Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042961 (volvulus)
 4,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A remarkably high number of patients with epilepsy was observed in Kyarusozi subcounty, Uganda, where infection with Onchocerca volvulus is hyperendemic. A survey was conducted from April 22 to May 4, 1991, in Kyarusozi subcounty when all patients with epilepsy and growth retardation were invited for medical examination. A full history was taken and a physical examination as well as a mental state assessment were carried out for all patients. A total of 231 persons were screened, of whom, 91% were below the age of 19 years. The infection rate with Onchocerca volvulus in patients with epilepsy (61%) and retarded growth (70%) was significantly higher than in the general population of Kyarusozi subcounty. The prevalence of epilepsy in the study area was estimated to be at least 2%. The cardinal clinical features were pigeon chest, increased curvature of the dorsum, hyperextended joints, poor oral hygiene, and dental caries with disproportionately large, and displaced maloccluded teeth. Additional features were malnutrition, including dry atrophic scaly skin, skin sores, and golden hair. The thyroid gland was enlarged in 7.4% of the children with physical growth retardation. Secondary sexual characteristics were absent or poorly developed in a further 1.3%. The data seemed to indicate that social adaptation and psychological functioning are more often disturbed in individuals who suffer from the combined effects of epilepsy, onchocerciasis, and growth retardation than in patients with onchocerciasis, epilepsy, or growth retardation along. This investigation suggests that onchocerciasis is associated with epilepsy, psychological impairment, retarded growth, and retarded sexual development. Should further studies confirm a relationship between Onchocerca volvulus infection, epilepsy, and mental development, the public health importance of onchocerciasis would have the be reconsidered to control Onchocerca volvulus infection more vigorously.
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PMID:Epilepsy and retarded growth in a hyperendemic focus of onchocerciasis in rural western Uganda. 147 7

A two-year longitudinal study carried out in five villages in a forest region of Gorama Chiefdom, Kono District, Sierra Leone, revealed that infection with Onchocerca volvulus was hyperendemic, the overall rate of infection being 61.6%. Prevalence rose from 28.6% in the 1-5-year age group, peaking among the 21-30-year age group (82.5%) and then levelling off. The intensity of infection though low, peaked in the 31-40-year-old males and in the 41-50-year-old female cohorts. The iliac crest was more sensitive for microfilarial (mf) recovery than the shoulder and the outer canthus. The majority of the nodules were located in the pelvic region. Microfilariae invasion of the eye was low, with low anterior chamber lesions but high posterior chamber lesions comprising mainly optic atrophy and choroidoretinitis. The rate of blindness was 1.6%, ocular onchocerciasis being the leading cause of blindness followed by cornea opacities.
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PMID:Onchocerca Volvulus infection in Sierra Leone: relation between prevalence, intensity of infection, and ocular problems in a 'forest' region. 148 96

The humoral immune responses of a paediatric population of 224 children, 2-15 years of age, residing in an onchocerciasis endemic area of Sierra Leone, were studied to gain information that may be useful in the serodiagnosis of prepatent and low-level infections with Onchocerca volvulus. The antigen-specific levels of IgG and IgG4 were determined and evaluated in the context of the parasitological status of the child. Over 87% of the microfilaria-negative children had significant levels of antigen-specific antibodies against O. volvulus, suggesting that a large percentage of this paediatric population were harbouring prepatent or low-level infections. Over 60% of the children in the group that had detectable numbers of microfilariae in skin snips had elevated levels of O. volvulus-specific IgG4. In contrast, only 23% of the microfilaria-negative children had detectable IgG4 responses. The results presented here indicate that measures of O. volvulus-specific IgG4 may be a useful indicator of the parasitological status of children during the very early stages of onchocerciasis.
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PMID:Anti-Onchocerca volvulus immunoglobulin subclass response in children from Sierra Leone. 151 51

