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Sample records for onchocerca volvulus comparison

  1. The mitogenome of Onchocerca volvulus from the Brazilian Amazonia focus.

    PubMed

    Crainey, James L; Silva, Túllio R R da; Encinas, Fernando; Marín, Michel A; Vicente, Ana Carolina P; Luz, Sérgio L B

    2016-01-01

    We report here the first complete mitochondria genome of Onchocerca volvulus from a focus outside of Africa. An O. volvulus mitogenome from the Brazilian Amazonia focus was obtained using a combination of high-throughput and Sanger sequencing technologies. Comparisons made between this mitochondrial genome and publicly available mitochondrial sequences identified 46 variant nucleotide positions and suggested that our Brazilian mitogenome is more closely related to Cameroon-origin mitochondria than West African-origin mitochondria. As well as providing insights into the origins of Latin American onchocerciasis, the Brazilian Amazonia focus mitogenome may also have value as an epidemiological resource. PMID:26814648

  2. The mitogenome of Onchocerca volvulus from the Brazilian Amazonia focus

    PubMed Central

    Crainey, James L; da Silva, Túllio RR; Encinas, Fernando; Marín, Michel A; Vicente, Ana Carolina P; Luz, Sérgio LB

    2016-01-01

    We report here the first complete mitochondria genome of Onchocerca volvulus from a focus outside of Africa. An O. volvulus mitogenome from the Brazilian Amazonia focus was obtained using a combination of high-throughput and Sanger sequencing technologies. Comparisons made between this mitochondrial genome and publicly available mitochondrial sequences identified 46 variant nucleotide positions and suggested that our Brazilian mitogenome is more closely related to Cameroon-origin mitochondria than West African-origin mitochondria. As well as providing insights into the origins of Latin American onchocerciasis, the Brazilian Amazonia focus mitogenome may also have value as an epidemiological resource. PMID:26814648

  3. The effects of drugs on Onchocerca volvulus

    PubMed Central

    Duke, B. O. L.

    1968-01-01

    Antimonial preparations (Pentostam, Neostibosan, stibophen, and tartar emetic) have occasionally been used in the treatment of onchocerciasis without very promising results. The advent of the preparations TWSb (stibocaptate) and MSbE (Friedheim) of allegedly reduced toxicity made it desirable to test them against Onchocerca volvulus. The action of both preparations on the parasites was found to vary from one patient to another, ranging from complete elimination of all parasites in a few cases to no detectable action in others. A microfilaricidal action was detectable in many patients, particularly after treatment with TWSb, which was used at higher doses than MSbE. A lethal or sterilizing action on some or all adult female worms was observed in some patients. However, toxic reactions to the drugs were common and distressing, and often it was necessary to stop treatment on this account. Anorexia, nausea, vomiting and prostration were the most common manifestations, and there was one fatality from coincident yellow fever, which may well have been aggravated by antimony treatment. The uncertain action of these preparations on O. volvulus and the toxic manifestations that accompany their use render them unsuitable for the treatment of onchocerciasis, and it is probable that the effects of antimony on O. volvulus are produced only at or above the normal level of human tolerance. PMID:4881067

  4. Emergence of Onchocerca volvulus from Skin Mimicking Dracunculiasis medinensis

    PubMed Central

    Eberhard, Mark L.; Ruiz-Tiben, Ernesto; Korkor, Andrew S.; Roy, Sharon L.; Downs, Philip

    2010-01-01

    We describe 11 cases of suspected Dracunculus medinensis infection in which the worm recovered was identified as Onchocerca volvulus. Identification was based on morphology of the examined specimen. PMID:21118947

  5. The effects of drugs on Onchocerca volvulus

    PubMed Central

    Duke, B. O. L.

    1970-01-01

    The effects of the arsenical drug melarsonyl potassium on Onchocerca volvulus were investigated in patients in Cameroon infected with the Cameroon forest and Sudan savanna strains of the parasite. Two intramuscular dosage schedules were tested: the first comprised 4 consecutive daily doses of 200 mg repeated once after a 10-14 day interval, i.e., 2 (4×200 mg). The second was a single dose schedule at 7.1 mg/kg—10 mg/kg, with a maximum of 500 mg. In most trials the drug had no immediate action on microfilarial concentrations. Only after the 2(4×200 mg) melarsonyl course against the Sudan savanna strain was a slight microfilaricidal action detected. The 2(4×200 mg) course of melarsonyl apparently killed or sterilized most or all of the adult female worms in the patients tested, leaving the residual population of microfilariae to decline gradually, from natural mortality, over the ensuing 2 years. These residual microfilariae could be killed with diethylcarbamazine. Single doses of melarsonyl at 7.1 mg/kg—10 mg/kg were somewhat less effective in killing or sterilizing adult worms, but it is suggested that if doses at the higher end of this range were to be repeated annually patients could be rendered free from microfilariae by the end of 3 years. It is emphasized that the risks of arsenical encephalopathy should at present preclude the use of melarsonyl potassium in the treatment of onchocerciasis, but that if this danger could be avoided the drug might prove to be of considerable use for mass therapy in control campaigns. PMID:5309509

  6. Strain differentiation of Onchocerca volvulus from Uganda using DNA probes.

    PubMed

    Fischer, P; Bamuhiiga, J; Kilian, A H; Büttner, D W

    1996-04-01

    Polymerase chain reaction (PCR) combined with non-radioactive DNA hybridization was applied for the detection and characterization of a 150 bp tandem repeat of Onchocerca volvulus. DNA of worms from western Uganda was amplified and then probed with a digoxygenin-labelled oligonucleotide, specific for the forest form of O. volvulus and compared to samples from various African countries. Hybridization was only observed with PCR products from the forest in Liberia, south-eastern Ghana, Benin and southern Cameroon, but not with worms from Uganda or the savannah in Burkina Faso and northern Ghana. A nested PCR using primers derived form the forest form-specific DNA sequence confirmed these results. Morphometric studies revealed length differences between the microfilariae of Ugandan O. volvulus to those of West Africa, especially to those of the savannah in Burkina Faso. It is concluded that the forest/savannah classification of O. volvulus from West Africa is not suitable for Simulium neavei-transmitted O. volvulus from Uganda. PMID:8935951

  7. A diagnostic skin test for Onchocerca volvulus infection.

    PubMed

    Ngu, J L; Ndumbe, P M; Titanji, V; Leke, R

    1981-09-01

    Onchocerca supernatant (OS) was prepared by a technique permitting live microfilariae to migrate from nodule tissue through agar gel into sterile Hanks balanced salt/Penicillin-Streptomycin solution where they metabolized. The OS, after dialysis, was passed through Seitz viral filter and either concentrated or lyophilized. Using rabbit antiserum in immunodiffusion and immunoelectrophoresis tests, microfilariae proteins and also human protein were detected in out OS. No common antigens were found between this and somatic extracts of Loa loa, O. gutturosa, O. volvulus, L. carinii, D. immittis and A. lumbricoides. 125I labelled OS was purified by passage through protein A column and then through immunosorbent column of horse anti-human serum linked to CNB-activated sepharose 4B. Autoradiography, after sodium dodecyl sulphate polyacylamide slab gel eletrophoresis of purified OS, showed 10 protein bands in the molecular range 10,000 to 125,000. Skin prick tests with OS, shown not to be contaminated with Hepatitis B antigens, elicited immediate hypersensitivity reaction. Using our criteria, positive reactions were seen in 81% of proven onchocerca cases and only occasionally in Loasis 4.5%, ascaridiasis 13.5% or healthy controls 2.4%. The poor skin reactivity to OS in loasis was not due to immunosuppression as these patients, when also infested with ascaris, reacted just as well as onchocerca patients with ascaris to skin prick test using somatic extracts of ascaris. PMID:6808726

  8. Interruption of Onchocerca volvulus transmission in Northern Venezuela

    PubMed Central

    2013-01-01

    Background Onchocerciasis is caused by Onchocerca volvulus and transmitted by Simulium species (black flies). In the Americas, the infection has been previously described in 13 discrete regional foci distributed among six countries (Brazil, Colombia, Ecuador, Guatemala, Mexico and Venezuela) where more than 370,000 people are currently considered at risk. Since 2001, disease control in Venezuela has relied on the mass drug administration to the at-risk communities. This report provides empirical evidence of interruption of Onchocerca volvulus transmission by Simulium metallicum in 510 endemic communities from two Northern foci of Venezuela, after 10–12 years of 6-monthly Mectizan® (ivermectin) treatment to all the eligible residents. Methods In-depth entomologic and epidemiologic surveys were serially conducted from 2001–2012 in selected (sentinel and extra-sentinel) communities from the North-central (NC) and North-east (NE) onchocerciasis foci of Venezuela in order to monitor the impact of ivermectin treatment. Results From 2007–2009, entomological indicators in both foci confirmed that 0 out of 112,637 S. metallicum females examined by PCR contained L3 infection in insect heads. The upper bound of the 95% confidence intervals of the infective rate of the vector reached values below 1% by 2009 (NC) and 2012 (NE). Additionally, after 14 (NC) and 22 (NE) rounds of treatment, the seasonal transmission potential (±UL CIs) of S. metallicum was under the critical threshold of 20 L3 per person per season. Serological analysis in school children < 15 years-old demonstrated that 0 out of 6,590 individuals were harboring antibodies to Ov-16. Finally, epidemiological surveys made during 2010 (NC) and 2012 (NE) showed no evidence of microfilariae in the skin and eyes of the population. Conclusions These results meet the WHO criteria for absence of parasite transmission and disease morbidity in these endemic areas which represent 91% of the population previously at

  9. [A case of cross infection by Onchocerca volvulus and Onchocerca ochengi in Simulium damnosum S.L].

    PubMed

    Toe, L; Adjami, A; Bissan, Y; Hougard, J M

    1998-01-01

    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. asynchronous development of parasites of the same species or specific differences in the duration of parasite cycles. Further study will be needed to determine the incidence and scope of cross infection in areas where accurate assessment of the impact of vector control on transmission of onchocerciasis in man is required. PMID:10088105

  10. Immune recognition of Onchocerca volvulus proteins in the human host and animal models of onchocerciasis.

    PubMed

    Manchang, T K; Ajonina-Ekoti, I; Ndjonka, D; Eisenbarth, A; Achukwi, M D; Renz, A; Brattig, N W; Liebau, E; Breloer, M

    2015-05-01

    Onchocerca volvulus is a tissue-dwelling, vector-borne nematode parasite of humans and is the causative agent of onchocerciasis or river blindness. Natural infections of BALB/c mice with Litomosoides sigmodontis and of cattle with Onchocerca ochengi were used as models to study the immune responses to O. volvulus-derived recombinant proteins (OvALT-2, OvNLT-1, Ov103 and Ov7). The humoral immune response of O. volvulus-infected humans against OvALT-2, OvNLT-1 and Ov7 revealed pronounced immunoglobulin G (IgG) titres which were, however, significantly lower than against the lysate of O. volvulus adult female worms. Sera derived from patients displaying the hyperreactive form of onchocerciasis showed a uniform trend of higher IgG reactivity both to the single proteins and the O. volvulus lysate. Sera derived from L. sigmodontis-infected mice and from calves exposed to O. ochengi transmission in a hyperendemic area also contained IgM and IgG1 specific for O. volvulus-derived recombinant proteins. These results strongly suggest that L. sigmodontis-specific and O. ochengi-specific immunoglobulins elicited during natural infection of mice and cattle cross-reacted with O. volvulus-derived recombinant antigens. Monitoring O. ochengi-infected calves over a 26-month period, provided a comprehensive kinetic of the humoral response to infection that was strictly correlated with parasite load and occurrence of microfilariae. PMID:24721822

  11. Molecular cloning of an Onchocerca volvulus extracellular Cu-Zn superoxide dismutase.

    PubMed Central

    James, E R; McLean, D C; Perler, F

    1994-01-01

    Onchocerca volvulus, a human parasitic nematode, is the third leading cause of preventable blindness worldwide. This study describes the molecular cloning of a novel superoxide dismutase (SOD) from the parasite. This putative O. volvulus extracellular SOD (OvEcSOD) is 628 nucleotides (nt) long, including a 22-nt 5' spliced leader (SL1) and a portion encoding an N-terminal hydrophobic 42-amino-acid signal peptide. The remainder of the cDNA shares 71% identity with an O. volvulus cytosolic SOD sequence and is 3 nt longer. All residues involved in metal ion binding, active site formation, folding, and dimer formation in SODs are conserved. Data indicate the OvEcSOD and O. volvulus cytosolic SOD are separate gene products and that the OvEcSOD appears to possess the characteristics of a membrane-bound or secreted enzyme which may be involved in the parasite defense against phagocyte-generated reactive oxygen species. Images PMID:8300230

  12. The novel cuticular collagen Ovcol-1 of Onchocerca volvulus is preferentially recognized by immunoglobulin G3 from putatively immune individuals.

    PubMed Central

    Stewart, G R; Zhu, Y; Parredes, W; Tree, T I; Guderian, R; Bradley, J E

    1997-01-01

    The cDNA sequence encoding an Onchocerca volvulus collagen, Ovcol-1, has been isolated and the corresponding native antigen has been identified. The cDNA encodes an open reading frame of 96 amino acid residues containing an uninterrupted 66-residue Gly-X-Y repeat triple-helical (TH) domain (where X and Y may be any amino acids) flanked by a 26-residue amino non-TH domain and a 4-residue carboxyl non-TH domain. The size (9.7 kDa) and structure of the deduced molecule are unique among previously identified collagen chains. This novel collagen type has been designated "mini-chain collagen." Native Ovcol-1 is aqueous soluble and resolves by sodium dodecyl sulfate-polyacrylamide gel electrophoresis at 14.2 kDa under reducing conditions. Immunoelectron microscopy of adult female O. volvulus localized Ovcol-1 to the cuticles of both the adult worm and uterine microfilaria. A group of individuals from an area in Ecuador where O. volvulus is hyperendemic have been classified as putatively immune (PI) to O. volvulus infection. Analysis of the humoral immune responses to Ovcol-1 demonstrated that immunoglobulin G3 (IgG3) of PI individuals preferentially recognized this antigen in comparison to IgG3 of infected individuals. PMID:8975907

  13. A Simple Isothermal DNA Amplification Method to Screen Black Flies for Onchocerca volvulus Infection

    PubMed Central

    Alhassan, Andy; Makepeace, Benjamin L.; LaCourse, Elwyn James; Osei-Atweneboana, Mike Y.; Carlow, Clotilde K. S.

    2014-01-01

    Onchocerciasis is a debilitating neglected tropical disease caused by infection with the filarial parasite Onchocerca volvulus. Adult worms live in subcutaneous tissues and produce large numbers of microfilariae that migrate to the skin and eyes. The disease is spread by black flies of the genus Simulium following ingestion of microfilariae that develop into infective stage larvae in the insect. Currently, transmission is monitored by capture and dissection of black flies and microscopic examination of parasites, or using the polymerase chain reaction to determine the presence of parasite DNA in pools of black flies. In this study we identified a new DNA biomarker, encoding O. volvulus glutathione S-transferase 1a (OvGST1a), to detect O. volvulus infection in vector black flies. We developed an OvGST1a-based loop-mediated isothermal amplification (LAMP) assay where amplification of specific target DNA is detectable using turbidity or by a hydroxy naphthol blue color change. The results indicated that the assay is sensitive and rapid, capable of detecting DNA equivalent to less than one microfilaria within 60 minutes. The test is highly specific for the human parasite, as no cross-reaction was detected using DNA from the closely related and sympatric cattle parasite Onchocerca ochengi. The test has the potential to be developed further as a field tool for use in the surveillance of transmission before and after implementation of mass drug administration programs for onchocerciasis. PMID:25299656

  14. A simple isothermal DNA amplification method to screen black flies for Onchocerca volvulus infection.

    PubMed

    Alhassan, Andy; Makepeace, Benjamin L; LaCourse, Elwyn James; Osei-Atweneboana, Mike Y; Carlow, Clotilde K S

    2014-01-01

    Onchocerciasis is a debilitating neglected tropical disease caused by infection with the filarial parasite Onchocerca volvulus. Adult worms live in subcutaneous tissues and produce large numbers of microfilariae that migrate to the skin and eyes. The disease is spread by black flies of the genus Simulium following ingestion of microfilariae that develop into infective stage larvae in the insect. Currently, transmission is monitored by capture and dissection of black flies and microscopic examination of parasites, or using the polymerase chain reaction to determine the presence of parasite DNA in pools of black flies. In this study we identified a new DNA biomarker, encoding O. volvulus glutathione S-transferase 1a (OvGST1a), to detect O. volvulus infection in vector black flies. We developed an OvGST1a-based loop-mediated isothermal amplification (LAMP) assay where amplification of specific target DNA is detectable using turbidity or by a hydroxy naphthol blue color change. The results indicated that the assay is sensitive and rapid, capable of detecting DNA equivalent to less than one microfilaria within 60 minutes. The test is highly specific for the human parasite, as no cross-reaction was detected using DNA from the closely related and sympatric cattle parasite Onchocerca ochengi. The test has the potential to be developed further as a field tool for use in the surveillance of transmission before and after implementation of mass drug administration programs for onchocerciasis. PMID:25299656

  15. Chemokines and cytokines in patients with an occult Onchocerca volvulus infection.

    PubMed

    Lechner, Christian J; Gantin, Richard G; Seeger, Tanja; Sarnecka, Alicja; Portillo, Jennifer; Schulz-Key, Hartwig; Karabou, Potochoziou K; Helling-Giese, Gertrud; Heuschkel, Christoph; Banla, Meba; Soboslay, Peter T

    2012-05-01

    Repeated ivermectin treatment will clear microfilaria (Mf) of Onchocerca volvulus from skin and eyes of onchocerciasis patients while adult filaria remains alive and reproductive, and such occult O. volvulus infection may persist for years. To investigate the effect of residual adult filaria on the immune response profile, chemokines and cytokines were quantified 1) in onchocerciasis patients who developed an occult O. volvulus infection (Mf-negative) due to repeated ivermectin treatments, 2) patients who became Mf-negative without ivermectin treatments due to missing re-infection, and 3) endemic and non-endemic O. volvulus Mf-negative controls. With occult O. volvulus infection, serum levels of pro-inflammatory chemokines MCP-1/CCL2, MIP-1α/CCL3, MIP-1β/CCL4, MPIF-1/CCL23 and CXCL8/IL-8 enhanced and approached higher concentrations as determined in infection-free controls, whilst regulatory and Th2-type cytokines and chemokines MCP-4/CCL13, MIP-1δ/CCL15, TARC/CCL17 and IL-13 lessened. Levels of Eotaxin-2/CCL24, MCP-3/CCL7 and BCA-1/CXCL13 remained unchanged. At 3 days post-initial ivermectin treatment, MCP-1/CCL2, MCP-4/CCL13, MPIF-1/CCL23 and Eotaxin-2/CCL24 were strongly enhanced, suggesting that monocytes and eosinophil granulocytes have mediated Mf clearance. In summary, with occult and expiring O. volvulus infections the serum levels of inflammatory chemokines enhanced over time while regulatory and Th2-type-promoting cytokines and chemokines lessened; these changes may reflect a decreasing effector cell activation against Mf of O. volvulus, and in parallel, an enhancing inflammatory immune responsiveness. PMID:22202179

  16. Preliminary studies on the histochemical differentiation of strains of Onchocerca volvulus microfilariae in Togo*

    PubMed Central

    Braun-Munzinger, R. A.; Southgate, B. A.

    1977-01-01

    Skin snips were taken from 75 people living in four villages of northern Togo. The 7824 microfilariae that emerged were examined by staining for the presence of acid phosphatase. Four distinct patterns of enzyme staining were observed, and descriptions of the stained microfilariae are given. The study confirms the view that a number of biological strains or variants of Onchocerca volvulus coexist in West Africa, and suggestions are made for further research that could result in the practical application of these observations in onchocerciasis control programmes. ImagesFig. 1Fig. 2Fig. 3Fig. 4 PMID:303958

  17. Development of Onchocerca volvulus microfilariae injected into Simulium species from Cameroon.

    PubMed

    Eichner, M; Renz, A; Wahl, G; Enyong, P

    1991-07-01

    Microfilariae (mff) of the savanna and forest strains of Onchocerca volvulus (Leuckart) were injected intrathoracically into adult females of Simulium damnosum Theobald sensu stricto, S.sirbanum Vajime & Dunbar, S.squamosum Enderlein and S.mengense Vajime & Dunbar. Nine days post infection (pi) 27-29% of the savanna mff and 31-38% of the forest strain had developed to third-stage larvae (L3), irrespective of the fly species, size or injection dose (5, 10 or 15 mff). Savanna flies supported the development of forest O.volvulus better than forest flies, in contrast to the results after per os infections. Therefore, in these four species of the S.damnosum complex from Cameroon, the peritrophic membrane is considered to be the main factor limiting the success rate of microfilarial development following the ingestion of blood infections, while the fly's haemolymph and intracellular environment play minor roles. PMID:1768922

  18. Elimination of Onchocerca volvulus Transmission in the Huehuetenango Focus of Guatemala.

    PubMed

    Cruz-Ortiz, Nancy; Gonzalez, Rodrigo J; Lindblade, Kim A; Richards, Frank O; Sauerbrey, Mauricio; Zea-Flores, Guillermo; Dominguez, Alfredo; Oliva, Orlando; Catú, Eduardo; Rizzo, Nidia

    2012-01-01

    In Latin America, onchocerciasis is targeted for elimination by 2012 through twice-yearly mass treatment of the eligible population with ivermectin. In Guatemala, two of the four historical endemic foci have demonstrated elimination of transmission, following World Health Organization guidelines. Using established guidelines ophthalmological, serological, and entomological evaluations were conducted in 2007-8 to determine the transmission status of onchocerciasis in the Huehuetenango focus. The prevalence of Onchocerca volvulus microfilariae in the anterior segment of the eye in 365 residents was 0% (95% confidence interval [CI] 0-0.8%), the prevalence of infection of O. volvulus in Simulium ochraceum among 8252 flies collected between November 2007 and April 2008 was 0% (95% CI 0-0.02%), and the prevalence of antibodies to a recombinant O. volvulus antigen in 3118 school age children was 0% (95% CI 0-0.1%). These results showed transmission interruption; thus, in 2009 mass treatment was halted and posttreatment surveillance began. To verify for potential recrudescence an entomological evaluation (from December 2010 to April 2011) was conducted during the 2nd and 3rd year of posttreatment surveillance. A total of 4587 S. ochraceum were collected, and the prevalence of infection of O. volvulus was 0% (95% CI 0-0.04%). Transmission of onchocerciasis in the Huehuetenango focus has been eliminated. PMID:22970346

  19. Successful Interruption of Transmission of Onchocerca volvulus in the Escuintla-Guatemala Focus, Guatemala

    PubMed Central

    Gonzalez, Rodrigo J.; Cruz-Ortiz, Nancy; Rizzo, Nidia; Richards, Jane; Zea-Flores, Guillermo; Domínguez, Alfredo; Sauerbrey, Mauricio; Catú, Eduardo; Oliva, Orlando; Richards, Frank O.; Lindblade, Kim A.

    2009-01-01

    Background Elimination of onchocerciasis (river blindness) through mass administration of ivermectin in the six countries in Latin America where it is endemic is considered feasible due to the relatively small size and geographic isolation of endemic foci. We evaluated whether transmission of onchocerciasis has been interrupted in the endemic focus of Escuintla-Guatemala in Guatemala, based on World Health Organization criteria for the certification of elimination of onchocerciasis. Methodology/Principal Findings We conducted evaluations of ocular morbidity and past exposure to Onchocerca volvulus in the human population, while potential vectors (Simulium ochraceum) were captured and tested for O. volvulus DNA; all of the evaluations were carried out in potentially endemic communities (PEC; those with a history of actual or suspected transmission or those currently under semiannual mass treatment with ivermectin) within the focus. The prevalence of microfilariae in the anterior segment of the eye in 329 individuals (≥7 years old, resident in the PEC for at least 5 years) was 0% (one-sided 95% confidence interval [CI] 0–0.9%). The prevalence of antibodies to a recombinant O. volvulus antigen (Ov-16) in 6,432 school children (aged 6 to 12 years old) was 0% (one-sided 95% IC 0–0.05%). Out of a total of 14,099 S. ochraceum tested for O. volvulus DNA, none was positive (95% CI 0–0.01%). The seasonal transmission potential was, therefore, 0 infective stage larvae per person per season. Conclusions/Significance Based on these evaluations, transmission of onchocerciasis in the Escuintla-Guatemala focus has been successfully interrupted. Although this is the second onchocerciasis focus in Latin America to have demonstrated interruption of transmission, it is the first focus with a well-documented history of intense transmission to have eliminated O. volvulus. PMID:19333366

  20. Exposure of seasonal migrant workers to Onchocerca volvulus on coffee plantations in Guatemala.

    PubMed

    Lindblade, Kim A; Richards, Michael; Richards, Jane; Gonzalez, Rodrigo J; Cruz-Ortiz, Nancy; Zea-Flores, Guillermo; Morales, Alba Lucia; Sauerbrey, Mauricio; Castro, Julio; Catú, Eduard; Arana, Byron; Richards, Frank O; Klein, Robert E

    2009-09-01

    Onchocerciasis (river blindness), which is close to being eliminated from Guatemala through semiannual administration of ivermectin, is still transmitted in one area of the country that coincidentally receives an annual influx of migrant workers to harvest coffee. Migrant workers generally are not included in semiannual ivermectin treatments, but if infected could serve as a reservoir. We report on two studies undertaken to measure the exposure to onchocerciasis (presence of IgG4 antibodies to a recombinant Onchocerca volvulus antigen, OV-16) among migrant workers. During two coffee harvest seasons, 170 migrant workers with a history of working in the disease-endemic area were tested and 1 (0.6%, 95% confidence interval = 0-3.2%) was seropositive. This low rate of exposure in migrant workers indicates that they are unlikely to play a significant role in transmission of onchocerciasis and may indicate that transmission in the last remaining disease-endemic area of Guatemala is decreasing significantly. PMID:19706910

  1. A Recombinant Positive Control for Serology Diagnostic Tests Supporting Elimination of Onchocerca volvulus

    PubMed Central

    Golden, Allison; Stevens, Eric J.; Yokobe, Lindsay; Faulx, Dunia; Kalnoky, Michael; Peck, Roger; Valdez, Melissa; Steel, Cathy; Karabou, Potochoziou; Banla, Méba; Soboslay, Peter T.; Adade, Kangi; Tekle, Afework H.; Cama, Vitaliano A.; Fischer, Peter U.; Nutman, Thomas B.; Unnasch, Thomas R.; de los Santos, Tala; Domingo, Gonzalo J.

    2016-01-01

    Background Serological assays for human IgG4 to the Onchocerca volvulus antigen Ov16 have been used to confirm elimination of onchocerciasis in much of the Americas and parts of Africa. A standardized source of positive control antibody (human anti-Ov16 IgG4) will ensure the quality of surveillance data using these tests. Methodology/Principal Findings A recombinant human IgG4 antibody to Ov16 was identified by screening against a synthetic human Fab phage display library and converted into human IgG4. This antibody was developed into different positive control formulations for enzyme-linked immunosorbent assay (ELISA) and rapid diagnostic test (RDT) platforms. Variation in ELISA results and utility as a positive control of the antibody were assessed from multiple laboratories. Temperature and humidity conditions were collected across seven surveillance activities from 2011–2014 to inform stability requirements for RDTs and positive controls. The feasibility of the dried positive control for RDT was evaluated during onchocerciasis surveillance activity in Togo, in 2014. When the anti-Ov16 IgG4 antibody was used as a standard dilution in horseradish peroxidase (HRP) and alkaline phosphatase (AP) ELISAs, the detection limits were approximately 1ng/mL by HRP ELISA and 10ng/mL by AP ELISA. Positive control dilutions and spiked dried blood spots (DBS) produced similar ELISA results. Used as a simple plate normalization control, the positive control antibody may improve ELISA data comparison in the context of inter-laboratory variation. The aggregate temperature and humidity monitor data informed temperature parameters under which the dried positive control was tested and are applicable inputs for testing of diagnostics tools intended for sub-Saharan Africa. As a packaged positive control for Ov16 RDTs, stability of the antibody was demonstrated for over six months at relevant temperatures in the laboratory and for over 15 weeks under field conditions. Conclusions The

  2. [The epidemiological significance of neo-natal parasitism with microfilariae of Onchocerca volvulus (author's transl)].

    PubMed

    Prost, A; Gorim de Ponsay, E

    1979-12-01

    Between April 1977 and June 1978, 214 babies born of 210 mothers infected with Onchocerciasis, were examined at the maternity of Po Hospital (Upper Volta). In four of them (1.9%) dermal microfilariae of Onchocerca volvulus were found during the first week after birth. In two other cases microfilariae were seen in the tissue of the umbilical cord. All specimens from placentas and amniotic fluid gave negative results. The infected babies were reexamined monthly monthly from 2 to 18 months, depending on the cases. One child remained positive until the 6th month follow-up. The base-line examination of 5.757 children less than 2 years old from different villages in the WHO Onchocerciasis Control Programme in the Volta River Basin Area showed that 1% of children less than one year old and 2% of children of 12 to 23 months old were carriers of dermal microfilariae. These results indicate that in meso- or hyperendemic areas children less than one year old and carriers of microfilariae of Onchocerca volbulus may have been infected in utero. The existence of such cases, in an area of vector control, does not prove a residual vector borne transmission. PMID:575449

  3. Efficiency of Simulium sanctipauli as a vector of Onchocerca volvulus in the forest zone of Ghana.

    PubMed

    Kutin, K; Kruppa, T F; Brenya, R; Garms, R

    2004-06-01

    The role of Simulium sanctipauli Vajime & Dunbar (Diptera: Simuliidae) as a vector of Onchocerca volvulus (Leuckart) (Spirurida: Onchocercidae) in the forest zone of central Ghana was studied in the Upper Denkyira district, where onchocerciasis is hyperendemic. Simulium sanctipauli was found to be a highly efficient vector, with a mean of 377 infective (L3) larvae in the heads of 1000 parous and 122 in the heads of 1000 biting flies. The overall infection rate of 44% of the parous flies with L1, L2 and L3 stages of O. volvulus (identity confirmed by polymerase chain reaction) demonstrates marked anthropophily. Female flies dispersed over a wide area and can transmit onchocerciasis up to at least 10 km away from their breeding sites. Annual community-directed treatments with ivermectin did not have a noticeable effect on the infection rates and parasitic loads of fly populations, which were as high 2 months after as 3 months before the distribution of ivermectin. This failure can be attributed to poor coverage, with treatment taken by only 24.4% of the population of the six study villages. PMID:15189242

  4. Onchocerca volvulus-neurotransmitter tyramine is a biomarker for river blindness.

    PubMed

    Globisch, Daniel; Moreno, Amira Y; Hixon, Mark S; Nunes, Ashlee A K; Denery, Judith R; Specht, Sabine; Hoerauf, Achim; Janda, Kim D

    2013-03-12

    Onchocerciasis, also known as "river blindness", is a neglected tropical disease infecting millions of people mainly in Africa and the Middle East but also in South America and Central America. Disease infectivity initiates from the filarial parasitic nematode Onchocerca volvulus, which is transmitted by the blackfly vector Simulium sp. carrying infectious third-stage larvae. Ivermectin has controlled transmission of microfilariae, with an African Program elimination target date of 2025. However, there is currently no point-of-care diagnostic that can distinguish the burden of infection--including active and/or past infection--and enable the elimination program to be effectively monitored. Here, we describe how liquid chromatography-MS-based urine metabolome analysis can be exploited for the identification of a unique biomarker, N-acetyltyramine-O,β-glucuronide (NATOG), a neurotransmitter-derived secretion metabolite from O. volvulus. The regulation of this tyramine neurotransmitter was found to be linked to patient disease infection, including the controversial antibiotic doxycycline treatment that has been shown to both sterilize and kill adult female worms. Further clues to its regulation have been elucidated through biosynthetic pathway determination within the nematode and its human host. Our results demonstrate that NATOG tracks O. volvulus metabolism in both worms and humans, and thus can be considered a host-specific biomarker for onchocerciasis progression. Liquid chromatography-MS-based urine metabolome analysis discovery of NATOG not only has broad implications for a noninvasive host-specific onchocerciasis diagnostic but provides a basis for the metabolome mining of other neglected tropical diseases for the discovery of distinct biomarkers and monitoring of disease progression. PMID:23440222

  5. Onchocerca volvulus: enzyme polymorphism in relation to the differentiation of forest and savannah strains of this parasite.

