| immunological cross-reaction between an onchocerca paramyosin-like molecule and a microfilaria surface antigen. | a monoclonal antibody (2a5b9), previously shown to be reactive with a 14 kd surface associated antigen of onchocerca microfilariae, was found to recognise a 92 kd molecule present in an adult worm extract. the antibody was used to select cdna clones with a coding capacity larger than 14 kd, from a lambda gt11 library of o. volvulus. nucleotide sequencing of the cdna of one such clone revealed extensive homology to the myosin (unc-54) and paramyosin (unc-15) genes of caenorhabditis elegans, simil ... | 1992 | 1281925 |
| antigenic and dynamic properties of the surface of onchocerca microfilariae. | we analyzed the antigenicity and stability of the surface of skin microfilariae (mf) of onchocerca cervicalis, a horse parasite. these mf express antigens on their surface that are cross-reactive with the cattle parasite o. lienalis and with the human parasite o. volvulus. the surface of living o. cervicalis mf was radioiodinated using iodogen and the labeled components were solubilized in buffers containing sodium dodecyl sulphate (sds), or extracted with the milder detergent octyl-beta-d-gluco ... | 1990 | 2200104 |
| experimental ocular onchocerciasis: local and systemic antibody and cell-mediated immune responses. | hartley guinea pigs injected subconjunctivally with onchocerca lienalis (ol) microfilariae (mf) develop punctate corneal opacities resembling the punctate keratitis of human onchocerciasis. antibody production and antigen-induced proliferative responses were studied in conjunctival-associated lymphoid tissues (calt), spleens (sl) and peripheral blood lymphocytes (pbl) from experimentally infected guinea pigs. cultured single cell suspensions of calt, sl and pbl were assayed for igg1, igg2, iga a ... | 1990 | 2255838 |
| distribution of microfilariae of onchocerca lienalis and onchocerca gutturosa in the skin of cattle in germany and their development in simulium ornatum and culicoides nubeculosus following artificial infestation. | onchocerca microfilariae were isolated form the umbilicus and neck of 438 cow hides at the abattoir in tübingen, f.r.g. the overall onchocerca infection rate was 40.4%. the presence of onchocerca lienalis and o. gutturosa microfilariae, which are difficult to distinguish by morphological criteria, was retrospectively demonstrated after artifically infesting simulium ornatum and culicoides nubeculosus and identifying the infective larvae recovered. nine of 16 samples of umbilical microfilariae fe ... | 1990 | 2399652 |
| an in vitro radiolabel uptake viability assay for onchocerca microfilariae. | a radiolabel uptake viability assay for onchocerca cervicalis using [3h]2-deoxy-d-glucose in hanks' balanced salt solution, ph 7.5, at 30 c is described and compared to the traditional visual motility assay. a correlation of r = 0.92 between the assays was found, with the radiolabel uptake method apparently a more sensitive indicator of microfilarial viability. | 1989 | 2918434 |
| the relationship between innate susceptibility to onchocerca, and haemolymph attenuation of microfilarial motility in vitro using british and west african blackflies. | the effect of haemolymph from individual flies of differing species of simulium were compared in their ability to attenuate onchocerca microfilariae in vitro. small maintenance systems, each of 3-4 microliters total volume, were set up in terasaki plates. three british species of greatly differing susceptibilities to onchocerca lienalis (simulium ornatum, s. equinum and s. vernum) were compared in their effect on o. lienalis. three forms of the s. damnosum complex from liberia (s. yahense and 2 ... | 1988 | 3194666 |
| ingestion of microfilariae from different sources by culicoides nubeculosus (diptera: ceratopogonidae) through an artificial membrane. | laboratory-hatched culicoides nubeculosus midges were membrane-fed on cattle blood containing various onchocerca microfilariae which had been isolated from the hides of red deer (cervus elaphus) and from australian and native german cattle. all microfilariae were ingested through the membrane except those of o. tarsicola, which were too large. onchocerca gibsoni and o. lienalis reached the thoracic musculature, but no further development occurred. microfilariae of o. flexuosa developed to the "s ... | 1988 | 3420793 |
