of excretory/secretory products of onchocerca volvulus. | onchocerca volvulus excretory/secretory products [esp] free of host contaminants are often needed for immunologic and biochemical studies. since prolonged in vitro survival of o. volvulus in culture requires the presence of human serum, as a supplement, it was necessary to investigate other culture medium supplements in which pure esp could be generated. thus heat-inactivated normal rabbit serum, fetal calf serum and the synthetic serum substitute ultroser-g were tested for their abilities to su ... | 1997 | 9587603 |
| [mectizan and onchocerciasis: 10 years of mectizan in africa, a partnership for prolonged success]. | | 1998 | 9592889 |
| current status of onchocerciasis in colombia. | to assess the current epidemiologic status of onchocerciasis in colombia two surveys were undertaken in 1995 in a suspected new focus on the border between colombia and ecuador and in the known focus located on the micay river. no new focus was found along the colombia-ecuador border. in the known focus, communities along the upper micay river and its tributaries were surveyed; 655 adults underwent physical examinations and skin biopsies. infected individuals were found almost exclusively in the ... | 1998 | 9598447 |
| [human onchocerciasis in africa]. | before the 1980s, the only available method for control of onchocerciasis was elimination of blackfly vector populations. this strategy was used with considerable success in the onchocerciasis control programme in west africa (ocp). the discovery of ivermectin, the first effective drug suitable for mass treatment of onchocerciasis, has revived international interest not only in fundamental research but also in development of new strategies to control onchocerciasis in the countries outside the o ... | 1997 | 9612783 |
| the role of eosinophils and neutrophils in helminth-induced keratitis. | intrastromal injection of mice with antigens from the parasitic helminth that causes river blindness (onchocerca volvulus) induces eosinophil recruitment to the corneal stroma at the time of maximum corneal opacification and neovascularization. the present study was conducted to examine the role of eosinophils and neutrophils in onchocercal keratitis in control c57bl/6 mice and in interleukin-5 gene knockout (il-5(-/-)) mice. | 1998 | 9620077 |
| novel, sensitive and low-cost diagnostic tests for 'river blindness'--detection of specific antigens in tears, urine and dermal fluid. | sensitive, specific and low-cost diagnostic tests for onchocerciasis are indispensable for monitoring the efficacy of control programs, as well as for preventing blindness (when the tests are combined with efficacious chemotherapy. three new tests to detect onchocerca-specific antigens in tears, dermal fluid and urine employ antibodies to o. volvulus-specific recombinant proteins, oncho-c27 and ovd3b, encoded by genes within the immunodominant onchocerca ov 33-3 gene family, and expressed in yea ... | 1998 | 9623938 |
| chemotherapy for onchocerciasis: results of in vitro experiments with promising new compounds. | an improved short-term in vitro culture system was used for the routine screening of hundreds of promising new compounds with the target organism, the filarial nematode onchocerca volvulus. the most active leads were identified among the pyrimidinylguanidines, amidine derivatives, the imidazolinylhydrazones, thiosemicarbazone derivatives and thiadiazole derivatives. single compounds of these leads demonstrated strong macrofilaricidal efficacy in minimum effective dose trials down to 0.1 microm a ... | 1998 | 9623946 |
| research notes from the onchocerciasis chemotherapy research centre, ghana. | brief notes are given on drugs which have been tested at the onchocerciasis chemotherapy research centre at tamale and hohoe and found to have activity against onchocerca volvulus. ivermectin in single doses as high as 800 micrograms/kg was found to be no more effective than the standard dose of 150 micrograms/kg. the benzimidazole carbamates, mebendazole and albendazole, differ in their effects on o. volvulus. the former has microfilaricidal effects and is toxic to developing embryos surrounded ... | 1997 | 9625924 |
| tropomyosin implicated in host protective responses to microfilariae in onchocerciasis. | a cdna from adult female onchocerca volvulus encoding the c-terminal portion of a tropomyosin isoform (termed mov-14) has been shown previously to confer protective immunity in rodent models of onchocerciasis. the full-length sequence (designated ov-tmy-1) obtained by pcr amplification, codes for a protein of 33 kda and shares 91% identity with tropomyosins from other nematodes, falling to 57% identity with human alpha-tropomyosin. ov-tmy-1 migrates with an apparent molecular mass of 42 kda on s ... | 1998 | 9636187 |
| [occurrence of onchocerciasis in subjects coming from non-endemic areas and migrating to a hyperendemic area]. | the incidence of onchocerca volvulus infection was measured from 1992-93 to 1995 in six villages of initially uninfected migrants who settled in 1991 in the vina valley (cameroon), an area of ongoing transmission of onchocerciasis. the mean annual incidence (mai) exceeded 20% in the three communities located in the first line, and fewer than 15 km from the hyperendemic areas of the central african republic. the mai was lower than 16% in the second line communities. as these populations are parti ... | 1998 | 9642478 |
| [entomologic study on the transmission of onchocerciasis in a forest-savanna transition area of cameroon]. | an entomological study was conducted in the basin area of middle sanaga (cameroon) in order to document the pattern of onchocerciasis transmission in a region where a high prevalence of infection had been recorded in villages located 30 km from the main rivers. the main vector of o. volvulus was found to be s. squamosum s.s. no breeding site was found in the small tributaries of the sanaga and mbam rivers, and the dispersal of s. damnosum s.l. in the area thus appeared to be particularly high. t ... | 1998 | 9642481 |
| onchocerciasis. | an estimated 17.7 million persons, most of them in africa, are infected with the parasite onchocerca volvulus. onchocerciasis has caused blindness in 270,000 and left another 500,000 with severe visual impairment. onchocerciasis also can cause disfiguring skin changes, musculoskeletal complaints, weight loss, changes in immune function, epilepsy, and growth arrest. the development of ivermectin and its donation by the manufacturer has reduced transmission in many parts of africa and latin ame ... | 1998 | 9643811 |