    PubMed

    Flockhart, H A; Cibulskis, R E; Karam, M; Albiez, E J

    1986-01-01

    Isozyme analysis was carried out on Onchocerca volvulus worms collected from Liberia, Ivory Coast, Burkina Faso and Sudan to see whether this technique could detect differences between forest and savannah populations of this parasite. A total of 243 forest and 189 savannah individual female worms were electrophoresed and stained for seven enzymes. Four showed some polymorphism, LDH, MDH, PGM and MPI and the other three, GAPDH, PEP and GPI were invariant. Statistical analysis of the results showed that the relative proportions of genotypes from within the different countries conformed to Hardy-Weinberg expectations. Pairwise comparisons of allele frequencies between countries showed that populations from Liberia and Ivory Coast had a very similar composition; there was some divergence between all the other pairs of populations and the genetic distance was calculated to summarize the degree of divergence. The number of loci examined was small and the genetic distances were within the range expected for separate geographical populations of the same species. The usefulness of this technique in worm identification is discussed. PMID:3024365

  6. Immunoglobulin G subclass responses of children during infection with Onchocerca volvulus.

    PubMed Central

    Gbakima, A A; Nutman, T B; Bradley, J E; McReynolds, L A; Winget, M D; Hong, Y; Scott, A L

    1996-01-01

    To characterize the patterns of immunoglobulin G (IgG) subclass and IgE reactivity during the early stages of onchocerciasis, sera were collected from 224 children (age groups, 2 to 5, 6 to 10, and 11 to 15 years) residing in a region of Sierra Leone where Onchocerca volvulus is endemic, and these samples were tested by enzyme-linked immunosorbent assay for their reactivity to adult antigens (OvAg) and against four recombinant proteins (OV11, OV27, OV29, and OV16). Over 88% of the samples contained detectable levels of anti-OvAg IgG. In samples from microfilaria (MF)-positive children, IgG4 responses were significantly elevated and constituted on average 39, 35 and 28% of the total IgG responses for the age groups of 2 to 5, 6 to 10, and 11 to 15 years, respectively. For MF-negative individuals, the mean contributions of IgG4 to the total IgG response were 11% (2 to 5 years), 27% (6 to 10 years), and 56% (11 to 15 years). OvAg-specific IgE was detectable in the sera from both MF-negative and MF-positive individuals. To increase the specificity of the response, recombinant antigens OV11, OV27, and OV29 were tested individually or as a cocktail. Nearly 50% of the MF-negative children and 85% of the MF-positive children had detectable levels of IgG against at least one of the recombinant antigens. Only a small portion of the IgG against the recombinant peptides was IgG4. The prevalence of IgG against OV16 in samples from MF-negative children was 51%, and that for MF-positive children was 75%. The general profile of the humoral immune responses mounted by both MF-positive and a large percentage of the MF-negative children during the initial phases of infection with O. volvulus is similar to the profile reported for adults harboring chronic O. volvulus infections. These results suggest that very quickly after infection, the interactions between parasite and host result in an immunological environment that may contribute to the maintenance of a long-term, chronic

  7. Interruption of Onchocerca volvulus transmission in the Abu Hamed focus, Sudan.

    PubMed

    Higazi, Tarig B; Zarroug, Isam M A; Mohamed, Hanan A; Elmubark, Wigdan A; Deran, Tong Chor M; Aziz, Nabil; Katabarwa, Moses; Hassan, Hassan K; Unnasch, Thomas R; Mackenzie, Charles D; Richards, Frank; Hashim, Kamal

    2013-07-01

    Abu Hamed, Sudan, the northernmost location of onchocerciasis in the world, began community-directed treatment with ivermectin (CDTI) in 1998, with annual treatments enhanced to semiannual in 2007. We assessed the status of the parasite transmission in 2011 entomologically, parasitologically, and serologically. O-150 pool screening showed no parasite DNA in 17,537 black flies collected in 2011 (95% confidence interval upper limit [95% CI UL] = 0.023). Skin microfilariae, nodules, and signs of skin disease were absent in 536 individuals in seven local communities. Similarly, no evidence of Onchocerca volvulus Ov16 antibodies was found in 6,756 school children ≤ 10 years (95% CI UL = 0.03%). Because this assessment of the focus meets the 2001 World Health Organization (WHO) criteria for interrupted transmission, treatment was halted in 2012, and a post-treatment surveillance period was initiated in anticipation of declaration of disease elimination in this area. We provide the first evidence in East Africa that long-term CDTI alone can interrupt transmission of onchocerciasis. PMID:23690554

  8. Viability of adult Onchocerca volvulus after six 2-weekly doses of ivermectin.

    PubMed Central

    Duke, B. O.; Pacqué, M. C.; Muñoz, B.; Greene, B. M.; Taylor, H. R.

    1991-01-01

    Ivermectin is a safe, effective microfilaricide and microfilarial suppressant for Onchocerca volvulus; but in single doses of 100-200 micrograms/kg body weight it has no macrofilaricidal action. The present trial aimed to determine whether 6 doses of 100 micrograms/kg ivermectin, given at 2-week intervals, would kill the adult worms. Eighty-two nodules from 28 otherwise healthy adult male Liberian patients treated with this ivermectin schedule, and 102 nodules from a similar group of 25 control patients, were removed four months after the last dose of ivermectin. They were coded and assessed in a masked fashion either by routine histology or by examination of whole worms extracted from the nodules after collagenase digestion. The drug had no visible effect on adult male worms. More adult female worms were assessed as moribund or dead in the ivermectin-treated group than in the control group (for the collagenase digests P = 0.09; for the histological assessment P = 0.47). The data suggest that repeated dosage with ivermectin may lead to a slow attrition of some female worms and this possibility should be investigated in patients receiving regular doses every 3, 6 or 12 months as part of onchocerciasis control programmes. PMID:1860146

  9. A stochastic model for the aggregation of Onchocerca volvulus in nodules.

    PubMed

    Duerr, H P; Dietz, K; Buttner, D W; Schulz-Key, H

    2001-08-01

    A model is presented which describes the aggregation of female Onchocerca volvulus in nodules and their distribution in the human population. The basic model is based on a single parameter, the formation probability q, which represents the probability with which incoming larvae form a new nodule. This parameter describes parasite behaviour which cannot easily be recognized in available data without modelling. The estimate for the average formation probability of muq = 0.39 suggests an attraction of the invading infective larvae to already existing nodules or resident worms with probability 0.61. No significant difference in muq was found between the forest and savanna parasite strains. The model can be used inversely to estimate the worm burden of persons from palpation data. The observed variance in the number of nodules per person requires the assumption of a variance-increasing mechanism which was implemented by heterogeneity within the host population (extended model with 2 parameters). Possible reasons for this heterogeneity are presented and its implications concerning the reproductive biology of the parasite are discussed. PMID:11510685

  10. Histochemical enzyme-staining patterns of onchocerca volvulus microfilariae and their occurrence in different onchocerciasis areas.

    PubMed

    Omar, M S

    1978-12-01

    Histochemical differentiation of Onchocerca volvulus microfilariae from 164 patients in West African rain-forest (Liberia), Sudan-savanna (Upper Volta), Guatemala and the Yemen has been carried out using a staining method for the demonstration of acid phosphatase. Intrauterine microfilariae showed considerable changes in their enzyme activity during embryonic development which are probably associated with the maturation of the parasite before migration to the tissues. Five distinct types of staining patterns could be distinguished among microfilariae from the skin according to the localization of the enzyme in specific structures of the microfilaria. Two or more types of staining patterns were found in most persons in the different geographic regions. There were significant differences in the overall distribution of the various staining patterns in persons from the different areas. At the present state of our knowledge, little is known about the nature and significance of these differences in the staining patterns of microfilariae. The question of whether they can be ascribed to an ageing process, strain differences or other factors is discussed. PMID:84419

  11. Lack of Active Onchocerca volvulus Transmission in the Northern Chiapas Focus of Mexico

    PubMed Central

    Rodríguez-Pérez, Mario A.; Unnasch, Thomas R.; Domínguez-Vázquez, Alfredo; Morales-Castro, Alba L.; Richards, Frank; Peña-Flores, Graciela P.; Orozco-Algarra, María Eugenia; Prado-Velasco, Gibert

    2010-01-01

    The northern Chiapas onchocerciasis focus has undergone 11 years of ivermectin mass treatment. No evidence of microfilariae in the cornea and/or anterior chamber of the eye or in skin snips was seen in residents examined in 2006 in two sentinel communities (upper limit of the 95% confidence interval [UL 95% CI] = 0.5% and 0.3%, respectively). In children 10 and under, 0 of 305 were found to harbor antibodies to Ov16, a marker of parasite exposure; 0 of 4,400 Simulium ochraceum s.l. collected in 2005 contained parasite DNA, giving an UL 95% CI for the infective rate of 0.9/2,000, and an UL 95% CI of the seasonal transmission potential of 1.2 L3/person. These data, assumed to be representative of the focus as a whole, suggest that there is no ongoing transmission of Onchocerca volvulus in the northern Chiapas focus. Community-wide treatments with ivermectin were halted in 2008, and a post-treatment surveillance phase was initiated. PMID:20595471

  12. Detection of Onchocerca volvulus in Latin American black flies for pool screening PCR using high-throughput automated DNA isolation for transmission surveillance.

    PubMed

    Rodríguez-Pérez, Mario A; Gopal, Hemavathi; Adeleke, Monsuru Adebayo; De Luna-Santillana, Erick Jesús; Gurrola-Reyes, J Natividad; Guo, Xianwu

    2013-11-01

    The posttreatment entomological surveillance (ES) of onchocerciasis in Latin America requires quite large numbers of flies to be examined for parasite infection to prove that the control strategies have worked and that the infection is on the path of elimination. Here, we report a high-throughput automated DNA isolation of Onchocerca volvulus for PCR using a major Latin American black fly vector of onchocerciasis. The sensitivity and relative effectiveness of silica-coated paramagnetic beads was evaluated in comparison with phenol chloroform (PC) method which is known as the gold standard of DNA extraction for ES in Latin America. The automated method was optimized in the laboratory and validated in the field to detect parasite DNA in Simulium ochraceum sensu lato flies in comparison with PC. The optimization of the automated method showed that it is sensitive to detect O. volvulus with a pool size of 100 flies as compared with PC which utilizes 50 flies pool size. The validation of the automated method in comparison with PC in an endemic community showed that 5/67 and 3/134 heads pools were positive for the two methods, respectively. There was no statistical variation (P < 0.05) in the estimation of transmission indices generated by automated method when compared with PC method. The fact that the automated method is sensitive to pool size up to 100 confers advantage over PC method and can, therefore, be employed in large-scale ES of onchocerciasis transmission in endemic areas of Latin America. PMID:24030195

  13. Analysis of Wuchereria bancrofti infections in a village community in northern Nigeria: increased prevalence in individuals infected with Onchocerca volvulus.

    PubMed

    Engelbrecht, Fred; Oettl, Tobias; Herter, Ursula; Link, Claudia; Philipp, Diana; Edeghere, Henry; Kaliraj, P; Enwezor, Felicia

    2003-03-01

    Infections with Wuchereria bancrofti causing lymphatic filariasis still represent one of the major health problems in the tropics, with 120 million people infected and over 750 million exposed to this filarial parasite. We have studied lymphatic filariasis infections as part of a multi-parasite survey in a village community in the savannah of northern Nigeria. We analysed serum samples from 341 individuals aged 5-70 years, detecting a W. bancrofti circulating antigen using the commercially available ICT Filariasis card test. The prevalence of infections was 10% and clearly age-dependent, increasing from below 2% in children to over 20% in subjects older than 40 years. Measuring IgG4 antibodies against the recombinant W. bancrofti antigen SXP1 showed that 36% of all tested individuals had been at least exposed to the parasite. Antibody levels also increased very significantly with age. A further analysis measuring Onchocerca volvulus-specific IgG4 antibodies showed a very significant association between infections with O. volvulus and those with W. bancrofti. Our data show that infections with W. bancrofti in Nigeria are still a frequently occurring health problem, since they are more prevalent than previously reported, and that individuals with an O. volvulus infection are more often infected with W. bancrofti than expected statistically. PMID:12543143

  14. Single nucleotide polymorphisms in β-tubulin selected in Onchocerca volvulus following repeated ivermectin treatment: possible indication of resistance selection.

    PubMed

    Nana-Djeunga, Hugues; Bourguinat, Catherine; Pion, Sébastien D S; Kamgno, Joseph; Gardon, Jacques; Njiokou, Flobert; Boussinesq, Michel; Prichard, Roger K

    2012-09-01

    The control of onchocerciasis or river blindness by mass treatment of the population with ivermectin (IVM) has been a great success until now, so that in certain foci its elimination has become feasible. However, after more than 20 years of repeated IVM mass treatment, the disease still persists in many endemic countries. Sub-optimal responses and genetic changes have been reported in Onchocerca volvulus populations under high IVM pressure but more work is needed to determine whether resistance is developing. The situation needs to be urgently clarified to preserve the achievements of onchocerciasis control programs. In this study, O. volvulus adult worms were collected from the same individuals, before IVM exposure and following three years of annual or three-monthly treatments at 150 μg/kg or 800 μg/kg. Four single nucleotide polymorphisms (SNPs) occurring in the β-tubulin gene of these parasites were investigated. We found changes in genotype frequencies in O. volvulus β-tubulin gene associated with IVM treatments. The SNP at position 1545 (A/G) showed a significant increase in frequency of the less common nucleotide in the female worms following treatment. After 13 three-monthly treatments, female worm homozygotes with the less common genotype, prior to treatment, increased in frequency. The selected homozygotes, as well as heterozygotes, appeared to be less fertile (without or with very few embryonic stages in their uteri) than the wild-type homozygotes. These results provide additional evidence for genetic selection and strengthen the warning that selection for IVM resistance may be occurring in some O. volvulus populations. PMID:22677339

  15. Genotypic analysis of β-tubulin in Onchocerca volvulus from communities and individuals showing poor parasitological response to ivermectin treatment.

    PubMed

    Osei-Atweneboana, Mike Y; Boakye, Daniel A; Awadzi, Kwablah; Gyapong, John O; Prichard, Roger K

    2012-12-01

    Ivermectin (IVM) has been in operational use for the control of onchocerciasis for two decades and remains the only drug of choice. To investigate the parasitological responses and genetic profile of Onchocerca volvulus, we carried out a 21 month epidemiological study to determine the response of the parasite to IVM in 10 Ghanaian endemic communities. Onchocerca nodules were surgically removed from patients in three IVM response categories (good, intermediate and poor) and one IVM naïve community. DNA from adult worms was analyzed to determine any association between genotype and IVM response phenotypic. Embryogramme analysis showed significantly higher reproductive activity in worms from poor response communities, which had up to 41% of females with live stretched microfilaria (mf) in utero, despite IVM treatment, compared with good response communities, which had no intra-uterine stretched mf. β-tubulin isotype 1 gene has been shown to be linked to IVM selection in O. volvulus and also known to be associated with IVM resistance in veterinary nematodes. We have genotyped the full length genomic DNA sequence of the β-tubulin gene from 127 adult worms obtained from the four community categories. We found SNPs at 24 sites over the entire 3696 bp. Eight of the SNPs occurred at significantly higher (p < 0.05) frequencies in the poor response communities compared with the good response communities and the IVM naïve community. Phenotypic and genotypic analyses show that IVM resistance has been selected and the genotype (1183GG/1188CC/1308TT/1545GG) was strongly associated with the resistance phenotype. Since the region in the β-tubulin gene where these four SNPs occur is within 362 bp, it is feasible to develop a genetic marker for the early detection of IVM resistance. PMID:24533268

  16. Genotypic analysis of β-tubulin in Onchocerca volvulus from communities and individuals showing poor parasitological response to ivermectin treatment

    PubMed Central

    Osei-Atweneboana, Mike Y.; Boakye, Daniel A.; Awadzi, Kwablah; Gyapong, John O.; Prichard, Roger K.

    2012-01-01

    Ivermectin (IVM) has been in operational use for the control of onchocerciasis for two decades and remains the only drug of choice. To investigate the parasitological responses and genetic profile of Onchocerca volvulus, we carried out a 21 month epidemiological study to determine the response of the parasite to IVM in 10 Ghanaian endemic communities. Onchocerca nodules were surgically removed from patients in three IVM response categories (good, intermediate and poor) and one IVM naïve community. DNA from adult worms was analyzed to determine any association between genotype and IVM response phenotypic. Embryogramme analysis showed significantly higher reproductive activity in worms from poor response communities, which had up to 41% of females with live stretched microfilaria (mf) in utero, despite IVM treatment, compared with good response communities, which had no intra-uterine stretched mf. β-tubulin isotype 1 gene has been shown to be linked to IVM selection in O. volvulus and also known to be associated with IVM resistance in veterinary nematodes. We have genotyped the full length genomic DNA sequence of the β-tubulin gene from 127 adult worms obtained from the four community categories. We found SNPs at 24 sites over the entire 3696 bp. Eight of the SNPs occurred at significantly higher (p < 0.05) frequencies in the poor response communities compared with the good response communities and the IVM naïve community. Phenotypic and genotypic analyses show that IVM resistance has been selected and the genotype (1183GG/1188CC/1308TT/1545GG) was strongly associated with the resistance phenotype. Since the region in the β-tubulin gene where these four SNPs occur is within 362 bp, it is feasible to develop a genetic marker for the early detection of IVM resistance. PMID:24533268

  17. Transmission of Onchocerca volvulus by Simulium neavei in Mount Elgon focus of Eastern Uganda has been interrupted.

    PubMed

    Katabarwa, Moses; Lakwo, Tom; Habomugisha, Peace; Agunyo, Stella; Byamukama, Edson; Oguttu, David; Ndyomugyenyi, Richard; Tukesiga, Ephraim; Ochieng, Galex Orukan; Abwaimo, Francis; Onapa, Ambrose; Lwamafa, Dennis W K; Walsh, Frank; Unnasch, Thomas R; Richards, Frank O

    2014-06-01

    The study determined that Simulium neavei-transmitted onchocerciasis in Mount Elgon onchocerciasis focus had been interrupted. Annual mass treatment with ivermectin changed to two times per year along with vector elimination in 2007. Then, baseline microfilaria (mf) prevalence data of 1994 in five sentinel communities were compared with follow-up data in 2005 and 2011. Blood spots from 3,051 children obtained in 2009 were analyzed for Onchocerca volvulus immunoglobulin G4 antibodies. Fresh water crab host captures and blackflies collected indicated their infestation with larval stages of S. neavei and presence or absence of the vector, respectively. Mf rates dropped from 62.2% to 0.5%, and 1 (0.03%) of 3,051 children was positive for O. volvulus antibodies. Crab infestation dropped from 41.9% in 2007 to 0%, and S. neavei biting reduced to zero. Both remained zero for the next 3 years, confirming interruption of onchocerciasis transmission, and interventions were halted. PMID:24686740

  18. Is nodding syndrome an Onchocerca volvulus-induced neuroinflammatory disorder? Uganda's story of research in understanding the disease.

    PubMed

    Idro, Richard; Opar, Bernard; Wamala, Joseph; Abbo, Catherine; Onzivua, Sylvester; Mwaka, Deogratius Amos; Kakooza-Mwesige, Angelina; Mbonye, Anthony; Aceng, Jane R

    2016-04-01

    Nodding syndrome is a devastating neurological disorder, mostly affecting children in eastern Africa. An estimated 10000 children are affected. Uganda, one of the most affected countries, set out to systematically investigate the disease and develop interventions for it. On December 21, 2015, the Ministry of Health held a meeting with community leaders from the affected areas to disseminate the results of the investigations made to date. This article summarizes the presentation and shares the story of studies into this peculiar disease. It also shares the results of preliminary studies on its pathogenesis and puts into perspective an upcoming treatment intervention. Clinical and electrophysiological studies have demonstrated nodding syndrome to be a complex epilepsy disorder. A definitive aetiological agent has not been established, but in agreement with other affected countries, a consistent epidemiological association has been demonstrated with infection by Onchocerca volvulus. Preliminary studies of its pathogenesis suggest that nodding syndrome may be a neuroinflammatory disorder, possibly induced by antibodies to O. volvulus cross-reacting with neuron proteins. Histological examination of post-mortem brains has shown some yet to be characterized polarizable material in the majority of specimens. Studies to confirm these observations and a clinical trial are planned for 2016. PMID:26987477

  19. Comparative analysis of macrophage migration inhibitory factors (MIFs) from the parasitic nematode Onchocerca volvulus and the free-living nematode Caenorhabditis elegans.

    PubMed

    Ajonina-Ekoti, Irene; Kurosinski, Marc Andre; Younis, Abuelhassan Elshazly; Ndjonka, Dieudonne; Tanyi, Manchang Kingsley; Achukwi, Mbunkah; Eisenbarth, Albert; Ajonina, Caroline; Lüersen, Kai; Breloer, Minka; Brattig, Norbert W; Liebau, Eva

    2013-09-01

    The macrophage migration inhibitory factors (MIFs) from the filarial parasite Onchocerca volvulus (OvMIF) were compared to the MIFs from the free-living nematode Caenorhabditis elegans (CeMIF) with respect to molecular, biochemical and immunological properties. Except for CeMIF-4, all other MIFs demonstrated tautomerase activity. Surprisingly, OvMIF-1 displayed oxidoreductase activity. The strongest immunostaining for OvMIF-1 was observed in the outer cellular covering of the adult worm body, the syncytial hypodermis; moderate immunostaining was observed in the uterine wall. The generation of a strong humoral immune response towards OvMIF-1 and reduced reactivity to OvMIF-2 was indicated by high IgG levels in patients infected with O. volvulus and cows infected with the closely related Onchocerca ochengi, both MIFs revealing identical amino acid sequences. Using Litomosoides sigmodontis-infected mice, a laboratory model for filarial infection, MIFs derived from the tissue-dwelling O. volvulus, the rodent gut-dwelling Strongyloides ratti and from free-living C. elegans were recognized, suggesting that L. sigmodontis MIF-specific IgM and IgG1 were produced during L. sigmodontis infection of mice and cross-reacted with all MIF proteins tested. Thus, MIF apparently functions as a target of B cell response during nematode infection, but in the natural Onchocerca-specific human and bovine infection, the induced antibodies can discriminate between MIFs derived from parasitic or free-living nematodes. PMID:23820606

  20. Classical ligands interact with native and recombinant tubulin from Onchocerca volvulus with similar rank order of magnitude.

    PubMed

    Wampande, Eddie M; Richard McIntosh, J; Lubega, George W

    2007-10-01

    The alpha- and beta-tubulin genes from Onchocerca volvulus were individually expressed for the first time in Escherichia coli (DH5alpha). The recombinant tubulins were purified, renatured and reconstituted into oligomers, probably dimers, which were competent to bind three classical tubulin ligands: mebendazole (MBZ), taxol (TAX) and vinblastine (VBN). A new charcoal-dependent binding assay allowed accurate discrimination between specific and non-specific ligand binding in crude cell extracts. To compare the magnitude of binding of both native and recombinant forms of tubulin, we developed an ELISA assay for estimating the amount of tubulin in soluble protein extracts of O. volvulus. Binding assays were performed; both the maximum binding at saturating ligand concentrations (B(max)) and the equilibrium dissociation constants (K(d)) were determined. The B(max) values of the different ligands were significantly different from one another (P<0.05), but the order of the B(max) and K(d) for each drug were VBN > TAX > MBZ for both native and recombinant tubulin. Indeed, B(max) values for MBZ with native and recombinant tubulins were similar. On average, native tubulin had higher or similar binding capacity (B(max)) but a consistently higher affinity (lower K(d)) than the recombinant tubulin. We conclude that at least some of the recombinant molecules form receptors that are similar to those in native tubulin dimers. These data suggest that recombinant tubulin can be used to develop a molecular screen for novel anti-tubulin ligands to develop into drugs against onchocerciasis. PMID:17662615

  1. Rapid Point-of-Contact Tool for Mapping and Integrated Surveillance of Wuchereria bancrofti and Onchocerca volvulus Infection.

    PubMed

    Steel, Cathy; Golden, Allison; Stevens, Eric; Yokobe, Lindsay; Domingo, Gonzalo J; de los Santos, Tala; Nutman, Thomas B

    2015-08-01

    Elimination programs for Wuchereria bancrofti and Onchocerca volvulus are in critical need of sensitive, specific, and point-of-contact (POC) tools that can be used for surveillance years beyond cessation of mass drug administration when infection intensities are low. Previously, Wb123 and Ov16 were identified individually as potential filarial antigens for an antibody-based POC test. The present study compares single-antigen Wb123- and Ov16-based POC tests with an integrated configuration to detect antibodies to Wb123 and Ov16 simultaneously. Wb123 and Ov16 isolates were striped onto lateral flow strips containing anti-IgG4. Sera from W. bancrofti-, O. volvulus-, and other helminth-infected or -uninfected individuals were added to the strips with buffer. Strips were read for the appearance of a positive or negative test line for both antigens at 20 min and following drying. Sensitivity, specificity, and predictive values were calculated for the single-antigen and biplex strips. Single and biplex lateral flow strips showed nearly identical results, with >90% sensitivity for Ov16 and >92% sensitivity for Wb123. Overall specificities for the single and biplex tests were 98% and 96% for Ov16 and Wb123, respectively. Biplex tests performed as well as the single-antigen tests regardless of the intensity of patient IgG4 response. The high sensitivity and specificity make these new biplex tests extremely useful for POC long-term surveillance following mass drug administration in Africa that should reduce time and cost in areas where bancroftian filariasis and onchocerciasis are coendemic. PMID:26018537

  2. Diurnal biting activity and transmission of Onchocerca volvulus (Filariata: Onchocercidae) by Simulium yahense (Diptera: Simuliidae) in Liberia.

    PubMed

    Davis, J R; Wasserman, S S; Trpis, M

    1994-03-01

    To determine the influence of meterological factors on the diurnal biting cycle of Simulium yahense Vajime & Dunbar (a member of the Simulium damnosum Theoblad complex), we captured host-seeking females as they landed on the exposed lower legs of humans in the Harbel area of Liberia. Biting activity was greatest during the morning hours and was characterized by a unimodal harmonic curve. Although meteorological conditions had no decisive influence on the unimodal pattern of diurnal biting activity, hourly variation in the number of S. yahense captured at human bait was affected by meterological factors (i.e., the diurnal pattern of S. yahense biting activity is regulated by an internal clock, but the number of bits during any given hour is in response to meterological conditions). The transmission of Onchocerca volvulus (Leuckart) was highest during the morning hours when high transmission potentials were in phase with peak human activity and served to maintain the hyperendemicity of onchocerciasis in the Harbel area. PMID:8189413

  3. Vaccines to combat river blindness: expression, selection and formulation of vaccines against infection with Onchocerca volvulus in a mouse model.

    PubMed

    Hess, Jessica A; Zhan, Bin; Bonne-Année, Sandra; Deckman, Jessica M; Bottazzi, Maria Elena; Hotez, Peter J; Klei, Thomas R; Lustigman, Sara; Abraham, David

    2014-08-01

    Human onchocerciasis is a neglected tropical disease caused by Onchocerca volvulus and an important cause of blindness and chronic disability in the developing world. Although mass drug administration of ivermectin has had a profound effect on control of the disease, additional tools are critically needed including the need for a vaccine against onchocerciasis. The objectives of the present study were to: (i) select antigens with known vaccine pedigrees as components of a vaccine; (ii) produce the selected vaccine antigens under controlled conditions, using two expression systems and in one laboratory and (iii) evaluate their vaccine efficacy using a single immunisation protocol in mice. In addition, we tested the hypothesis that joining protective antigens as a fusion protein or in combination, into a multivalent vaccine, would improve the ability of the vaccine to induce protective immunity. Out of eight vaccine candidates tested in this study, Ov-103, Ov-RAL-2 and Ov-CPI-2M were shown to reproducibly induce protective immunity when administered individually, as fusion proteins or in combination. Although there was no increase in the level of protective immunity induced by combining the antigens into one vaccine, these antigens remain strong candidates for inclusion in a vaccine to control onchocerciasis in humans. PMID:24907553

  4. Ongoing Transmission of Onchocerca volvulus after 25 Years of Annual Ivermectin Mass Treatments in the Vina du Nord River Valley, in North Cameroon

    PubMed Central

    Eisenbarth, Albert; Achukwi, Mbunkah Daniel; Renz, Alfons

    2016-01-01

    Background Recent reports of transmission interruption of Onchocerca volvulus, the causing agent of river blindness, in former endemic foci in the Americas, and more recently in West and East Africa, raise the question whether elimination of this debilitating disease is underway after long-term treatment of the population at risk with ivermectin. The situation in Central Africa has not yet been clearly assessed. Methods and findings Entomologic data from two former endemic river basins in North Cameroon were generated over a period of 43 and 48 months to follow-up transmission levels in areas under prolonged ivermectin control. Moreover, epidemiologic parameters of animal-borne Onchocerca spp. transmitted by the same local black fly vectors of the Simulium damnosum complex were recorded and their impact on O. volvulus transmission success evaluated. With mitochondrial DNA markers we unambiguously confirmed the presence of infective O. volvulus larvae in vectors from the Sudan savannah region (mean Annual Transmission Potential 2009–2012: 98, range 47–221), but not from the Adamawa highland region. Transmission rates of O. ochengi, a parasite of Zebu cattle, were high in both foci. Conclusions/significance The high cattle livestock density in conjunction with the high transmission rates of the bovine filaria O. ochengi prevents the transmission of O. volvulus on the Adamawa plateau, whereas transmission in a former hyperendemic focus was markedly reduced, but not completely interrupted after 25 years of ivermectin control. This study may be helpful to gauge the impact of the presence of animal-filariae for O. volvulus transmission in terms of the growing human and livestock populations in sub-Saharan countries. PMID:26926855

  5. Histochemical enzyme variation in Onchocerca volvulus microfilariae from rain-forest and Sudan-savanna areas of the Onchocerciasis Control Programme in West Africa

    PubMed Central

    Omar, M. S.; Prost, A.; Marshall, T. F. de C.

    1982-01-01

    Histochemical staining methods for acid phosphatase were used to study the differences among microfilariae of various West African strains of Onchocerca volvulus in both forest and Sudan-savanna onchocerciasis zones. The results have shown statistically significant differences in the staining patterns of microfilarial populations in the two zones. In the rain-forest areas, where onchocerciasis is transmitted by Simulium yahense, S. sanctipauli, S. soubrense and S. squamosum, there were no significant differences of microfilarial staining patterns in patients, by age and sex, between the three Simulium—Onchocerca complexes studied. There was a close relationship between the “strain differences”, as revealed morphoenzymatically, and the clinical picture of the disease in both the forest and the Sudan-savanna zones. The present findings are in favour of the hypothesis that there are intrinsic differences in the strains of the parasite occurring in the two areas. The application of the histochemical means of parasite characterization appears to be a useful tool in differentiating strains of O. volvulus and could contribute towards a better understanding of the epidemiology of human onchocerciasis in different bioclimatic zones where the disease is endemic. ImagesPlate 1 PMID:6186410

  6. DNA vaccine encoding the moonlighting protein Onchocerca volvulus glyceraldehyde-3-phosphate dehydrogenase (Ov-GAPDH) leads to partial protection in a mouse model of human filariasis.

    PubMed

    Steisslinger, Vera; Korten, Simone; Brattig, Norbert W; Erttmann, Klaus D

    2015-10-26

    River blindness, caused by the filarial parasite Onchocerca volvulus, is a major socio-economic and public health problem in Sub-Saharan Africa. In January 2015, The Onchocerciasis Vaccine for Africa (TOVA) Initiative has been launched with the aim of providing new tools to complement mass drug administration (MDA) of ivermectin, thereby promoting elimination of onchocerciasis in Africa. In this context we here present Onchocerca volvulus glyceraldehyde-3-phosphate dehydrogenase (Ov-GAPDH) as a possible DNA vaccine candidate. We report that in a laboratory model for filariasis, immunization with Ov-GAPDH led to a significant reduction of adult worm load and microfilaraemia in BALB/c mice after challenge infection with the filarial parasite Litomosoides sigmodontis. Mice were either vaccinated with Ov-GAPDH.DNA plasmid (Ov-pGAPDH.DNA) alone or in combination with recombinantly expressed Ov-GAPDH protein (Ov-rGAPDH). During the following challenge infection of immunized and control mice with L. sigmodontis, those formulations which included the DNA plasmid, led to a significant reduction of adult worm loads (up to 57% median reduction) and microfilaraemia (up to 94% reduction) in immunized animals. In a further experiment, immunization with a mixture of four overlapping, synthetic Ov-GAPDH peptides (Ov-GAPDHpept), with alum as adjuvant, did not significantly reduce worm loads. Our results indicate that DNA vaccination with Ov-GAPDH has protective potential against filarial challenge infection in the mouse model. This suggests a transfer of the approach into the cattle Onchocerca ochengi model, where it is possible to investigate the effects of this vaccination in the context of a natural host-parasite relationship. PMID:26320419

  7. A Randomized, Single-Ascending-Dose, Ivermectin-Controlled, Double-Blind Study of Moxidectin in Onchocerca volvulus Infection

    PubMed Central

    Opoku, Nicholas O.; Attah, Simon K.; Lazdins-Helds, Janis; Kuesel, Annette C.

    2014-01-01

    Background Control of onchocerciasis as a public health problem in Africa relies on annual mass ivermectin distribution. New tools are needed to achieve elimination of infection. This study determined in a small number of Onchocerca volvulus infected individuals whether moxidectin, a veterinary anthelminthic, is safe enough to administer it in a future large study to further characterize moxidectin's safety and efficacy. Effects on the parasite were also assessed. Methodology/Principal Findings Men and women from a forest area in South-eastern Ghana without ivermectin mass distribution received a single oral dose of 2 mg (N = 44), 4 mg (N = 45) or 8 mg (N = 38) moxidectin or 150 µg/kg ivermectin (N = 45) with 18 months follow up. All ivermectin and 97%–100% of moxidectin treated participants had Mazzotti reactions. Statistically significantly higher percentages of participants treated with 8 mg moxidectin than participants treated with ivermectin experienced pruritus (87% vs. 56%), rash (63% vs. 42%), increased pulse rate (61% vs. 36%) and decreased mean arterial pressure upon 2 minutes standing still after ≥5 minutes supine relative to pre-treatment (61% vs. 27%). These reactions resolved without treatment. In the 8 mg moxidectin and ivermectin arms, the mean±SD number of microfilariae/mg skin were 22.9±21.1 and 21.2±16.4 pre-treatment and 0.0±0.0 and 1.1±4.2 at nadir reached 1 and 3 months after treatment, respectively. At 6 months, values were 0.0±0.0 and 1.6±4.5, at 12 months 0.4±0.9 and 3.4±4.4 and at 18 months 1.8±3.3 and 4.0±4.8, respectively, in the 8 mg moxidectin and ivermectin arm. The reduction from pre-treatment values was significantly higher after 8 mg moxidectin than after ivermectin treatment throughout follow up (p<0.01). Conclusions/Significance The 8 mg dose of moxidectin was safe enough to initiate the large study. Provided its results confirm those from this study, availability of moxidectin to control

  8. Functional characterization and immune recognition of the extracellular superoxide dismutase from the human pathogenic parasite Onchocerca volvulus (OvEC-SOD).