| the status of human filariasis in relation to clinical signs in endemic areas of the niger delta. | a study was carried out in selected parts of the niger delta basin on human filariasis and its relationship to clinical signs. one hundred and seventy-six (13.0%) of 1351 individuals examined were infected with microfilaria. forty-six percent of microfilaria positive cases had m. perstans; 25.6% had w. bancrofti, 19.3% had l. loa, and 9.0% had o. volvulus. the prevalence of filariasis increased with age. microfilarial density was generally low, 28.4% of infected individuals had counts of 50-100 ... | 1986 | 3539045 |
| [epidemiology of filariasis (onchocerciasis and bancroftosis) in the tala-mokolo region (mandara mountains of north cameroon)]. | the effect of the bancroftian filariasis on the health of the inhabitants are minimal in the study area, where the prevalence of the disease (nocturnal microfilaremia) is 0.4% only. but skin snips harboring onchocerca microfilariae are seen in 12.1% of the sample studied. onchocerciasis skin lesions, low visual acuity and blindness are often seen in the villages where the prevalence is high, among inhabitants more than 40 years of age. simulium damnosum is seldom seen in the area, except in the ... | 1986 | 3549025 |
| invasion of the mouse eye by onchocerca microfilariae. | onchocerca cervicalis microfilariae (mf) were injected s.c. into the scalp between the eyes of cba/h mice. invasion was followed by slit-lamp biomicroscopy and h & e stained serial sections at varying times post infection. the first mf observed were found 24 hr p.i. on the corneal surface in tear fluid. at 48 hr mf were observed actively swimming in the anterior chamber and by 3 d in the corneal stroma. histologically mf appeared in orbital muscle connective tissue, subcutaneously in the eyebrow ... | 1986 | 3563315 |
| resistance to onchocerca lienalis microfilariae in mice conferred by egg antigens of homologous and heterologous onchocerca species. | embryonic stages of various onchocerca species have been used to stimulate resistance in cba mice to challenge injections with the microfilariae of onchocerca lienalis. comparable levels of resistance to challenge (29-37% reductions) were conferred by living, freeze-killed, or sonicated organisms administered with freunds' complete adjuvant (fca). antigens extracted in saline, or with the detergent sodium deoxycholate, were also protective. adjuvants enhanced the protective effect, particularly ... | 1987 | 3614990 |
| further studies on the resistance to onchocerca microfilariae in cba mice. | various factors governing resistance to the microfilariae (mf) of onchocerca lienalis in mice have been examined to provide baseline data for use of this model in immunological studies. the survival of mf during a primary infection followed a similar course in the skin from most anatomical regions of the body. mice were highly resistant to secondary infections, manifested by parasite densities over the body that were reduced by 83-100% compared with controls. recoveries of mf from the ears, used ... | 1986 | 3787123 |
| immediate hypersensitivity responses in the immunopathogenesis of human onchocerciasis. | it is not clear what role immediate hypersensitivity immune responses have in the pathogenesis of human onchocerciasis, but it is certain that these responses are prominent both in the course of natural infection and during the mazzotti reactions that follow treatment with diethylcarbamazine. in humans, the levels of total serum ige associated with onchocerciasis are as high or higher than those associated with almost any helminth infection, although specific ige antibodies to onchocerca volvulu ... | 1985 | 4070917 |
| onchocerciasis in venezuela: prevalence of microfilaraemia in amerindians and morphological characteristics of the microfilariae from the upper orinoco focus. | data are presented on microfilaraemia in 191 yanomami amerindians from two areas of venezuela's upper orinoco basin, where an endemic focus of onchocerciasis has been recently detected. onchocerca microfilariae were found in the blood of 12.6% of the persons examined. in the village with the higher number of examined individuals (n = 162), the prevalence of microfilaraemia in the age groups covaried with the prevalence of microfilariae in the skin and with the parasite load (mf/mg of skin). a po ... | 1984 | 6495385 |
| ocular immunopathologic findings of experimental onchocerciasis. | ocular immunopathologic responses of inbred guinea pigs infected with onchocerca microfilariae from domesticated animals were studied as a laboratory model of human ocular onchocerciasis. a single intracorneal infection of normal guinea pigs with microfilariae produced only minimal ocular lesions. in contrast, intracorneal infection of guinea pigs previously immunized by systemic infection with microfilariae produced intense corneal and uveal inflammation. transfer of splenic lymphocytes from im ... | 1984 | 6704026 |