| polymorphic microsatellites in simulium damnosum s.l. and their use for differentiating two savannah populations: implications for epidemiological studies. | in west africa, onchocerca volvulus, the cause of human onchocerciasis, is transmitted by sibling species of the simulium damnosum complex. little is known about blackfly intraspecific variability and its consequences on vectorial capacity. this study reports the use of microsatellite markers for differentiating populations of s. damnosum s.l. five microsatellite loci were characterized and used to analyze individuals from two savannah populations in mali, 120 km apart. four loci were highly pol ... | 1998 | 9644826 |
| onchocerciasis control in uganda. | in 1990 a community-based programme of onchocerciasis control, involving the use of ivermectin, was introduced in uganda. the problems confronting it are discussed and suggestions are made for making it sustainable. | 1998 | 9652221 |
| detection of onchocerca volvulus infection by o-150 polymerase chain reaction analysis of skin scratches. | the standard assay for onchocerciasis diagnosis is microscopic detection of parasites in skin snips. skin snipping is painful and may potentially transmit bloodborne infections. thus, an alternative method for the diagnosis of onchocerciasis that does not require skin snipping is needed. a polymerase chain reaction (pcr)-based assay was shown to detect the presence of parasite dna in superficial skin scrapings. detection of parasite dna in both skin snips and skin scratches was found to be more ... | 1998 | 9652456 |
| 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 ... | 1998 | 9657514 |
| detection of the filarial parasite mansonella streptocerca in skin biopsies by a nested polymerase chain reaction-based assay. | to differentiate the skin-dwelling filariae mansonella streptocerca and onchocerca volvulus, a nested polymerase chain reaction (pcr) assay was developed from small amounts of parasite material present in skin biopsies. one nonspecific and one specific pair of primers were used to amplify the 5s rdna spacer region of m. streptocerca. biopsies with different microfilaria densities obtained from 104 ugandans living in an area endemic for m. streptocerca were tested using both the nested pcr assay ... | 1998 | 9660471 |
| molecular cloning of an enzymatically active thioredoxin peroxidase from onchocerca volvulus. | | 1998 | 9662714 |
| mast cells in onchocercomas from patients with hyperreactive onchocerciasis (sowda). | in onchocerciasis, variations of the host's immune responsiveness produce a spectrum of clinical manifestations ranging from the common generalized to the rare hyperreactive form (sowda). for further characterization of the immune response, the localization and frequency of mast cells in onchocercomas from untreated and ivermectin-treated patients with hyperreactive onchocerciasis from liberia and the yemen were analysed and compared to the generalized form by immunohistochemistry with antibodie ... | 1998 | 9698269 |
| studies on immunodiagnosis of dracunculiasis. i. detection of specific serum antibodies. | to explore the possibility for development of an immunodiagnostic test for dracunculus medinensis infections, the antibody responses (igg1, igg2, igg3, igg4 and ige) to antigen preparations made from adult female worms (adgw) and first stage larvae (lvgw) of d. medinensis were analysed. by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (sds-page)/western blotting, sera from individuals with patent d. medinensis infection reacted extensively and similarly with adgw and lvgw over a bro ... | 1998 | 9707366 |
| onchocerca volvulus: microfilariae secrete elastinolytic and males nonelastinolytic matrix-degrading serine and metalloproteases. | host tissue penetration by parasitic nematodes may be mediated by both mechanical processes and proteolytic enzymes released by the parasites. analysis of excretory-secretory (es) products of onchocerca volvulus microfilariae and adult stages on substrate gels demonstrated that they contain several distinct proteolytic enzymes. the analysis of the es products of the microfilariae revealed one low and two high molecular weight proteolytic bands that degraded gelatin in substrate gels. the low mol ... | 1998 | 9709027 |
| detection of onchocerca volvulus dna in pools of wild-caught simulium ochraceum by use of the polymerase chain reaction. | the presence of onchocerca volvulus dna in experimentally infected flies can now be detected by use of the pcr, so that, for example, one infected simulium damnosum can be detected in a pool of 100 uninfected flies or one s. ochraceum can be detected in pools of 20-40. as this pcr technique is specific for o. volvulus, the results are not confounded by the presence of other, unimportant, onchocerca species, and the technique could replace time-consuming, manual dissection of flies. in 1996 and 1 ... | 1998 | 9713545 |
| prevalence of onchocerca volvulus nodules in the sankuru river valley, democratic republic of the congo, and reliability of verbal assessment as a method for determining prevalence. | the epidemiology of onchocerciasis in much of the democratic republic of the congo (formerly zaire) is not well established. we report the results of an onchocerciasis rapid assessment survey carried out in 18 villages of the sankuru river valley in the central part of this country in preparation for mass distribution of ivermectin. thirty men from each village were randomly selected and examined for subcutaneous nodules. the prevalence of nodules among these men in each village ranged from 82.5 ... | 1998 | 9715937 |
| immune responses to third stage larvae of onchocerca volvulus in interferon-gamma and interleukin-4 knockout mice. | to shed clarity on the dichotomy of reported results relative to the significance of t helper-1 vs t helper-2 immune responses in onchocerciasis, we compared the survivability of onchocerca volvulus third-stage larvae (l3) in immunized mice that had either a targeted disruption of the interleukin-4 or interferon-gamma gene. treatment groups consisted of control mice and mice immunized with irradiated o. volvulus l3. all mice were challenged with diffusion chambers containing viable l3. vaccinate ... | 1998 | 9717193 |