    PubMed

    Ajonina-Ekoti, Irene; Ndjonka, Dieudonne; Tanyi, Manchang Kingsley; Wilbertz, Meike; Younis, Abuelhassan Elshazly; Boursou, Djafsia; Kurosinski, Marc Andre; Eberle, Raphael; Lüersen, Kai; Perbandt, Markus; Breloer, Minka; Brattig, Norbert W; Liebau, Eva

    2012-10-01

    Onchocerca volvulus is a human pathogenic filarial nematode causing chronic onchocerciasis, a disease characterized by chronic skin and eye lesions. Despite attempts to control this infection from many perspectives, it still remains a threat to public health because of adverse effects of available drugs and recent reports of drug resistance. Under control of an intact immune system, O. volvulus survives for a long time in the host by employing a variety of strategies including the utility of antioxidant enzymes. In the present study, we focus on the extracellular superoxide dismutase from O. volvulus (OvEC-SOD) found in the excretory/secretory products of adult worms. Contrary to previous studies, the OvEC-SOD was found to have a 19 amino acid long signal peptide that is cleaved off during the process of maturation. To validate this result, we designed a novel method based on Caenorhabditis elegans cup5(ar465) mutants to specifically evaluate signal peptide-mediated secretion of nematodal proteins. Following purification, the recombinant OvEC-SOD was active as a dimer. Site-directed mutagenesis of the three cysteines present in the OvEC-SOD shows that enzyme activity is markedly reduced in the Cys-192 mutant. A homology model of the OvEC-SOD underlines the importance of Cys-192 for the stabilization of the adjacent active site channel. The generation of a humoral immune response to secretory OvEC-SOD was indicated by demonstrating IgG reactivity in sera from patients infected with O. volvulus while the cross-reactivity of IgG in plasma samples from cows, infected with the most closely related parasite Onchocerca ochengi, occurred only marginally. High IgG1 and IgM titres were recorded in sera from mice infected with the filaria Litomosoides sigmodontis, however, low or no cellular proliferative responses were observed. Thus, the present data suggest that secretory OvEC-SOD is a target of the humoral immune response in human onchocerciasis and induced strongest Ig

  9. Recombinant Ov-ASP-1, a Th1-biased protein adjuvant derived from the helminth Onchocerca volvulus, can directly bind and activate antigen-presenting cells.

    PubMed

    He, Yuxian; Barker, Sophie J; MacDonald, Angus J; Yu, Yu; Cao, Long; Li, Jingjing; Parhar, Ranjit; Heck, Susanne; Hartmann, Susanne; Golenbock, Douglas T; Jiang, Shibo; Libri, Nathan A; Semper, Amanda E; Rosenberg, William M; Lustigman, Sara

    2009-04-01

    We previously reported that rOv-ASP-1, a recombinant Onchocerca volvulus activation associated protein-1, was a potent adjuvant for recombinant protein or synthetic peptide-based Ags. In this study, we further evaluated the adjuvanticity of rOv-ASP-1 and explored its mechanism of action. Consistently, recombinant full-length spike protein of SARS-CoV or its receptor-binding domain in the presence of rOv-ASP-1 could effectively induce a mixed but Th1-skewed immune response in immunized mice. It appears that rOv-ASP-1 primarily bound to the APCs among human PBMCs and triggered Th1-biased proinflammatory cytokine production probably via the activation of monocyte-derived dendritic cells and the TLR, TLR2, and TLR4, thus suggesting that rOv-ASP-1 is a novel potent innate adjuvant. PMID:19299698

  10. Detection of Onchocerca volvulus in Skin Snips by Microscopy and Real-Time Polymerase Chain Reaction: Implications for Monitoring and Evaluation Activities.

    PubMed

    Thiele, Elizabeth A; Cama, Vitaliano A; Lakwo, Thomson; Mekasha, Sindeaw; Abanyie, Francisca; Sleshi, Markos; Kebede, Amha; Cantey, Paul T

    2016-04-01

    Microscopic evaluation of skin biopsies is the monitoring and evaluation (M and E) method currently used by multiple onchocerciasis elimination programs in Africa. However, as repeated mass drug administration suppresses microfilarial loads, the sensitivity and programmatic utility of skin snip microscopy is expected to decrease. Using a pan-filarial real-time polymerase chain reaction with melt curve analysis (qPCR-MCA), we evaluated 1) the use of a single-step molecular assay for detecting and identifying Onchocerca volvulus microfilariae in residual skin snips and 2) the sensitivity of skin snip microscopy relative to qPCR-MCA. Skin snips were collected and examined with routine microscopy in hyperendemic regions of Uganda and Ethiopia (N= 500 each) and "residual" skin snips (tissue remaining after induced microfilarial emergence) were tested with qPCR-MCA. qPCR-MCA detected Onchocerca DNA in 223 residual snips: 139 of 147 microscopy(+) and 84 among microscopy(-) snips, suggesting overall sensitivity of microscopy was 62.3% (139/223) relative to qPCR-MCA (75.6% in Uganda and 28.6% in Ethiopia). These findings demonstrate the insufficient sensitivity of skin snip microscopy for reliable programmatic monitoring. Molecular tools such as qPCR-MCA can augment sensitivity and provide diagnostic confirmation of skin biopsies and will be useful for evaluation or validation of new onchocerciasis M and E tools. PMID:26880774

  11. Assessments of the transmission of Onchocerca volvulus by Simulium sanctipauli in the Upper Denkyira District, Ghana, and the intermittent disappearance of the vector.

    PubMed

    Garms, R; Badu, K; Owusu-Dabo, E; Baffour-Awuah, S; Adjei, O; Debrah, A Y; Nagel, M; Biritwum, N K; Gankpala, L; Post, R J; Kruppa, T F

    2015-03-01

    Following studies on the transmission of Onchocerca volvulus (Leuckart) by Simulium sanctipauli Vajime & Dunbar (Diptera, Simuliidae) in Upper Denkyira District in Ghana in 2001 and 2002 (Kutin et al., Med Vet Ent 18:167-173, 2004), further assessments were carried out in 2006 and 2013/2014 to determine whether transmission parameters had changed since community-directed ivermectin treatment (CDTI) began in 1999. There were no marked changes of the transmission intensities in 2006. Only slight, but non-significant, reductions were observed in infection rates of parous flies with larval stages (L1-L3) of O. volvulus from 44.1 % (of 1672 parous flies) in 2001/2002 to 42.1 % (506) in 2006 and from 6.5 to 5.9 % of flies carrying infective larvae in their heads. This suggested that there was an ongoing transmission in the area and the parasite reservoir in the human population was still high. Unexpectedly, further assessments conducted in October 2013 and March and October 2014 revealed that the vector S. sanctipauli had apparently disappeared and transmission had ceased, probably as a result of intensified gold mining activities along the rivers Ofin and Pra. The water of both rivers was extremely turbid, heavily loaded with suspended solids, probably preventing the development of blackfly larvae. Some breeding and biting of Simulium yahense Vajime & Dunbar was observed in a small tributary of the Pra, the Okumayemfuo, which is not affected by gold mining. However, the infection rate of flies was low, only 3.7 % of 163 parous flies were infected with first stage (L1) larvae of O. volvulus. PMID:25592754

  12. Identification of potential vaccine and drug target candidates by expressed sequence tag analysis and immunoscreening of Onchocerca volvulus larval cDNA libraries.

    PubMed

    Lizotte-Waniewski, M; Tawe, W; Guiliano, D B; Lu, W; Liu, J; Williams, S A; Lustigman, S

    2000-06-01

    The search for appropriate vaccine candidates and drug targets against onchocerciasis has so far been confronted with several limitations due to the unavailability of biological material, appropriate molecular resources, and knowledge of the parasite biology. To identify targets for vaccine or chemotherapy development we have undertaken two approaches. First, cDNA expression libraries were constructed from life cycle stages that are critical for establishment of Onchocerca volvulus infection, the third-stage larvae (L3) and the molting L3. A gene discovery effort was then initiated by random expressed sequence tag analysis of 5,506 cDNA clones. Cluster analyses showed that many of the transcripts were up-regulated and/or stage specific in either one or both of the cDNA libraries when compared to the microfilariae, L2, and both adult stages of the parasite. Homology searches against the GenBank database facilitated the identification of several genes of interest, such as proteinases, proteinase inhibitors, antioxidant or detoxification enzymes, and neurotransmitter receptors, as well as structural and housekeeping genes. Other O. volvulus genes showed homology only to predicted genes from the free-living nematode Caenorhabditis elegans or were entirely novel. Some of the novel proteins contain potential secretory leaders. Secondly, by immunoscreening the molting L3 cDNA library with a pool of human sera from putatively immune individuals, we identified six novel immunogenic proteins that otherwise would not have been identified as potential vaccinogens using the gene discovery effort. This study lays a solid foundation for a better understanding of the biology of O. volvulus as well as for the identification of novel targets for filaricidal agents and/or vaccines against onchocerciasis based on immunological and rational hypothesis-driven research. PMID:10816503

  13. Macrofilaricidal Activity after Doxycycline Only Treatment of Onchocerca volvulus in an Area of Loa loa Co-Endemicity: A Randomized Controlled Trial

    PubMed Central

    Turner, Joseph D.; Tendongfor, Nicholas; Esum, Mathias; Johnston, Kelly L.; Langley, R. Stuart; Ford, Louise; Faragher, Brian; Specht, Sabine; Mand, Sabine; Hoerauf, Achim; Enyong, Peter; Wanji, Samuel; Taylor, Mark J.

    2010-01-01

    Background The risk of severe adverse events following treatment of onchocerciasis with ivermectin in areas co-endemic with loiasis currently compromises the development of control programmes and the treatment of co-infected individuals. We therefore assessed whether doxycycline treatment could be used without subsequent ivermectin administration to effectively deliver sustained effects on Onchocerca volvulus microfilaridermia and adult viability. Furthermore we assessed the safety of doxycycline treatment prior to ivermectin administration in a subset of onchocerciasis individuals co-infected with low to moderate intensities of Loa loa microfilaraemia. Methods A double-blind, randomized, field trial was conducted of 6 weeks of doxycycline (200 mg/day) alone, doxycycline in combination with ivermectin (150 µg/kg) at +4 months or placebo matching doxycycline + ivermectin at +4 months in 150 individuals infected with Onchocerca volvulus. A further 22 individuals infected with O. volvulus and low to moderate intensities of Loa loa infection were administered with a course of 6 weeks doxycycline with ivermectin at +4 months. Treatment efficacy was determined at 4, 12 and 21 months after the start of doxycycline treatment together with the frequency and severity of adverse events. Results One hundred and four (60.5%) participants completed all treatment allocations and follow up assessments over the 21-month trial period. At 12 months, doxycycline/ivermectin treated individuals had lower levels of microfilaridermia and higher frequency of amicrofilaridermia compared with ivermectin or doxycycline only groups. At 21 months, microfilaridermia in doxycycline/ivermectin and doxycycline only groups was significantly reduced compared to the ivermectin only group. 89% of the doxycycline/ivermectin group and 67% of the doxycycline only group were amicrofilaridermic, compared with 21% in the ivermectin only group. O. volvulus from doxycycline groups were depleted of Wolbachia

  14. One Hundred Years After Its Discovery in Guatemala by Rodolfo Robles, Onchocerca volvulus Transmission Has Been Eliminated from the Central Endemic Zone.

    PubMed

    Richards, Frank; Rizzo, Nidia; Diaz Espinoza, Carlos Enrique; Monroy, Zoraida Morales; Crovella Valdez, Carol Guillermina; de Cabrera, Renata Mendizabal; de Leon, Oscar; Zea-Flores, Guillermo; Sauerbrey, Mauricio; Morales, Alba Lucia; Rios, Dalila; Unnasch, Thomas R; Hassan, Hassan K; Klein, Robert; Eberhard, Mark; Cupp, Ed; Domínguez, Alfredo

    2015-12-01

    We report the elimination of Onchocerca volvulus transmission from the Central Endemic Zone (CEZ) of onchocerciasis in Guatemala, the largest focus of this disease in the Americas and the first to be discovered in this hemisphere by Rodolfo Robles Valverde in 1915. Mass drug administration (MDA) with ivermectin was launched in 1988, with semiannual MDA coverage reaching at least 85% of the eligible population in > 95% of treatment rounds during the 12-year period, 2000-2011. Serial parasitological testing to monitor MDA impact in sentinel villages showed a decrease in microfilaria skin prevalence from 70% to 0%, and polymerase chain reaction (PCR)-based entomological assessments of the principal vector Simulium ochraceum s.l. showed transmission interruption by 2007. These assessments, together with a 2010 serological survey in children 9-69 months of age that showed Ov16 IgG4 antibody prevalence to be < 0.1%, meeting World Health Organization (WHO) guidelines for stopping MDA, and treatment was halted after 2011. After 3 years an entomological assessment showed no evidence of vector infection or recrudescence of transmission. In 2015, 100 years after the discovery of its presence, the Ministry of Health of Guatemala declared onchocerciasis transmission as having been eliminated from the CEZ. PMID:26503275

  15. A computational analysis of the binding mode of closantel as inhibitor of the Onchocerca volvulus chitinase: insights on macrofilaricidal drug design.

    PubMed

    Segura-Cabrera, Aldo; Bocanegra-García, Virgilio; Lizarazo-Ortega, Cristian; Guo, Xianwu; Correa-Basurto, José; Rodríguez-Pérez, Mario A

    2011-12-01

    Onchocerciasis is a leading cause of blindness with at least 37 million people infected and more than 120 million people at risk of contracting the disease; most (99%) of this population, threatened by infection, live in Africa. The drug of choice for mass treatment is the microfilaricidal Mectizan(®) (ivermectin); it does not kill the adult stages of the parasite at the standard dose which is a single annual dose aimed at disease control. However, multiple treatments a year with ivermectin have effects on adult worms. The discovery of new therapeutic targets and drugs directed towards the killing of the adult parasites are thus urgently needed. The chitinase of filarial nematodes is a new drug target due to its essential function in the metabolism and molting of the parasite. Closantel is a potent and specific inhibitor of chitinase of Onchocerca volvulus (OvCHT1) and other filarial chitinases. However, the binding mode and specificity of closantel towards OvCHT1 remain unknown. In the absence of a crystallographic structure of OvCHT1, we developed a homology model of OvCHT1 using the currently available X-ray structures of human chitinases as templates. Energy minimization and molecular dynamics (MD) simulation of the model led to a high quality of 3D structure of OvCHIT1. A flexible docking study using closantel as the ligand on the binding site of OvCHIT1 and human chitinases was performed and demonstrated the differences in the closantel binding mode between OvCHIT1 and human chitinase. Furthermore, molecular dynamics simulations and free-energy calculation were employed to determine and compare the detailed binding mode of closantel with OvCHT1 and the structure of human chitinase. This comparative study allowed identification of structural features and properties responsible for differences in the computationally predicted closantel binding modes. The homology model and the closantel binding mode reported herein might help guide the rational development of

  16. Transmission of Onchocerca volvulus and prospects for the elimination of its vector, the blackfly Simulium neavei in the Mpamba-Nkusi focus in Western Uganda.

    PubMed

    Lakwo, T L; Ndyomugyenyi, R; Onapa, A W; Twebaze, C

    2006-03-01

    The transmission of Onchocerca volvulus Leuckart (Spirudida: Onchocercidae) and the prospects of Simulium neavei Roubaud (Diptera: Simuliidae) vector elimination through ground larviciding were investigated in the Mpamba-Nkusi focus, western Uganda. Transmission levels and the initiated vector elimination activities were assessed to supplement the ongoing ivermectin mass distribution programme. Searches for breeding sites, adult fly catches, dissection of flies, river treatment with temephos (Abate) and a review of annual ivermectin treatment data were conducted. High levels of crab infestation with S. neavei sensu stricto immature stages were recorded; 57.9% and 100% for the Mpamba and Nyabugando river systems, respectively. The mean numbers of larvae/pupae per crab were 3.6 +/- 0.5 in the Mpamba and 20.6 +/- 1.8 in the Nyabugando systems. Pre-intervention mean biting densities were 39 and 32 flies/(man day) in 2001 and 2002, respectively, and an annual biting rate in 2001 of > 14 000. The bimodal biting pattern of S. neavei s.s. consisted of two peaks; one in the morning (09.00-10.00 hours) and one in the afternoon (14.00-15.00 hours) with a mid-day lull in biting. The infection/infective rates were 13.3%/2.8% and 16.6%/2.9% in the dissected parous flies from the Mpamba and Nyabugando river systems, respectively. Out of approximately 1000 parous flies, 129 and 109 were found to be harbouring infective larvae of Onchocerca volvulus in their heads from the Mpamba and Nyabugando river systems, respectively. In spite of the > 10 years of ivermectin treatment, at a mean coverage of 71.3%, infection remained relatively high. Ground larviciding with temephos (Abate) initiated in June and October 2002 had a significant impact. In the Mpamba river system there was a significant (P < 0.001) reduction in positive crabs from 57.9% in 2001 to 0.06% in 2003 and a decrease in the mean number of larvae/pupae per crab from 3.6 +/- 0.5 in 2001 to 0.0007 +/- 0.0001 (P < 0.002) in

  17. The Immunomodulatory Role of Adjuvants in Vaccines Formulated with the Recombinant Antigens Ov-103 and Ov-RAL-2 against Onchocerca volvulus in Mice

    PubMed Central

    Hess, Jessica A.; Zhan, Bin; Torigian, April R.; Patton, John B.; Petrovsky, Nikolai; Zhan, Tingting; Bottazzi, Maria Elena; Hotez, Peter J.; Klei, Thomas R.; Lustigman, Sara; Abraham, David

    2016-01-01

    Background In some regions in Africa, elimination of onchocerciasis may be possible with mass drug administration, although there is concern based on several factors that onchocerciasis cannot be eliminated solely through this approach. A vaccine against Onchocerca volvulus would provide a critical tool for the ultimate elimination of this infection. Previous studies have demonstrated that immunization of mice with Ov-103 and Ov-RAL-2, when formulated with alum, induced protective immunity. It was hypothesized that the levels of protective immunity induced with the two recombinant antigens formulated with alum would be improved by formulation with other adjuvants known to enhance different types of antigen-specific immune responses. Methodology/ Principal Findings Immunizing mice with Ov-103 and Ov-RAL-2 in conjunction with alum, Advax 2 and MF59 induced significant levels of larval killing and host protection. The immune response was biased towards Th2 with all three of the adjuvants, with IgG1 the dominant antibody. Improved larval killing and host protection was observed in mice immunized with co-administered Ov-103 and Ov-RAL-2 in conjunction with each of the three adjuvants as compared to single immunizations. Antigen–specific antibody titers were significantly increased in mice immunized concurrently with the two antigens. Based on chemokine levels, it appears that neutrophils and eosinophils participate in the protective immune response induced by Ov-103, and macrophages and neutrophils participate in immunity induced by Ov-RAL-2. Conclusions/Significance The mechanism of protective immunity induced by Ov-103 and Ov-RAL-2, with the adjuvants alum, Advax 2 and MF59, appears to be multifactorial with roles for cytokines, chemokines, antibody and specific effector cells. The vaccines developed in this study have the potential of reducing the morbidity associated with onchocerciasis in humans. PMID:27387453

  18. Extended result reading window in lateral flow tests detecting exposure to Onchocerca volvulus: a new technology to improve epidemiological surveillance tools.

    PubMed

    Golden, Allison; Steel, Cathy; Yokobe, Lindsay; Jackson, Emily; Barney, Rebecca; Kubofcik, Joseph; Peck, Roger; Unnasch, Thomas R; Nutman, Thomas B; de los Santos, Tala; Domingo, Gonzalo J

    2013-01-01

    Onchocerciasis is a neglected tropical disease caused by infection with the parasite Onchocerca volvulus (Ov). An estimated 180 million people are at risk for Ov infection, and 37 million people are infected, mostly in Africa. A lateral flow-based assay to detect human IgG4 antibodies to the Ov-specific antigen Ov-16 was developed as a rapid tool to detect exposure to Ov. The test, when performed on 449 sera specimens from patients with microfiladermia and Ov-negative patients, has a sensitivity of 89.1% (95% confidence interval: 86.2%-92.0%), and specificity of 97% (95% confidence interval: 95.4%-98.6%). Because the intended use of the test is for surveillance, it is highly desirable to have a stable, long-lasting result. An extended read window is thus desirable for a high-volume, busy workflow and facilitates post-surveillance quality assurance. The main restriction on achieving an extended read window for this assay was the erythrocyte lysis that can alter the signal-to-noise ratio, especially in those with low IgG4 levels (weak positives). We describe a test housing that incorporates a user-independent feature driven by assay fluid and an expanding wick that detaches the blood separation membrane from the nitrocellulose used in the assay, but before hemolysis occurs. We demonstrated material functionality at extreme operational conditions (37°C, 80% relative humidity) and a read window of a minimum of 70 days. The fluid-driven assay device performs equally as well with whole blood as with plasma, as demonstrated with 100 spiked clinical specimens (with a correlation coefficient of 0.96). We show a novel, inexpensive, and simple approach to actuating the detachment of the blood separation membrane from the nitrocellulose test with no impact on the performance characteristics of the test. PMID:23935960

  19. Importance of migrants infected with Onchocerca volvulus in west African river valleys protected by 14 to 15 years of Simulium control.

    PubMed

    De Sole, G; Remme, J

    1991-06-01

    A study was done to determine the importance of human migration from non-controlled endemic onchocerciasis foci to the river valleys that have been protected for the past 14 to 15 years by the vector control operations of the Onchocerciasis Control Programme in West Africa. The aim of the study was to assess the contribution of migrants to the prevalence and intensity of infection in villages from 5 major river valleys and their potential role in causing relapse of transmission once the vector is allowed to return. In Burkina Faso the migrant population varied from 0.0% to 18.1% of the village population, and averaged 4.9%. Migrants accounted only for 0.6% of the population in Ghanaian and Ivorian villages along the Black Volta river. The prevalence of infection was significantly higher in migrants (8.2%) than in non migrants (1.1%) in the surveyed villages in Burkina Faso, and 1.5% of migrants had infections with more than 16 microfilariae per snip as against 0.2% of non migrants. Nearly all infected migrants came from the south of the Côte d'Ivoire. The study shows that human migration has caused the importation of Onchocerca volvulus from non-controlled areas. However, the epidemiological importance of this phenomenon is limited because of the very small number of infected migrants per village while two-third of the infected migrants are believed to be infected with the less pathogenic forest strain of the parasite. Because migration patterns changes geographically and over time similar studies will be continued on a regular basis. PMID:1654591

  20. Uptake of Onchocerca volvulus (Nematoda: Onchocercidae) by Simulium (Diptera: Simuliidae) is not strongly dependent on the density of skin microfilariae in the human host.

    PubMed

    Soumbey-Alley, Edoh; Basáñez, María-Gloria; Bissan, Yeriba; Boatin, Boakye A; Remme, Jan H F; Nagelkerke, Nico J D; de Vlas, Sake J; Borsboom, Gerard J J M; Habbema, J Dik F

    2004-01-01

    The relation between the number of microfilariae (mf) ingested by host-seeking vectors of human onchocerciasis and skin mf load is an important component of the population biology of Onchocerca volvulus, with implications for disease control and evaluation of the risk of transmission recrudescence. The microsimulation model ONCHOSIM has been used to assess such risk in the area of the Onchocerciasis Control Program (OCP) in West Africa, based on a strongly nonlinear relation between vector mf uptake and human mf skin density previously published. However, observed levels of recrudescence have exceeded predictions, warranting a recalibration of the model. To this end, we present the results of a series of fly-feeding experiments carried out in savanna and forest localities of West Africa. Flies belonging to Simulium damnosum s.s., S. sirbanum, S. soubrense, and S. leonense were fed on mf carriers and dissected to assess the number of ingested mf escaping imprisonment by the peritrophic matrix (the number of exo-peritrophic mf), a predictor of infective larval output. The method of instrumental variables was used to obtain (nearly) unbiased estimates of the parameters of interest, taking into account error in the measurement of skin mf density. This error is often neglected in these types of studies, making it difficult to ascertain the degree of density-dependence truly present in the relation between mf uptake and skin load. We conclude that this relation is weakly (yet significantly) nonlinear in savanna settings but indistinguishable from linearity in forest vectors. Exo-peritrophic mf uptake does not account for most of the density dependence in the transmission dynamics of the parasite as previously thought. The number of exo-mf in forest simuliids is at least five times higher than in the savanna vectors. Parasite abundance in human onchocerciasis is regulated by poorly known mechanisms operating mainly on other stages of the lifecycle. PMID:14989351

  1. Molecular characterization and evaluation of Onchocerca volvulus-secreted larval acidic protein 1 (SLAP1) as a putative vaccine candidate on endemic population of lymphatic filariasis.

    PubMed

    Mahalakshmi, Natarajan; Aparnaa, Ramanathan; Ansel Vishal, Lawrance; Kaliraj, Perumal

    2013-09-01

    Filarial parasites infected nearly 160 million of the global population with onchocerciasis and lymphatic filariasis, and further, a billion of people are estimated to be at risk of infection, rendering them among the most prevalent infectious agents in the world today. Given the complexity of their life cycle and the immune evasion mechanisms of these organisms, development of a vaccine remains to be a long-term challenge. Though a number of immunodominant antigens have been characterized, the presence of homologous proteins in humans or the allelic variants are some of the major drawbacks. One of the extensively studied vaccine candidates is abundant larval transcripts (ALT) family of proteins for the following properties: highly regulated expression, abundance, excreted-secreted product of infective stage larvae, and essentially for parasite establishment and survival in the host. In the present study, stage-specific expression of secreted larval acidic protein 1 (SLAP1) was identified; an ALT orthologue from Onchocerca volvulus was cloned, expressed, and purified as a recombinant protein. Immunogenicity of OvSLAP1 was demonstrated with sera and peripheral blood mononuclear cells from endemic regions of Brugia malayi and Wuchereria bancrofti. OvSLAP1 antibodies were predominated by IgG1 and IgG2 in endemic normal (EN) and chronic pathology (CP) subjects. It has also induced marked cellular response as observed by lymphoproliferation assay. The study revealed that OvSLAP1 can segregate humoral (EN mean optical density (OD) = 0.87 ± 0.035, CP mean OD = 0.59 ± 0.029) and cellular (EN mean stimulation index (SI) = 5.87 ± 0.167, CP mean SI = 3.5 ± 0.134) immune responses between EN and CP individuals (P < 0.001), signifying its prophylactic ability and vitality for protection from filarial infections in endemic population. PMID:23828189

  2. Doxycycline Leads to Sterility and Enhanced Killing of Female Onchocerca volvulus Worms in an Area With Persistent Microfilaridermia After Repeated Ivermectin Treatment: A Randomized, Placebo-Controlled, Double-Blind Trial

    PubMed Central

    Debrah, Alexander Yaw; Specht, Sabine; Klarmann-Schulz, Ute; Batsa, Linda; Mand, Sabine; Marfo-Debrekyei, Yeboah; Fimmers, Rolf; Dubben, Bettina; Kwarteng, Alexander; Osei-Atweneboana, Mike; Boakye, Daniel; Ricchiuto, Arcangelo; Büttner, Marcelle; Adjei, Ohene; Mackenzie, Charles D.; Hoerauf, Achim

    2015-01-01

    Background. Ivermectin (IVM) has been the drug of choice for the treatment of onchocerciasis. However, there have been reports of persistent microfilaridermia in individuals from an endemic area in Ghana after many rounds of IVM, raising concerns of suboptimal response or even the emergence of drug resistance. Because it is considered risky to continue relying only on IVM to combat this phenomenon, we assessed the effect of targeting the Onchocerca volvulus Wolbachia endosymbionts with doxycycline for these individuals with suboptimal response. Methods. One hundred sixty-seven patients, most of them with multiple rounds of IVM, were recruited in areas with IVM suboptimal response and treated with 100 mg/day doxycycline for 6 weeks. Three and 12 months after doxycycline treatment, patients took part in standard IVM treatment. Results. At 20 months after treatment, 80% of living female worms from the placebo group were Wolbachia positive, whereas only 5.1% in the doxycycline-treated group contained bacteria. Consistent with interruption of embryogenesis, none of the nodules removed from doxycycline-treated patients contained microfilariae, and 97% of those patients were without microfilaridermia, in contrast to placebo patients who remained at pretreatment levels (P < .001). Moreover, a significantly enhanced number of dead worms were observed after doxycycline. Conclusions. Targeting the Wolbachia in O. volvulus is effective in clearing microfilariae in the skin of onchocerciasis patients with persistent microfilaridermia and in enhanced killing of adult worms after repeated standard IVM treatment. Strategies can now be developed that include doxycycline to control onchocerciasis in areas where infections persist despite the frequent use of IVM. Clinical Trials Registration. ISRCTN 66649839. PMID:25948064

  3. [African programme for onchocerciasis control (APOC): entomological aspects of Onchocerca volvulus transmission by Simulium neavei in the Basin of Sankuru (Eastern Kasai, Democratic Republic of Congo)].

    PubMed

    Traoré, S; Enyong, P; Mandiangu, M L; Kayembé, D; Noma, M; Sékétéli, A

    2007-02-01

    As part of a study to evaluate the long-term impact of community-directed treatment with ivermectin (CDTI), baseline entomological data on the transmission of onchocerciasis in the forest zone of the Eastern Kasai Province were collected from July 1998 to January 1999. Species of the Simulium neavei complex were the only vectors found in the site during the study. Nuisance activity was low with a mean biting rate of only 32.5 bites/man/day. The mean parturity rate was 29.4%, the mean rate of infected females was 14.5% and the mean number of infective Onchocerca larvae per 1000 parous flies was 659. These findings clearly show that the S. neavei population at the study site has high vector capability and constitutes a large microfilarial reservoir. The entomological features found in the study area are consistent with a hyper-endemic zone. PMID:17506270

  4. 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.

    PubMed

    Basáñez, M G; Rodríguez-Pérez, M A; Reyes-Villanueva, F; Collins, R C; Rodríguez, M H

    1998-09-01

    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 the aggregation parameter k, but the degree of larval overdispersion increased as the mean larval load decreased, invalidating the use of a common kc value. A linear relationship between k and the mean (mu) was established, k(mu) = k1 mu, which permitted exploration of the relationship between the observed proportion of infected flies, p, and the estimated mean larval burden per fly, m (all larval stages in parous flies). This would allow mean numbers of larvae per parous fly to be predicted from presence-absence data (e.g., from infection rates provided by polymerase chain reaction methods applied to pools of flies), assuming that k1 is a known parameter. Given that both p and m are naturally low in S. ochraceum, their relationship was practically linear within the range of observed values. Predictions were tested with the Mexican data from which the clumping parameter was estimated as well as for Guatemalan data for which this information was not available. Results showed a highly satisfactory degree of agreement between predictions and observations. The sample sizes required to estimate mean larval loads from prevalence data for fixed levels of precision (defined as the ratio between SE[m] and m) were calculated for realistic S. ochraceum infection rates (those found in published pre- and postcontrol field surveys as well as in this work). For the special case in which the relationship between k and the mean is linear and goes through the origin, k(mu) = k1 mu, the number

  5. Molecular evidence of 'Siisa form', a new genotype related to Onchocerca ochengi in cattle from North Cameroon.

    PubMed

    Eisenbarth, Albert; Ekale, David; Hildebrandt, Julia; Achukwi, Mbunkah Daniel; Streit, Adrian; Renz, Alfons

    2013-09-01

    Onchocerca ochengi, a filarial nematode parasite from African Zebu cattle is considered to be the closest relative of Onchocerca volvulus, the causative agent of river blindness. Both Onchocerca species share the vector, black flies of the Simulium damnosum complex. Correct identification of their infective third-stage larvae in man-biting vectors is crucial to distinguish the transmission of human or animal parasites. In order to identify different closely related Onchocerca species we surveyed the sequences from the three mitochondrial loci 12S rRNA, 16S rRNA and coxI in both adult worms isolated from Onchocerca-induced nodules in cattle and infective third stage larvae isolated from vector flies from North Cameroon. Two distinct groups of mitochondrial haplotypes were found in cattle as well as in flies. One of them has been formerly mentioned in the literature as Onchocerca sp. 'Siisa', a filaria isolated from the vector S. damnosum sensu lato in Uganda with hitherto unknown host. Both variants are found sympatric, also in the same nodule of the animal host and in the vector. In the flies we also found the mitochondrial haplotype that had been described for O. volvulus which is about equally different from the two previously mentioned ones as they are from each other. These results suggest a higher genetic diversification of Onchocerca ochengi than previously reported. PMID:23727461

  6. [Cecal volvulus].