| separation of viable and non-viable onchocerca microfilariae using an ion exchanger. | a technique has been developed for separating viable and non-viable onchocerca lienalis microfilariae (mff) by passing a suspension of the parasites through a column of deae cellulose. a proportion (between 42% and 87%) of normally motile parasites, whether unfrozen or cryopreserved, passed through the cellulose columns and retained their viability. non-motile and sluggish mff were retained by the cellulose. the proportion of viable cryopreserved mff was greater after passage through the column ... | 1982 | 7164142 |
| immunization of calves against the microfilariae of onchocerca lienalis. | three jersey bull calves were immunized by subcutaneous injections of sonicated onchocerca lienalis microfilariae suspended in phosphate buffered saline, and three control animals were injected with medium only. all calves received booster injections 27 days later, and were challenged with live microfilariae 44 days after the booster. following challenge, only the immunized animals developed an elevated level of circulating eosinophils. when necropsied ten days after challenge there was a 97% re ... | 1982 | 7166632 |
| quantification of a cryopreservation technique for onchocerca microfilariae in skin snips. | | 1981 | 7229333 |
| natural vectors of three bovine onchocerca species (nematoda: onchocercidae) and seasonal transmission by three blackfly species (diptera: simuliidae) in central kyushu, japan. | eleven blackfly species were examined in relation to the transmission of bovine onchocerciasis in central kyushu, japan. a total of 19,005 out of 47,746 females captured from june 1989 to june 1990 at two cattle sheds each in oita and kumamoto were dissected for their parities, infections with onchocerca larvae, and intakes of onchocerca microfilariae. overall results showed that simulium bidentatum (shiraki), the predominant species, is a natural vector of the two bovine onchocerca species, i.e ... | 1994 | 8057315 |
| immunolocalization of superoxide dismutase in dirofilaria immitis adult worms. | superoxide dismutase (sod) may not only perform a housekeeping role in filarial worms but also assist in defense against oxidants generated by host immune cells. both dirofilaria and onchocerca adult filariae and microfilariae contain relatively high activities of the antioxidant enzyme sod; adult dirofilaria worms also secrete sod in vitro. in addition, superoxide radicals are relatively impotent against dirofilaria and onchocerca microfilariae in vitro. in assessing the role of sod, we determi ... | 1993 | 8432599 |
| il-5-dependent immunity to microfilariae is independent of il-4 in a mouse model of onchocerciasis. | th2 lymphocyte responses under the control of il-4 and il-5 are frequently associated with protective responses to parasitic helminths. studies on the role of these cytokines in acquired resistance to parasitic nematodes indicate that, in the case of gastrointestinal nematodes, immunity is mediated by il-4, while immunity to tissue-dwelling nematodes is dependent on il-5. here we investigate the role of il-5 and eosinophils in protective immunity to onchocerca microfilariae in il-4-deficient mic ... | 1998 | 9605145 |
| il-5 dominates cytokine responses during expression of protective immunity to onchocerca lienalis microfilariae in mice. | in a model of protective immunity against onchocerca microfilariae (mf), it has been demonstrated previously that immunocompetent mice clear a primary infection and are highly resistant to re-infection. this immunity correlates with cd4+ th2 cells, is dependent on il-5 but not il-4, and can be transferred adoptively with spleen cells. in the current investigation, high levels of spontaneous proliferation and of ifn gamma production were observed in splenocyte cultures from immune mice, compared ... | 1999 | 10101718 |
| interleukin-12 modulates t-cell responses to microfilariae but fails to abrogate interleukin-5-dependent immunity in a mouse model of onchocerciasis. | infection of mice with microfilariae of onchocerca lienalis induces high levels of protective immunity to reinfection, which is dependent on interleukin (il)-5 but not il-4. here, we have investigated the effect of exogenous il-12 administration during either the priming or effector phases of the immune response. when administered during priming, il-12 induced down-regulation of parasite-specific serum immunoglobulin (ig)e and up-regulation of igg2a. antigen-specific il-4 responses were strongly ... | 1999 | 10583601 |