| identification of a peroxidoxin protein (ovpxn-2) of the human parasitic nematode onchocerca volvulus by sequential protein fractionation. | | 1998 | 9719517 |
| immunoelectron microscopic evidence for release of eosinophil granule matrix protein onto microfilariae of onchocerca volvulus in the skin after exposure to amocarzine. | the involvement of eosinophils in the host reaction to microfilariae (mf) of onchocerca volvulus was studied by immunohistochemistry and immunoelectron microscopy. skin biopsies were obtained from patients after transepidermal administration of the microfilaricide amocarzine. at 20-28 h after the application of amocarzine, mf were degenerated or dead and a marked eosinophil-parasite adherence (epa) reaction was seen, with intense staining for intra- and extracellular eosinophil granule proteins ... | 1998 | 9747932 |
| the peroxidoxin 2 protein of the human parasite onchocerca volvulus: recombinant expression, immunolocalization, and demonstration of homologous molecules in other species. | the peroxidoxin protein of the filarial parasite onchocerca volvulus (ovpxn-2) belongs to a group of highly conserved antioxidant molecules. for a more detailed characterization of this protein and for determination of its expression pattern the ovpxn-2 protein was recombinantly expressed as a his-tagged protein. under reducing conditions the recombinant protein had an apparent molecular mass of 28 kda. considering the size of the his-tag and the flag epitope introduced to the recombinant protei ... | 1998 | 9747934 |
| [identifying areas of epidemiological stratification in an onchocerciasis focus in yanomami territory, roraima, brazil]. | in this paper, aimed at suitable planning, analysis, and follow-up of treatment, control, and eradication in a human onchocerciasis program, were studied 27 geographic areas and examined 3,974 inhabitants. four epidemiological areas with different prevalences were identified and stratified. | 1998 | 9761614 |
| use of p-glycoprotein gene probes to investigate anthelmintic resistance in haemonchus contortus and comparison with onchocerca volvulus. | a p-glycoprotein gene probe from the sheep parasitic nematode haemonchus contortus was developed and used to analyse restriction fragment length polymorphisms between susceptible isolates and isolates resistant to either benzimidazole; levamisole and benzimidazole; or benzimidazole, ivermectin and closantel. no polymorphism could be correlated with any of the different resistances. a p-glycoprotein gene probe was also isolated from the human nematode parasite onchocerca volvulus and an onchocerc ... | 1998 | 9762570 |
| the mitochondrial genome of onchocerca volvulus: sequence, structure and phylogenetic analysis. | the complete dna sequence of the mitochondrial genome of onchocerca volvulus is described. the o. volvulus mitochondrial genome is 13747 bp, slightly smaller than the mitochondrial genomes of the nematodes ascaris suum and caenorhabditis elegans, and the smallest metazoan mitochondrial dna molecule reported to date. the o. volvulus mitochondrial genome contains genes for two ribosomal rnas, 22 transfer rnas and 12 proteins. consistent with the small size of the genome, four gene pairs overlap an ... | 1998 | 9763293 |
| a recombinant protein disulfide isomerase homologue from ancylostoma caninum. | the objective of this study was to characterize a recombinant antigen of ancylostoma caninum that had been identified by immunoscreening with selected antisera as described elsewhere. in vitro expression of clone ac38-1 produced a protein with an apparent molecular mass of approximately 38 kda, which reacted in western blots with the antiserum from rabbits experimentally infected with l3 and also with affinity-purified antibodies against hydrophilic proteins of the cephalic glands obtained from ... | 1998 | 9766908 |
| t cell responses in coinfection with onchocerca volvulus and the human immunodeficiency virus type 1. | onchocerca volvulus and the human immunodeficiency virus (hiv) are two immunocompromising infectious agents of major public health concern in uganda. to examine the effect of coinfection with o. volvulus and hiv on cellular immune responses, lymphocyte proliferative responses and cytokine production of peripheral blood mononuclear cells (pbmc) from persons infected with o. volvulus with and without hiv type 1 infection were compared. proliferation of pbmc to pha and tuberculin (ppd) in coinfecti ... | 1998 | 9767610 |
| [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 ... | 1991 | 9768181 |
| resistance of filarial nematode parasites to oxidative stress. | all filariae examined to date express a comprehensive repertoire of both cytoplasmic and secreted anti-oxidant enzymes, although significant differences exist between species and life-cycle stages. adult brugia malayi, dirofilaria immitis and onchocerca volvulus secrete cuzn superoxide dismutases, and the former two species also secrete a selenocysteine-independent glutathione peroxidase. this enzyme has been localised to the cuticular matrix of b. malayi, and the preferential reduction of fatty ... | 1998 | 9770616 |
| 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 ... | 1998 | 9775604 |
| detection of a chemotactic factor for neutrophils in extracts of female onchocerca volvulus. | neutrophilic granulocytes and macrophages are the dominant inflammatory cell types observed in the vicinity of and attached to adult onchocerca volvulus in the subcutaneous nodules. crude extract from female o. volvulus was examined for chemotactic activity for peripheral neutrophils from healthy individuals by use of an endogenous component chemotactic assay in boyden chambers. significant chemotactic responses of neutrophils were detected using o. volvulus extracts at > or = 15 microg/ml in a ... | 1998 | 9776142 |
| blackfly control: what choices after onchocerciasis? | blackflies are reappearing in areas of west africa where they used to be controlled with insecticides because they were vectors of the parasite onchocerca volvulus. even though they no longer transmit onchocerciasis in these areas they can hinder optimal land use through their biting behaviour. the authors discuss the problems associated with resuming the use of insecticides to control the blackfly and recommend that ground treatment be restricted to areas where it is likely to be effective on a ... | 1998 | 9786050 |