    PubMed

    Abita, T; Lachachi, F; Durand-Fontanier, S; Maisonnette, F; Roudaut, P Y; Valleix, D; Descottes, B

    2005-01-01

    The cecum is the second most common site of colonic volvulus after the sigmoid. The mechanism is torsion or hyperflexion of the enlarged, poorly-fixed, and hypermobile cecum. It presents clinically as an acute bowel obstruction with strangulation. Diagnosis can be made by plain abdominal X-ray in more than half the cases on the basis of cecal distention (with a classical "teardrop" or "comma" appearance), proximal small bowel distention with air-fluid levels, and a gasless distal colon. Barium enema shows lack of filling of the cecum, often with a "beaked" termination of the column of contrast. CT images are pathognomonic when they reveal a cecal "vortex". After surgical reduction of the torsion, ileo-cecal resection is usually the best therapeutic alternative. Cecopexy may be aDDrouriate in older and debilitated Datients if there is no concomitant cecal necrosis. PMID:16335894

  7. Dual protonophore-chitinase inhibitors dramatically affect O. volvulus molting.

    PubMed

    Gooyit, Major; Tricoche, Nancy; Lustigman, Sara; Janda, Kim D

    2014-07-10

    The L3-stage-specific chitinase OvCHT1 has been implicated in the development of Onchocerca volvulus, the causative agent of onchocerciasis. Closantel, a known anthelmintic drug, was previously discovered as a potent and specific OvCHT1 inhibitor. As closantel is also a known protonophore, we performed a simple scaffold modulation to map out the structural features that are relevant for its individual or dual biochemical roles. Furthermore, we present that either OvCHT1 inhibition or protonophoric activity was capable of affecting O. volvulus L3 molting and that the presence of both activities in a single molecule yielded more potent inhibition of the nematode's developmental process. PMID:24918716

  8. Reproductive biology of Onchocerca ochengi, a nodule forming filarial nematode in zebu cattle.

    PubMed

    Hildebrandt, Julia C; Eisenbarth, Albert; Renz, Alfons; Streit, Adrian

    2014-09-15

    Onchocerca ochengi is a nodule-forming filarial nematode parasite of cattle in tropical Africa and closely related to the human pathogen Onchocerca volvulus. The adult worms reside in intradermal nodules. While females are sedentary, males may move between nodules. The first stage larvae (microfilariae) disperse in the skin of the host waiting to be taken up by the intermediate host. The density of microfilariae in the skin is largely independent of the number of adult worms present indicating some form of density dependent control. Recently, Onchocerca sp. Siisa, a form of Onchocerca distinguishable from O. ochengi by mitochondrial DNA sequences but not by morphology, was described to occur in cattle. This raised the question if Onchocerca sp. Siisa represents a different mitochondrial clade of O. ochengi or a new species. In order to study the reproductive biology and to understand this self-control of the off-spring population we systematically analyzed all Onchocerca nodules from the skin of one zebu cow and we examined a sample of microfilariae from a skin biopsy. We identified 87 O. ochengi females and 146 males. 56 (64.4%) of the females contained developing embryos. In order to assign the progeny to their respective parents we determined the genotypes at six nuclear and two mitochondrial molecular genetic markers in the adult worms, in a fraction of the progeny present in the uteri of the females and in the skin microfilariae. The 121 skin microfilariae we analyzed originated from at least 17 different mothers, which contributed rather differently to the total. Forty-five larvae (37.2%) were the progeny of a single female. Of the adult worms 16.7% were of the type Onchocerca sp. Siisa. These worms appeared to interbreed freely with the rest of the O. ochengi population and therefore belong to the same species. PMID:24986433

  9. The Emergence of Zoonotic Onchocerca lupi Infection in the United States--A Case-Series.

    PubMed

    Cantey, Paul T; Weeks, Jessica; Edwards, Morven; Rao, Suchitra; Ostovar, G Amin; Dehority, Walter; Alzona, Maria; Swoboda, Sara; Christiaens, Brooke; Ballan, Wassim; Hartley, John; Terranella, Andrew; Weatherhead, Jill; Dunn, James J; Marx, Douglas P; Hicks, M John; Rauch, Ronald A; Smith, Christiana; Dishop, Megan K; Handler, Michael H; Dudley, Roy W R; Chundu, Kote; Hobohm, Dan; Feiz-Erfan, Iman; Hakes, Joseph; Berry, Ryan S; Stepensaski, Shelly; Greenfield, Benjamin; Shroeder, Laura; Bishop, Henry; de Almeida, Marcos; Mathison, Blaine; Eberhard, Mark

    2016-03-15

    This case-series describes the 6 human infections with Onchocerca lupi, a parasite known to infect cats and dogs, that have been identified in the United States since 2013. Unlike cases reported outside the country, the American patients have not had subconjunctival nodules but have manifested more invasive disease (eg, spinal, orbital, and subdermal nodules). Diagnosis remains challenging in the absence of a serologic test. Treatment should be guided by what is done for Onchocerca volvulus as there are no data for O. lupi. Available evidence suggests that there may be transmission in southwestern United States, but the risk of transmission to humans is not known. Research is needed to better define the burden of disease in the United States and develop appropriately-targeted prevention strategies. PMID:26611778

  10. Intestinal volvulus in cetaceans.

    PubMed

    Begeman, L; St Leger, J A; Blyde, D J; Jauniaux, T P; Lair, S; Lovewell, G; Raverty, S; Seibel, H; Siebert, U; Staggs, S L; Martelli, P; Keesler, R I

    2013-07-01

    Intestinal volvulus was recognized as the cause of death in 18 cetaceans, including 8 species of toothed whales (suborder Odontoceti). Cases originated from 11 institutions from around the world and included both captive (n = 9) and free-ranging (n = 9) animals. When the clinical history was available (n = 9), animals consistently demonstrated acute dullness 1 to 5 days prior to death. In 3 of these animals (33%), there was a history of chronic gastrointestinal illness. The pathological findings were similar to those described in other animal species and humans, and consisted of intestinal volvulus and a well-demarcated segment of distended, congested, and edematous intestine with gas and bloody fluid contents. Associated lesions included congested and edematous mesentery and mesenteric lymph nodes, and often serofibrinous or hemorrhagic abdominal effusion. The volvulus involved the cranial part of the intestines in 85% (11 of 13). Potential predisposing causes were recognized in most cases (13 of 18, 72%) but were variable. Further studies investigating predisposing factors are necessary to help prevent occurrence and enhance early clinical diagnosis and management of the condition. PMID:23150643

  11. Exploiting the Polypharmacology of ß-Carbolines to Disrupt O. volvulus Molting

    PubMed Central

    2015-01-01

    Onchocerciasis is an infection caused by the filarial worm Onchocerca volvulus, which can eventually result in blindness. The lack of an effective macrofilaricide and the possible development of ivermectin-resistant strains of O. volvulus necessitate the need for alternative treatment strategies. We have shown that targeting the L3-stage-specific chitinase OvCHT1 impairs the shedding of the filarial cuticle. In our continued efforts to discover OvCHT1 inhibitors, we identified the β-carboline alkaloid scaffolding as a chitinase inhibitor that is capable of penetrating the worm cuticle. Herein, we disclose the rich polypharmacology of the β-carboline class of compounds as an approach to abrogate the molting of the parasite and thus the initiation of infection in the human host. PMID:25815157

  12. Exploiting the Polypharmacology of ß-Carbolines to Disrupt O. volvulus Molting.

    PubMed

    Gooyit, Major; Tricoche, Nancy; Javor, Sacha; Lustigman, Sara; Janda, Kim D

    2015-03-12

    Onchocerciasis is an infection caused by the filarial worm Onchocerca volvulus, which can eventually result in blindness. The lack of an effective macrofilaricide and the possible development of ivermectin-resistant strains of O. volvulus necessitate the need for alternative treatment strategies. We have shown that targeting the L3-stage-specific chitinase OvCHT1 impairs the shedding of the filarial cuticle. In our continued efforts to discover OvCHT1 inhibitors, we identified the β-carboline alkaloid scaffolding as a chitinase inhibitor that is capable of penetrating the worm cuticle. Herein, we disclose the rich polypharmacology of the β-carboline class of compounds as an approach to abrogate the molting of the parasite and thus the initiation of infection in the human host. PMID:25815157

  13. Studies on nodules and adult Onchocerca volvulus during a nodulectomy trial in hyperendemic villages in Liberia and Upper Volta. II. Comparison of the macrofilaria population in adult nodule carriers.

    PubMed

    Albiez, E J; Büttner, D W; Schulz-Key, H

    1984-09-01

    In the Liberian rain-forest and the savanna of Upper Volta 189 adult nodule carriers were operated on. From 2231 extirpated nodules 3327 male and 5713 female macrofilariae were isolated. About 98% of the male worms and 88% of the female worms were found alive. The sex ratio of the live male and female worms was 1:1.5 in Liberia and 1:1.6 in Upper Volta. Less than 1% of all live macrofilariae were immature in both countries. 22% of the live male worms in Liberia were regarded as old. The percentage of old male and female worms in Upper Volta and that of the old female worms in Liberia were similar (5-7%). The portion of old worms was independent of the age of the patients in Liberia. Dead worms were found in 66% of the Liberians and in 85% of the Voltaics. The percentage of patients with dead worms increased with the age. About 0.5% of all male and 8% of all female worms were calcified. In Liberia the percentage of calcified worms increased with the age of the patients. In both countries the highest number of live and dead worms were found on the pelvic girdle. On the thorax many more macrofilariae were found in Upper Volta than in Liberia. This may contribute to the severe eye lesions in this savanna area. The presented findings provide some basic information for the planning and performance of trials with macrofilaricidal drugs in hyperendemic areas of West Africa. However, the striking differences between individual worm burdens have to be considered. PMID:6541822

  14. Loa loa and Onchocerca ochengi miRNAs detected in host circulation.

    PubMed

    Tritten, Lucienne; O'Neill, Maeghan; Nutting, Chuck; Wanji, Samuel; Njouendoui, Abdel; Fombad, Fanny; Kengne-Ouaffo, Jonas; Mackenzie, Charles; Geary, Timothy

    2014-11-01

    A combination of deep-sequencing and bioinformatics analysis enabled identification of twenty-two microRNA candidates of potential nematode origin in plasma from Loa loa-infected baboons and a further ten from the plasma of an Onchocerca ochengi-infected cow. The obtained data were compared to results from previous work on miRNA candidates from Dirofilaria immitis and O. volvulus found in host circulating blood, to examine the species specificity of the released miRNA. None of the miRNA candidates was found to be present in all four host-parasite scenarios and most of them were specific to only one of them. Eight candidate miRNAs were found to be identical in the full sequence in at least two different infections, while nine candidate miRNAs were found to be similar but not identical in at least four filarial species. PMID:25461483

  15. Efficacy of three-week oxytetracycline or rifampin monotherapy compared with a combination regimen against the filarial nematode Onchocerca ochengi.

    PubMed

    Bah, Germanus S; Ward, Emma L; Srivastava, Abhishek; Trees, Alexander J; Tanya, Vincent N; Makepeace, Benjamin L

    2014-01-01

    Onchocerciasis (river blindness), caused by the filarial nematode Onchocerca volvulus, is a major cause of visual impairment and dermatitis in sub-Saharan Africa. As O. volvulus contains an obligatory bacterial symbiont (Wolbachia), it is susceptible to antibiotic chemotherapy, although current regimens are considered too prolonged for community-level control programs. The aim of this study was to compare the efficacies of oxytetracycline and rifampin, administered separately or in combination, against a close relative of O. volvulus (Onchocerca ochengi) in cattle. Six animals per group were treated with continuous or intermittent oxytetracycline regimens, and effects on adult worm viability, dermal microfilarial loads, and Wolbachia density in worm tissues were assessed. Subsequently, the efficacies of 3-week regimens of oxytetracycline and rifampin alone and a combination regimen were compared, and rifampin levels in plasma and skin were quantified. A 6-month regimen of oxytetracycline with monthly dosing was strongly adulticidal, while 3-week and 6-week regimens exhibited weaker adulticidal effects. However, all three regimens achieved >2-log reductions in microfilarial load. In contrast, rifampin monotherapy and oxytetracycline-rifampin duotherapy failed to induce substantive reductions in either adult worm burden or microfilarial load, although a borderline effect on Wolbachia density was observed following duotherapy. Dermal rifampin levels were maintained above the MIC for >24 h after a single intravenous dose. We conclude that oxytetracycline-rifampin duotherapy is less efficacious against O. ochengi than oxytetracycline alone. Further studies will be required to determine whether rifampin reduces oxytetracycline bioavailability in this system, as suggested by human studies using other tetracycline-rifampin combinations. PMID:24247133

  16. Efficacy of Three-Week Oxytetracycline or Rifampin Monotherapy Compared with a Combination Regimen against the Filarial Nematode Onchocerca ochengi

    PubMed Central

    Bah, Germanus S.; Ward, Emma L.; Srivastava, Abhishek; Trees, Alexander J.; Tanya, Vincent N.

    2014-01-01

    Onchocerciasis (river blindness), caused by the filarial nematode Onchocerca volvulus, is a major cause of visual impairment and dermatitis in sub-Saharan Africa. As O. volvulus contains an obligatory bacterial symbiont (Wolbachia), it is susceptible to antibiotic chemotherapy, although current regimens are considered too prolonged for community-level control programs. The aim of this study was to compare the efficacies of oxytetracycline and rifampin, administered separately or in combination, against a close relative of O. volvulus (Onchocerca ochengi) in cattle. Six animals per group were treated with continuous or intermittent oxytetracycline regimens, and effects on adult worm viability, dermal microfilarial loads, and Wolbachia density in worm tissues were assessed. Subsequently, the efficacies of 3-week regimens of oxytetracycline and rifampin alone and a combination regimen were compared, and rifampin levels in plasma and skin were quantified. A 6-month regimen of oxytetracycline with monthly dosing was strongly adulticidal, while 3-week and 6-week regimens exhibited weaker adulticidal effects. However, all three regimens achieved >2-log reductions in microfilarial load. In contrast, rifampin monotherapy and oxytetracycline-rifampin duotherapy failed to induce substantive reductions in either adult worm burden or microfilarial load, although a borderline effect on Wolbachia density was observed following duotherapy. Dermal rifampin levels were maintained above the MIC for >24 h after a single intravenous dose. We conclude that oxytetracycline-rifampin duotherapy is less efficacious against O. ochengi than oxytetracycline alone. Further studies will be required to determine whether rifampin reduces oxytetracycline bioavailability in this system, as suggested by human studies using other tetracycline-rifampin combinations. PMID:24247133

  17. Human ocular filariasis: further evidence on the zoonotic role of Onchocerca lupi

    PubMed Central

    2012-01-01

    Background Among ocular vector-borne pathogens, Onchocerca volvulus, the agent of the so-called “river blindness”, affects about 37 million people globally. Other Onchocerca spp. have been sporadically reported as zoonotic agents. Cases of canine onchocerciasis caused by Onchocerca lupi are on the rise in the United States and Europe. Its zoonotic role has been suspected but only recently ascertained in a single case from Turkey. The present study provides further evidence on the occurrence of O. lupi infesting human eyes in two patients from Turkey (case 1) and Tunisia (case 2). The importance of obtaining a correct sample collection and preparation of nematodes infesting human eyes is highlighted. Methods In both cases the parasites were identified with morpho-anatomical characters at the gross examination, histological analysis and anatomical description and also molecularly in case 1. Results The nematode from the first case was obviously O. lupi based on their morphology at the gross examination, histological analysis and anatomical description. In the second case, although the diagnostic cuticular characters were not completely developed, other features were congruent with the identification of O. lupi. Furthermore, the morphological identification was also molecularly confirmed in the Turkish case. Conclusions The results of this study suggest that O. lupi infestation is not an occasional finding but it should be considered in the differential diagnosis of other zoonotic helminths causing eye infestation in humans (e.g., D. immitis and Dirofilaria repens). Both cases came from areas where no cases of canine onchocerciasis were previously reported in the literature, suggesting that an in depth appraisal of the infestation in canine populations is necessary. Physicians and ophthalmologists are advised on how to preserve nematode samples recovered surgically, to allow a definitive, correct etiological diagnosis. PMID:22541132

  18. Stage-specific Proteomes from Onchocerca ochengi, Sister Species of the Human River Blindness Parasite, Uncover Adaptations to a Nodular Lifestyle*

    PubMed Central

    Armstrong, Stuart D.; Xia, Dong; Bah, Germanus S.; Krishna, Ritesh; Ngangyung, Henrietta F.; LaCourse, E. James; McSorley, Henry J.; Kengne-Ouafo, Jonas A.; Chounna-Ndongmo, Patrick W.; Wanji, Samuel; Enyong, Peter A.; Taylor, David W.; Blaxter, Mark L.; Wastling, Jonathan M.; Tanya, Vincent N.; Makepeace, Benjamin L.

    2016-01-01

    Despite 40 years of control efforts, onchocerciasis (river blindness) remains one of the most important neglected tropical diseases, with 17 million people affected. The etiological agent, Onchocerca volvulus, is a filarial nematode with a complex lifecycle involving several distinct stages in the definitive host and blackfly vector. The challenges of obtaining sufficient material have prevented high-throughput studies and the development of novel strategies for disease control and diagnosis. Here, we utilize the closest relative of O. volvulus, the bovine parasite Onchocerca ochengi, to compare stage-specific proteomes and host-parasite interactions within the secretome. We identified a total of 4260 unique O. ochengi proteins from adult males and females, infective larvae, intrauterine microfilariae, and fluid from intradermal nodules. In addition, 135 proteins were detected from the obligate Wolbachia symbiont. Observed protein families that were enriched in all whole body extracts relative to the complete search database included immunoglobulin-domain proteins, whereas redox and detoxification enzymes and proteins involved in intracellular transport displayed stage-specific overrepresentation. Unexpectedly, the larval stages exhibited enrichment for several mitochondrial-related protein families, including members of peptidase family M16 and proteins which mediate mitochondrial fission and fusion. Quantification of proteins across the lifecycle using the Hi-3 approach supported these qualitative analyses. In nodule fluid, we identified 94 O. ochengi secreted proteins, including homologs of transforming growth factor-β and a second member of a novel 6-ShK toxin domain family, which was originally described from a model filarial nematode (Litomosoides sigmodontis). Strikingly, the 498 bovine proteins identified in nodule fluid were strongly dominated by antimicrobial proteins, especially cathelicidins. This first high-throughput analysis of an Onchocerca spp

  19. Stage-specific Proteomes from Onchocerca ochengi, Sister Species of the Human River Blindness Parasite, Uncover Adaptations to a Nodular Lifestyle.

    PubMed

    Armstrong, Stuart D; Xia, Dong; Bah, Germanus S; Krishna, Ritesh; Ngangyung, Henrietta F; LaCourse, E James; McSorley, Henry J; Kengne-Ouafo, Jonas A; Chounna-Ndongmo, Patrick W; Wanji, Samuel; Enyong, Peter A; Taylor, David W; Blaxter, Mark L; Wastling, Jonathan M; Tanya, Vincent N; Makepeace, Benjamin L

    2016-08-01

    Despite 40 years of control efforts, onchocerciasis (river blindness) remains one of the most important neglected tropical diseases, with 17 million people affected. The etiological agent, Onchocerca volvulus, is a filarial nematode with a complex lifecycle involving several distinct stages in the definitive host and blackfly vector. The challenges of obtaining sufficient material have prevented high-throughput studies and the development of novel strategies for disease control and diagnosis. Here, we utilize the closest relative of O. volvulus, the bovine parasite Onchocerca ochengi, to compare stage-specific proteomes and host-parasite interactions within the secretome. We identified a total of 4260 unique O. ochengi proteins from adult males and females, infective larvae, intrauterine microfilariae, and fluid from intradermal nodules. In addition, 135 proteins were detected from the obligate Wolbachia symbiont. Observed protein families that were enriched in all whole body extracts relative to the complete search database included immunoglobulin-domain proteins, whereas redox and detoxification enzymes and proteins involved in intracellular transport displayed stage-specific overrepresentation. Unexpectedly, the larval stages exhibited enrichment for several mitochondrial-related protein families, including members of peptidase family M16 and proteins which mediate mitochondrial fission and fusion. Quantification of proteins across the lifecycle using the Hi-3 approach supported these qualitative analyses. In nodule fluid, we identified 94 O. ochengi secreted proteins, including homologs of transforming growth factor-β and a second member of a novel 6-ShK toxin domain family, which was originally described from a model filarial nematode (Litomosoides sigmodontis). Strikingly, the 498 bovine proteins identified in nodule fluid were strongly dominated by antimicrobial proteins, especially cathelicidins. This first high-throughput analysis of an Onchocerca spp

  20. An Unusual Case of Small Bowel Volvulus

    PubMed Central

    Manjunath, Srinidhi; Balasubramanya, Kanakapura Srinivasamurthy; Nanjaiah, Basavaraju

    2015-01-01

    Small bowel volvulus is a rare and life threatening surgical emergency. Nearly 75% of volvulus occurs in colon and 25% occurs in small bowel. Small bowel volvulus is abnormal twisting of bowel loops around the axis of its own mesentry leading to twisting and occlusion of mesenteric vessels causing intestinal obstruction, venous engorgement, gangrene and perforation. Small bowel volvulus is more common in neonates and young adults and very rare in adults. We are reporting a first case of small bowel volvulus and gangrene caused by herniation of ovarian cyst through mesenteric defect and twisting of small bowel around the axis of ovarian cyst leading to closed loop obstruction, small bowel volvulus and gangrene. Outcome of the disease is mainly based on the early diagnosis and intervention. Mortality is about 5.8 - 8% in nongangrenous SBV which increases drastically to 20 – 100% in gangrenous bowel. PMID:26676224

  1. Undiagnosed hypothyroidism presenting with sigmoid volvulus

    PubMed Central

    Meytes, Vadim; Schulberg, Steven P.; Morin, Nicholas; Glinik, Galina

    2016-01-01

    The incidence of hypothyroidism presenting with sigmoid volvulus, a phenomenon known as myxedema pseudovolvulus, is exceedingly rare. A male in his late thirties presented to our institution with a chief complaint of abdominal pain. The patient underwent CT scan, which was consistent with massive colonic dilatation with sigmoid volvulus. He was taken to the operating room for exploration and was found to have sigmoid volvulus and underwent a segmental resection. Postoperatively, the patient was newly diagnosed with severe hypothyroidism. PMID:27106615

  2. Undiagnosed hypothyroidism presenting with sigmoid volvulus.

    PubMed

    Meytes, Vadim; Schulberg, Steven P; Morin, Nicholas; Glinik, Galina

    2016-01-01

    The incidence of hypothyroidism presenting with sigmoid volvulus, a phenomenon known as myxedema pseudovolvulus, is exceedingly rare. A male in his late thirties presented to our institution with a chief complaint of abdominal pain. The patient underwent CT scan, which was consistent with massive colonic dilatation with sigmoid volvulus. He was taken to the operating room for exploration and was found to have sigmoid volvulus and underwent a segmental resection. Postoperatively, the patient was newly diagnosed with severe hypothyroidism. PMID:27106615

  3. Anti-onchocerca Metabolites from Cyperus articulatus: Isolation, In Vitro Activity and In Silico 'Drug-Likeness'.

    PubMed

    Metuge, Jonathan Alunge; Babiaka, Smith B; Mbah, James A; Ntie-Kang, Fidele; Ayimele, Godfred A; Cho-Ngwa, Fidelis

    2014-08-01

    The aims of this investigation were to isolate active ingredients from the roots/rhizomes of Cyperus articulatus used as herbal medicine in Cameroon for the treatment of human onchocerciasis and to assess the efficacy of the metabolites on the Onchocerca worm. The antifilarial activity was evaluated in vitro on microfilariae (Mfs) and adult worms of the bovine derived Onchocerca ochengi, a close relative of Onchocerca volvulus. Cytotoxicity was assessed in vitro on monkey kidney epithelial cells. The structures of the active compounds were determined using spectroscopic methods and their drug-likeness evaluated using Lipinski parameters. Two secondary metabolites, AMJ1 [containing mustakone (1) as the major component] and linoleic acid or (9Z,12Z)-octadeca-9,12-dienoic acid (2) were isolated. Both compounds were found to kill both the microfilariae and adult worms of O. ochengi in a dose dependent manner. The IC50s for AMJ1 were 15.7 µg/mL for Mfs, 17.4 µg/mL for adult males and 21.9 µg/mL for adult female worms while for linoleic acid the values were, 15.7 µg/mL for Mfs, 31.0 µg/mL for adult males and 44.2 µg/mL for adult females. The present report provides the first ever evidence of the anti-Onchocerca efficacy of AMJ1 and linoleic acid. Thus, these secondary metabolites may provide a lead for design and development of new antifilarial agents. PMID:25089243

  4. Intestinal malrotation and midgut volvulus.

    PubMed

    Hamidi, Hidayatullah; Obaidy, Yalda; Maroof, Sahar

    2016-09-01

    A four-day-old boy presented with persistent bilious vomiting, bloody stained stool, and mild abdominal distension. Transabdominal ultrasound demonstrated a round soft-tissue mass-like structure in the right upper quadrant. With color Doppler ultrasound, the whirlpool sign was observed. Abdominal radiograph showed nonspecific findings. Upper gastrointestinal series revealed upper gastrointestinal tract obstruction at the level of distal duodenum. The diagnosis of intestinal malrotation with midgut volvulus was established and the treated surgically. Intestinal malrotation is congenital abnormal positioning of the bowel loops within the peritoneal cavity resulting in abnormal shortening of mesenteric root that is predisposed to midgut volvulus. Neonates and infants with persistent bilious vomiting should undergo diagnostic workup and preferably ultrasound as the first step. With classic sonographic appearance of whirlpool sign, even further imaging investigations is often not needed, and the surgeon should be alerted to plan surgery. PMID:27594965

  5. Model-Based Geostatistical Mapping of the Prevalence of Onchocerca volvulus in West Africa

    PubMed Central

    O’Hanlon, Simon J.; Slater, Hannah C.; Cheke, Robert A.; Boatin, Boakye A.; Coffeng, Luc E.; Pion, Sébastien D. S.; Boussinesq, Michel; Zouré, Honorat G. M.; Stolk, Wilma A.; Basáñez, María-Gloria

    2016-01-01

    Background The initial endemicity (pre-control prevalence) of onchocerciasis has been shown to be an important determinant of the feasibility of elimination by mass ivermectin distribution. We present the first geostatistical map of microfilarial prevalence in the former Onchocerciasis Control Programme in West Africa (OCP) before commencement of antivectorial and antiparasitic interventions. Methods and Findings Pre-control microfilarial prevalence data from 737 villages across the 11 constituent countries in the OCP epidemiological database were used as ground-truth data. These 737 data points, plus a set of statistically selected environmental covariates, were used in a Bayesian model-based geostatistical (B-MBG) approach to generate a continuous surface (at pixel resolution of 5 km x 5km) of microfilarial prevalence in West Africa prior to the commencement of the OCP. Uncertainty in model predictions was measured using a suite of validation statistics, performed on bootstrap samples of held-out validation data. The mean Pearson’s correlation between observed and estimated prevalence at validation locations was 0.693; the mean prediction error (average difference between observed and estimated values) was 0.77%, and the mean absolute prediction error (average magnitude of difference between observed and estimated values) was 12.2%. Within OCP boundaries, 17.8 million people were deemed to have been at risk, 7.55 million to have been infected, and mean microfilarial prevalence to have been 45% (range: 2–90%) in 1975. Conclusions and Significance This is the first map of initial onchocerciasis prevalence in West Africa using B-MBG. Important environmental predictors of infection prevalence were identified and used in a model out-performing those without spatial random effects or environmental covariates. Results may be compared with recent epidemiological mapping efforts to find areas of persisting transmission. These methods may be extended to areas where data are sparse, and may be used to help inform the feasibility of elimination with current and novel tools. PMID:26771545

  6. A simple technique to assess the total number of Onchocerca volvulus microfilariae in skin snips.

    PubMed

    Schulz-Key, H

    1978-03-01

    A technique for the assessment of the total number of microfilariae in skin snips from onchocerciasis patients is described. For the digestion of the skin tissue the biopsies are incubated at room temperature for 24 hours in medium 199, containing 3 mg/ml collagenase and antibiotics. This process leaves the microfilariae unharmed. A comparative study of the emergence of the microfilariae in different media showed that only 20% of the total number were released after 30 minutes in distilled water. After 24 hours incubation in isotonic saline 80% were found. PMID:205977

  7. Interruption of Transmission of Onchocerca volvulus in the Oaxaca Focus, Mexico

    PubMed Central

    Rodríguez-Pérez, Mario A.; Unnasch, Thomas R.; Domínguez-Vázquez, Alfredo; Morales-Castro, Alba L.; Peña-Flores, Graciela P.; Orozco-Algarra, María E.; Arredondo-Jiménez, Juan I.; Richards, Frank; Vásquez-Rodríguez, Miguel A.; Rendón, Vidal García

    2010-01-01

    All endemic communities of the Oaxaca focus of onchocerciasis in southern Mexico have been treated annually or semi-annually with ivermectin since 1994. In-depth epidemiologic assessments were performed in communities during 2007 and 2008. None of the 52,632 Simulium ochraceum s.l. collected in four sentinel communities was found to contain parasite DNA when tested by polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA), resulting in an upper bound of the infection rate in the vectors of 0.07/2,000. The prevalence of microfilariae (mf) in the cornea and/or anterior chamber of the eye was also zero (0 of 1,039 residents examined; 95%-UL = 0.35%). Similarly, all 1,164 individuals examined by skin biopsy were mf negative (95%-UL = 0.31%), and sera collected from 3,569 children from 25 communities did not harbor Ov16 IgG4-antibodies (95%-UL = 0.09%). These meet the criteria for absence of morbidity and parasite transmission in the Oaxaca focus. As a result mass treatments with ivermectin were halted in 2009. PMID:20595472

  8. Single worm genotyping demonstrates that Onchocerca ochengi females simultaneously produce progeny sired by different males.

    PubMed

    Hildebrandt, Julia C; Eisenbarth, Albert; Renz, Alfons; Streit, Adrian

    2012-11-01

    Onchocerca ochengi is a filarial nematode parasite of African cattle and most closely related to Onchocerca volvulus, the causing agent of river blindness. O. ochengi females induce the formation of a nodule in the dermis of the host, in which they remain sedentary in very close association with the host's tissue. Males, which do not adhere to the host's tissue, are also found within the nodules at an average number of about one male per nodule. Young O. ochengi females tend to avoid the immediate proximity of existing nodules. Therefore, O. ochengi nodules are dispersed in the ventral inguinal skin at considerable distances from each other. It has been speculated that males avoid the risk of leaving a female once they have found one and remain in the nodule as territorial males rendering the reproductive strategy of O. ochengi essentially monogamous. We developed a protocol that allows reliable PCR amplification of single copy loci from different developmental stages of O. ochengi including embryos and microfilariae. From 32 O. ochengi nodules, we genotyped the female worms and the 67 adult male worms, found in these nodules, together with a fraction of the progeny from within the uteri of females. In 18 of 32 gravid females progeny derived from multiple males were found. In five nodules, the males isolated from the same nodule as the female were not sufficient to explain the genotypes of the entire progeny. We conclude that frequently O. ochengi females simultaneously produce progeny sired by different males and that most but not all males are still present in the nodule when their offspring is ready to hatch. PMID:22706958

  9. Chemoprophylaxis of Onchocerca infections: in a controlled, prospective study ivermectin prevents calves becoming infected with O. ochengi.

    PubMed

    Tchakouté, V L; Bronsvoort, M; Tanya, V; Renz, A; Trees, A J

    1999-02-01

    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 activity against naturally transmitted, O. ochengi infections in a controlled, prospective study in northern Cameroon. Calves were treated monthly with ivermectin at either 200 micrograms/kg or 500 micrograms/kg for 21 months. None of 15 treated calves developed adult worm infection, whereas 5/6 untreated controls became infected (P < 0.001) with a total of 54 O. ochengi nodules, and all 5 developed patent microfilaridermia. These results have significant implications for the use of ivermectin in humans, and suggest that strategic chemotherapy at times of maximal transmission will confer prophylactic as well as therapeutic benefits. PMID:10028534

  10. Severe Hypothyroidism-Induced Volvulus.

    PubMed

    Khan, Rafay; Ahmed, Amar; Tulpule, Sunil; Regeti, Kalyani; Sen, Shuvendu; Mathew, Teena

    2015-12-01

    Thyroid disorders have been found to be associated with multiple organ systems and thus have a broad spectrum of presenting symptoms and clinical conditions. Certain aspects of the gastrointestinal (GI) system have yet to be fully understood and documented. Hypothyroidism and even hyperthyroidism have been identified in patients with motility symptoms involving the GI tract. These symptoms can vary and can be a complication of undertreated or undiagnosed condition involving the thyroid. Unfortunately, the mechanism in which these hormones can impact intestinal motility remains poorly understood and not well documented. In this case report, we discuss the presentation of a 71-year-old female with poorly managed hypothyroidism presenting with significant abdominal distention and pain secondary to underlying volvulus formation. By better understanding the complications induced by hypothyroidism, physicians may be able to prevent further life-threatening outcomes with early management and intervention. PMID:26566414

  11. Management of the colonic volvulus in 2016.

    PubMed

    Perrot, L; Fohlen, A; Alves, A; Lubrano, J

    2016-06-01

    Colonic volvulus is the third leading cause of colonic obstruction worldwide, occurring at two principal locations: the sigmoid colon and cecum. In Western countries, sigmoid volvulus preferentially affects elderly men whereas cecal volvulus affects younger women. Some risk factors, such as chronic constipation, high-fiber diet, frequent use of laxatives, personal past history of laparotomy and anatomic predispositions, are common to both locations. Clinical symptomatology is non-specific, including a combination of abdominal pain, gaseous distention, and bowel obstruction. Abdominopelvic computerized tomography is currently the gold standard examination, allowing positive diagnosis as well as detection of complications. Specific management depends on the location, patient comorbidities and colonic wall viability, but treatment is an emergency in every case. If clinical or radiological signs of gravity are present, emergency surgery is mandatory, but is associated with high morbidity and mortality rates. For sigmoid volvulus without criteria of gravity, the ideal strategy is an endoscopic detorsion procedure followed, within 2 to 5 days, by surgery that includes a sigmoid colectomy with primary anastomosis. Exclusively endoscopic therapy must be reserved for patients who are at excessive risk for surgical intervention. In cecal volvulus, endoscopy has no role and surgery is the rule. PMID:27132752

  12. Obstructive jaundice secondary to chronic midgut volvulus.

    PubMed Central

    Spitz, L; Orr, J D; Harries, J T

    1983-01-01

    A case of progressive extrahepatic biliary obstruction due to chronic midgut volvulus secondary to malrotation in a 5-month-old girl is presented. The obstruction to the bile duct was relieved after correction of the malrotation and division of the obstructing bands. Images Fig. 1 Fig. 2 PMID:6859923

  13. [Intestinal volvulus due to yeyunal duplication].