| integrin-like rgd-dependent cell adhesion mechanism is involved in the rapid killing of onchocerca microfilariae during early infection of simulium damnosum s.l. | injection trials with compatible and non-compatible onchocerca species into s. damnosum s.l., the vector of human and bovine onchocerciasis, demonstrated that the rapid killing of microfilariae within the blackfly's haemocoel is species specific. in the presence of the peptide rgds as a blocking agent for integrin-like receptors of haemocytes, the survival of o. ochengi microfilariae in its natural intermediate host was significantly increased. this increased survival 24 h p.i. correlated with a ... | 2001 | 11315176 |
| humoral immune response of simulium damnosum s.l. following filarial and bacterial infections. | the time-course of the humoral immune response of female blackflies after a challenge with bacteria, different onchocerca microfilariae species, bacterial endotoxin and microfilarial extract was investigated. strong bacteriolytic and growth inhibition activities against the gram-positive bacterium micrococcus luteus were induced by all agents. specific differences were found in activity levels and time-course. notably the endotoxin lipopolysaccharide (lps) induced a very early, profound bacterio ... | 2002 | 12403324 |
| doxycycline in the treatment of human onchocerciasis: kinetics of wolbachia endobacteria reduction and of inhibition of embryogenesis in female onchocerca worms. | recently, experts have warned that mass treatment with ivermectin alone may not interrupt the transmission of onchocerca. hence, additional drugs are needed, such as antibiotics acting on symbiotic endobacteria of the filariae, the causative agents of onchocerciasis. based on animal experiments, human onchocerciasis was treated with doxycycline, and preliminary observations published in 2001 in the lancet showed sterility in female worms by depletion and marked reduction in symbiotic wolbachia e ... | 2003 | 12706439 |
| epidemiological mapping of human onchocerciasis in transmission suspected districts of bale, borena, and west arsi zones of eastern ethiopia. | onchocerciasis is mainly found in western part of ethiopia and there is no evidence of transmission in the east ward. however, some zones (bale, borena, and west arsi) are suspected for transmission given the area has fast flowing rivers and is covered with vegetation. therefore, this study was conducted to map onchocerciasis transmission in those zones. about 19 villages were selected based on proximity to the rivers, representation of districts, zones, and vegetation covers, whereas the study ... | 2016 | 27648069 |
| accelerated clearance of onchocerca microfilariae and resistance to reinfection in interleukin-4 gene knockout mice. | immunity to onchocerca microfilariae (mf) in mice is associated with cd4+ th2 cells and is dependent on il-5. in view of the role of il-4 in the development of th2 cells, we have utilized il-4 gene knockout mice (il-4-/-) to investigate microfilarial clearance and resistance to reinfection. paradoxically, in the absence of il-4 there is accelerated clearance of microfilariae during a primary infection and unimpeded expression of resistance to reinfection. il-4-/- mice showed a lack of an ige res ... | 1995 | 8834765 |
| studies on a 14-kilodalton surface protein of onchocerca microfilariae. | a 14-kda antigen present on the surface of uterine microfilariae of onchocerca spp. has been identified using monoclonal antibodies. the antigen was also found in skin microfilariae, but in a masked or cryptic form. a complementary dna clone encoding the epitope recognised by one of the monoclonal antibodies was identified in a lambda gt11 library. nucleotide sequencing revealed that the 233-bp cdna fragment codes for the carboxy-terminus of the antigen. the deduced amino acid sequence consists ... | 1991 | 1852166 |
| protection of cryopreserved onchocerca microfilariae (nematoda) from dilution shock by the use of serum. | | 1982 | 7116907 |
| an improved technique for the cryopreservation of onchocerca microfilariae. | experimental describe the use of ethanediol to store onchocerca microfilariae in liquid nitrogen. the technique involves a 2-stage incubation of the parasites at 37 degrees c and 0 degrees c in ethanediol, before rapid cooling to -196 degrees c. viability has been assessed by motility, by migration in a proxy host and by development to the infective stage in the insect vector. a total of 71-79% of the cryopreserved microfilariae was shown to be viable compared to unfrozen controls. the technique ... | 1981 | 7267145 |