| short report: total serum levels of the nitric oxide derivatives nitrite/nitrate during microfilarial clearance in human filarial disease. | nitric oxide (no) has recently been shown to be cytotoxic to both microfilariae and adult brugia malayi in vitro and in a murine model, as well against onchocerca lienalis microfilariae in vitro. we studied the kinetics of nitrite/nitrate, both stable end products of no, by high-pressure liquid chromatography during microfilaricidal chemotherapy in four filariasis (three loa loa, and one onchocerca volvulus) patients. high serum levels of nitrite/nitrate were released during microfilarial cleara ... | 1998 | 9790422 |
| a divergent multi-domain cyclophilin is highly conserved between parasitic and free-living nematode species and is important in larval muscle development. | a divergent multi-domain cyclophilin from the filarial nematodes brugia malayi, onchocerca volvulus and dirofilaria immitis has a highly conserved orthologue in the free-living nematodes caenorhabditis elegans and c. briggsae. cyclophilins are the receptors for the immunosuppressive and anti-parasitic agent cyclosporin a and additionally these ubiquitously expressed proteins have protein folding capabilities, and exhibit proline isomerase activity. these divergent nematode cyclophilins (cyp-4 is ... | 1998 | 9803414 |
| 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 ( ... | 1998 | 9806045 |
| onchocerciasis in an expatriate living in cameroon. | travelers to west, central and eastern africa as well as to selected areas of latin america are at risk for infection with onchocerca volvulus. infection with this tissue nematode may cause chorioretinitis and keratitis, and it is responsible in endemic areas for blindness in millions.1 in addition to ocular manifestations, it can produce a distressing pruriginous dermatitis or subcutaneous nodules. clinical manifestations vary according to the parasitic load, previous immunity, and duration of ... | 1997 | 9815471 |
| filarial nematode parasites secrete a homologue of the human cytokine macrophage migration inhibitory factor. | filarial nematode parasites establish long-term chronic infections in the context of an antiparasite immunity that is strongly biased toward a th2 response. the mechanisms that lead to this th2 bias toward filarial antigens are not clear, but one possibility is that the parasites produce molecules that have the capacity to proactively modify their immunological environment. here we report that filarial parasites of humans secrete a homologue of the human proinflammatory cytokine macrophage migra ... | 1998 | 9826378 |
| onchocerciasis and chagas' disease control: the evolution of control via applied research through changing development scenarios. | this paper addresses the development of control strategies of two different parasitic diseases and identifies commonalities which have contributed to the success of regional intercountry programmes of onchocerciasis control in africa, the onchocerciasis control programme (ocp), and the new african programme for onchocerciasis control (apoc) and the chagas' disease control programme in the southern cone of south america. | 1998 | 9830200 |
| long-term quantitative ecological assessment of insecticides treatments in four african rivers: a methodological approach. | in west africa different insecticides had been applied in selected river areas for the reduction of the blackfly populations vectors of onchocerca volvulus, a parasite causing blindness. to evaluate the possible long term effects of the larvicides on the non target fauna an aquatic monitoring programme has been up from the initial phase of the project. addressing the attention to the invertebrates data collected in four countries during a maximum period ranging from 1977 to 1996, this paper show ... | 1998 | 9839403 |
| gene structure, activity and localization of a catalase from intracellular bacteria in onchocerca volvulus. | within the context of studies on the antioxidant enzymes in onchocerca volvulus, dna clones encoding catalase (cat) were isolated from an o. volvulus adult lambda zapii cdna library. analysis of their nucleotide and encoded amino acid sequences revealed that they derive from intracellular bacteria, rather than the o. volvulus nuclear genome. the endobacterial cat gene was found to lie in a gene cluster, followed by a ferritin gene and an excinuclease gene. the endobacterial cat gene encodes a fu ... | 1998 | 9851608 |
| characterization of an onchocerca volvulus l3-specific larval antigen, ov-alt-1. | | 1998 | 9851616 |
| ivermectin influence on the mast cell activity in nodules of onchocerciasis patients. | onchocercal nodules were stained immunohistochemically using antibodies specific for human mast cells and ige to elucidate the localization and frequency of mast cells after a single oral dose of 150 microg/kg ivermectin. tryptase-and chymase-positive mast cells occurred predominantly in mixed inflammatory infiltrates and perivascularly, and never adhered to adult worms or microfilariae. up to three days after ivermectin, mast cells and ige-positive cells were markedly increased in the capsular ... | 1998 | 9855406 |
| onchocerciasis: the burden of disease. | the greatest burdens related to human onchocerciasis are the result of the eye and skin lesions and severe itching produced by the microfilariae. although the major manifestations of the disease do show geographical variation (e.g. onchocercal blindness is not a common complication in all endemic countries), they are often sufficiently severe to prevent human use of the often very fertile land close to the rivers in which the vectors breed. though for many years thought to be of relatively minor ... | 1998 | 9861275 |
| the burden of onchocerca volvulus in sudan. | onchocerciasis has been reported in sudan since 1908 and now prevails in three endemic regions known as the southern, northern and eastern foci. the southern focus is the largest, with nodule and blindness rates exceeding 80% and 12%, respectively, in certain villages. onchocercal infection in this region causes only a mild skin reaction although microfilarial loads in the skin are high. in contrast, those with onchocerciasis in the northern focus, located between the fourth and fifth nile catar ... | 1998 | 9861278 |