    PubMed

    Rodríguez Iglesias, P; Carazo Palacios, M E; Lluna González, J; Ibáñez Pradas, V; Rodríguez Caraballo, L

    2014-10-01

    Duplications of the alimentary tract are congenital malformations. The ileum is the most commonly affected organ. A lot of duplications are incidentally diagnosed but most of patients present a combination of pain or complications such as obstructive symptoms, intestinal intussusception, perforation or volvulus. We report the case of a 6-years-old girl, with intermittent abdominal pain and vomits for two months long. Laboratory work was completely normal and in the radiology analysis (abdominal sonography and magnetic resonance) a cystic image with intestinal volvulus was observed. The patient underwent laparotomy, Ladd's procedure was done and the cyst was resected. In conclusion, if a patient is admitted with abdominal pain and obstructive symptoms, it is important to consider duplication of the alimentary tract as a possible diagnosis. PMID:26065113

  14. Chronic gastric volvulus: is it so rare?

    PubMed

    Bautista-Casasnovas, A; Varela-Cives, R; Fernandez-Bustillo, J M; Estévez Martínez, E; Prada Arias, M; Villanueva Jeremias, A; Pavón Belinchon, P; Peña Guitian, J

    2002-04-01

    Gastric volvulus has traditionally been considered a rare entity in children, and standard texts on paediatrics typically make scant reference to it. In our experience, however, careful radiographic study of children with digestive symptoms reveals gastric volvulus to be more frequent than is commonly thought. We report 52 cases of this disorder, and discuss its diagnosis and treatment. Material and Methods. We performed a retrospective study of all children treated for chronic gastric volvulus in our department since 1976. Results. All 52 patients (27 boys, 25 girls) were term infants, mean age 2.8 months at diagnosis. The principal symptoms were crying and colic (90 %), vomiting and nausea (67 %). The mean age at onset of symptoms was 1.1 months. Diagnosis was in all cases on the basis of upper intestinal transit studies. The most frequent radiological signs were high greater curvature (87 %) and greater curvature crossing the oesophagus (83 %). Nine of the 52 children underwent primary surgery. The remaining 43 patients underwent conservative (i.e. postural) treatment; 11 of these patients showed no significant improvement and thus underwent surgery. We performed 20 surgical interventions (19 simple anterior gastropexies and one a percutaneous endoscopic gastrostomy). All patients showed good recovery after surgery. Conclusion. Careful examination of patients with vomiting, abdominal distension, gastro-oesophageal reflux, colic, crying, retarded growth, sleep problems, anxiety, and even repeated respiratory infections will reveal chronic gastric volvulus with greater frequency than has traditionally been thought. We believe that this entity is often undetected, and that, as a result, it is often inappropriately treated. PMID:12015655

  15. Seasonal Variation in Biting Rates of Simulium damnosum sensu lato, Vector of Onchocerca volvulus, in Two Sudanese Foci

    PubMed Central

    Zarroug, Isam M. A.; Hashim, Kamal; Elaagip, Arwa H.; Samy, Abdallah M.; Frah, Ehab A.; ElMubarak, Wigdan A.; Mohamed, Hanan A.; Deran, Tong Chor M.; Aziz, Nabil; Higazi, Tarig B.

    2016-01-01

    Background The abundance of onchocerciasis vectors affects the epidemiology of disease in Sudan, therefore, studies of vector dynamics are crucial for onchocerciasis control/elimination programs. This study aims to compare the relative abundance, monthly biting-rates (MBR) and hourly-based distribution of onchocerciasis vectors in Abu-Hamed and Galabat foci. These seasonally-based factors can be used to structure vector control efforts to reduce fly-biting rates as a component of onchocerciasis elimination programs. Methods A cross-sectional study was conducted in four endemic villages in Abu-Hamed and Galabat foci during two non-consecutive years (2007–2008 and 2009–2010). Both adults and aquatic stages of the potential onchocerciasis vector Simulium damnosum sensu lato were collected following standard procedures during wet and dry seasons. Adult flies were collected using human landing capture for 5 days/month. The data was recorded on handheld data collection sheets to calculate the relative abundance, MBR, and hourly-based distribution associated with climatic factors. The data analysis was carried out using ANOVA and Spearman rank correlation tests. Results Data on vector surveillance revealed higher relative abundance of S. damnosum s.l. in Abu- Hamed (39,934 flies) than Galabat (8,202 flies). In Abu-Hamed, vector populations increased in January-April then declined in June-July until they disappeared in August-October. Highest black fly density and MBR were found in March 2007 (N = 9,444, MBR = 58,552.8 bites/person/month), and March 2010 (N = 2,603, MBR = 16,138.6 bites/person/month) while none of flies were collected in August-October (MBR = 0 bites/person/month). In Galabat, vectors increased in September-December, then decreased in February-June. The highest vector density and MBR were recorded in September 2007 (N = 1,138, MBR = 6,828 bites/person/month) and September 2010 (N = 1,163, MBR = 6,978 bites/person/month), whereas, none appeared in collection from April to June. There was a significant difference in mean monthly density of S. damnosum s.l. across the two foci in 2007–2008 (df = 3, F = 3.91, P = 0.011). Minimum temperature showed significant correlation with adult flies counts in four areas sampled; the adult counts were increased in Nady village (rs = 0.799) and were decreased in Kalasecal (rs = - 0.676), Gumaiza (rs = - 0.585), and Hilat Khateir (rs = - 0.496). Maximum temperature showed positive correlation with black fly counts only in Galabat focus. Precipitation was significantly correlated with adult flies counts in Nady village, Abu-Hamed, but no significance was found in the rest of the sampled villages in both foci. Hourly-based distribution of black flies showed a unimodal pattern in Abu-Hamed with one peak (10:00–18:00), while a bimodal pattern with two peaks (07:00–10:00) and (14:00–18:00) was exhibited in Galabat. Conclusion Transmission of onchocerciasis in both foci showed marked differences in seasonality, which may be attributed to ecology, microclimate and proximity of breeding sites to collection sites. The seasonal shifts between the two foci might be related to variations in climate zones. This information on black fly vector seasonality, ecology, distribution and biting activity has obvious implications in monitoring transmission levels to guide the national and regional onchocerciasis elimination programs in Sudan. PMID:26943668

  16. An evaluation of skin snip techniques used in the quantitative assessment of microfilarial densities of Onchocerca volvulus*

    PubMed Central

    Kale, O. O.; Bammeke, A. O.; Ayeni, O.

    1974-01-01

    A study was undertaken to determine whether significant variations occur in the quantitative assessment of onchocercal microfilarial densities when different methods of treating skin snips are used. The results show that teasing of the snip should be avoided because it reduces the sensitivity of the method. PMID:4549504

  17. Epidemiological impact of vector control. I. Incidence and changes in prevalence and intensity of Onchocerca volvulus infection.

    PubMed

    De Sole, G; Remme, J; Dadzie, K Y

    1990-01-01

    Since 1974, the Onchocerciasis Control Programme (OCP) has been engaged in a large scale attempt to control the savanna species of the vector of onchocerciasis in seven West African countries. The effect of the vector control effort has been measured by epidemiological evaluation. For this purpose 474 villages have been examined by means of skin snip surveys between 1975 and 1983 and of these, 184 have been retained to-date for follow-up surveys which have documented over the years the reduction of the parasite population. The latest results of the epidemiological evaluation clearly demonstrate an outstanding success of the vector control campaign. The parasite has been or is close to being eliminated from the hyperendemic foci of the core area of the Programme. Major improvements have been registered in the reinvaded areas located at the Western and Eastern borders of the Programme. A major improvement has been found along the river Marahoué, the only focus of the intermediate area between the savanna and the forest where at the previous survey, the endemic situation was still similar to the pre-control situation. The exceptions to this gratifying picture are foci along the Dienkoa and Kulpawn rivers, both located in the core area, where transmission has relapsed and several more years of an effective vector control will be needed to eliminate the local parasite population. PMID:2378200

  18. Ischaemia/reperfusion injury in experimentally induced abomasal volvulus in sheep.

    PubMed

    Sharifi, K; Mostaghni, K; Maleki, M; Badiei, K

    2007-07-01

    The purpose of the study was to evaluate ischaemia/reperfusion injury in simulated abomasal volvulus in sheep. Sixteen ewes were randomly allocated to three groups. The control group (n=4) served as sham-operated controls. The animals of the ischaemia group and reperfusion group (n=6, each) underwent a simulated 'abomasal volvulus'. The abomasum was exteriorized under general inhalation anesthesia and forced into a 180( composite function) anticlockwise rotation around its longitudinal axis, followed by another 270( composite function) anticlockwise rotation around its transectional axis. All ewes were monitored for 4 h. In the reperfusion group, volvulus was released after 3 h (i.e., 1 h of reperfusion). In the ischaemia group, the volvulus remained for 4 h (no reperfusion). Vital signs were monitored and some haematological and biochemical parameters were measured, without any significant differences. Full-section biopsy specimens were taken at the 3rd and 4th hours from the greater curvature of the abomasum. Histopathological lesions were scored according to the severity of mucosal oedema, submucosal oedema, haemorrhage submucosal and submuscularis layers, and polymorphonuclear infiltration on a scale of 0 to 4 (nil, mild, moderate, severe, and extreme). Another biopsy specimen was taken at the 4th hour for transmission electron microscopic examination. The scored lesions in light-microscopic examination were significantly different at the 3rd and 4th hours between the control and the experimental groups (p<0.05). There was no significant difference between the reperfusion and ischaemia groups (p>0.1). Within-group comparisons (3rd hour with 4th hour) revealed no significant differences. In transmission electron microscopic examination there were no remarkable changes in the control group, but in the ischaemia and reperfusion groups there were remarkable cellular (epithelial and goblet cells), mitochondrial and microvillous changes that strongly implied the

  19. Diagnosis and treatment of caecal volvulus

    PubMed Central

    Consorti, E; Liu, T

    2005-01-01

    Caecal volvulus is an infrequently encountered clinical condition and an uncommon cause of intestinal obstruction. Patients with this condition may present with highly variable clinical presentations ranging from intermittent, self limiting abdominal pain to acute abdominal pain associated with intestinal strangulation and sepsis. Lack of familiarity with this condition is a factor contributing to diagnostic and treatment delays. The objective of this review is to promote clinicians' awareness of this disease through patient case illustration, discussion of disease pathogenesis, clinical features, and management strategies. PMID:16344301

  20. In vitro radiolabel uptake viability assay for Onchocerca microfilariae

    SciTech Connect

    Callahan, H.L.; Wakeman, J.M.; Crouch, R.K.; James, E.R.

    1989-02-01

    A radiolabel uptake viability assay for Onchocerca cervicalis using (/sup 3/H)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.

  1. Human case of Onchocerca lupi infection, Germany, August 2014.

    PubMed

    Bergua, A; Hohberger, B; Held, J; Muntau, B; Tannich, E; Tappe, D

    2015-01-01

    Onchocerca lupi, a nematode parasite infecting dogs and cats with a hitherto unknown arthropod vector, is also being recognised as a parasite also responsible for human eye infections. Here we describe a case of human eye infection diagnosed molecularly by nematode 12S rDNA PCR in a German patient who had travelled to Tunisia and Turkey. The patient recovered after treatment with antibiotic and anti-inflammatory therapy. PMID:25953271

  2. [Caecal volvulus after heart surgery with artificial circulation].

    PubMed

    Korostelev, A N; Kuznetsov, A M; Chzhao, A V

    2016-01-01

    Presented herein is a description of a rare complication, i.e. caecal volvulus, after heart surgery. This case report illustrates difficulty of diagnosis of abdominal organs complications after artificial circulation and necessity of active surgical policy. PMID:27336350

  3. Immunotherapy with mutated onchocystatin fails to enhance the efficacy of a sub-lethal oxytetracycline regimen against Onchocerca ochengi.

    PubMed

    Bah, Germanus S; Tanya, Vincent N; Makepeace, Benjamin L

    2015-08-15

    Human onchocerciasis (river blindness), caused by the filarial nematode Onchocerca volvulus, has been successfully controlled by a single drug, ivermectin, for over 25 years. Ivermectin prevents the disease symptoms of severe itching and visual impairment by killing the microfilarial stage, but does not eliminate the adult parasites, necessitating repeated annual treatments. Mass drug administration with ivermectin does not always break transmission in forest zones and is contraindicated in individuals heavily co-infected with Loa loa, while reports of reduced drug efficacy in Ghana and Cameroon may signal the development of resistance. An alternative treatment for onchocerciasis involves targeting the essential Wolbachia symbiont with tetracycline or its derivatives, which are adulticidal. However, implementation of antibiotic therapy has not occurred on a wide scale due to the prolonged treatment regimen required (several weeks). In the bovine Onchocerca ochengi system, it has been shown previously that prolonged oxytetracycline therapy increases eosinophil counts in intradermal nodules, which kill the adult worms by degranulating on their surface. Here, in an "immunochemotherapeutic" approach, we sought to enhance the efficacy of a short, sub-lethal antibiotic regimen against O. ochengi by prior immunotherapy targeting onchocystatin, an immunomodulatory protein located in the adult female worm cuticle. A key asparagine residue in onchocystatin was mutated to ablate immunomodulatory activity, which has been demonstrated previously to markedly improve the protective efficacy of this vaccine candidate when used as an immunoprophylactic. The immunochemotherapeutic regimen was compared with sub-lethal oxytetracycline therapy alone; onchocystatin immunotherapy alone; a gold-standard prolonged, intermittent oxytetracycline regimen; and no treatment (negative control) in naturally infected Cameroonian cattle. Readouts were collected over one year and comprised adult

  4. Endoscopic management of sigmoid volvulus in children

    PubMed Central

    Parolini, Filippo; Orizio, Paolo; Bulotta, Anna Lavinia; Garcia Magne, Miguel; Boroni, Giovanni; Cengia, Gianpaolo; Torri, Fabio; Alberti, Daniele

    2016-01-01

    Sigmoid volvulus (SV) is extremely uncommon in children and is usually associated with a long-standing history of constipation or pseudo-obstruction. An early diagnosis and management are crucial in order to prevent the appearance of hemorrhagic infarction of the twisted loop, avoiding further complications such as necrosis, perforation and sepsis. In patients with no evidence of peritonitis or ischemic bowel, treatment starts with resuscitation and detorsion of the SV, accomplished by means of sigmoidoscopy and concomitant rectal tube placement. The bowel is then prepared and surgery is undertaken electively during the same hospitalization. We report a detailed review of the literature focusing on technical details, risks and benefits of endoscopic management of SV in childhood. PMID:27358669

  5. First description of Onchocerca jakutensis (Nematoda: Filarioidea) in red deer (Cervus elaphus) in Switzerland.

    PubMed

    Bosch, Felix; Manzanell, Ralph; Mathis, Alexander

    2016-08-01

    Twenty-seven species of the genus Onchocerca (Nematoda; Filarioidea) can cause a vector-borne parasitic disease called onchocercosis. Most Onchocerca species infect wild and domestic ungulates or the dog, and one species causes river blindness in humans mainly in tropical Africa. The European red deer (Cervus e. elaphus) is host to four species, which are transmitted by blackflies (simuliids) or biting midges (ceratopogonids). Two species, Onchocerca flexuosa and Onchocerca jakutensis, produce subcutaneous nodules, whereas Onchocerca skrjabini and Onchocerca garmsi live free in the hypodermal serous membranes. During the hunting season, September 2013, red deer (n = 25), roe deer (Capreolus c. capreolus, n = 6) and chamois (Rupicapra r. rupicapra, n = 7), all shot in the Grisons Region (Switzerland) were investigated for the presence of subcutaneous nodules which were enzymatically digested, and the contained Onchocerca worms were identified to species by light and scanning electron microscopy as well as by PCR/sequencing. In addition, microfilariae from skin samples were collected and genetically characterized. Neither nodules nor microfilariae were discovered in the roe deer and chamois. Adult worms were found in 24% of red deer, and all of them were identified as O. jakutensis. Two morphologically different microfilariae were obtained from five red deer, and genetic analysis of a skin sample of one red deer indicated the presence of another Onchocerca species. This is the first report of O. jakutensis in Switzerland with a prevalence in red deer similar to that in neighbouring Germany. PMID:27617204

  6. Cutaneous Manifestations of a Zoonotic Onchocerca Species in an Adult Male, Acquired in Nova Scotia, Canada

    PubMed Central

    Lai, Jonathan H.; Walsh, Noreen M. G.; Pritt, Bobbi S.; Sloan, Lynne; Gibson, Lawrence E.; Desormeau, Leon

    2014-01-01

    A 65-year-old male with known hypertension and hypercholesterolemia sought medical attention because of a 3-month history of skin swelling on his upper back. Histopathology and molecular techniques were employed and identified an organism in the Onchocerca genus. This represents a very uncommon example of cutaneous infection by a zoonotic Onchocerca species. PMID:24501037

  7. Development by injection in Simulium damnosum s.l. of two Onchocerca species from the wart hog to infective larvae resembling type D larvae (Duke, 1967).

    PubMed

    Wahl, G; Bain, O

    1995-03-01

    Four wart hogs (Phacochoerus aethiopicus) examined in the Sudan savanna of North-Cameroon were all found infected with two types of skin microfilariae. One was O. ramachandrini Bain, Wahl and Renz, 1993, the adult worms of which live in the subcutaneous tissues of the feet. The other, smaller type belongs to a new Onchocerca species, the adult worms of which were not yet found. O. ramachandrini-microfilariae were evenly distributed across the whole body surface, those of Onchocerca sp. were concentrated on the back. The two species of microfilariae were isolated from an infected hide separated under the dissecting microscope and injected into the thorax of pupae-hatched S. squamosum and S. damnosum s.slr. females. Both filariae developed in both flies at high rates (33-47% of injected microfilariae) and without pathological forms to infective larvae L3). Both L3-species had a caudal tip, were long, slender and very motile and had a conspicuous glandular oesophagus. L3 from O. ramachandrini-microfilariae had a long glandular oesophagus (55% of total L3 length), a round head and measured an average of 955 microns long and 19.2 microns wide. L3 from the other microfilaria-species were shorter (845 microns, P < 0.001) and thinner (16.7 microns, P < 0.001) and had a shorter glandular oesophagus (36%, P < 0.001), a shorter tail (P < 0.01) and a conical head. Both L3-species, by their caudal tip, their long and slender silhouette, their great motility and their conspicuous glandular oesophagus resemble non-O. volvulus filarial L3 known, since many years, to occur in "wild" S. damnosum s.l. in Cameroon (Type D larvae, Duke, 1967) and in Liberia (Agamofilaria Type VI, Voelker and Garms, 1972). During our study, L3 such larvae were found in 12 wild S. damnosum s.l. from two geographically different areas of North Cameroon and all identified as O. ramachandrini. The excellent development of the two Onchocerca species from the wart hog in S. damnosum s.l. after artificial

  8. [Megacolon and sigmoid volvulus: incidence and physiopathology].

    PubMed

    Saravia Burgos, Jaime; Acosta Canedo, Abel

    2015-01-01

    The etiology of Megacolon is multiple. One of these causes and the most frequent is Chagas disease. Its complication: sigmoid volvulus was de main diagnosis in the admitted patients at the Bolivian and Japanese Gastroenterological Institute of Cochabamba Bolivia. It usually affects people of a low economic income. In this Gastroenterological Hospital a transversal and prospective study has been done, in order to know the real incidence and the physiopathology of this disease. In a six year period, from 2000 to 2006, 8.954 patients were admitted to the Hospital: of these, 814 (9.09%), where diagnosticated as lower intestinal obstruction. In 608 (74.7%) the final diagnosis was sigmoid torsion. Radiological diagnosis was made in 84% of the patients and endoscopic decompression was successful in 88.7%. As reported in the medical literature, the main cause of megacolon in this part of the world is Chagas disease. In our investigation 22% (98 patients), were serology positive to Chagas disease, and another 21.44% (95 patients) were serology negative. They were coca leaf chewers. One of coca leaf compounds is cocaine which blocks the adrenaline and noradrenaline degradation by mean of monoamine oxidase inactivation. These two hormones stay a long term of time in the target organ: the large bowel. By this mean chronic and persistent vessel constriction develops intestinal wall atrophy and lower resistance to the intraintestinal pressure. PMID:25875517

  9. Sigmoid volvulus: an uncommon complication of Hirschsprung's disease.

    PubMed

    Ranjan, Abhishek; Jain, Vishesh; Sharma, Shilpa; Gupta, Devendra Kumar

    2016-01-01

    Sigmoid volvulus is a rare and potentially life-threatening condition that is usually seen in adults, however, when diagnosed in children, it is often associated with Hirschsprung's disease (HD). We report a case of an 11-year-old boy who presented with a history of constipation since 1.5 months of age, with acute onset of severe abdominal pain and marked distention of the abdomen. Sigmoid volvulus was suspected, detected and successfully managed with resection of the sigmoid colon and primary Scott Boley's pull-through. This report underscores the importance of suspecting sigmoid volvulus in the pertinent clinical setting; also, a primary definitive procedure can be performed in select cases. PMID:27229747

  10. Sigmoid volvulus after laparoscopic surgery for sigmoid colon cancer.

    PubMed

    Sadatomo, Ai; Miyakura, Yasuyuki; Zuiki, Toru; Koinuma, Koji; Horie, Hisanaga; Lefor, Alan T; Yasuda, Yoshikazu

    2013-08-01

    We report the first case of sigmoid volvulus after laparoscopic surgery for sigmoid colon cancer. The patient is a 75-year-old man who presented with the sudden onset of severe abdominal pain. He had undergone laparoscopic sigmoidectomy for cancer 2 years before presentation. CT scan showed a distended sigmoid colon with a mesenteric twist, or "whirl sign." Colonoscopy showed a mucosal spiral and luminal stenosis with dilated sigmoid colon distally and ischemic mucosa. The diagnosis of ischemic colonic necrosis due to sigmoid volvulus was established. Resection of the necrotic sigmoid colon was performed and a descending colon stoma was created. A long remnant sigmoid colon and chronic constipation may contribute to the development of sigmoid volvulus after laparoscopic sigmoidectomy. Prompt diagnosis is essential for adequate treatment, and colonoscopy aids in the diagnosis of ischemic changes in patients without definitive findings of a gangrenous colon. PMID:23879414

  11. [Prenatal discovery of Joubert syndrome associated with small bowel volvulus].

    PubMed

    Aurégan, C; Donciu, V; Millischer, A-E; Khen-Dunlop, N; Deloison, B; Sonigo, P; Magny, J-F

    2016-03-01

    Joubert syndrome and prenatal volvulus are difficult to diagnose during pregnancy. Joubert syndrome and related diseases should be considered in case of prenatal abnormal features of the fourth ventricle. Small bowel volvulus is also a surgical emergency because of the risk of intestinal necrosis before or after delivery. This type of condition justifies the transfer of pregnant women to a specialized hospital where the newborn may receive appropriate care. We report the case of a 31-week and 4-day gestational-age fetus in whom intrauterine growth retardation and small-bowel volvulus were diagnosed. Additional imaging revealed associated Joubert syndrome. This highlights the need for regular ultrasound monitoring during pregnancy and the comanagement of obstetricians and pediatricians to provide appropriate care before and after delivery. PMID:26850151

  12. Colonoscopy in the emergency treatment of colonic volvulus in Nigeria.

    PubMed

    Arigbabu, A O; Badejo, O A; Akinola, D O

    1985-11-01

    The commonest cause of large-bowel obstruction in Nigeria is sigmoid volvulus. Patients usually present late, dehydrated, and in very poor condition. The mortality of emergency colonic surgery is undoubtedly high, more so in developing countries poorly equipped to cope with such a condition. To reduce the mortality rate and improve management of the patients, a four-year prospective study of detorsion followed by elective surgery after adequate resuscitation and bowel preparation was carried out between January 1979 and December 1982. Volvulus is classified into three groups: torsion, obstruction, and strangulation. Criteria for short colonoscopic detorsion of torsion and obstruction types are discussed, and the contraindication in the case of strangulation type mentioned. This article describes the management of 92 cases of sigmoid volvulus between 1979 and 1982. PMID:4053889

  13. Absolute constipation caused by sigmoid volvulus in a young man

    PubMed Central

    Nuevo, Sergio Pozo; Macías Robles, María Dolores; Sevillano, Ramón Delgado; Pérez-Gallarza, Susana Serrano

    2013-01-01

    We describe a challenging case of sigmoid volvulus where a previously unrecognised anatomical condition, rather than the patient's age, was the main predisposing factor. A man in his thirties presented to the emergency department with a 3-day history of constipation and acute abdominal pain. Initial assessment and studies were inconclusive, but a CT scan revealed torsion of the large bowelSigmoid volvulus is a frequent cause of bowel obstruction that can be missed if appropriate imaging is not available. Clinical presentation and blood analysis can be similar to the findings in acute abdomen caused by other more common causes. PMID:23744852

  14. A Spiral Tack as a Lead Point for Volvulus

    PubMed Central

    Rogers, Ann

    2006-01-01

    Background and Objectives: We present a case of small bowel volvulus around an endotack applied during total extraperitoneal laparoscopic hernia repair (TEP). This complication prompts reconsideration of the role of tacks during extraperitoneal laparoscopic hernia repairs. Methods: We undertook a chart review and provide a case presentation with review of the literature. Result: A 66-year-old male with bilateral inguinal hernias underwent elective, bilateral, total extraperitoneal laparoscopic hernia repair. During dissection, a small peritoneal tear occurred. The tear was closed with a spiral tack. On postoperative day 22, the patient developed an acute abdomen. Exploratory laparotomy revealed a volvulus rotated around an adhesion to the spiral tack. Discussion: Volvulus can cause vascular compromise leading to bowel ischemia and necrosis. A tack resulting in adhesion and volvulus is an unusual, but serious, complication. Repair of a peritoneal tear during preperitoneal hernia repair is advocated to improve visualization obstructed by a pneumoperitonuem and decrease adhesions to the abdominal wall. Conclusion: The use of blunt Endoloops or crimps may prove safer than tacks for repairing the peritoneum and placement in proximity to delicate or thin tissues. Additionally, careful placement of foreign bodies to ensure their stability and to minimize protrusion may decrease the risk of erosion of the hardware. PMID:16882430

  15. Sigmoid volvulus in pregnancy: case report and review of literature.

    PubMed

    Serafeimidis, Costas; Waqainabete, Ifereimi; Creaton, Anne; Vakamacawai, Esala; Kumar, Ronal

    2016-08-01

    Sigmoid volvulus in pregnancy is a very rare condition. Despite this, clinicians should have a high index of suspicion of this condition if they encounter a pregnant woman with symptoms suggestive of bowel obstruction. Incorrect diagnosis may be catastrophic, resulting in major complications, including fetal and maternal death. PMID:27525078

  16. Magnetic Resonance Imaging Diagnosis of Volvulus through Mesenteric Defect in Neonate

    PubMed Central

    Leopold, Scott; Al-Qaraghouli, Mohammed; Hussain, Naveed; Finck, Christine

    2016-01-01

    Antenatal midgut volvulus is a rare surgical emergency in which bowel is severely compromised. Rarely the etiology is a mesenteric defect. Early diagnosis is essential and lifesaving in the immediate newborn period. Typically upper gastrointestinal or ultrasound imaging can be suggestive of the diagnosis of volvulus in the neonate. Sometimes, however, the diagnosis may be elusive. Herein, we report on the use of neonatal magnetic resonance imaging to diagnose a midgut volvulus that occurred through a congenital mesenteric defect. PMID:27551577

  17. Gastric Dilatation and Volvulus in a Red Panda (Ailurus fulgens)

    PubMed Central

    Neilsen, Colleen; Mans, Christoph; Colopy, Sara A.

    2014-01-01

    A 12-year-old male red panda (Ailurus fulgens) was evaluated for acute onset inappetance, staggering, collapse, and tachypnea. Gastric dilatation and volvulus (GDV) was diagnosed by radiography, abdominal ultrasonography, and exploratory celiotomy. Torsion of the stomach was corrected and an incisional gastropexy performed to prevent recurrence. No organs were devitalized, no other abnormalities detected, and the red panda recovered fully within 72 hours. PMID:24467661

  18. [Dolichomegacolon of the Andes and intestinal volvulus due to altitude].

    PubMed

    Frisancho, Oscar

    2008-01-01

    Sigmoid volvulus is a frequent cause of emergencies in hospitals in the Andean area, representing more than 50% of all intestinal obstructions. Andean dolichomegacolon (DCMA) and retractile mesocolonitis are the main contributing factors for volvulus. The mesocolonitis nears the proximal and distal segment of the sigmoid handle, favoring its torsion. Copious intake of fermentable food is the precipitating factor for volvulus. The majority of patients are seen during sowing and harvest periods, in which the consumption of this type of food increases. Andean people who live at an altitude of 3,000 m have a larger and thicker colon than coastal residents. We call this acquired characteristic the Andean dolichomegacolon (DCMA). A fiber-rich diet may inhibit the histological phenomenon known as elastogenesis, developing--over the years--the megacolon. Another important factor may be the lower atmospheric pressure in the altitude, and according to Boyle and Mariotte's physical law, the expansion of intraluminal gas may have an influence on intestinal enlargement. DCMA has many special anatomic, clinical, radiological, histological and serological features which make it different from the . chagasic megacolon. Mild emergency procedures may be performed to treat the sigmoid volvulus, such as endoscopic disvolvulation. Changing the colon rotation is helpful in diminishing abdominal pressure and restore complete blood circulation. An emergency surgery treatment must take the patient's general condition and the colon handle condition during surgery as a guiding point. High rates of mortality are found in relation to elderly patients, disease evolution time and stage of intestinal ischemia. Other new therapeutic procedures such as percutaneous sigmoidpexy, laparoscopic sigmoidectomy and mesosigmoplasty are under review, and have precise indications. Wider series are needed to evaluate them better. PMID:18958141

  19. Redescription of Onchocerca lupi (Spirurida: Onchocercidae) with histopathological observations

    PubMed Central

    2013-01-01

    Background Onchocerca lupi is a dog parasite of increasing zoonotic concern, with new human cases diagnosed in Turkey, Tunisia, Iran, and the United States. Information about the morphology of this nematode is scant and a detailed re-description of this species is overdue. In addition, histopathological data of potential usefulness for the identification of O. lupi infections are provided. Methods Male and female nematodes, collected from the connective tissue of a dog, were examined using light microscopy and scanning electron microscopy (SEM), and an histological evaluation was performed on biopsy samples from periocular tissues. Results The morphological identification was confirmed by molecular amplification and partial sequencing of cytochrome oxidase subunit 1 gene. This study provides the first comprehensive morphological and morphometric description of O. lupi from a dog based on light microscopy, SEM, molecular characterization, and histological observations. Conclusions Data herein presented contribute to a better understanding of this little known parasitic zoonosis, whose impact on human and animal health is still underestimated. The presence of granulomatous reactions only around the female adult suggests that the release of microfilariae from the uterus might be the cause of the inflammatory reaction observed. PMID:24499611

  20. Inherited and predisposing factors in the development of gastric dilatation volvulus in dogs.

    PubMed

    Bell, Jerold S

    2014-09-01

    This review article summarizes what is known as well as what is undetermined concerning the inherited and environmental pathogenesis of gastric dilatation volvulus in dogs. The disorder primarily affects large and giant, deep-chested breeds. A concise description of a typical dog affected with gastric dilatation volvulus is presented. PMID:25496921

  1. Volvulus of Sigmoid Colon During Full Term Pregnancy with Rectovaginal Fistula: A Case Report

    PubMed Central

    Gautam, Shefali; Prakash, Ravi; Sidhartha, Kanishka; Shashikant

    2014-01-01

    Intestinal obstruction due to sigmoid colon volvulus during pregnancy is a rare complication but associated with significant fetomaternal mortality. We describe a case of sigmoid volvulus in a patient with 37 wk pregnancy causing huge dilation of left colon. Patient developed rectovaginal fistula following nonmedical method to relieve distention by inserting stick as told by patient. PMID:25478399

  2. A Case of Fetal Intestinal Volvulus Without Malrotation Causing Severe Anemia

    PubMed Central

    Nakagawa, Tomoko; Tachibana, Daisuke; Kitada, Kohei; Kurihara, Yasushi; Terada, Hiroyuki; Koyama, Masayasu; Sakae, Yukari; Morotomi, Yoshiki; Nomura, Shiho; Saito, Mika

    2015-01-01

    Fetal intestinal volvulus without malrotation is a rare, life-threatening disease. Left untreated, hemorrhage from necrotic bowel tissue will lead to severe fetal anemia and even intrauterine death. We encountered a case of fetal intestinal volvulus causing severe anemia, which was diagnosed postnatally and successfully treated with surgical intervention. PMID:25628516

  3. Volvulus of the jejunum on cystic lymphangioma: About a clinical case

    PubMed Central

    Coulibaly, Yacaria; Keita, Soumaila; Doumbia, Aliou; Togo, Adegne

    2016-01-01

    Intestinal volvulus on mesenteric cysticum lymphangioma (CL) is rare in children. The clinical picture is not very suggestive. We report a case of intestinal volvulus on CL in a 7-year-old girl after an abdominal trauma. Resection and anastomosis were made. The confirmation diagnosis was done by anatomopathological examination. Early diagnosis of intra-abdominal CL will allow avoiding complication. PMID:27251660

  4. Volvulus of the ascending colon: an unusual complication of non-rotation of the midgut.

    PubMed

    Berger, R B; Hillemeier, A C; Stahl, R S; Markowitz, R I

    1982-01-01

    A case of non-rotation of the bowel is presented wherein volvulus of the colon occurred causing acute obstruction. Spontaneous reduction following a barium enema as well as the patient's history leads us to suspect that volvulus had occurred in the past and was responsible for the intermittent nature of the patient's symptoms. This type of volvulus is distinctly different from midgut volvulus and is a rare complication of the anomaly of intestinal rotation and fixation known as non-rotation of the bowel. Efforts should be made to study patients with malrotation anomalies at a time when they are acutely symptomatic so that intermittent volvulus such as shown here is not overlooked. PMID:7162881

  5. Chronic Gastric Volvulus with Laparoscopic Gastropexy after Endoscopic Reduction: A Case Report

    PubMed Central

    Lee, Hye Yeon; Park, Jung Hyun

    2015-01-01

    Gastric volvulus is an uncommon clinical entity. There are three types of gastric volvulus; organoaxial, mesenteroaxial and combined type. This condition can lead to a closed-loop obstruction or strangulation. Traditional surgical therapy for gastric volvulus is based on an open approach. Here we report a successful case of a patient with chronic gastric volvulus with a laparoscopic treatment. A 79-year-old woman came to the emergency department with epigastric pain accompanied by nausea for 2 weeks. Abdominal computed tomography revealed markedly distended stomach with transposition of gastroesophageal Junction and gastric antrum. Barium meal study revealed presence of the antrum was folded over 180 degrees that was located above gastroesophageal junction. We attempted an endoscopic reduction, but it was unsuccessful. The patient got laparoscopic anterior gastropexy. Based on our result, laparoscopic gastropexy can be considered as a good choice of the treatment for gastric volvulus. PMID:26161290

  6. Aberrant laryngeal location of Onchocerca lupi in a dog.

    PubMed

    Alho, Ana Margarida; Cruz, Luís; Coelho, Ana; Martinho, Filipe; Mansinho, Mário; Annoscia, Giada; Lia, Riccardo P; Giannelli, Alessio; Otranto, Domenico; de Carvalho, Luís Madeira

    2016-06-01

    Onchocerca lupi (Spirurida, Onchocercidae) is an emerging vector-borne helminth that causes nodular lesions associated with acute or chronic ocular disease in dogs and cats. Since its first description in dogs in 1991, this zoonotic filarioid has been increasingly reported in Europe and the United States. An 8-year-old outdoor mixed-breed female dog from the Algarve (southern Portugal) was presented with a history of severe dyspnoea. Cervical and thoracic radiographs revealed a slight reduction in the diameter of the cervical trachea and a moderate increase in radiopacity of the laryngeal soft tissue. An exploratory laryngoscopy was performed, revealing filiform worms associated with stenosis of the thyroid cartilage and a purulent necrotic tissue in the larynx lumen. A single sessile nodule, protruding from the dorsal wall of the laryngeal lumen caused a severe reduction of the glottis and tracheal diameter. Fragments of the worms were morphologically and molecularly identified as O. lupi. Histological examination of the nodule showed a granulomatous reaction with sections of coiled gravid female nematodes. Following laryngoscopy, a tracheostomy tube was inserted to relieve dyspnoea and ivermectin (300 μg/kg, once a week, for 8 weeks) combined with prednisolone was prescribed. The dog showed a complete recovery. Although O. lupi has been isolated in human patients from the spinal cord, this is the first report of an aberrant migration of O. lupi in a dog. The veterinary medical community should pay attention to aberrant location of O. lupi and consider onchocercosis as a differential diagnosis for airway obstruction in dogs. PMID:26732654

  7. Factors Associated with Ivermectin Non-Compliance and Its Potential Role in Sustaining Onchocerca volvulus Transmission in the West Region of Cameroon

    PubMed Central

    Senyonjo, Laura; Oye, Joseph; Bakajika, Didier; Biholong, Benjamin; Tekle, Afework; Boakye, Daniel; Schmidt, Elena; Elhassan, Elizabeth

    2016-01-01

    Background Community Directed Treatment with ivermectin is the cornerstone of current efforts to eliminate onchocerciasis. However recent studies suggest there are foci where long-term annual distribution of the drug alone has failed to ensure elimination thresholds are reached. It is important to achieve high levels of compliance in order to obtain elimination targets. An epidemiological and entomological evaluation conducted in the western region of Cameroon in 2011 revealed that two health districts remained with a high prevalence of infection, despite long-term distribution of ivermectin since 1996. This paper explores potential factors that may have contributed to the non-interruption of transmission, focusing on ivermectin treatment compliance and the importance of systematic non-compliance within the population. Methodology/Principal findings A mixed methods approach was used, including a population-based survey to assess treatment compliance and factors associated and qualitative assessments including focus group discussions and in-depth interviews with key programme stakeholders and drug distributors. Compliance was reported at 71.2% (95%CI: 61.7–79.2%;n = 853/1198). The key factors related to compliance in the most recent round related to either programmatic and delivery issues, primarily absenteeism at the time of the campaign or alternatively individual determinants. An individual’s experience of side effects in the past was strongly associated with non-compliance to ivermectin. Other factors included ethnicity, how long lived in the village and age. There was a high percentage of reported systematic non-compliance at 7.4% (95% CI: 4.3–12.3%; n = 86/1165), higher amongst females. This group may be important in facilitating the sustainment of on-going transmission. Conclusions/Significance Efforts to reduce the number of systematic non-compliers and non-compliance in certain groups may be important in ensuring the interruption of transmission in the study area. However, in areas with high pre-control force of transmission, as in these districts, annual distribution with ivermectin, even if sustaining high levels of compliance, may still be inadequate to achieve elimination. Further studies are required to better understand the transmission dynamics and focus of on-going transmission in the study districts. PMID:27529622

  8. Analysis of the mdr-1 gene in patients co-infected with Onchocerca volvulus and Loa loa who experienced a post-ivermectin serious adverse event.

