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Query: UMLS:C0042961 (volvulus)
 4,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In Mali, a comparative study of O. volvulus and D. viteae filariasis antigens was made on 52 onchocerciasis sera with immunofluorescence immunoassay. At a dilution greater than 1/40, 34 sera are positive with homologous Ag against 24 with heterologous Ag.
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PMID:[Indirect immunofluorescence in onchocerciasis in Mali: comparison of O. volvulus antigen and D. viteae antigen for detecting circulating antibodies]. 351 49

We show here an automated (50 samples/h) assay for serum IgG4 having a throughput time of 40 min per sample and a sensitivity of 10 micrograms/ml. The assay procedure is based on the inhibition by sample of the agglutination reaction between monoclonal anti-IgG4 antibodies and latex particles to which IgG4 myeloma protein has been coupled. Assay reliability was ascertained by testing for linearity, analytical recovery (96.4%), interassay precision (less than or equal to 8%), specificity and correlation between the results obtained with monoclonal and polyclonal anti-IgG4 antibodies (n = 84; rs = 0.97). Application of the assay to sera from various groups of patients indicated significantly (p less than 0.00005) higher geometrical means (Gx) in patients suffering from atopy (n = 87; Gx = 617 micrograms/ml), atopic dermatitis (n = 28; Gx = 1,043 micrograms/ml), filariasis with Onchocerca volvulus (n = 48; Gx = 1,681 micrograms/ml) and Brugia malayi (n = 20; Gx = 1,078 micrograms/ml) as compared to nonatopic subjects (n = 103; Gx = 302 micrograms/ml) and randomized paired maternal/cord sera (n = 41; Gx = 276 and 296 micrograms/ml, respectively). IgG4 in the paired maternal/cord sera correlated (r = 0.98; p less than 0.00005). There was no significant influence of age or sex on the IgG4 levels either among the nonatopics or the atopics even though low IgG4 (less than or equal to 30 micrograms/ml) was more common among women. The results suggest that IgG4 and IgE responses are somehow closely related in atopic and parasite-infested patients at the physiological, pathogenic or genetic level.
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PMID:Raised serum IgG4 levels in patients with atopy and filariasis: application of an automated particle-counting immunoassay using monoclonal antibody. 353 90

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 microfilaria per 20 mm3 blood, 12.5% had counts less than five microfilaria per 20 mm3 blood. Onchocerca microfilariae did not exceed five microfilaria per snip. Microfilarial density was high among individuals aged between 20 and 49 years, but declined with increasing age above 50 years. Acute clinical signs of febrile attack, sink eruptions, and chronic clinical signs of chyluria, hydrocoele, elephantiasis and ocular lesions were observed in 61.9% of infected individuals, 73.4% of clinical cases were febrile attack and skin eruptions, 5.5% were chyluria, 12.8% were elephantiasis of the leg and scrotum, 7.3% were hydrocoele and 0.9% were ocular lesions. Chronic clinical signs were more prevalent in individuals over 40 years of age.
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PMID:The status of human filariasis in relation to clinical signs in endemic areas of the Niger Delta. 353 45

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 immunoprecipitated only by the onchocerciasis serum pools, with Mr ranging from 20,000 up to 43,000 Daltons. These results suggest that the lower Mr O. volvulus antigens are more species specific than the other antigens. The significance of these findings for the immunodiagnosis of onchocerciasis is discussed.
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PMID:Identification of non-cross-reacting antigens of Onchocerca volvulus with lymphatic filariasis serum pools. 378 77

Skin and ocular lesions were studied in murids Lemniscomys striatus L. infested by 2 isolates of Monanema spp, a rodent filaria with skin-dwelling microfilariae. Histologic examination disclosed microfilariae in lymphatic vessels. Penetration of microfilariae in extra-vascular tissues caused vascular changes, subacute inflammatory cells infiltration, granulomatous nodules and scarring lesions. These alterations corresponded to the successive stages of an inflammatory process. No correlation noted between tissular lesions, delay of filarial infestations and number of microfilariae in the "snip". The presence of lesions in one or several tissular areas demonstrated that extravascular escaping of microfilariae was not synchronous. Symptomatology of filariasis depended on the localization of the lesions. Similarities between the lesions noted in murids Lemniscomys striatus L. and those observed in man showed that the 2 isolates of Monanema spp. used in this study were very close to O. volvulus in the pathological domain. They might be considered as a valuable and reproducible experimental model.
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PMID:[Anatomo-pathologic study of skin and ocular lesions in rodents infested by Monanema spp.: significance for the study of human onchocerciasis]. 381 17

Immunological study of individuals (aged 4 to 70 years) living in an area of Mali hyperendemic for onchocerciasis revealed an 83% prevalence of skin microfilariae (mf). Microfilariae counts from skin snips were highly age-dependent. Screening for concomitant helminth infections showed a low prevalence of hookworms and Mansonella (Dipetalonema) perstans, but neither schistosomiasis nor bancroftian filariasis. Immunological results revealed strong correlation between radioallergosorbent test (RAST) and skin test (5 and 50 ng adult O. volvulus extract), between RAST and total IgE, and between IFAT and ELISA. A negative correlation exists between mf counts and skin tests and between mf counts and RAST; the lowest median values were obtained in the group with high mf counts. Skin sensitizing antibodies were detected in most locally born children aged 4-5 years. Intradermal tests showed a high rate of sensitization to O. volvulus antigen in mf-negative children, whereas ELISA and IFAT values were significantly lower in these children than in mf-positive children. Increasing concentrations of circulating IgE antibodies were found in children aged 4-11 years by RAST, and, in individuals aged 12-19 years (age group for which mf counts sharply increase), skin testing revealed a state of anergy. In long lasting infections (adults greater than 20 years) skin reactivity was comparable to that of young children or was depressed. ELISA and IFAT achieved similar results in each age group.
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PMID:Seroepidemiological investigations of onchocerciasis in a hyperendemic area of West Africa. 389 85