| the significance of guinea worm infection in the immunological diagnosis of onchocerciasis and bancroftian filariasis. | infections with dracunculus medinensis frequently occur in the same geographical area as infections with onchocerca volvulus and wuchereria bancrofti. this study analysed the significance of d. medinensis infections for the specificity and sensitivity of available tests for antibody-based diagnosis of onchocerciasis (using individual recombinant clones ov-10, ov-11 and ov-16, and the ov-7/ov-10/ov-16 tri-cocktail, in an enzyme-linked immunosorbent assay) and for circulating antigen-based diagnos ... | 1998 | 9861367 |
| mgbg analogues as potent inhibitors of s-adenosylmethionine decarboxylase of onchocerca volvulus. | polyamines are essential for cell growth and differentiation and therefore, s-adenosylmethionine decarboxylase (samdc), a key regulatory enzyme of the polyamine biosynthesis, is considered as a potentially important target for chemotherapy of filarial infections. recombinant onchocerca volvulus samdc was expressed in escherichia coli and characterised. the enzyme activity was found to be stimulated 15-fold by addition of 1 mm putrescine. the km-value for s-adenosylmethionine was determined to be ... | 1998 | 9879883 |
| a cocktail of recombinant onchocerca volvulus antigens for serologic diagnosis with the potential to predict the endemicity of onchocerciasis infection. | we report here the evaluation of the potential of a serologic test to determine the endemicity of onchocercal infection in hyper, meso, and hypoendemic communities by the detection of antibodies to a cocktail of recombinant antigens. parasitologic parameters of infection prevalence and intensity were compared with serologic results. infection prevalence by serology was consistently but not significantly higher than that defined by parasitology. differences between the communities defined by micr ... | 1998 | 9886193 |
| onchocerca volvulus: immunolocalization of the extracellular cuzn superoxide dismutase using antibodies raised against a 15-mer epitope of this enzyme. | the study describes the immunohistological localization of the extracellular cuzn superoxide dismutase (sod2) in the parasitic nematode onchocerca volvulus. using specific antiserum raised against a 15-amino-acid peptide from the n-terminal region of the mature protein, this enzyme is detected primarily in the intestinal epithelium of the adult worms and to a lesser extent in the muscle cells of the uterine wall. a blocking experiment with the sod2 peptide reduced the staining significantly, con ... | 1999 | 9920037 |
| antibody to the dirofilaria immitis aspartyl protease inhibitor homologue is a diagnostic marker for feline heartworm infections. | feline heartworm disease, caused by the filarial nematode dirofilaria immitis, has been diagnosed with increased frequency in areas endemic for canine heartworm infection. the routine methods for determining the infection status of dogs, such as identification of circulating microfilariae in blood or identification of circulating antigen in serum, plasma or blood, have proven inadequate for screening cats. the inadequacies are due to the likelihood of single-sex infections and clinical disease d ... | 1998 | 9920319 |
| in-vitro uptake of ivermectin by adult male onchocerca ochengi. | ivermectin is not lethal to the adult worms of onchocerca volvulus or to those of o. ochengi, a cattle parasite closely related to o. volvulus. although ivermectin penetrates the nodules in which the adults of these nematodes live, it is not known what levels of the drug enter the worms. adult male o. ochengi were incubated in [3h]ivermectin in a saturated solution of unlabelled ivermectin (11.44 microm), to measure uptake by the oral and transcuticular routes, and in [3h]inulin, to ascertain if ... | 1998 | 9924550 |
| eosinophil sequestration and activation are associated with the onset and severity of systemic adverse reactions following the treatment of onchocerciasis with ivermectin. | to investigate the role of eosinophil activation and sequestration in the development and severity of adverse reactions after the treatment of onchocerca volvulus infection, 40 o. volvulus-infected ghanaians were randomized to receive placebo or standard- or high-dose ivermectin. subjects were examined for typical physiologic and clinical events before and up to 48 h after treatment. plasma samples were tested for interleukin (il)-5 and eosinophil degranulation products (e.g., eosinophil-derived ... | 1999 | 9952390 |
| pool screen polymerase chain reaction for estimating the prevalence of onchocerca volvulus infection in simulium damnosum sensu lato: results of a field trial in an area subject to successful vector control. | detection of infective parasites in the vector population can be an early indicator of recrudescence in areas freed of new cases of onchocerciasis. however, dissection of vector black flies is inefficient in areas subject to effective control. recently, a polymerase chain reaction (pcr)-based assay has been used to detect a single onchocerca volvulus-infected black fly in pools containing large numbers of uninfected flies. this method had not been validated on wild-caught black flies in an area ... | 1999 | 9988335 |
| chemoprophylaxis of onchocerca infections: in a controlled, prospective study ivermectin prevents calves becoming infected with o. ochengi. | onchocerciasis ('river blindness'), caused by the filarial nematode onchocerca volvulus is of major public health importance in west africa. ivermectin, a drug originally developed for veterinary use, is now being incorporated in control strategies but whilst it has potent efficacy against l1 larvae (microfilariae), ivermectin is not lethal to adult (l5) o. volvulus, nor to adults of the related cattle parasite o. ochengi. we have exploited this model to determine if ivermectin has prophylactic ... | 1999 | 10028534 |
| induction of specific cell-mediated immunity in mice by oral immunization with salmonella expressing onchocerca volvulus glutathione s-transferase. | cellular and humoral immune responses of mice to onchocerca volvulus glutathione s-transferase (ovgst) presented via in vivo expression in attenuated salmonella typhimurium were examined and compared with the same antigen administered by subcutaneous injection with freund's adjuvant. after infection with recombinant s. typhimurium, maximal numbers of bacteria were recovered from the mesenteric lymph nodes and spleens during the second week postinfection. by weeks 3-4, bacteria were absent from t ... | 1999 | 10078605 |