    PubMed

    Bourguinat, Catherine; Kamgno, Joseph; Boussinesq, Michel; Mackenzie, Charles D; Prichard, Roger K; Geary, Timothy G

    2010-07-01

    Ivermectin (IVM) is exceptionally safe in humans, and is used for mass treatment of onchocerciasis and lymphatic filariasis. However, cases of encephalopathy, sometimes fatal, have been reported in a small number of individuals who harbored large numbers of Loa loa microfilariae (mf). A loss-of-function mutation in the mdr-1 gene in some dog breeds and in mice leads to accumulation of the drug in the brain, causing coma and death. This hypothesis was tested in four individuals from Cameroon who experienced a post-IVM serious adverse event (SAE) and in nine non-SAE matched controls. No loss-of-function mutation was detected in mdr-1 in any subject. However, haplotypes, associated with altered drug disposition, were present as homozygotes in two of the SAE patients (50%), but absent as homozygotes in the controls (0%). An association of high Loa mf load and a genetic predisposition to altered IVM distribution could be involved in IVM SAEs. PMID:20595473

  9. Transmission of Onchocerca volvulus continues in Nyagak-Bondo focus of northwestern Uganda after 18 years of a single dose of annual treatment with ivermectin.

    PubMed

    Katabarwa, Moses N; Lakwo, Tom; Habomugisha, Peace; Agunyo, Stella; Byamukama, Edson; Oguttu, David; Tukesiga, Ephraim; Unoba, Dickson; Dramuke, Patrick; Onapa, Ambrose; Tukahebwa, Edridah M; Lwamafa, Dennis; Walsh, Frank; Unnasch, Thomas R

    2013-08-01

    The objective of the study was to determine whether annual ivermectin treatment in the Nyagak-Bondo onchocerciasis focus could safely be withdrawn. Baseline skin snip microfilariae (mf) and nodule prevalence data from six communities were compared with data collected in the 2011 follow-up in seven communities. Follow-up mf data in 607 adults and 145 children were compared with baseline (300 adults and 58 children). Flies collected in 2011 were dissected, and poolscreen analysis was applied to ascertain transmission. Nodule prevalence in adults dropped from 81.7% to 11.0% (P < 0.0001), and mf prevalence dropped from 97.0% to 23.2% (P < 0.0001). In children, mf prevalence decreased from 79.3% to 14.1% (P < 0.0001). Parous and infection rates of 401 flies that were dissected were 52.9% and 1.5%, respectively, whereas the infective rate on flies examination by polymerase chain reaction (PCR) was 1.92% and annual transmission potential was 26.9. Stopping ivermectin treatment may result in onchocerciasis recrudescence. PMID:23690555

  10. Studies on nodules and adult Onchocerca volvulus during a nodulectomy trial in hyperendemic villages in Liberia and Upper Volta. I. Palpable and impalpable onchocercomata.

    PubMed

    Albiez, E J

    1983-03-01

    In hyperendemic onchocerciasis areas of West Africa nodulectomy trials were performed. 163 nodule carriers from four villages in the Liberian rain-forest and 52 nodule carriers from a savanna village in Upper Volta were operated on. During the surveys in the villages in Liberia and Upper Volta, an average of three and five nodules respectively per patient were palpated. Before each operation a further palpation was done and two more nodules per patient from both countries were found. The nodulectomies revealed 75% more nodules in the Liberian patients and 53% more in the patients from Upper Volta than were palpated immediately before. Half of these additional subcutaneous nodules extirpated in Liberians were superficially located, the other half deeper and impalpable through the skin. In the patients from Upper Volta two thirds of the additional nodules were seated in the depth of the subcutis. In both countries an average of three deep subcutaneous nodules per patient were found and this was equivalent to 20% of all extirpated onchocercomata. Most of these deep subcutaneous nodules were at those sites where most of the superficial nodules were located. PMID:6682581

  11. Onchocerca lupi Nematodes in Dogs Exported from the United States into Canada

    PubMed Central

    Conboy, Gary; Lejeune, Manigandan; Marron, Fany; Hanna, Paul; MacDonald, Erin; Skorobohach, Brian; Wilcock, Brian; Kutz, Susan J.; Gilleard, John S.

    2016-01-01

    The Onchocerca lupi nematode is an emerging helminth capable of infecting pets and humans. We detected this parasite in 2 dogs that were imported into Canada from the southwestern United States, a region to which this nematode is endemic. We discuss risk for establishment of O. lupi in Canada. PMID:27434170

  12. Onchocerca lupi Nematodes in Dogs Exported from the United States into Canada.

    PubMed

    Verocai, Guilherme G; Conboy, Gary; Lejeune, Manigandan; Marron, Fany; Hanna, Paul; MacDonald, Erin; Skorobohach, Brian; Wilcock, Brian; Kutz, Susan J; Gilleard, John S

    2016-08-01

    The Onchocerca lupi nematode is an emerging helminth capable of infecting pets and humans. We detected this parasite in 2 dogs that were imported into Canada from the southwestern United States, a region to which this nematode is endemic. We discuss risk for establishment of O. lupi in Canada. PMID:27434170

  13. Spontaneous Acute Mesenteroaxial Gastric Volvulus Diagnosed by Computed Tomography Scan in a Young Man

    PubMed Central

    Jabbour, Gaby; Afifi, Ibrahim; Ellabib, Mohamed; El-Menyar, Ayman; Al-Thani, Hassan

    2016-01-01

    Patient: Male, 23 Final Diagnosis: Acute spontaneous gastric volvulus Symptoms: — Medication: — Clinical Procedure: Laparotomy Specialty: Gastroenterology and Hepatology Objective: Rare disease Background: Acute gastric volvulus is a surgical emergency that requires early recognition and treatment. Acute idiopathic mesenteroaxial gastric volvulus is a rare sub-type and there are few cases reported in children and there are even fewer reports in adults. Case Report: We report a rare case of a 23-year-old man who presented with a 1-day history of vomiting, epigastric pain, distention, and constipation. The diagnosis for mesenteroaxial type gastric volvulus was confirmed by abdominal radiography and computed tomography. The patient was successfully treated by laparotomy with resection of the ischemic stomach wall and anastomosis. Acute spontaneous mesenteroaxial gastric volvulus is rare in adults and early diagnosis is challenging due to non-specific symptoms. A missed or delayed diagnosis may result in serious complications due to gastric obstruction. Conclusions: A patient presenting with severe epigastric pain and clinical evidence of gastric outlet obstruction should be considered as a surgical emergency to rule out gastric volvulus. High index of suspicion, early diagnosis and prompt surgical management are important for favorable outcome in patients with acute spontaneous gastric volvulus. PMID:27112797

  14. Fetal primary small bowel volvulus in a child without intestinal malrotation.

    PubMed

    Chung, Jae Hee; Lim, Gye-Yeon; We, Ji Sun

    2013-07-01

    Fetal primary small bowel volvulus without atresia or malrotation is an extremely rare but life-threatening surgical emergency. We report a case of primary small bowel volvulus that presented as sudden fetal distress and was diagnosed on the basis of the 'whirl-pool sign' of fetal sonography. This diagnosis led to emergency operation after birth at the third trimester with a good outcome. Although the pathogenesis of fetal primary small bowel volvulus is unclear, ganglion cell immaturity may play a role in the etiology. PMID:23895987

  15. A Fatal Twist: Volvulus of the Small Intestine in a 46-Year-Old Woman

    PubMed Central

    Klein, Jared; Baxstrom, Kathryn; Donnelly, Stephen; Feasel, Patrick; Koles, Paul

    2015-01-01

    A 46-year-old woman presented to two emergency departments within 12 hours because of acute abdominal pain. Physical exam demonstrated tenderness and epigastric guarding. An ultrasound was interpreted as negative; she was discharged home. Later that evening, she was found dead. Postmortem exam revealed acute hemorrhagic necrosis of a segment of jejunum secondary to volvulus. Clinical clues suggesting presentations of small bowel volvulus are usually nonspecific; the diagnosis is typically confirmed at surgery. Her unremitting abdominal pain, persistent vomiting, and absolute neutrophilia were consistent with an acute process. The etiology of this volvulus was caused by an elastic fibrous band at the root of the jejunal mesentery. While congenital fibrous bands are rare in adults, this interpretation is favored for two reasons. First, the band was located 20 cm superior to postsurgical adhesions in the lower abdomen and pelvis. Second, there was no history of trauma or previous surgery involving the site of volvulus. PMID:26612989

  16. Acute gastric volvulus and congenital diaphragmatic hernia, case report and review.

    PubMed

    Pérez-Egido, Laura; Parente, Alberto; Cerdá, Julio Arturo

    2015-01-01

    Congenital diaphragmatic hernia (CDH) is the result of the incomplete fusion and closure of the pleuroperitoneal canal during the fetal development. CDH is usually diagnosed prenatally but, if undiagnosed, the clinical presentation ranges from asymptomatic children to serious respiratory or gastrointestinal symptoms. Acute gastric volvulus associated with CDH is a rare surgical emergency in children. We report two cases of acute gastric volvulus associated with CDH and review the literature. PMID:26612128

  17. Spontaneous Acute Mesenteroaxial Gastric Volvulus Diagnosed by Computed Tomography Scan in a Young Man.

    PubMed

    Jabbour, Gaby; Afifi, Ibrahim; Ellabib, Mohamed; El-Menyar, Ayman; Al-Thani, Hassan

    2016-01-01

    BACKGROUND Acute gastric volvulus is a surgical emergency that requires early recognition and treatment. Acute idiopathic mesenteroaxial gastric volvulus is a rare sub-type and there are few cases reported in children and there are even fewer reports in adults. CASE REPORT We report a rare case of a 23-year-old man who presented with a 1-day history of vomiting, epigastric pain, distention, and constipation. The diagnosis for mesenteroaxial type gastric volvulus was confirmed by abdominal radiography and computed tomography. The patient was successfully treated by laparotomy with resection of the ischemic stomach wall and anastomosis. Acute spontaneous mesenteroaxial gastric volvulus is rare in adults and early diagnosis is challenging due to non-specific symptoms. A missed or delayed diagnosis may result in serious complications due to gastric obstruction. CONCLUSIONS A patient presenting with severe epigastric pain and clinical evidence of gastric outlet obstruction should be considered as a surgical emergency to rule out gastric volvulus. High index of suspicion, early diagnosis and prompt surgical management are important for favorable outcome in patients with acute spontaneous gastric volvulus. PMID:27112797

  18. Gastric Dilitation-Volvulus in a Red Panda (Ailurus fulgens)

    PubMed Central

    SCHLANSER, Justin R.; AGNEW, Dalen; PAPERD, Deborah W.; HARRISON, Tara M.

    2014-01-01

    ABSTRACT A 10-year-old male red panda presented acutely with symptoms of shock due to acute abdominal distress and respiratory compromise. Abdominal ultrasound confirmed a severely distended stomach for which passage of an orogastric tube for relief was unsuccessful. Intra-operatively, the stomach was found to be distended and torsed around its long axis supporting the diagnosis of Gastric dilitation-volvulus (GDV). The animal arrested and died intra-operatively and was submitted for necropsy with lesions supportive of the diagnosis of GDV. No risk factors for GDV were found to correlate between the panda and those described in domestic dogs. This case suggests that red pandas can be susceptible to this condition in captive settings. PMID:24521795

  19. Single-port laparoscopic surgery for sigmoid volvulus

    PubMed Central

    Choi, Byung Jo; Jeong, Won Jun; Kim, Say-June; Lee, Sang Chul

    2015-01-01

    AIM: To report our experience with single-port laparoscopic surgery (SPLS) for sigmoid volvulus (SV). METHODS: Between October 2009 and April 2013, 10 patients underwent SPLS for SV. SPLS was performed transumbilically or through a predetermined stoma site. Conventional straight and rigid-type laparoscopic instruments were used. After intracorporeal, segmental resection of the affected sigmoid colon, the specimen was extracted through the single-incision site. Patient demographics and perioperative data were analyzed. RESULTS: SPLS for SV was successful in all 10 patients (4, resection and primary anastomosis; 6, Hartmann’s procedure). The median operative time and postoperative hospitalization period were 168 (range, 85-315) min and 6.5 (range, 4-29) d, respectively. No intraoperative complications were noted; there were 2 postoperative complications, including 1 anastomotic leak. CONCLUSION: SPLS was a safe and feasible therapeutic approach for SV, when performed by a surgeon experienced in conventional laparoscopic surgery. PMID:25741145

  20. Zoonotic filariasis caused by Onchocerca dewittei japonica in a resident of Hiroshima Prefecture, Honshu, Japan.

    PubMed

    Uni, Shigehiko; Boda, Tomoyuki; Daisaku, Koichi; Ikura, Yoshihiro; Maruyama, Haruhiko; Hasegawa, Hideo; Fukuda, Masako; Takaoka, Hiroyuki; Bain, Odile

    2010-09-01

    A female of Onchocerca sp. was found to be the probable causative agent of a subcutaneous nodule in the left knee of a 70-year-old man in a rural area of Hiroshima Prefecture, Honshu, the main island of Japan. We compared the characteristics of the agent with the features of the four previously suspected species found in cattle and horses in various parts of the world, as well as O. lupi and O. jakutensis that were suspected or proved, respectively, in zoonotic cases in Europe. In addition, the morphologic characteristics of this parasite were compared with those of the four Onchocerca species found in wild animals in Japan. Based on such characteristics as the large triangle ridges, the considerable distance between any two adjacent ridges, and the absence of inner cuticular striae in the longitudinal sections, we found the causative agent in the present case to be identical to the female of Onchocerca dewittei japonica. All five previous cases of zoonotic onchocerciasis in Japan had been found in Oita, Kyushu, the main southern island. This human case caused by O. dewittei japonica suggests that zoonotic onchocerciasis is liable to occur in rural areas in Japan where wild boar, Simulium vectors, and humans overlap. PMID:20561913

  1. A case of cecal volvulus mimicking Ogilvie Syndrome in a hospitalized patient with a pelvis fracture

    PubMed Central

    Tampakis, Athanasios; Droeser, Raoul A.; Tampaki, Ekaterini Christina; von Holzen, Urs; Delko, Tarik

    2016-01-01

    Introduction Cecal volvulus and ogilvie syndrome are two entities which may display similar clinical presentation but require different treatment approaches. Presentation of case An 84-year old male patient admitted for conservative treatment of a pelvis fracture, complained of abdominal cramps and flatulence on the third hospitalization day. Abdominal radiographs arose suspicion of cecal volvulus. The diagnosis was ruled out on the CT scan but however was later confirmed by an exploratory laparotomy. Discussion The management of cecal volvulus requires prompt (emergency) surgical intervention while Ogilvie syndrome can be principally managed with conservative treatment. Our patient's profile was typical for both entities. The absence of air throughout all colonic segments including the rectosigmoid on plain abdominal radiographs seems to be the most important sign in the exclusion of the Ogilvie syndrome diagnosis. Conclusion Cecal volvulus and Ogilvie syndrome display overlapping clinical features at their time of presentation and need to be carefully distinguished. By uncertainty, an exploratory laparotomy should always be performed, in view of the reported high mortality rate of cecal volvulus if surgery is delayed. PMID:27054035

  2. An unexpected cause of small bowel obstruction in an adult patient: midgut volvulus.

    PubMed

    Söker, Gökhan; Yılmaz, Cengiz; Karateke, Faruk; Gülek, Bozkurt

    2014-01-01

    The most important complication of intestinal malrotation is midgut volvulus because it may lead to intestinal ischaemia and necrosis. A 29-year-old male patient was admitted to the emergency department with abdominal pain. Ultrasonography (US), colour Doppler ultrasonography (CDUS), CT and barium studies were carried out. On US and CDUS, twisting of intestinal segments around the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) and alteration of the SMA-SMV relationship were detected. CT demonstrated that the small intestine was making a rotation around the SMA and SMV, which amounted to more than 360°. The upper gastrointestinal barium series revealed a corkscrew appearance of the duodenum and proximal jejunum, which is a pathognomonic finding of midgut volvulus. Prior knowledge of characteristic imaging findings of midgut volvulus is essential in order to reach proper diagnosis and establish proper treatment before the development of intestinal ischaemia and necrosis. PMID:24811563

  3. A Rare Case of Splenic Torsion with Sigmoid Volvulus in a 14-Year-Old Girl.

    PubMed

    Ahmadi, Hamid; Tehrani, Mahdieh Mohammad Khan

    2016-01-01

    Wandering spleen is an uncommon entity in adults and has been described only rarely with sigmoid volvulus, that rarely affects children and adolescents. It is usually described in adults.Wandering spleen characterized by the abnormal location of the spleen, caused by incomplete fusion of the four primary splenic ligaments, allowing the spleen to be mobile within the abdomen.The wandering spleen can lead to torsion and subsequent splenic infarction or rupture. Clinical suspicion plus urgent investigation and intervention are important. We present a rare clinical case of acute abdomen due to torsion of wandering spleen and volvulus of sigmoid in a 14-year-old girl presented with painful periumbilical mass. Detorsion of sigmoid occurred while undergoing exploratory laparotomy and splenectomy was performed. The possibility of torsion and its complication like gastric, pancreas tail and colon volvulus should be kept in mind in the differential diagnosis of the acute abdomen to avoid serious complications. PMID:26853294

  4. Diagnosis of a sigmoid volvulus in pregnancy: ultrasonography and magnetic resonance imaging findings.

    PubMed

    Palmucci, Stefano; Lanza, Maria Letizia; Gulino, Fabrizio; Scilletta, Beniamino; Ettorre, Giovanni Carlo

    2014-02-01

    Sigmoid volvulus complicating pregnancy is a rare, non-obstetric cause of abdominal pain that requires prompt surgical intervention (decompression) to avoid intestinal ischemia and perforation. We report the case of a 31-week pregnant woman with abdominal pain and subsequent development of constipation. Preoperative diagnosis was achieved using magnetic resonance imaging and ultrasonography: the large bowel distension and a typical whirl sign - near a sigmoid colon transition point - suggested the diagnosis of sigmoid volvulus. The decision to refer the patient for emergency laparotomy was adopted without any ionizing radiation exposure, and the pre-operative diagnosis was confirmed after surgery. Imaging features of sigmoid volvulus and differential diagnosis from other non-obstetric abdominal emergencies in pregnancy are discussed in our report, with special emphasis on the diagnostic capabilities of ultrasonography and magnetic resonance imaging. PMID:24967020

  5. Primary intrathoracic gastric volvulus in the neonatal period: a differential diagnosis of esophageal atresia

    PubMed Central

    El Azzouzi, Driss

    2014-01-01

    Intrathoracic gastric volvulus in the neonatal period is a rare surgical emergency. Delays in diagnosis and treatment are life-threatening due to progressive deterioration of the gastric walls. Presentation in this period can be confused with the possibility of esophageal atresia or esophageal web. The upper gastrointestinal tract contrast study is diagnostic in this disease. The authors report a case of acute intrathoracic gastric volvulus diagnosis by radiologic-contrast-study in 1-day-old girl that was confirmed at surgery. The physiopathology, classification and different presentations of this entity are briefly reviewed. PMID:25309661

  6. Acute gastric volvulus: a deadly but commonly forgotten complication of hiatal hernia

    PubMed Central

    Olivieri, Brandon; Vincentelli, Cristina

    2016-01-01

    Gastric volvulus is a rare condition resulting from rotation of the stomach beyond 180 degrees. It is a difficult condition to diagnose, mostly because it is rarely considered. Furthermore, the imaging findings are often subtle resulting in many cases being diagnosed at the time of surgery or, as in our case, at autopsy. We present the case of a 76-year-old man with an extensive medical history, including coronary artery disease with multiple bypass grafts, who became diaphoretic and nauseated while eating. His presumptive diagnosis at arrival to the hospital was an acute coronary event; however, his initial cardiac work-up was negative. A computed tomography scan revealed a type III hiatal hernia. The following day, after consistent complaints of nausea and episodes of nonbloody emesis, he suddenly became hypotensive, tachycardic and had an episode of coffee-ground emesis. Subsequently, the patient's condition suddenly deteriorated and resuscitation attempts were unsuccessful. The autopsy revealed a partially sliding hiatal hernia, which was consistent with the radiologic impression. Additionally, a gastric volvulus was present with extensive, focally transmural necrosis involving the body/fundus. Gastric volvulus is a rare entity with variable, nonspecific clinical presentations, which requires a high level of suspicion for radiologic diagnosis. Acute cases have a high mortality rate and require emergency surgery. This case highlights the value of autopsy in the diagnosis of unsuspected cases of gastric volvulus when death occurs prior to surgical intervention. PMID:27284537

  7. Volvulus of the ascending colon in a non-rotated midgut: Plain film and MDCT findings

    PubMed Central

    Camera, Luigi; Calabrese, Milena; Mainenti, Pier Paolo; Masone, Stefania; Vecchio, Walter Del; Persico, Giovanni; Salvatore, Marco

    2012-01-01

    Colonic volvulus is a relatively uncommon cause of large bowel obstruction usually involving mobile, intra-peritoneal, colonic segments. Congenital or acquired anatomic variation may be associated with an increased risk of colonic volvulus which can occasionally involve retro-peritoneal segments. We report a case of 54-year-old female who presented to our Institution to perform a plain abdominal film series for acute onset of cramping abdominal pain. Both the upright and supine films showed signs of acute colonic obstruction which was thought to be due to an internal hernia of the transverse colon into the lesser sac. The patient was therefore submitted to a multi-detector contrast-enhanced computed tomography (CT). CT findings were initially thought to be consistent with the presumed diagnosis of internal hernia but further evaluation and coronal reformatting clearly depicted the presence of a colonic volvulus possibly resulting from a retro-gastric colon. At surgery, a volvulus of the ascending colon was found and a right hemi-colectomy had to be performed. However, a non rotated midgut with a right-sided duodeno-jejunal flexure and a left sided colon was also found at laparotomy and overlooked in the pre-operative CT. Retrospective evaluation of CT images was therefore performed and a number of CT signs of intestinal malrotation could be identified. PMID:23150768

  8. Recurrent intestinal volvulus in midgut malrotation causing acute bowel obstruction: A case report

    PubMed Central

    Sheikh, Fayed; Balarajah, Vickna; Ayantunde, Abraham Abiodun

    2013-01-01

    Intestinal malrotation occurs when there is a disruption in the normal embryological development of the bowel. The majority of patients present with clinical features in childhood, though rarely a first presentation can take place in adulthood. Recurrent bowel obstruction in patients with previous abdominal operation for midgut malrotation is mostly due to adhesions but very few reported cases have been due to recurrent volvulus. We present the case of a 22-year-old gentleman who had laparotomy in childhood for small bowel volvulus and then presented with acute bowel obstruction. Preoperative computerised tomography scan showed small bowel obstruction and features in keeping with midgut malrotation. Emergency laparotomy findings confirmed midgut malrotation with absent appendix, abnormal location of caecum, ascending colon and small bowel. In addition, there were small bowel volvulus and a segment of terminal ileal stricture. Limited right hemicolectomy was performed with excellent postoperative recovery. This case is presented to illustrate a rare occurrence and raise an awareness of the possibility of dreadful recurrent volvulus even several years following an initial Ladd’s procedure for midgut malrotation. Therefore, one will need to exercise a high index of suspicion and this becomes very crucial in order to ensure prompt surgical intervention and thereby preventing an attendant bowel ischaemia with its associated high fatality. PMID:23556060

  9. Ultrasonographic findings in cows with right displacement of the abomasum and abomasal volvulus.

    PubMed

    Braun, U; Feller, B

    2008-03-01

    Seventeen cows with right displacement of the abomasum (rda) without abomasal volvulus, nine cows with abomasal volvulus and 10 clinically healthy cows were examined ultrasonographically. A 5.0 MHz transducer was used to scan the eighth to 12th intercostal spaces and the cranial and caudal aspects of the flank on the right side. The position, size and dorsal and ventral margins of the abomasum were determined at each imaging position. In both groups of diseased cows, the ventral abomasum contained fluid ingesta, which appeared hypoechogenic with diffuse echogenic stippling. The abomasal folds could be seen clearly as echogenic sickle-shaped structures within the ingesta. The dorsal abomasal gas cap varied in size and was characterised by reverberation artefacts, which appeared as echogenic lines running parallel to the body surface. Compared with the healthy cows, the abomasum was larger and located significantly closer to the midline of the dorsum in both groups of cows. Compared with the cows with rda, the abomasum in the cows with abomasal volvulus was significantly smaller in the eighth intercostal space and significantly larger in the 11th intercostal space. It was not possible to differentiate between rda and abomasal volvulus on the basis of the ultrasonographic findings. PMID:18326843

  10. The adjuvanticity of an O. volvulus-derived rOv-ASP-1 protein in mice using sequential vaccinations and in non-human primates.

    PubMed

    Wang, Jing; Tricoche, Nancy; Du, Lanying; Hunter, Meredith; Zhan, Bin; Goud, Gaddam; Didier, Elizabeth S; Liu, Jing; Lu, Lu; Marx, Preston A; Jiang, Shibo; Lustigman, Sara

    2012-01-01

    Adjuvants potentiate antigen-specific protective immune responses and can be key elements promoting vaccine effectiveness. We previously reported that the Onchocerca volvulus recombinant protein rOv-ASP-1 can induce activation and maturation of naïve human DCs and therefore could be used as an innate adjuvant to promote balanced Th1 and Th2 responses to bystander vaccine antigens in mice. With a few vaccine antigens, it also promoted a Th1-biased response based on pronounced induction of Th1-associated IgG2a and IgG2b antibody responses and the upregulated production of Th1 cytokines, including IL-2, IFN-γ, TNF-α and IL-6. However, because it is a protein, the rOv-ASP-1 adjuvant may also induce anti-self-antibodies. Therefore, it was important to verify that the host responses to self will not affect the adjuvanticity of rOv-ASP-1 when it is used in subsequent vaccinations with the same or different vaccine antigens. In this study, we have established rOv-ASP-1's adjuvanticity in mice during the course of two sequential vaccinations using two vaccine model systems: the receptor-binding domain (RBD) of SARS-CoV spike protein and a commercial influenza virus hemagglutinin (HA) vaccine comprised of three virus strains. Moreover, the adjuvanticity of rOv-ASP-1 was retained with an efficacy similar to that obtained when it was used for a first vaccination, even though a high level of anti-rOv-ASP-1 antibodies was present in the sera of mice before the administration of the second vaccine. To further demonstrate its utility as an adjuvant for human use, we also immunized non-human primates (NHPs) with RBD plus rOv-ASP-1 and showed that rOv-ASP-1 could induce high titres of functional and protective anti-RBD antibody responses in NHPs. Notably, the rOv-ASP-1 adjuvant did not induce high titer antibodies against self in NHPs. Thus, the present study provided a sound scientific foundation for future strategies in the development of this novel protein adjuvant. PMID

  11. Zoonotic ocular onchocercosis caused by Onchocerca lupi in dogs in Romania.

    PubMed

    Tudor, Poliana; Turcitu, Mihai; Mateescu, Cosmin; Dantas-Torres, Filipe; Tudor, Niculae; Bărbuceanu, Florica; Ciuca, Lavinia; Burcoveanu, Ioana; Acatrinei, Dumitru; Rinaldi, Laura; Mateescu, Romanița; Bădicu, Adina; Ionașcu, Iuliana; Otranto, Domenico

    2016-02-01

    Onchocerca lupi is a filarial nematode, which infects the scleral conjunctival tissue of dogs, wolves and cats. Whilst adult nematodes localize in the conjunctive tissue of sclera or in the retrobulbar, microfilariae are found in the skin, and they are rarely diagnosed in asymptomatic animals. Since the first report of human ocular infection 5 years ago, up to 10 zoonotic cases have been identified in patients worldwide. We report, for the first time in Romania, three cases of canine ocular onchocercosis in dogs. Fragments of the harvested worms were characterized morphologically and molecularly. This article expands knowledge on the distribution of this parasite in Eastern Europe and sounds an alarm bell for ophthalmologists about the possible occurrence of human cases of O. lupi infection. PMID:26561013

  12. Isolation of Onchocerca lupi in Dogs and Black Flies, California, USA

    PubMed Central

    Hassan, Hassan K.; Bolcen, Shanna; Kubofcik, Joseph; Nutman, Thomas B.; Eberhard, Mark L.; Middleton, Kelly; Wekesa, Joseph Wakoli; Ruedas, Gimena; Nelson, Kimberly J.; Dubielzig, Richard; De Lombaert, Melissa; Silverman, Bruce; Schorling, Jamie J.; Adler, Peter H.; Beeler, Emily S.