A longitudinal investigation has been conducted into the cell-mediated immune responses of onchocerciasis patients after a single-dose treatment with ivermectin. Untreated patients tested for delayed cutaneous hypersensitivity (DCH) to seven recall antigens showed lower responses than infection-free control individuals (P less than 0.01), but 6 and 14 months after treatment DCH reactions increased to similar levels to those seen in the controls. The in vitro cellular reactivity to Onchocerca volvulus-derived antigen (OvAg) was reduced in untreated patients as compared with controls, and the lymphocyte blastogenic responses to OvAg and streptolysin-O clearly improved up to 14 months after treatment. Peripheral blood mononuclear cells (PBMC) from untreated patients produced IL-1 beta, tumour necrosis factor-alpha (TNF-alpha) and IL-6 in response to mitogenic stimulation with phytohaemagglutinin (PHA), only low levels of IL-1 beta, IL-2 and TNF-alpha in response to OvAg, but higher amounts of IL-4 and interferon-gamma (IFN-gamma) in response to OvAg than control individuals. After ivermectin treatment, the OvAg-induced production of IL-1 beta and TNF-alpha increased significantly 1 and 14 months after treatment. The PHA-induced production of IL-2 and IL-4 increased 1 month after treatment and remained significantly elevated until 14 months after treatment, whereas the OvAg-specific secretion of IL-2, IL-4 and IFN-gamma did not change after ivermectin treatment. Flow cytometric analysis of lymphocyte-subsets in the peripheral blood of untreated patients revealed a relative and absolute (P less than 0.01) diminution of CD4+ cells and a significantly smaller CD4+/CD8+ cell ratio as compared with controls. By 4 weeks after treatment and thereafter, CD4+ T cells increased relatively and absolutely (P less than 0.01); likewise there was an absolute increase in T-helper-inducer cells (CD4+CD45RO+) and a temporarily improved CD4+/CD8+ cell ratio (P = 0.001). The expression of the low-affinity receptor for IgE (CD23) on total lymphocytes decreased from 14% to 7% by 14 months after treatment. The CD8+ cells and CD3+TCR gamma delta + cells were higher in patients than in controls and both remained elevated until 14 months after treatment. These results suggest a distinctly improved cellular immunity in human onchocerciasis that was facilitated by ivermectin therapy.
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PMID:Ivermectin-facilitated immunity in onchocerciasis. Reversal of lymphocytopenia, cellular anergy and deficient cytokine production after single treatment. 151 57

A prevalence survey of onchocerciasis was done in the Kabarole district, Uganda, in 1990. The objective was to determine the prevalence of onchocerciasis among communities living in previously known foci. A total of 1186 persons were included in the study. The infection rate among the communities studied ranged from 0%-67%. The most frequent clinical signs and symptoms of onchocerciasis were: pruritus (80%), rough skin (46%), skin rash (30%), leopard skin (6%), and sclerosing keratitis (7%). 3.6% of all cases with onchocerciasis had no light perception and the total number of cases in the district was estimated to be 32,000. The study showed that the foci, where Simulium neavei is the vector, are still active. In contrast, very few infections with Onchocerca volvulus were found in the Rwenzori focus, where S. damnosum s.l. was the vector. The results indicate that onchocerciasis is an important public health issue in the Kaborale district and must be controlled.
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PMID:Onchocerciasis prevalence in previously known foci in western Uganda: results from a preliminary survey in Kabarole district. 151 30

The identification and characterization of a recombinant cDNA clone (OV103) expressing a microfilarial surface-associated antigen of Onchocerca volvulus is described. OV103 was identified and isolated from a lambda gt11 cDNA expression library derived from adult O. volvulus mRNA using a chimpanzee antiserum, taken 2 years after infection with third-stage larvae of O. volvulus. The cDNA clone encodes a 12.5-kDa protein that corresponds to a 15-kDa parasite protein present in microfilariae and adult female worms. The antigen encoded by this clone is located in the basal layer of the cuticle and the hypodermis of the female adult worm, and on the surface of microfilariae. OV103 fusion polypeptide is recognized only by some sera from onchocerciasis infected subjects (57%), but more significantly (89%) by sera from individuals that have low levels of patent infection. In addition, the antibody response to this protein developed before appearance of microfilariae in the skin of chimpanzees that had developed non-patent or low level patent infections, while the antibody response in chimpanzees with high levels of microfilariae appeared later at the time of appearance of microfilariae. Preliminary experiments indicated that affinity purified antibodies directed against OV103 fusion polypeptide mediated killing of nodular microfilariae in vitro in the presence of normal peripheral blood granulocytes.
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PMID:Identification and characterization of an Onchocerca volvulus cDNA clone encoding a microfilarial surface-associated antigen. 154 18