| molecular cloning of the 22-24 kda excretory-secretory 22u protein of dirofilaria immitis and other filarial nematode parasites. | | 1999 | 10080399 |
| onchocerciasis and epilepsy: a matched case-control study in the central african republic. | the occurrence of epileptic seizures during onchocercal infestation has been suspected. epidemiologic studies are necessary to confirm the relation between onchocerciasis and epilepsy. a matched case-control study was conducted in dispensaries of three northwestern towns of the central african republic. each epileptic case was matched against two nonepileptic controls on the six criteria of sex, age (+/-5 years), residence, treatment with ivermectin, date of last ivermectin dose, and the number ... | 1999 | 10084246 |
| [a case of cross infection by onchocerca volvulus and onchocerca ochengi in simulium damnosum s.l]. | during a routine entomological survey conducted within the framework of the program to control onchocerciasis in west africa, a female simulium forest fly was found to be contaminated by 13 onchocerca volvulus larvae and 7 onchocerca ochengi larvae. the two onchocerca species were identified using specific dna probes. we speculate that cross infection could be related either to behavioral factors, e.g. interruption of blood meals on two different hosts, or developmental factors, e.g. asynchronou ... | 1998 | 10088105 |
| [the campaign against onchocerciasis in africa: update]. | two methods are being used to control onchocerciasis. the first has a delayed effect and consists in reducing or interrupting transmission of onchocerca volvulus by eradication of the vector at its most vulnerable developmental stage, i.e. the larval stage. the second method has more immediate effects and consists in mass treatment using ivermectin, the only widely available drug, to reduce the density of microfilariae (the pathogenic stage of the parasite) in the population. both strategies hav ... | 1998 | 10088109 |
| [onchocerciasis]. | | 1999 | 10201255 |
| effects of an onchocerca-derived cysteine protease inhibitor on microfilariae in their simuliid vector. | a recombinant cysteine protease inhibitor, onchocystatin of the parasitic nematode onchocerca volvulus, was tested for its role in microfilarial development in the simuliid vector. onchocystatin was found to be present in female adults and skin microfilariae of the bovine parasite o. ochengi, the closest relative of o. volvulus. in addition the inhibitor could be detected as an excretory-secretory (e-s) product of the microfilariae. co-injection of onchocystatin and the o. ochengi microfilariae ... | 1999 | 10205807 |
| eosinophils, eosinophil cationic protein and eosinophil-derived neurotoxin in serum and urine of patients with onchocerciasis coinfected with intestinal nematodes and in urinary schistosomiasis. | eosinophils, eosinophil cationic protein (ecp), eosinophil-derived neurotoxin (edn/epx), myeloperoxidase (mpo) and ige were measured in blood, serum and/or urine in schistosoma haematobium- and onchocerca volvulus-infected guineans and o. volvulus- and s. haematobium-negative guineans coinfected or infected with intestinal nematodes. the number of eosinophils and levels of eosinophil granule proteins but not of mpo were found to be strongly elevated in all africans as compared to european contro ... | 1999 | 10206116 |
| comparison of serological and parasitological assessments of onchocerca volvulus transmission after 7 years of mass ivermectin treatment in mexico. | to compare the utility of an elisa using 3 recombinant antigens with that of the skin biopsy to estimate incidence of infections in a sentinel cohort of individuals living in an endemic community in southern mexico during a set of 11 subsequent ivermectin treatments. | 1999 | 10206263 |
| [proteolytic activity of adult worm extracts of onchocerca volvulus]. | studying proteolytic activity of onchocerca volvulus (nematode causing "river blindness") shows that it is able to digest a variety of substrates such as: azoalbumine, azocoll and elastin-orcein with specific activity of 0.28, 0.57 and 1.48 mg/hour/mg of extract respectively. these enzymes are active at various ph such as ph 5.0, 8.0 and 10.0 with highest activity at ph 8.0. the effect of specific inhibitors and activators indicates that the extract might contain serine, metallo and thyoprotease ... | 1999 | 10214511 |
| [important parasitic nephropathies: update from the recent literature]. | renal involvement in parasitic infections are polymorphic. plasmodium malariae often leads to membranoproliferative glomerulonephritis whereas acute tubular necrosis or post-infectious acute glomerulonephritis are observed with plasmodium falciparum. urogenital taxis of schistosoma haematobium is responsible for frequency of chronic tubular and interstitial nephritis. without specific treatment, the renal function progressively deteriorates and urological complications appear. schistosoma manson ... | 1999 | 10227026 |
| distribution of the blinding and nonblinding strains of onchocerca volvulus in nigeria. | onchocerciasis remains an important public health problem throughout much of sub-saharan africa. nigeria is the country whose population is most afflicted by onchocerciasis; however, little is known concerning the epidemiology of onchocerciasis in this country. previous studies demonstrated that onchocerciasis in west africa exists in two forms, which differ in their clinical and epidemiologic characteristics. this is believed to be due to the existence of 2 strains of onchocerca volvulus, the c ... | 1999 | 10228087 |
| do filarid nematodes have a vascular system? | | 1999 | 10322327 |
| onchocerciasis in the amazonian focus of southern venezuela: altitude and blackfly species composition as predictors of endemicity to select communities for ivermectin control programmes. | in preparation for an ivermectin distribution programme, the prevalence and intensity of infection due to onchocerca volvulus as well as the species composition and abundance of simulium vectors were investigated in 22 yanomami communities situated along 2 altitudinal transects in the southern venezuelan onchocerciasis focus. these transects corresponded to the ocamo-putaco and orinoco-orinoquito river systems, covering a range of elevation between 50 m and 740 m above sea level (asl). a total o ... | 1998 | 10326102 |