The nature of the lymphoid infiltrate in nodules of Onchocerca volvulus was assessed using monoclonal antibodies to lymphoid cell surface markers. Although B cells were generally absent, T cells were present, but in variable amounts. The ratio of T4+ (helper phenotype) to T8+ (suppressor-cytotoxic phenotype) was usually in the normal peripheral blood range of about 3, although ratios ranging from 1 to 10 were seen in selected areas of the onchocercoma. The possibility of immunosuppression through dominance of T4+, Leu-8+ cells (suppressor-inducer phenotype) within the T4+ population was also excluded. The T cells did not tend to concentrate in close proximity to the parasite, and there was no general bias in favour of the T suppressor cell phenotype (T8) within the infiltrate. Macrophages and dendritic cells were consistently observed and consisted of three defined cell types in approximately equal proportions: normal, unactivated macrophages (HLA-DR-, acid phosphatase positive), activated macrophages (HLA-DR+, acid phosphatase positive) and cells of dendritic morphology (HLA-DR+, acid phosphatase negative). These results are discussed in relation to immune suppression in filariasis.
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PMID:Human macrophages and T-lymphocyte subsets infiltrating nodules of Onchocerca volvulus. 390 94

A standardised method for serodiagnosis of lymphatic filariasis W. bancrofti (var. pacifica) was performed. The authors used indirect fluorescent assay with papain treated microfilariae as source of antigen. Very high levels of antibodies were obtained in 96% microfilaremic patients. The geometric mean titers were 22.7 for healthy subjects and 605.5 for the filariasis patients. Cross reactivity was studied with two subcutaneous and one lymphatic filariasis. The geometric mean titers were 211.1 for Onchocerca volvulus, 105.6 for Loa-loa and 254 for Brugia malayi patients. No significant reactivity was observed with some other parasites.
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PMID:[Use of microfilaria treated with papain in the serodiagnosis of lymphatic filariasis caused by Wuchereria bancrofti (Var. pacifica)]. 390 47

The development of monoclonal antibodies against parasites can facilitate analysis of host-parasite interactions and can lead to the identification and characterization of antigens that induce protective responses in the immunized host. As diagnostic reagents for human and bovine onchocerciasis, monoclonal antibodies have been used to detect circulating antigens. So far only complex antigens have been used to generate monoclonal antibodies against filarial parasites. The use of such heterogeneous immunogens may result in interference or even in inhibition of the response to the desired parasite antigen(s). Epitopes that are similar or identical to determinants on host molecules or that are components of other infectious agents serve to complicate the generation and selection of monoclonal antibodies against Onchocerca volvulus antigens, and cross-reactivity can be due to monoclonal antibodies reacting with phosphorylcholine, which is present in many preparations of helminth antigens. Because of the host-dependent immunogenicity of filarial agents, reagents should be screened carefully for species specificity by use of a set of different helminth antigens. It is hoped that active collaboration among all investigators engaged in filariasis research will facilitate resolution of such difficulties.
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PMID:Monoclonal antibodies as investigative tools in onchocerciasis. 407 Sep 21

Factors affecting transmission of D. immitis between dogs are summarized in table 4. Although this list may not be exhaustive, it illustrates the complexity of heartworm epidemiology. There are interesting and provocative similarities in the epidemiology of canine and human filariasis. Ottesen (148) has described the spectrum of disease observed in regions endemic for lymphatic filariasis. It includes patients with 1) microfilariae, but no symptoms; 2) disease, but no microfilariae; 3) tropical pulmonary eosinophilia of filarial etiology; and 4) no disease and no evidence of infection. A dog population in areas endemic for D. immitis may show a similar range of clinical manifestations. For example, dogs with microfilariae may not demonstrate clinical disease; dogs with occult infection may show signs ranging from none to severe, including signs similar to the human tropical pulmonary eosinophilia syndrome. Although some dogs live in endemic areas and, apparently, are not infected, it is difficult to determine whether those dogs are resistant to infection or if they have not had adequate exposure. One study has explored the relationship between human W. bancrofti infection and genetic factors (149). Although familial clustering of cases was apparent, the authors were unable to distinguish with certainty whether this association was due to environmental or genetic influences. Carefully designed seroepidemiologic studies of canine heartworm infection may shed some light on genetic or other factors which confer resistance or susceptibility to filarial infections. Natural strain variation has been recognized in several filariae of medical importance including O. volvulus (150), B. malayi (151), and L. loa (2). Strain variation may be manifested as differences in behavior patterns such as microfilarial periodicity, vector and host affinities, and pathogenicity. A laboratory study (88) demonstrated how such strains could arise. In this study, a strain of Brugia patei was adapted to a new, normally refractory host, by artificial selection. The possible existence of different physiologic races of D. immitis should be investigated. Experimental infections with D. immitis have been achieved under laboratory conditions in numerous mosquito species (77).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Epidemiology of canine heartworm infection. 613 88


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