    2015-01-01

    In southern California, ocular infections caused by Onchocerca lupi were diagnosed in 3 dogs (1 in 2006, 2 in 2012). The infectious agent was confirmed through morphologic analysis of fixed parasites in tissues and by PCR and sequencing of amplicons derived from 2 mitochondrially encoded genes and 1 nuclear-encoded gene. A nested PCR based on the sequence of the cytochrome oxidase subunit 1 gene of the parasite was developed and used to screen Simulium black flies collected from southern California for O. lupi DNA. Six (2.8%; 95% CI 0.6%–5.0%) of 213 black flies contained O. lupi DNA. Partial mitochondrial16S rRNA gene sequences from the infected flies matched sequences derived from black fly larvae cytotaxonomically identified as Simulium tribulatum. These data implicate S. tribulatum flies as a putative vector for O. lupi in southern California. PMID:25897954

  13. Wandering spleen with gastric volvulus and intestinal non-rotation in an adult male patient.

    PubMed

    Ooka, Minako; Kohda, Eiichi; Iizuka, Yuo; Nagamoto, Masashi; Ishii, Tomotaka; Saida, Yoshihisa; Shimizu, Norikazu; Gomi, Tatsuya

    2013-01-01

    We report an extremely rare case of wandering spleen (WS) complicated with gastric volvulus and intestinal non-rotation in a male adult. A 22-year-old man who had been previously treated for Wilson disease was admitted with severe abdominal pain. Radiological findings showed WS in the midline of the pelvic area. The stomach was mesenteroaxially twisted and intestinal non-rotation was observed. Radiology results did not show any evidence of splenic or gastrointestinal (GI) infarction. Elective emergency laparoscopy confirmed WS and intestinal non-rotation; however, gastric volvulus was not observed. It was suspected that the stomach had untwisted when gastric and laparoscopic tubes were inserted. Surgery is strongly recommended for WS because of the high risk of serious complications; however, some asymptomatic adult patients are still treated conservatively, such as the patient in this study. The present case is reported with reference to the literature. PMID:24349711

  14. Wandering spleen with gastric volvulus and intestinal non-rotation in an adult male patient

    PubMed Central

    Kohda, Eiichi; Iizuka, Yuo; Nagamoto, Masashi; Ishii, Tomotaka; Saida, Yoshihisa; Shimizu, Norikazu; Gomi, Tatsuya

    2013-01-01

    We report an extremely rare case of wandering spleen (WS) complicated with gastric volvulus and intestinal non-rotation in a male adult. A 22-year-old man who had been previously treated for Wilson disease was admitted with severe abdominal pain. Radiological findings showed WS in the midline of the pelvic area. The stomach was mesenteroaxially twisted and intestinal non-rotation was observed. Radiology results did not show any evidence of splenic or gastrointestinal (GI) infarction. Elective emergency laparoscopy confirmed WS and intestinal non-rotation; however, gastric volvulus was not observed. It was suspected that the stomach had untwisted when gastric and laparoscopic tubes were inserted. Surgery is strongly recommended for WS because of the high risk of serious complications; however, some asymptomatic adult patients are still treated conservatively, such as the patient in this study. The present case is reported with reference to the literature. PMID:24349711

  15. Gastric dilatation and volvulus in a brachycephalic dog with hiatal hernia.

    PubMed

    Aslanian, M E; Sharp, C R; Garneau, M S

    2014-10-01

    A brachycephalic dog was presented with an acute onset of retching and abdominal discomfort. The dog had a chronic history of stertor and exercise intolerance suggestive of brachycephalic airway obstructive syndrome. Radiographs were consistent with a Type II hiatal hernia. The dog was referred and within hours of admission became acutely painful and developed tympanic abdominal distension. A right lateral abdominal radiograph confirmed gastric dilatation and volvulus with herniation of the pylorus through the hiatus. An emergency exploratory coeliotomy was performed, during which the stomach was derotated, and an incisional gastropexy, herniorrhaphy and splenectomy were performed. A staphylectomy was performed immediately following the exploratory coeliotomy. The dog recovered uneventfully. Gastric dilatation and volvulus is a potentially life-threatening complication that can occur in dogs with Type II hiatal hernia and should be considered a surgical emergency. PMID:24871205

  16. Umbilical incision laparoscopic surgery with one assist port for an elderly patient with recurrent sigmoid volvulus

    PubMed Central

    Matsuoka, Tasuku; Osawa, Naoshi; Yoh, Taiho; Hirakawa, Kosei

    2012-01-01

    Single-port access laparoscopic surgery has recently emerged as a method to improve morbidity and cosmetic benefit of conventional laparoscopic surgery. Herein, we report the experience of transumbilical incision laparoscopic sigmoidectomy with one assist port in a 71-year-old man who had developed recurrent sigmoid volvulus in these several years since his first visit to the hospital. The patient presented abdominal distension and severe constipation. A plain x-ray film and CT of the abdomen showed grossly distended sigmoid colon loops and stenosis of recto-sigmoid colon. Sigmoid volvulus associated with megacolon was diagnosed and emergence endoscopic decompression was performed. After his condition improved, transumbilical incision laparoscopic sigmoidectomy was carried out as the minimally invasive approach, due to the several risk of patient such as aging and pulmonary disorder. Postoperative course was uneventful and on postoperative visit to the hospital he reported resolution of abdominal distension. PMID:23235104

  17. Umbilical incision laparoscopic surgery with one assist port for an elderly patient with recurrent sigmoid volvulus.

    PubMed

    Matsuoka, Tasuku; Osawa, Naoshi; Yoh, Taiho; Hirakawa, Kosei

    2012-01-01

    Single-port access laparoscopic surgery has recently emerged as a method to improve morbidity and cosmetic benefit of conventional laparoscopic surgery. Herein, we report the experience of transumbilical incision laparoscopic sigmoidectomy with one assist port in a 71-year-old man who had developed recurrent sigmoid volvulus in these several years since his first visit to the hospital. The patient presented abdominal distension and severe constipation. A plain x-ray film and CT of the abdomen showed grossly distended sigmoid colon loops and stenosis of recto-sigmoid colon. Sigmoid volvulus associated with megacolon was diagnosed and emergence endoscopic decompression was performed. After his condition improved, transumbilical incision laparoscopic sigmoidectomy was carried out as the minimally invasive approach, due to the several risk of patient such as aging and pulmonary disorder. Postoperative course was uneventful and on postoperative visit to the hospital he reported resolution of abdominal distension. PMID:23235104

  18. Le volvulus gastrique idiopathique aigu: à propos d'une nouvelle observation

    PubMed Central

    Abdelilah, Mouhsine; Jihad, Anzaoui; Rachid, Bouchentouf

    2013-01-01

    Le volvulus gastrique est une rotation anormale de l'estomac autour de son axe. La forme aiguë constitue une urgence chirurgicale. Le diagnostic est souvent retardé en raison d'une symptomatologie fréquemment non spécifique. Des signes respiratoires tels la dyspnée et le hoquet peuvent révéler cette pathologie. Les auteurs rapportent une nouvelle observation de volvulus gastrique aigu chez un adolescent de 17 ans, diagnostiqué par la tomodensitométrie, et confirmé par une intervention chirurgicale. Le traitement est chirurgical et consiste à détordre et fixer l'estomac pour prévenir la récidive. PMID:23503200

  19. Imaging, Endoscopic and Genetic Assessment of Marfan Syndrome Presenting with Sigmoid Volvulus: A Review.

    PubMed

    Inayat, Faisal; Hurairah, Abu; Shaikh, Faiq

    2016-01-01

    The Marfan syndrome (MFS) is a pleiotropic, autosomal dominant disorder of connective tissue with highly variable clinical manifestations. It primarily involves the skeletal, cardiovascular, and ocular systems; however, gastrointestinal complications are rare. Herein, we describe the case of a 31-year-old male who initially presented with acute abdominal pain for one day. His imaging features revealed a dilated sigmoid colon, consistent with sigmoid volvulus that was immediately decompressed. Surgical resection was recommended to treat the sigmoid volvulus. Preceding the treatment, the patient underwent an extensive workup, including an echocardiography that revealed aortic root dilatation. His clinical history, physical exam, and echocardiographic findings raised the suspicion for MFS. Subsequently, the diagnosis of MFS was confirmed on genetic testing. This is a case that highlights the multidisciplinary (clinical, radiological, endoscopic, molecular/genetic) approach to diagnose a patient with MFS who presented with symptomatic sigmoid volvulus. As this presentation may be a harbinger of more severe manifestations of MFS, it is important to identify it as such in order to accomodate for timely management. PMID:27382527

  20. Imaging, Endoscopic and Genetic Assessment of Marfan Syndrome Presenting with Sigmoid Volvulus: A Review

    PubMed Central

    Hurairah, Abu; Shaikh, Faiq

    2016-01-01

    The Marfan syndrome (MFS) is a pleiotropic, autosomal dominant disorder of connective tissue with highly variable clinical manifestations. It primarily involves the skeletal, cardiovascular, and ocular systems; however, gastrointestinal complications are rare. Herein, we describe the case of a 31-year-old male who initially presented with acute abdominal pain for one day. His imaging features revealed a dilated sigmoid colon, consistent with sigmoid volvulus that was immediately decompressed. Surgical resection was recommended to treat the sigmoid volvulus. Preceding the treatment, the patient underwent an extensive workup, including an echocardiography that revealed aortic root dilatation. His clinical history, physical exam, and echocardiographic findings raised the suspicion for MFS. Subsequently, the diagnosis of MFS was confirmed on genetic testing. This is a case that highlights the multidisciplinary (clinical, radiological, endoscopic, molecular/genetic) approach to diagnose a patient with MFS who presented with symptomatic sigmoid volvulus. As this presentation may be a harbinger of more severe manifestations of MFS, it is important to identify it as such in order to accomodate for timely management. PMID:27382527

  1. Cutaneous Distribution and Circadian Rhythm of Onchocerca lupi Microfilariae in Dogs

    PubMed Central

    Otranto, Domenico; Dantas-Torres, Filipe; Giannelli, Alessio; Abramo, Francesca; Ignjatović Ćupina, Aleksandra; Petrić, Dušan; Cardoso, Luís; Mutafchiev, Yasen; Cortes, Helder

    2013-01-01

    Background Among the arthropod-borne nematodes infesting dogs, Onchocerca lupi (Spirurida: Onchocercidae) is of increasing zoonotic concern, with new human cases of infection diagnosed in Turkey, Tunisia, Iran and the USA. Knowledge of the biology of this nematode is meagre. This study aimed at assessing the distribution and periodicity of O. lupi microfilariae from different body regions in naturally infested dogs. Methodology/Principal Findings Skin samples were collected from six dogs infested with O. lupi but without apparent clinical signs. Two skin samples were collected from 18 anatomical regions of dog 1 at necropsy. In addition, single skin biopsies were performed from the forehead, inter-scapular and lumbar regions of dogs 2–6, in the morning, afternoon, and at night. Two aliquots of the sediment of each sample were microscopically observed, microfilariae counted and morphologically and molecularly identified. Most of the 1,667 microfilariae retrieved from dog 1 were in the right ear (59.6%), nose (26.5%), left ear (6.7%), forehead (3.0%), and inter-scapular (2.9%) regions. In dogs 2–6, the overall mean number of microfilariae was larger on the head (n = 122.8), followed by the inter-scapular (n = 119.0) and lumbar (n = 12.8) regions. The overall mean number of microfilariae was larger in the afternoon (153.4), followed by night (75.4) and morning (25.8). Conclusions Onchocerca lupi microfilariae were more common in the head (i.e., ears and nose) than in the remaining part of the dog's body, indicating they tend to aggregate in specific body regions, which are the best sites to collect skin samples for diagnostic purposes. The periodicity pattern of microfilariae of O. lupi and their concentration in specific body regions is most likely a result of the co-evolution with their as-yet-unknown vector. The detection of skin microfilariae in asymptomatic animals, suggests the potential role of these animals as carriers and reservoirs of O. lupi

  2. Use of percutaneous endoscopic colostomy (PEC) to treat sigmoid volvulus: a systematic review

    PubMed Central

    Frank, Lucinda; Moran, Alex; Beaton, Ceri

    2016-01-01

    Background and aim: Percutaneous endoscopic colostomy provides an alternative management option for patients with recurrent sigmoid volvulus who are considered too high risk to undergo surgery. We reviewed the literature to assess whether the National Institute for Health and Clinical Excellence guidelines published in 2006 supporting the use of percutaneous endoscopic colostomy are still valid. Methods: A systematic literature search was conducted using PubMed, Web of Science, and Embase. The exploded search terms “Percutaneous Endoscopic Colostomy” and “Sigmoid Volvulus” were used. Librarian support was used to ensure the maximum number of relevant articles were returned. Identified abstracts were then analyzed and included if they met the inclusion criteria. Results: Five observational studies and 5 case reports were identified that met the inclusion criteria. They provided data on 56 patients with recurrent sigmoid volvulus treated with percutaneous endoscopic colostomy placement. Sixteen of the 56 patients were treated with a single percutaneous endoscopic colostomy (PEC) tube while 38 patients were treated with 2 PEC tubes. For 2 patients the details of the procedure were unknown. Five patients developed major complications following the procedure: 1 patient developed peritonitis after 4 days, due to fecal contamination secondary to tube migration and 2 patients with cognitive impairment pulled their PEC tubes out. Two other patients died following PEC insertion. Nine patients developed minor complications following the procedure. The most commonly reported minor complication was infection at the PEC site. Four of 56 patients developed a recurrent sigmoid volvulus with a PEC tube in situ. Conclusion: Although in these case series there is a 21 % risk of morbidity and 5 % risk of mortality from the use of a PEC, this is favorable compared to the mortality risk of 6.6 % to 44 % reported with operative intervention. This review of contemporary

  3. Cecal volvulus in a dairy cow: partial resection of the proximal portion of the ascending colon.

    PubMed

    Pankowski, R L; Fubini, S L; Stehman, S

    1987-08-15

    Cecal volvulus in a dairy cow with vascular compromise of the proximal portion of the ascending colon was corrected surgically with preservation of the ileocecocolic junction. Partial cecectomy was combined with resection of the proximal portion of the ascending colon and anastomosis of the remaining cecum to the distal portion of the ascending colon. The procedure was done with the use of mechanical suturing devices while the cow was standing. Previously, general anesthesia and relocation of the ileocecocolic junction had been suggested. PMID:3654317

  4. Emergency repair of Morgagni hernia with partial gastric volvulus: our approach.

    PubMed

    Razi, Kasra; Light, Duncan; Horgan, Liam

    2016-01-01

    Morgagni hernias are a rare form of congenital diaphragmatic hernias, thus there is paucity in literature about the diagnosis and management of the condition. We report an 83-year-old woman who presented with vomiting and a metabolic acidosis with a previous computed tomography diagnosis of Bochdalek's hernia. Diagnostic laparoscopy revealed a Morgagni hernia containing transverse colon, greater curvature of the stomach and a partial gastric volvulus. The hernia was reduced with the sac untouched, and the defect was closed with a composite mesh using tac fixation. The operation was done successfully in 45 minutes with no complications. PMID:27605660

  5. Small Bowel Ischemia due to Jejunum Volvulus in Pregnancy: A Case Report

    PubMed Central

    Vassiliou, Ioannis; Tympa, Aliki; Derpapas, Michalis; Kottis, Georgios; Vlahos, Nikolaos

    2012-01-01

    The diagnosis of intestinal obstruction in pregnancy is difficult, as the symptoms may mimic pregnancy-associated complaints. The surgical management is challenging, as the mortality rate of midgut volvulus in pregnancy is high. We report the case of a 35-year-old woman at 21 weeks and 5 days of gestation with small bowel obstruction who presented to our institution with a 24 h history of colicky abdominal pain and nausea and who finally had a successful open repair. PMID:23304583

  6. Neonatal obstructed Treitz’s hernia with abdominal cocoon simulating volvulus neonatorum

    PubMed Central

    Patel, Ramnik V; Lawther, Suzanne; Starzyk, Bozena; de la Hunt, Michael N

    2013-01-01

    A case of congenital obstructed Treitz's hernia presenting with bilious vomiting in a newborn baby girl has been presented. Internal herniation of contents within a peritoneal sac of the right paramesocolic hernia formed abdominal cocoon which simulated volvulus neonatorum. Plain radiographs and contrast studies were helpful in defining the nature and extent of the lesion. The patient underwent exploratory laparotomy, reduction of small bowel contents from the hernial sac forming an abdominal cocoon, Ladd's procedure to correct associated midgut malrotation with incidental appendicectomy uneventfully and recovered well. PMID:23832996

  7. The surgery of malrotation and midgut volvulus: a nine year experience in neonates.

    PubMed Central

    Welch, G. H.; Azmy, A. F.; Ziervogel, M. A.

    1983-01-01

    Thirty four neonates presented with acute duodenal obstruction due to malrotation during a 9 year period between 1973 and the end of 1981. Of these, 20 patients (58.8%) presented in the first week of life, and 24 (70.5%) had an associated midgut volvulus. This frequent association is stressed as bowel necrosis occurs very rapidly. Massive gangrene of small bowel was present in 5 patients, extensive resection was necessary in 3 patients, of whom 2 died postoperatively (5.8%). Five patients required reoperation and 10 had additional G.I. malformations (29.4%). Images Fig. 3 Fig. 4 Fig. 5 PMID:6870133

  8. New tools and insights to assist with the molecular identification of Simulium guianense s.l., main Onchocerca volvulus vector within the highland areas of the Amazonia onchocerciasis focus.

    PubMed

    Crainey, James L; Mattos-Glória, Aline; Hamada, Neusa; Luz, Sérgio L B

    2014-03-01

    Following the success of the Onchocerciasis Elimination Programme for the Americas (OEPA), there is now just one Latin American onchocerciasis focus where onchocerciasis transmission is described as 'on-going:' the Amazonia Onchocerciasis focus. In the hyperendemic highland areas of the Amazonia focus, Simulium guianense s.l. Wise are the most important vectors of the disease. Populations of S. guianense s.l. are, however, known to vary in their cytogenetics and in a range of behaviours, including in their biting habits. In the hypoendemic lowland areas of the Amazonia focus, for example, S. guianense s.l. are generally regarded as zoophilic and consequently unimportant to disease transmission. Robust tools, to discriminate among various populations of S. guianense s.l. have, however, not yet been developed. In the work reported here, we have assessed the utility of a ribosomal DNA sequence fragment spanning the nuclear ribosomal ITS-1, ITS-2 and 5.8S sequence regions and a ∼850 nucleotide portion of the mitochondrial cytochrome oxidase gene (CO1) for species-level identification and for resolving the within species substructuring. We report here how we have generated 78 CO1 sequences from a rich set of both zoophilic and anthropophilic populations of S. guianense s.l. that were collected from eight sites that are broadly distributed across Brazil. Consistent with previous findings, our analysis supports the genetic isolation of Simulium litobranchium from S. guianense s.l. In contrast with previous findings, however, our results did not provide support for the divergence of the two species prior to the radiation of S. guianense s.l. In our analysis of the S. guianense s.l. ribosomal DNA sequence trace files we generated, we provide clear evidence of multiple within-specimen single nucleotide polymorphisms and indels suggesting that S. guianense s.l. ribosomal DNA is not a good target for conventional DNA barcoding. This is the first report of S. guianense s.l. within individual ribosomal DNA variation and thus the first evidence that the species is not subject to the normal effects of concerted evolution. Collectively, these data illustrate the need for diverse sampling in the development of robust molecular tools for vector identification and suggest that ribosomal DNA might be able to assist with resolving S. guianense s.l. species substructuring that C01 barcoding has hitherto failed to. PMID:24200838

  9. Autopsy findings for a case of acute gastric volvulus in a child.

    PubMed

    Kozawa, Shuji; Murakami, Tomonori; Kakizaki, Eiji; Ikemura, Mayumi; Nakagawa, Yasuhisa; Kiyofuji, Yuma; Ikematsu, Kazuya; Nata, Masayuki

    2015-09-01

    Acute gastric volvulus resulting in abdominal compartment syndrome was determined to be the cause of death in a 4-year-old girl who presented with abdominal distension. At about 1AM on the day of her death, she was brought to our emergency medical center. Physical examination and plain abdominal X-ray revealed pronounced gastric dilatation. A decompression procedure was performed, followed by observation. She went into cardiopulmonary arrest around 1PM on the same day and died. Postmortem investigation, including an autopsy and computed tomography (CT), was performed to determine the cause of death. The findings included that the stomach was severely distended. Evidence was seen of mucosal hemorrhage in the gastric mucosa on the greater curvature side, which was thinned in places but without perforation. No necrosis of the gastric mucosa was observed; reversible changes were evident on histopathological examination. The postmortem CT images suggested that the pyloric region was positioned cranioventrally to the cardiac region. None of the findings indicated sudden blockage, and the cause of death was determined to be acute gastric volvulus resulting in abdominal compartment syndrome. The abnormal placement of the organs was difficult to determine based on physical examination alone; postmortem CT and careful examination were helpful in conducting the autopsy in this case. PMID:25957510

  10. [Volvulus of the pelvic colon. Apropos of 59 cases in the western Africa savannah area].

    PubMed

    Ribault, L; Gournier, J P; Barthe, B L

    1989-01-01

    The authors describe their experience after treatment of 59 cases of volvulus of the pelvic colon. This disorder is frequent in West Africa and affects the protein deficient malnourished population. A definite predominance of volvulus occurred during the dry season between December and April, perhaps related to a diet richer in cellulose or deficient in water. There was a delay in presentation at the Hospital Center; necrosis of the twisted loop, the age of the patient and multiple associated conditions all contributed to the severity of this condition. Treatment had three aims: removal of the obstruction, reestablishment of continuity and avoidance of recurrence. Indications were dictated by the patient's general condition and the vascular status of the loop of bowel. It is reasonable to attempt reduction via intubation if the loop of bowel appears viable. Success enables a colectomy to be performed after a preparation, while failure necessitates surgical correction of ideally colectomy in a one stage procedure. On the other hand, a gangrenous loop necessitates colectomy without untwisting, with closure of the distal end using the Hartmann technique and with reestablishment of continuity 3 weeks later. PMID:2805924

  11. Defining parasite biodiversity at high latitudes of North America: new host and geographic records for Onchocerca cervipedis (Nematoda: Onchocercidae) in moose and caribou

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Onchocerca cervipedis is a filarioid nematode of cervids reported from Central America to boreal regions of North America. It is found primarily in subcutaneous tissues of the legs, and is popularly known as ‘legworm’. Blackflies are intermediate hosts and transmit larvae to ungulates when they bloo...

  12. Occurrence and recurrence of gastric dilatation with or without volvulus after incisional gastropexy

    PubMed Central

    Przywara, John F.; Abel, Steven B.; Peacock, John T.; Shott, Susan

    2014-01-01

    This study investigated recurrence of gastric dilatation without (GD) or with volvulus (GDV) after incisional gastropexy (IG) in dogs that underwent IG for prevention of GDV. Signalment, concurrent surgical procedures, presence of GD or GDV at the time of IG were obtained from medical records of dogs that underwent IG. Owners were contacted to determine whether the dogs experienced GD or GDV after IG, dates of postoperative GD or GDV episodes, survival status, date of death for deceased dogs. Gastric dilatation and GDV recurrence rates were calculated for 40 dogs that had at least 2 y follow-up from the time when IG was performed and for dogs that experienced GD or GDV during the follow-up period. No dogs experienced GDV after IG and 2 dogs (5.0%) experienced GD after IG. The results suggest that GD and GDV rates after IG may be comparable to recurrence rates after other methods of gastropexy. PMID:25320388

  13. The role of sigmoidoscopy in thediagnosis and treatment of sigmoid volvulus

    PubMed Central

    Atamanalp, Sabri Selcuk; Atamanalp, Refik Selim

    2016-01-01

    Sigmoid volvulus (SV) is a rare form of acute intestinal obstruction in which the sigmoid colon wraps around itself. The disease generally presents as a mechanical bowel obstruction with clinical features that are not pathognomonic. Similarly, X-ray films are not diagnostic in most cases. It is difficult to establish the correct preoperative diagnosis when CT and MRI are not used. The principal strategy in the treatment of SV in uncomplicated patients is emergency endoscopic detorsion followed by elective surgery; emergent surgery is required in patients with bowel gangrene, bowel perforation, peritonitis, or unsuccessful endoscopic treatment. In this review, we have discussed the role of sigmoidoscopy in the diagnosis and treatment of SV. Additionally, we have retrospectively and prospectively evaluated our 49-year, 987-patient clinical experience, the largest single-center SV series ever reported. PMID:27022384

  14. Phosphorus homeostasis in dairy cows with abomasal displacement or abomasal volvulus.

    PubMed

    Grünberg, Walter; Constable, Peter; Schröder, Ulf; Staufenbiel, Rudolf; Morin, Dawn; Rohn, Marina

    2005-01-01

    Abnormal phosphorus homeostasis occurs in dairy cows with an abomasal displacement or volvulus. The goal of this study was to identify potential mechanisms for hypophosphatemia and hyperphosphatemia in cows with a left displaced abomasum (LDA), right displaced abomasum (RDA), or abomasal volvulus (AV). Accordingly, the results of preoperative clinicopathologic analyses for 1,368 dairy cows with an LDA (n = 1,189), RDA, or AV (n = 179) (data set 1) and for 44 cows with an AV (data set 2) were retrieved. Laboratory values were compared by Student's t-tests, and correlation and regression analyses were performed. Thirty-four percent of the animals from data set 1 (463/1,368) were hypophosphatemic (serum phosphorus concentration ([Pi]) < 1.4 mmol/L), and 9% (122/1,368) were hyperphosphatemic ([Pi] >2.3 mmol/L). Serum [Pi] was significantly lower (P < .05) in cows with an LDA (1.60 +/- 0.53 mmol/L; mean +/- SD) than in cows with an RDA or AV (1.85 +/- 0.68 mmol/L). For cows with an LDA, [Pi] was correlated with serum urea nitrogen concentration ([SUN]) (r = 0.34) and serum concentration of magnesium ([Mg]) (r = 0.20). For cows with an RDA or AV, linear correlations existed between [Pi] and [SUN] (r = 0.45), [Mg] (r = 0.43), and serum chloride concentration ([Cl]) (r = -0.27). Stepwise logistic regression analysis indicated that low [SUN] and the diagnosis of an LDA had the strongest associations with hypophosphatemia. In cows with hyperphosphatemia, [Pi] was most strongly associated with azotemia. In cows with an AV, the strongest correlations with [Pi] were found for [SUN] and serum creatinine. We conclude that hypophosphatemia in cows with an LDA is primarily due to decreased feed intake. In contrast, hyperphosphatemia in cattle with an RDA or AV appears to result from dehydration and decreased renal blood flow. PMID:16355687

  15. Volvulus - childhood

    MedlinePlus

    ... Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice . 8th ed. Philadelphia, PA: Elsevier Mosby; 2013:chap 95. Read More Abdominal pain Fetal development Intestinal obstruction Nausea and vomiting - adults Peritonitis - secondary ...

  16. Afferent Loop Syndrome after Roux-en-Y Total Gastrectomy Caused by Volvulus of the Roux-Limb

    PubMed Central

    Tahara, Kana; Yoshikawa, Kentaro; Lefor, Alan Kawarai; Kubota, Tadao; Mizokami, Ken

    2016-01-01

    Afferent loop syndrome is a rare complication of gastric surgery. An obstruction of the afferent limb can present in various ways. A 73-year-old man presented with one day of persistent abdominal pain, gradually radiating to the back. He had a history of total gastrectomy with a Roux-en-Y reconstruction. Abdominal computed tomography scan revealed dilation of the duodenum and small intestine in the left upper quadrant. Exploratory laparotomy showed volvulus of the biliopancreatic limb that caused afferent loop syndrome. In this patient, the 50 cm long limb was the cause of volvulus. It is important to fashion a Roux-limb of appropriate length to prevent this complication.

  17. CT Angiographic Demonstration of a Mesenteric Vessel "Whirlpool" in Intestinal Malrotation and Midgut Volvulus: a Case Report

    PubMed Central

    Ugurel, Mehmet Sahin; Ustunsoz, Bahri; Coskun, Unsal

    2008-01-01

    Although the color Doppler ultrasonography diagnosis of intestinal malrotation with midgut volvulus, based on the typical "whirlpool" appearance of the mesenteric vascular structures is well-defined in the peer-reviewed literature, the combination of both the angiographic illustration of these findings and the contemporary state-of-the-art imaging techniques is lacking. We report the digital subtraction angiography and multidetector computed tomography angiography findings of a 37-year-old male with intestinal malrotation. PMID:18838858

  18. Perforated Gastric Gangrene without Pneumothorax in an Adult Bochdalek Hernia due to Volvulus

    PubMed Central

    Sebastian, George Mathew; Ambady, Venugopal; Hariharan, Ramesh

    2016-01-01

    Bochdalek hernia is the most frequent congenital diaphragmatic hernia which occurs due to a defect in the posterior attachment of the diaphragm when there is a failure of closure of the pleuroperitoneal membrane in utero. It rarely presents for the first time in adults. We report one such case of a 23-year-old male patient who presented with an acute abdomen. Chest X-ray showed air under diaphragm and he was taken up for an emergency laparotomy. Intraoperatively an organoaxial volvulus of the stomach was found in a bochdaleks hernia with a focal gangrene of the stomach fundus with perforation and peritonitis. However, there was no breach of pleural cavity. A sleeve resection of the gangrenous portion of the stomach was performed and the diaphragmatic defect was repaired. Patient made an uneventful postoperative recovery. Gastric gangrene with perforation as a manifestation of the adult bochdalek hernia is indeed rare. A concomitant pneumothorax occurs along with this condition which requires an intercostal drainage tube prior to the laparotomy. We report this case for its unique presentation without pneumothorax. PMID:27190884

  19. Meteorological influence on the occurrence of gastric dilatation-volvulus in military working dogs in Texas

    NASA Astrophysics Data System (ADS)

    Moore, George E.; Levine, Michael; Anderson, Johnna D.; Trapp, Robert J.

    2008-01-01

    Gastric dilatation-volvulus (GDV) is a life-threatening condition in dogs and other species in which the stomach dilates and rotates on itself. The etiology of the disease is multi-factorial, but explicit precipitating causes are unknown. This study sought to determine if there was a significant association between changes in hourly-measured temperature and/or atmospheric pressure and the occurrence of GDV in the population of high-risk working dogs in Texas. The odds of a day being a GDV day, given certain temperature and atmospheric pressure conditions for that day or the day before, was estimated using logistic regression models. There were 57 days in which GDV(s) occurred, representing 2.60% of the days in the 6-year study period. The months of November, December, and January collectively accounted for almost half (47%) of all cases. Disease risk was negatively associated with daily maximum temperature. An increased risk of GDV was weakly associated with the occurrence of large hourly drops in temperature that day and of higher minimum barometric pressure that day and the day before GDV occurrence, but extreme changes were not predictive of the disease.

  20. Peritoneal fluid analysis in dairy cows with left displaced abomasum and abomasal volvulus.

    PubMed

    Grosche, A; Fürll, M; Wittek, T

    2012-04-21

    Peritoneal fluid (PF) was evaluated in 40 cows with left displaced abomasum (LDA) and 15 cows with abomasal volvulus (AV). PF was obtained by abdominocentesis at the right ventral abdomen at admission. Simultaneously, a blood sample was taken from the jugular vein. Biochemical and cytological variables in blood and PF specific for ischaemia, inflammation and cell damage were compared. Total protein, albumin, glucose and cholesterol were normal in PF of cows with LDA and AV. Although L-lactate increased in both groups, cows with AV had significantly higher values (LDA: 1.47/0.69/2.68 mmol/l; AV: 6.45/4.55/12.89 mmol/l (median/1. quartile/3. quartile)). D-dimer (LDA: 0.50/0.22/0.88 mg/l; AV: 1.11/0.40/1.85 mg/l) and LDH (LDA: 663/437/943 U/l; AV: 1099/750/1439 U/l) were only increased in PF of cows with AV. The number of leucocytes was normal; however, significantly more peritoneal neutrophils appeared necrotic or apoptotic after AV. PF of cows with abomasal displacement showed distinctive features of ischaemia and inflammation. Characteristics of haemostatic dysfunction and cell damage were mainly evident in PF of cows with AV. The results suggest that anti-inflammatory therapy is indicated in each cow with abomasal displacement. Additionally, medical treatment should be directed to prevent complications of ischaemia and reperfusion in cows with AV. PMID:22383328

  1. A case of acute mesentero-axial gastric volvulus in a patient with a diaphragmatic hernia: experience with a laparoscopic approach

    PubMed Central

    Al-Faraj, Dalal; Al-Haddad, Mohanned; Al-Hadeedi, Omar; Al-Subaie, Saud

    2015-01-01

    Gastric volvulus is an uncommon but serious surgical condition mandating an early diagnosis and surgical intervention. It may present either acutely or chronically with epigastric pain, retching and vomiting. There are two types of gastric volvulus: organo-axial and mesentero-axial. We report a case of a mesentero-axial gastric volvulus in a 49-year-old woman with a left-sided diaphragmatic hernia. She presented with a significant epigastric pain and vomiting. A flexible upper endoscopy, a barium meal and a contrast-enhanced computed tomography imaging had confirmed the diagnosis. She was treated with a laparoscopic mesh repair of the diaphragmatic defect followed by a gastropexy. She had an uneventful postoperative course and was asymptomatic thereafter. PMID:26391688

  2. Cross-sectional study of the association of abomasal displacement or volvulus with serum electrolyte and mineral concentrations in dairy cows.

    PubMed Central

    Delgado-Lecaroz, R; Warnick, L D; Guard, C L; Smith, M C; Barry, D A

    2000-01-01

    The objective of this study was to evaluate serum mineral and electrolyte concentrations at the time of on-farm diagnosis of left displaced abomasum, right displaced abomasum, or abomasal volvulus in dairy cows. Data were collected from 104 affected cows and 96 control cows matched with cases, based on herd, parity, and stage of lactation. Cows with abomasal displacement or volvulus had significantly lower calcium, phosphorous, magnesium, potassium, and chloride concentrations and increased anion gap at the time of diagnosis compared with control cows from the same herds. The percentages of cases and controls with total serum calcium concentrations below the lower limit of the laboratory reference range (2.08 mmol/L [8.3 mg/dL]) were 70% and 23%, respectively. Based on the large percentage of cases with hypocalcemia, administering calcium salts at the time of treatment of field cases of abomasal displacement or volvulus may be beneficial. PMID:10769767

  3. Cross-sectional study of the association of abomasal displacement or volvulus with serum electrolyte and mineral concentrations in dairy cows.