| molecular characterization of fkbp13 from filarial parasites. | | 1999 | 10340490 |
| o-crystallin, arginine kinase and ferritin from the octopus lens. | three proteins have been identified in the eye lens of the octopus, octopus dofleini. a 22 kda protein comprising 3-5% of the soluble protein of the lens is 35-43% identical to a family of phosphatidylethanolamine-binding proteins of vertebrates. other members of this family include the immunodominant antigen of the filarial parasite, onchocerca volvulus, putative odorant-binding proteins of drosophila and a protein with unknown function of caenorhabditis elegans. we have called this protein o-c ... | 1999 | 10350626 |
| 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 ... | 1999 | 10365406 |
| [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. | 1999 | 10392419 |
| pathogenesis of onchocercal keratitis (river blindness). | onchocerciasis is a major cause of blindness. although the world health organization has been successful in reducing onchocerciasis as a public health problem in parts of west africa, there remain an estimated 17 million people infected with onchocerca volvulus, the parasite that causes this disease. ocular pathology can be manifested in any part of the eye, although disease manifestations are frequently characterized as either posterior or anterior eye disease. this review focuses on onchocerca ... | 1999 | 10398675 |
| [variations under genetic control of onchocerca infection as a function of clinical profile in the endemic center of cameroon]. | onchocerciasis, also known as "river blindness", presents a plenum of clinical manifestations which vary from one individual to another, and from one area to another. this large spectrum of clinical manifestations of the disease is an indication of the complexity of the pathogenesis of onchocerciasis and suggests that many interacting factors might influence the clinical features of the disease. the present study has focused on the heterogenicity of the host immune response as a plausible explan ... | 1999 | 10399595 |
| induction of histamine release in parasitized individuals by somatic and cuticular antigens from onchocerca volvulus. | the host immune response in onchocerciasis is believed to contribute to the clinical manifestations of infection. mazzotti and chronic inflammatory reactions might be mediated by mechanisms involving specific ige and reactivity of mast cells and basophils to the parasite antigens. in this report, we show that onchocerca volvulus antigens are capable of inducing histamine release. three types of extracts were prepared from the parasite: soluble total, surface, and cuticular collagen. soluble extr ... | 1999 | 10403330 |
| analysis of renal function in onchocerciasis patients before and after therapy. | the occurrence of renal abnormalities was investigated in patients with onchocerciasis in comparison to individuals without onchocerciasis in guinea. serum creatinine levels, excretion of urinary marker proteins, and kidney size by ultrasound were determined. a high prevalence of glomerular as well as tubular dysfunctions was observed; however, no association with onchocerciasis could be detected. we also hypothesized that patients with hyperreactive onchocerciasis might be prone to develop immu ... | 1999 | 10403331 |
| prenatal immune priming in onchocerciasis-onchocerca volvulus-specific cellular responsiveness and cytokine production in newborns from infected mothers. | this study investigated the effect of maternal onchocerca volvulus infection on humoral and cellular responsiveness in newborn children and their mothers. onchocerca volvulus-specific igg isotypes and ige were significantly elevated in infected mothers and their infants. one year post partum, o. volvulus-specific igg4 was strongly reduced in children of infected mothers, while igg1 responses weakened only slightly. umbilical cord mononuclear blood cells (ucbc) and peripheral blood cells (pbmc) f ... | 1999 | 10403926 |
| 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 ... | 1999 | 10409642 |
| temporal recruitment of neutrophils and eosinophils to the skin in a murine model for onchocercal dermatitis. | the parasitic helminth onchocerca volvulus causes ocular onchocerciasis (river blindness) and onchocercal skin disease. to understand the immunologic basis for early stage skin disease, we developed a model in which c57b1/6 mice were immunized subcutaneously and injected intradermally (in the ear) with soluble o. volvulus antigens (ovag). we found that ear thickness increased significantly after intradermal injection of ovag and remained elevated for at least 7 days. dermatitis was dependent on ... | 1999 | 10432048 |
| [onchocerciasis: the epidemiological and control aspects]. | | 1998 | 10444975 |
| regulatory effects of th1-type (ifn-gamma, il-12) and th2-type cytokines (il-10, il-13) on parasite-specific cellular responsiveness in onchocerca volvulus-infected humans and exposed endemic controls. | the present study investigated in vitro the regulatory effects of t helper 1 (th1)-type (interferon-gamma, ifn-gamma; interleukin-12, il-12) and th2-type cytokines (il-10, il-13) on onchocerca volvulus-specific cellular reactivity in onchocerciasis patients, and in exposed endemic control individuals presenting no clinical and parasitological signs of disease. in both patients and controls, addition of il-10 dose-dependently depressed o. volvulus antigen (ovag)-specific cellular proliferation, a ... | 1999 | 10447735 |
| the effects of high-dose ivermectin regimens on onchocerca volvulus in onchocerciasis patients. | ivermectin, at the standard dose of 150 micrograms/kg bodyweight, does not kill the adult worms of onchocerca volvulus and does not disrupt embryogenesis or spermatogenesis. repeated standard doses, if maintained, arrest microfilarial production but result in only a mild-to-modest macrofilaricidal effect. we investigated whether high doses would effectively kill the adult worms, and whether cessation of microfilarial production could be reproduced by an equivalent, single, high dose. one hundred ... | 1999 | 10450448 |