In most of the large scale vector control programs, the larviciding operations are not fully successful, resulting in a surviving vector population due to the use of sublethal doses. This problem leads the authors to study the effect of such doses upon the future of the residual population in order to know if it represents an epidemiologically dangerous population. One insect growth regulator was selected to study this phenomenon using Onchocerca volvulus as the parasite and Simulium damnosum s.l. as the vector. The experiment was conducted under field conditions by treating a river of a savanna area in north Cameroon where onchocerciasis remains endemic. The sublethal doses yielding 20% in adult blackflies from treated larvae was determined and the effects on physiological and vectorial capacities were assessed. The authors also carried out observations on the peritrophic membrane formation and the passage of microfilariae into the hemocele. The observation of flies fed on Onchocerca after larval treatment showed that this insecticide had a light effect on female longevity but did not induce any modifications in the life cycle of the parasite. An unusual high proportion of infected females, observed by the authors, is probably due to an anomaly in the phenomenon of limitation. However, the histological analysis showed to the evidence that no apparent difference between treated and untreated blackflies was observed although the process of blood meal digestion seemed slightly altered in treated flies.
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PMID:[Effect of a sublethal dose of an insect growth regulator on the physiology of onchocercosis vectors]. 156 65

Onchocerciasis, or river blindness, results from infection with Onchocerca volvulus. The parasite is endemic to West Africa, in both rain forest and savanna bioclimes. Several lines of evidence suggest that different strains of the parasite exist in the rain forest and savanna. Furthermore, epidemiologic evidence indicates that ocular onchocerciasis is most severe in savanna regions. This has led to the hypothesis that there is a strain association with ocular pathology. To test this hypothesis, parasites from villages in which severe and mild onchocerciasis were endemic were classified with two strain-specific DNA probes. A strong correlation (P less than .001) was found between disease severity and probe recognition, supporting the hypothesis that pathogenicity is strain related. The results suggest that pFS-1 and pSS-1BT may be used to predict the pathogenic potential of parasite populations throughout much of West Africa.
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PMID:Onchocerca volvulus DNA probe classification correlates with epidemiologic patterns of blindness. 156 51

In this study Onchocerca gutturosa was compared with O. volvulus in an ELISA test to detect Onchocerca-specific IgG and IgG subclasses. The test was developed and standardized to detect Onchocerca-specific IgG and IgG subclasses in sera of onchocerciasis patients and endemic controls. Onchocerca volvulus and O. gutturosa crude water-soluble antigens showed no significant difference in detecting onchocerca-specific IgG antibody (T = 1.88, P greater than 0.05). The levels of IgG subclasses varied greatly. IgG4 showed the highest detected mean level (0.84 +/- 0.59) and the other three subclasses showed considerably lower mean levels (IgG1 = 0.27 +/- 0.16, IgG2 = 0.24 +/- 0.17, IgG3 = 0.28 +/- 0.12). The status and score of skin lesions were found to have significant effect on the IgG and IgG subclasses levels (all P less than 0.001). IgG4 showed a positive correlation with the microfilarial (Mf) load (r = 0.21, P less than 0.03). IgG3 levels have a significant negative correlation with the Mf load (r = -0.23, P less than 0.02). The biological significance of these IgG and IgG subclasses in onchocerciasis is discussed.
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PMID:The profile of IgG and IgG subclasses of onchocerciasis patients. 157 89

Monoclonal antibodies, reactive with antigens solubilised from the body wall of intact female Onchocerca volvulus using 2% 2-beta-mercaptoethanol, have been characterised. Two IgG1 antibodies, Cam1 and Cam28, recognised antigens of apparent molecular weights of 18,000 and 28,000; and 120,000, respectively. The target antigens of Cam1 and Cam28 could be localised in the cuticle. Inhibition ELISAs showed that target epitopes of both monoclonal antibodies induce an antibody response in onchocerciasis patients. 153 sera from Sierra Leonean patients were tested for their individual antibody levels against antigen epitopes recognised by Cam1 and Cam28. Patients within the age of 5-8 years had the highest levels of antibodies against the Cam28-epitope, whereas patients above 60 years had almost none. Amicrofilaremic patients had higher anti-Cam28 antibody levels than microfilaremic patients and there was a significant difference between groups with no chronic skin disease and those with mild or severe signs. A high percentage of patients (80.4%) recognised the Cam1-epitope, highest antibody levels being found in patients within the age group of 15 to 45 years and in microfilaremic patients. However, levels of antibodies inhibiting monoclonal antibody Cam1 could not be correlated with presence or absence of skin disease.
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PMID:Analysis of antibody responses directed against two Onchocerca volvulus antigens defined by monoclonal antibodies. 159 8


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