| onchocerciasis modulates the immune response to mycobacterial antigens. | chronic helminth infection induces a type-2 cellular immune response. in contrast to this, mycobacterial infections commonly induce a type-1 immune response which is considered protective. type-2 responses and diminished type-1 responses to mycobacteria have been previously correlated with active infection states such as pulmonary tuberculosis and lepromatous leprosy. the present study examines the immune responses of children exposed to both the helminth parasite onchocerca volvulus and the myc ... | 1999 | 10469056 |
| [effect of onchocerca volvulus infestation on plasma vitamin a concentration in school children in a rural region of cameroon]. | vitamin a deficiency is known to be associated with immune dysfunction and common childhood infections. however, little is known about the relationship between vitamin a deficiency and onchocerciasis in children. the aim of this study was to determine the prevalence of vitamin a deficiency and to investigate the relationship between vitamin a status and onchocerciasis. a total of 231 children, aged 6 to 15 years, were randomly selected between march 1995 and april 1996 at yambassa and balamba (c ... | 1999 | 10477403 |
| eotaxin expression in onchocerca volvulus-induced dermatitis after topical application of diethylcarbamazine. | in persons with onchocerciasis, topical application of the anthelminthic diethylcarbamazine (dec) induces clinical and histologic responses similar to acute papular onchodermatitis, including recruitment of eosinophils to the skin. to determine whether the eosinophil chemokine eotaxin is likely to be associated with eosinophil recruitment in onchodermatitis, dec was applied to a 5-cm2 area on the skin of infected persons, and biopsies were taken from lesions 24 h later. histologic analysis showe ... | 1999 | 10479181 |
| long-term suppression of mansonella streptocerca microfilariae after treatment with ivermectin. | the long-term effect of a single oral dose of 150 microg/kg of body weight of ivermectin on mansonella streptocerca microfilariae was studied in western uganda. before treatment, the geometric mean microfilaria density (mf) in 93 infected persons was 2.4 mf/mg of skin (range, 0.1-42.6). one year after treatment, 43 persons (46%) were microfilaria-negative, and the geometric mean in the remaining persons dropped significantly, to 0.7 mf/mg (range, 0.1-6.9). thus, ivermectin is highly effective ag ... | 1999 | 10479183 |
| discovery of a new focus of human onchocerciasis in central brazil. | an 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 ... | 1999 | 10492748 |
| onchocerciasis hyperendemic in the unturán mountains: the value of recombinant antigens in describing a new transmission area in southern venezuela. | a recently described hyperendemic onchocerciasis area, located in the unturán mountains (between the siapa and orinoco basins) of southern venezuela was studied using a cocktail of 3 low molecular weight onchocercal recombinant antigens (ovmbp/10, ovmbp/11, and ovmbp/29). the resulting seroepidemiological data were compared with those from a hypoendemic community (altamira) situated in the northern coastal mountain range. parasitological (skin biopsy) and serological (enzyme-linked immunosorbent ... | 1999 | 10492783 |
| delayed-type hypersensitivity reactions to onchocerca volvulus antigens in exposed and non-exposed african individuals. | although considered of critical importance, the mode of helper t-lymphocyte function in onchocerca volvulus infection is still unclear including the role of the th1/th2 dichotomy. we studied the delayed-type hypersensitivity (dth) reaction, which is the classical th1 response, to o. volvulus antigens in africans exposed and not exposed to the infection. dth reactions were found in a small percentage of patients with generalized onchocerciasis, but in a high percentage of patients with localized ... | 1999 | 10492804 |
| 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 ... | 1998 | 10497654 |
| 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 ... | 1999 | 10498183 |
| acanthocheilonema viteae: characterization of a molt-associated excretory/secretory 18-kda protein. | post-invasive third-stage larvae (pl3) of acanthocheilonema viteae were labeled with [(35)s]-methionine in vivo, and proteins released into the culture supernatant before and during the third molt were analyzed. the molting supernatant (msn) contained abundant proteins of 14, 18, 29, and 36 kda. the 14- and 29-kda proteins were exclusively found in the msn, while the 18- and 36-kda proteins were also produced by nonmolting pl3, albeit in much lower quantities. the cdna for the most abundant prot ... | 1999 | 10502469 |
| reports from the cutting edge of parasitic genome analysis. | this new feature in parasitology today will host reports from the laboratories involved in genomics of parasites, be that sequencing, mapping or 'functional genomics' - the mining and analysis of the sequence datasets, and the development of postgenomics tools to examine gene expression, response to drugs and population variability. it will publicize new technology to wider audiences, let communities of researchers know about novel resources (particularly those available through the world wide w ... | 1999 | 10511682 |
| wolbachia bacteria of filarial nematodes. | the finding that the intracellular bacteria of filarial nematodes are related to the wolbachia symbionts of arthropods has generated great interest. here, mark taylor and achim hoerauf review recent studies by several groups on the structure, distribution and phylogeny of these endosymbionts, and discuss the potential role for these bacteria in filarial disease and as a target for chemotherapy. | 1999 | 10511685 |
| an essential role for antibody in neutrophil and eosinophil recruitment to the cornea: b cell-deficient (micromt) mice fail to develop th2-dependent, helminth-mediated keratitis. | invasion of the corneal stroma by neutrophils and eosinophils and subsequent degranulation disrupts corneal clarity and can result in permanent loss of vision. in the current study, we used a model of helminth-induced inflammation to demonstrate a novel role for ab in mediating recruitment of these inflammatory cells to the central cornea. c57bl/6 and b cell-deficient (micromt) mice were immunized s. c. and injected intrastromally with ags from the parasitic helminth onchocerca volvulus (which c ... | 1999 | 10528201 |