    PubMed

    Delgado-Lecaroz, R; Warnick, L D; Guard, C L; Smith, M C; Barry, D A

    2000-04-01

    The objective of this study was to evaluate serum mineral and electrolyte concentrations at the time of on-farm diagnosis of left displaced abomasum, right displaced abomasum, or abomasal volvulus in dairy cows. Data were collected from 104 affected cows and 96 control cows matched with cases, based on herd, parity, and stage of lactation. Cows with abomasal displacement or volvulus had significantly lower calcium, phosphorous, magnesium, potassium, and chloride concentrations and increased anion gap at the time of diagnosis compared with control cows from the same herds. The percentages of cases and controls with total serum calcium concentrations below the lower limit of the laboratory reference range (2.08 mmol/L [8.3 mg/dL]) were 70% and 23%, respectively. Based on the large percentage of cases with hypocalcemia, administering calcium salts at the time of treatment of field cases of abomasal displacement or volvulus may be beneficial. PMID:10769767

  4. Acute gastric volvulus associated with wandering spleen in an adult treated laparoscopically after endoscopic reduction: a case report.

    PubMed

    Omata, Jiro; Utsunomiya, Katsuyuki; Kajiwara, Yoshiki; Takahata, Risa; Miyasaka, Nobuo; Sugasawa, Hidekazu; Sakamoto, Naoko; Yamagishi, Yoji; Fukumura, Makiko; Kitagawa, Daiki; Konno, Mitsuhiko; Okusa, Yasushi; Murayama, Michinori

    2016-12-01

    A 43-year-old female was referred to our hospital for sudden onset of abdominal pain, fullness, and vomiting. Physical examination revealed abdominal distension with mild epigastric tenderness. Abdominal radiography showed massive gastric distension and plain computed tomography (CT) a markedly enlarged stomach filled with gas and fluid. A large volume of gastric contents was suctioned out via a nasogastric (NG) tube. Contrast-enhanced CT showed a grossly distended stomach with displacement of the antrum above the gastroesophageal junction, and the spleen was dislocated inferiorly. Upper gastrointestinal (GI) series showed the greater curvature to be elevated and the gastric fundus to be lower than normal. Acute mesenteroaxial gastric volvulus was diagnosed. GI endoscopy showed a distortion of the gastric anatomy with difficulty intubating the pylorus. Various endoscopic maneuvers were required to reposition the stomach, and the symptoms showed immediate and complete solution. GI fluoroscopy was performed 3 days later. Initially, most of the contrast medium accumulated in the fundus, which was drawn prominently downward, and then began flowing into the duodenum with anteflexion. Elective laparoscopic surgery was performed 1 month later. The stomach was in its normal position, but the fundus was folded posteroinferiorly. The spleen attached to the fundus was normal in size but extremely mobile. We diagnosed a wandering spleen based on the operative findings. Gastropexy was performed for the treatment of gastric volvulus and wandering spleen. The patient remained asymptomatic, and there was no evidence of recurrence during a follow-up period of 24 months. This report describes a rare adult case of acute gastric volvulus associated with wandering spleen. Because delay in treatment can result in lethal complications, it is critical to provide a prompt and correct diagnosis and surgical intervention. We advocate laparoscopic surgery after endoscopic reduction because

  5. A case of fatal sigmoid volvulus visualized on postmortem radiography: The importance of image optimization with multidetector computed tomography.

    PubMed

    Usui, Akihito; Kawasumi, Yusuke; Hosokai, Yoshiyuki; Ishizuka, Yuya; Ikeda, Tomoya; Saito, Haruo; Funayama, Masato

    2016-03-01

    This report describes the case of a man who developed fatal sigmoid volvulus that was identified on postmortem radiography before forensic autopsy. Postmortem radiography is useful for visualizing the body prior to autopsy. We discuss postmortem multidetector computed tomography that was tailored for optimum image quality to allow reconstruction of the fatal findings in multiple axes and in three dimensions, helping to pinpoint the anatomical sites of interest. This involves techniques such as manipulation of the scanning beam pitch and overlapping CT section acquisition. These techniques are best performed by personnel with CT technology training. PMID:26980251

  6. Severe Symptomatic Hypermagnesemia Associated with Over-the-Counter Laxatives in a Patient with Renal Failure and Sigmoid Volvulus

    PubMed Central

    Khairi, Talal; Amer, Syed; Spitalewitz, Samuel; Alasadi, Lutfi

    2014-01-01

    Hypermagnesemia is an uncommon but a potentially serious clinical condition. Over-the-counter magnesium containing products are widely used as antacids or laxatives. Although generally well tolerated in patients with normal renal function, their unsupervised use in the elderly can result in severe symptomatic hypermagnesemia, especially in those patients with concomitant renal failure and bowel disorders. We report a case of severe symptomatic hypermagnesemia associated with over-the-counter laxatives in a 70-year-old male patient with renal failure and sigmoid volvulus, who was successfully treated with hemodialysis. PMID:24563801

  7. Role of the Enteric Nervous System in the Elongated Sigmoid Colon of Patients With Sigmoid Volvulus

    PubMed Central

    Tomita, Ryouichi; Sugitou, Kiminobu; Sakurai, Kenichi; Fujisaki, Shigeru; Ikeda, Taro; Koshinaga, Tsugumichi

    2014-01-01

    To clarify the physiologic function of the enteric nervous system (ENS) in the elongated sigmoid colon (ESC) of patients with sigmoid volvulus (SV), we examined the enteric nerve responses in lesional and normal longitudinal muscle strips (LMS) derived from patients with ESC and patients who underwent colon resection for colonic cancers. Thirty preparations of LMS were taken from the lesional sigmoid colons of 10 ESC patients with SV (8 men and 2 women, aged 53 to 80 years, mean 66.2 years). Forty preparations of LMS were taken from the normal sigmoid colons (NSC) of 20 patients with colonic cancer (12 men and 8 women, aged 55 to 76 years, mean 62.3 years). A mechanographic technique was used to evaluate in vitro muscle responses to electrical field stimulation (EFS) before and after treatment with various autonomic nerve blockers. Response to EFS before blockade of the adrenergic and cholinergic nerves was as follows: NSC and ESC significantly demonstrated relaxation reaction rather than contraction reaction (P = 0.0253, P < 0.0001, respectively). ESC showed relaxation reaction more than NSC (P = 0.1138). Response to EFS after blockade of the adrenergic and cholinergic nerves was as follows: NSC and ESC significantly demonstrated relaxation reaction via nonadrenergic noncholinergic (NANC) inhibitory nerves rather than contraction reaction via NANC excitatory nerves (P < 0.0001, P < 0.0001, respectively). ESC with SV significantly showed relaxation reaction more than NSC (P = 0.0092). An increased response of relaxation mediated NANC inhibitory nerves may play a role in impaired motility in the ESC of patients with SV. PMID:25437573

  8. Usability of Elective Laparoscopic Sigmoidectomy and Feasibility of Single-Incision Laparoscopic Surgery for Sigmoid Volvulus: Report of Three Cases

    PubMed Central

    Ueda, Masami; Onishi, Tadashi; Hata, Taishi; Nishida, Kentaro; Yanagawa, Takehiro; Fujita, Shoichiro; Fujita, Junya; Yoshida, Tetsuya; Tono, Takeshi; Monden, Takushi; Imaoka, Shingi; Mori, Masaki

    2015-01-01

    A therapeutic guideline for sigmoid volvulus (SV) has not been established, and the most recommended surgical procedure for SV has not been determined. Our objective is to assess the usability of elective laparoscopic sigmoidectomy and the feasibility of single-incision laparoscopic surgery for SV following endoscopic reduction. SV typically affects the elderly and accounts for 1% to 7% of intestinal obstructions in Western countries. We report on 3 patients with SV who underwent elective laparoscopic sigmoidectomy following endoscopic reduction, and we first describe single-port surgery for SV. We discuss the 3 patients (a 79-year-old male, an 88-year-old female, and a 67-year-old female) with SV who underwent elective laparoscopic sigmoidectomy following endoscopic reduction. All 3 patients underwent laparoscopic sigmoidectomy, and 2 patients underwent single-port laparoscopic surgery without complications. Recurrence of volvulus was not seen during the course of 12 to 24 months. In experienced hands, elective laparoscopic sigmoidectomy after colonoscopic detorsion is a valuable alternative, and single-port surgery is also feasible. PMID:25785318

  9. Usability of elective laparoscopic sigmoidectomy and feasibility of single-incision laparoscopic surgery for sigmoid volvulus: report of three cases.

    PubMed

    Ueda, Masami; Onishi, Tadashi; Hata, Taishi; Nishida, Kentaro; Yanagawa, Takehiro; Fujita, Shoichiro; Fujita, Junya; Yoshida, Tetsuya; Tono, Takeshi; Monden, Takushi; Imaoka, Shingi; Mori, Masaki

    2015-03-01

    A therapeutic guideline for sigmoid volvulus (SV) has not been established, and the most recommended surgical procedure for SV has not been determined. Our objective is to assess the usability of elective laparoscopic sigmoidectomy and the feasibility of single-incision laparoscopic surgery for SV following endoscopic reduction. SV typically affects the elderly and accounts for 1% to 7% of intestinal obstructions in Western countries. We report on 3 patients with SV who underwent elective laparoscopic sigmoidectomy following endoscopic reduction, and we first describe single-port surgery for SV. We discuss the 3 patients (a 79-year-old male, an 88-year-old female, and a 67-year-old female) with SV who underwent elective laparoscopic sigmoidectomy following endoscopic reduction. All 3 patients underwent laparoscopic sigmoidectomy, and 2 patients underwent single-port laparoscopic surgery without complications. Recurrence of volvulus was not seen during the course of 12 to 24 months. In experienced hands, elective laparoscopic sigmoidectomy after colonoscopic detorsion is a valuable alternative, and single-port surgery is also feasible. PMID:25785318

  10. Gastropexy for prevention of gastric dilatation-volvulus in dogs: history and techniques.

    PubMed

    Allen, Philip; Paul, April

    2014-09-01

    Gastric dilatation-volvulus (GDV) is a common and catastrophic disease of large and giant-breed dogs. Treatment of GDV includes medical stabilization followed by prompt surgical repositioning of the stomach in its normal anatomic position. To prevent reoccurrence, gastropexy is used to securely adhere the stomach to the body wall. Effective gastropexy decreases the recurrence of GDV from as high as 80% to less than 5%. The purpose of this article is to describe the history, indications, and techniques for gastropexy. Gastropexy was first reported in veterinary medicine in 1971 for the management of gastric reflux, and later in 1979 for treating and preventing the recurrence of GDV. Gastropexy is indicated in all dogs that undergo surgical correction of GDV. Additionally, prophylactic gastropexy should be strongly considered at the time of surgery in dogs undergoing splenectomy for splenic torsion and potentially other splenic pathology, and in dogs of at-risk breeds, such as Great Danes, that are undergoing exploratory celiotomy for any reason owing to evidence for increased risk of GDV in these patients. Although there are numerous techniques described, gastropexy is always performed on the right side of the abdomen, near the last rib. Ensuring an anatomically correct gastropexy location is vital to prevent postoperative complications such as partial pyloric outflow obstruction. Gastropexy can be performed as part of an open surgical approach to the abdomen or using a minimally invasive technique. When combined with surgical correction of GDV, gastropexy is almost always performed as an open procedure. The stomach is repositioned, the abdomen explored, and then a permanent gastropexy is performed. Techniques used for open gastropexy include incisional, belt-loop, circumcostal, and incorporating gastropexy, as well as gastrocolopexy. Each of these has been described later. Incisional gastropexy is currently the most commonly performed method of surgical gastropexy

  11. A rare case of ocular onchocerciasis in India.

    PubMed

    Barua, Purnima; Sharma, Ajanta; Hazarika, Naba Kumar; Barua, Nitin; Bhuyan, Saurabh; Alam, Syed Tanwir

    2011-11-01

    Onchocerca volvulus is a spirurid nematode that mainly affects the rural poor of Sub-Saharan Africa, Yemen and parts of Central and South Africa. River blindness, caused by Onchocerca volvulus, is considered to be the second commonest infectious cause of blindness worldwide. We report a rare case of ocular onchocerciasis where a live adult worm was extracted from the eye of a patient from a nonendemic region. The worm was identified as Onchocerca volvulus based on morphological features. The patient was treated with Ivermectin (0.2 mg/kg). At six months follow-up she had complete remission of symptoms. PMID:22299403

  12. Bacterial endosymbionts of plant-parasitic nematodes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several groups of bacteria have been reported as endosymbionts of various orders of nematodes including the filarial nematodes (Brugia malayi, Wucheria bancrofti and Onchocerca volvulus (Spiruida)), the entomopathogenic nematodes (Steinernema spp., and Heterorhabditis spp. (Rhabditida)), and plant-p...

  13. Defining parasite biodiversity at high latitudes of North America: new host and geographic records for Onchocerca cervipedis (Nematoda: Onchocercidae) in moose and caribou

    PubMed Central

    2012-01-01

    Background Onchocerca cervipedis is a filarioid nematode of cervids reported from Central America to boreal regions of North America. It is found primarily in subcutaneous tissues of the legs, and is more commonly known as ‘legworm’. Blackflies are intermediate hosts and transmit larvae to ungulates when they blood-feed. In this article we report the first records of O. cervipedis from high latitudes of North America and its occurrence in previously unrecognized host subspecies including the Yukon-Alaska moose (Alces americanus gigas) and the Grant’s caribou (Rangifer tarandus granti). Methods We examined the subcutaneous connective tissues of the metacarpi and/or metatarsi of 34 moose and one caribou for parasitic lesions. Samples were collected from animals killed by subsistence hunters or animals found dead in the Northwest Territories (NT), Canada and Alaska (AK), USA from 2005 to 2012. Genomic DNA lysate was prepared from nematode fragments collected from two moose. The nd5 region of the mitochondrial DNA was amplified by PCR and sequenced. Results Subcutaneous nodules were found in 12 moose from the NT and AK, and one caribou from AK. Nematodes dissected from the lesions were identified as Onchocerca cervipedis based on morphology of female and male specimens. Histopathological findings in moose included cavitating lesions with multifocal granulomatous cellulitis containing intralesional microfilariae and adults, often necrotic and partially mineralized. Lesions in the caribou included periosteitis with chronic cellulitis, eosinophilic and lymphoplasmacytic infiltrate, and abundant granulation associated with intralesional adult nematodes and larvae. Sequences of the nd5 region (471bp), the first generated for this species, were deposited with Genbank (JN580791 and JN580792). Representative voucher specimens were deposited in the archives of the United States National Parasite Collection. Conclusions The geographic range of O. cervipedis is broader than

  14. A Case of Apparent Life-Threatening Event: Comorbid Gastric Volvulus Associated Gastroesophageal Reflux Disease and Epilepsy in a 4-Month-Old Boy.

    PubMed

    Takano, Yoshihiko; Horiike, Masaki; Tatsumi, Ako; Sakamoto, Haruko; Fujino, Hisanori; Sumimoto, Shin-Ichi

    2016-01-01

    Most isolated episodes of apparent life-threatening events (ALTEs) do not lead to the diagnosis of serious conditions, and their prognoses are generally benign. However, recurrent ALTEs are often associated with a risk of future serious adverse events and should be evaluated for appropriate management. Here we present ALTE case in which gastric volvulus associated gastroesophageal reflux disease was detected as an etiology initially, followed by the detection of epilepsy as another etiology. Clinicians should consider possibility of two or more etiologies in a single recurrent ALTE case. PMID:27293941

  15. A Case of Apparent Life-Threatening Event: Comorbid Gastric Volvulus Associated Gastroesophageal Reflux Disease and Epilepsy in a 4-Month-Old Boy

    PubMed Central

    Takano, Yoshihiko; Horiike, Masaki; Tatsumi, Ako; Sakamoto, Haruko; Fujino, Hisanori; Sumimoto, Shin-ichi

    2016-01-01

    Most isolated episodes of apparent life-threatening events (ALTEs) do not lead to the diagnosis of serious conditions, and their prognoses are generally benign. However, recurrent ALTEs are often associated with a risk of future serious adverse events and should be evaluated for appropriate management. Here we present ALTE case in which gastric volvulus associated gastroesophageal reflux disease was detected as an etiology initially, followed by the detection of epilepsy as another etiology. Clinicians should consider possibility of two or more etiologies in a single recurrent ALTE case. PMID:27293941

  16. Zoonotic Onchocerca lupi infection in a 22-month-old child in Arizona: first report in the United States and a review of the literature.

    PubMed

    Eberhard, Mark L; Ostovar, Gholamabbas Amin; Chundu, Kote; Hobohm, Dan; Feiz-Erfan, Iman; Mathison, Blaine A; Bishop, Henry S; Cantey, Paul T

    2013-03-01

    A 22-month-old girl presented with neck pain and stiffness and magnetic resonance imaging showed an extradural mass extending from C2 through the C4 level with moderate to severe compression of the cord. A left unilateral C2-C4 laminectomy was performed revealing an extradural rubbery tumor; a small biopsy was obtained. Examination of stained tissue revealed the presence of a parasitic worm that was identified as a gravid female Onchocerca lupi. A magnetic resonance imaging at 7 weeks follow-up showed a significantly decreased size of the enhancing lesion and the patient's symptoms gradually resolved. This is the first report of zoonotic O. lupi in the United States. The parasite has been reported in dogs and cats in the western United States, and from people in four cases reported from Europe. A great deal more needs to be learned, including full host range and geographic distribution, before we fully understand O. lupi infections in animals and man. PMID:23382171

  17. Ivermectin Inhibits Growth of Chlamydia trachomatis in Epithelial Cells

    PubMed Central

    Pettengill, Matthew A.; Lam, Verissa W.; Ollawa, Ikechukwu; Marques-da-Silva, Camila; Ojcius, David M.

    2012-01-01

    Ivermectin is currently approved for treatment of both clinical and veterinary infections by nematodes, including Onchocerca cervicalis in horses and Onchocerca volvulus in humans. However, ivermectin has never been shown to be effective against bacterial pathogens. Here we show that ivermectin also inhibits infection of epithelial cells by the bacterial pathogen, Chlamydia trachomatis, at doses that could be envisioned clinically for sexually-transmitted or ocular infections by Chlamydia. PMID:23119027

  18. Ivermectin inhibits growth of Chlamydia trachomatis in epithelial cells.

    PubMed

    Pettengill, Matthew A; Lam, Verissa W; Ollawa, Ikechukwu; Marques-da-Silva, Camila; Ojcius, David M

    2012-01-01

    Ivermectin is currently approved for treatment of both clinical and veterinary infections by nematodes, including Onchocerca cervicalis in horses and Onchocerca volvulus in humans. However, ivermectin has never been shown to be effective against bacterial pathogens. Here we show that ivermectin also inhibits infection of epithelial cells by the bacterial pathogen, Chlamydia trachomatis, at doses that could be envisioned clinically for sexually-transmitted or ocular infections by Chlamydia. PMID:23119027

  19. A five-year-old child with a subcutaneous forehead nodule.

    PubMed

    Westblade, Lars F; Fischer, Peter U; Haghi, Nina; Schniederjan, Matthew J; Pritt, Bobbi S; Long, John G; Jerris, Robert C; Garola, Robert E

    2015-01-01

    We describe a case of a 5-year-old girl with onchocerciasis. The patient was recently adopted from Ethiopia and presented with a firm, raised nodule on the midportion of the forehead. Initially, Langerhans cell histiocytosis with bone involvement was suspected; however, histopathologic analysis of the excised nodule revealed the presence of a young-adult, female Onchocerca volvulus worm. This case exemplifies the importance of recognizing the key morphologic characteristics of adult O. volvulus worms isolated from pediatric patients in nonendemic areas to ensure adroit clinical management. PMID:25569144

  20. DPA1*02012: A DPA1*0201-related Mhc class II allele in West Africa

    SciTech Connect

    Meyer, C.G.; May, J.; Spauke, D.; Schnittger, L.

    1994-12-31

    DNA techniques such as sequence-specific oligonucleotide probe (SSOP) hybridizations, restriction-fragment length polymorphism (RFLP) analyses, and DNA sequencing have greatly supported the characterization of Mhc class II allelic polymorphism. Here the authors describe a DPA 1 allele which has been identified in two male individuals from Liberia and Benin, West Africa, during a survey study on Mhc class II associations with the different manifestations after infection with Onchocerca volvulus. 4 refs., 1 fig.

  1. A lack of confirmation with alternative assays questions the validity of IL-17A expression in human neutrophils using immunohistochemistry.

    PubMed

    Tamarozzi, Francesca; Wright, Helen L; Thomas, Huw B; Edwards, Steven W; Taylor, Mark J

    2014-12-01

    We identified IL-17A-positive neutrophils in Wolbachia-positive Onchocerca volvulus nodules using an antibody that has previously reported IL-17A-positive neutrophils in several inflammatory conditions. However, we could not detect IL-17A using a range of alternative assays. Our data question the IL-17A antibody specificity and the ability of human neutrophils to express IL-17A. PMID:25445614

  2. Recent developments in the treatment of onchocerciasis*

    PubMed Central

    Taylor, Hugh R.

    1984-01-01

    The treatment of onchocerciasis using diethylcarbamazine and suramin sodium, which can kill different stages of the parasite, Onchocerca volvulus, remains unsatisfactory. Recent studies have more clearly defined the serious limitations of the existing forms of treatment. However, two new classes of compounds, the benzimidazoles and avermectins, offer exciting new leads in the search for a safe and effective treatment that could be used on a large scale. PMID:6333293

  3. Clinical trials of amodiaquine in onchocerciasis

    PubMed Central

    Kale, Oladele O.

    1982-01-01

    Twenty onchocerciasis patients from the rain-forest zone of Western Nigeria were treated with amodiaquine in total dosages ranging from 22 to 68 mg/kg of body weight given over 2-9 days. There was no activity against either the microfilariae or adult forms of Onchocerca volvulus. It is concluded that the drug, which was poorly tolerated by 12 patients, is ineffective against human onchocerciasis. PMID:6761007

  4. Further trials of mebendazole and metrifonate in the treatment of onchocerciasis

    PubMed Central

    Kale, Oladele O.

    1982-01-01

    In clinical drug trials, mebendazole, given in various daily doses for up to 14 days to a maximum total of 16.8 g, was found to be ineffective against both adult Onchocerca volvulus and the microfilariae. Metrifonate, however, given in doses of 100 mg daily for 14 days or as four doses of 10 mg/kg of body weight either on alternate days or at weekly intervals showed moderate activity against the microfilariae but none against the adult worm. PMID:7044588

  5. Epidemiological studies on onchocerciasis by means of a new field technique*

    PubMed Central

    Scheiber, P.; Braun-Munzinger, R. A.; Southgate, B. A.; Agbo, K. N.

    1976-01-01

    A new membrane filter concentration technique for the detection and quantification of Onchocerca volvulus microfilariae in skin snips was compared for sensitivity and efficiency with a widely used “standard” technique. A field study was carried out in five villages in an onchocerciasis focus north-east of the town of Sokodé, Mô river valley, Togo. Use of the new technique resulted in a substantial rise in the observed prevalence and density of microfilariae. PMID:1086740

  6. Software Comparison

    NASA Technical Reports Server (NTRS)

    Blanchard, D. C.

    1986-01-01

    Software Comparison Package (SCP) compares similar files. Normally, these are 90-character files produced by CDC UPDATE utility from program libraries that contain FORTRAN source code plus identifier. SCP also used to compare load maps, cross-reference outputs, and UPDATE corrections sets. Helps wherever line-by-line comparison of similarly structured files required.

  7. Repurposing Auranofin as a Lead Candidate for Treatment of Lymphatic Filariasis and Onchocerciasis

    PubMed Central

    Bulman, Christina A.; Bidlow, Chelsea M.; Lustigman, Sara; Cho-Ngwa, Fidelis; Williams, David; Rascón, Jr, Alberto A.; Tricoche, Nancy; Samje, Moses; Bell, Aaron; Suzuki, Brian; Lim, K. C.; Supakorndej, Nonglak; Supakorndej, Prasit; Wolfe, Alan R.; Knudsen, Giselle M.; Chen, Steven; Wilson, Chris; Ang, Kean-Hooi; Arkin, Michelle; Gut, Jiri; Franklin, Chris; Marcellino, Chris; McKerrow, James H.; Debnath, Anjan; Sakanari, Judy A.

    2015-01-01

    Two major human diseases caused by filariid nematodes are onchocerciasis, or river blindness, and lymphatic filariasis, which can lead to elephantiasis. The drugs ivermectin, diethylcarbamazine (DEC), and albendazole are used in control programs for these diseases, but are mainly effective against the microfilarial stage and have minimal or no effect on adult worms. Adult Onchocerca volvulus and Brugia malayi worms (macrofilariae) can live for up to 15 years, reproducing and allowing the infection to persist in a population. Therefore, to support control or elimination of these two diseases, effective macrofilaricidal drugs are necessary, in addition to current drugs. In an effort to identify macrofilaricidal drugs, we screened an FDA-approved library with adult worms of Brugia spp. and Onchocerca ochengi, third-stage larvae (L3s) of Onchocerca volvulus, and the microfilariae of both O. ochengi and Loa loa. We found that auranofin, a gold-containing drug used for rheumatoid arthritis, was effective in vitro in killing both Brugia spp. and O. ochengi adult worms and in inhibiting the molting of L3s of O. volvulus with IC50 values in the low micromolar to nanomolar range. Auranofin had an approximately 43-fold higher IC50 against the microfilariae of L. loa compared with the IC50 for adult female O. ochengi, which may be beneficial if used in areas where Onchocerca and Brugia are co-endemic with L. loa, to prevent severe adverse reactions to the drug-induced death of L. loa microfilariae. Further testing indicated that auranofin is also effective in reducing Brugia adult worm burden in infected gerbils and that auranofin may be targeting the thioredoxin reductase in this nematode. PMID:25700363

  8. Repurposing auranofin as a lead candidate for treatment of lymphatic filariasis and onchocerciasis.

    PubMed

    Bulman, Christina A; Bidlow, Chelsea M; Lustigman, Sara; Cho-Ngwa, Fidelis; Williams, David; Rascón, Alberto A; Tricoche, Nancy; Samje, Moses; Bell, Aaron; Suzuki, Brian; Lim, K C; Supakorndej, Nonglak; Supakorndej, Prasit; Wolfe, Alan R; Knudsen, Giselle M; Chen, Steven; Wilson, Chris; Ang, Kean-Hooi; Arkin, Michelle; Gut, Jiri; Franklin, Chris; Marcellino, Chris; McKerrow, James H; Debnath, Anjan; Sakanari, Judy A

    2015-02-01

    Two major human diseases caused by filariid nematodes are onchocerciasis, or river blindness, and lymphatic filariasis, which can lead to elephantiasis. The drugs ivermectin, diethylcarbamazine (DEC), and albendazole are used in control programs for these diseases, but are mainly effective against the microfilarial stage and have minimal or no effect on adult worms. Adult Onchocerca volvulus and Brugia malayi worms (macrofilariae) can live for up to 15 years, reproducing and allowing the infection to persist in a population. Therefore, to support control or elimination of these two diseases, effective macrofilaricidal drugs are necessary, in addition to current drugs. In an effort to identify macrofilaricidal drugs, we screened an FDA-approved library with adult worms of Brugia spp. and Onchocerca ochengi, third-stage larvae (L3s) of Onchocerca volvulus, and the microfilariae of both O. ochengi and Loa loa. We found that auranofin, a gold-containing drug used for rheumatoid arthritis, was effective in vitro in killing both Brugia spp. and O. ochengi adult worms and in inhibiting the molting of L3s of O. volvulus with IC50 values in the low micromolar to nanomolar range. Auranofin had an approximately 43-fold higher IC50 against the microfilariae of L. loa compared with the IC50 for adult female O. ochengi, which may be beneficial if used in areas where Onchocerca and Brugia are co-endemic with L. loa, to prevent severe adverse reactions to the drug-induced death of L. loa microfilariae. Further testing indicated that auranofin is also effective in reducing Brugia adult worm burden in infected gerbils and that auranofin may be targeting the thioredoxin reductase in this nematode. PMID:25700363

  9. Production and immunological characterization of a recombinant subunit of a Loa loa polyprotein antigen.

    PubMed

    Azzibrouck, G Blampain; Akue, J P; Lenoble, D Richard

    2010-06-01

    Diagnosis of loiasis and analysis of the specific immune response are limited by a paucity of parasite material. To circumvent this problem, a Loa loa antigen has been expressed in a prokaryote vector (pTrcHis). Immunization of Balb/c mice with this soluble recombinant protein produced a strong antibody response, with antibodies recognizing 2 major bands of 38 and 20 kDa in a native crude extract of Loa loa adult worms and microfilariae on Western blots. The target molecule was located mainly in the hypodermis and cuticle of the adult worm. Analysis of human IgG subclasses against this antigen by enzyme-linked immunosorbent assay (ELISA) showed IgG1, IgG2 and IgG3 but not IgG4 reactivity. IgG2 against this recombinant antigen was 100% specific for loiasis when tested against samples from European donor individuals. The same IgG2 antibodies showed 91% specificity for loiasis by comparison with Wuchereria bancrofti, Onchocerca volvulus, Mansonnella perstans and other helminth infections. Furthermore, the IgG2 antibody level correlated with the density of Loa loa microfilariae (r=0.400; P=0.02). This recombinant 15r3 molecule and specific IgG2 assay may be useful for monitoring control programmes. PMID:20441677

  10. Genetic response to an environmental pathogenic agent: HLA-DQ and onchocerciasis in northwestern Ecuador.

    PubMed

    De Angelis, F; Garzoli, A; Battistini, A; Iorio, A; De Stefano, G F

    2012-02-01

    The aim of this study is to explore human leukocyte antigen (HLA)-DQ variability in two populations (Cayapas Amerindians and Afro-Ecuadorians) who live near one another along the Cayapa River and who are exposed to the same environmental stresses, such as infection by Onchocerca volvulus. HLA-DQA1 and HLA-DQB1 of 149 unrelated individuals (74 Cayapas and 75 Afro-Ecuadorians) have been analyzed. HLA high-resolution molecular typing was performed by sequence-based typing, sequence-specific oligonucleotides hybridization and sequence-specific primer (SSP) amplification. The comparison between affected (cases) and unaffected people (controls) in both populations shows the key role of several HLA-DQA1 alleles in susceptibility and protection against onchocerciasis. In both populations, there is strong evidence related to the protective role of DQA1*0401 against onchocerciasis. Alleles HLA-DQA1*0102 and *0103 seem to represent risk factors in Afro-Ecuadorians, while HLA-DQA1*0301 is only a suggestive susceptibility allele in Cayapas. These findings represent new positive/negative associations with onchocerciasis in South America, whereas previous findings pertained only to African populations. PMID:22117902

  11. Characterization of cofactor-independent phosphoglycerate mutase isoform-1 (Wb-iPGM) gene: a drug and diagnostic target from human lymphatic filarial parasite, Wuchereria bancrofti.

    PubMed

    Dhamodharan, R; Hoti, S L; Sankari, T

    2012-07-01

    The inter-conversion of 3-phosphoglycerate and 2-phosphoglycerate during glycolysis and gluconeogenesis in filarial nematodes, is catalyzed by a co-factor-independent phosphoglycerate mutase (iPGM). The gene encoding iPGM isoform-1 was amplified from Wuchereria bancrofti, the major causative agent of human lymphatic filariasis. Partial genomic DNA (gDNA) fragment of the gene was also amplified from periodic and sub-periodic forms of W. bancrofti and Brugia malayi and sequenced. The Wb-iPGM isoform-1 gene encodes an ORF of 515 amino acids and is found to share 99.4%, 96.0%, and 64.0% amino acid sequence identity with iPGM of B. malayi, Onchocerca volvulus, and Caenorhabditis elegans, respectively. Serine and all the other 13 amino acid residues involved in the catalytic function of iPGM are highly conserved. Further comparison of iPGM nucleotide and amino acid sequences of Wolbachia of B. malayi with Wb-iPGM showed 41% and 54.4% similarity, respectively. The analysis of partial genomic and amino acid sequences and phylogenetic tree of Wb-iPGM indicated that this gene, apart from being a potential drug target, could provide diagnostic, taxonomical, and evolutionary markers. This is the first report of the characterization of iPGM gene from W. bancrofti. PMID:22386851

  12. The evolution of ocular onchocerciasis in the Volta River Basin Area over a period of five years of vector control.

    PubMed

    Dadzie, K Y; Rolland, A; Thylefors, B

    1984-03-01

    The results of an ophthalmological evaluation conducted in seven West African savannah villages before and after 5 years of vector control, were analysed to determine the effect of an interrupted or greatly reduced transmission of Onchocerca volvulus on the evolution of ocular onchocerciasis. Cross-sectional data showed a significant reduction of the prevalence of ocular onchocerciasis in five of the villages, and the rates of irreversible ocular lesions and blindness were generally lower after 5 years of vector control. A longitudinal study of a defined population showed that the ocular status of most patients with ocular onchocerciasis remained stable or improved over the 5 year period, particularly in lightly infected cases. The evolution of ocular onchocerciasis showed a deterioration in a minor proportion, restricted to cases of already existing severe lesions, resulting in blindness. A comparison of ophthalmic data from adjacent areas without vector control, indicates that a five year period of vector control may reduce the risk of developing eye lesions or blindness due to onchocerciasis by 50%. PMID:6608814

  13. The Beffa form of Simulium soubrense of the S. damnosum complex in Togo and Benin.

    PubMed

    Cheke, R A; Garms, R; Ouedraogo, J; Somé, A; Sowah, S

    1987-01-01

    The Beffa form of Simulium soubrense Vajime & Dunbar, a member of the S. sanctipauli sub-complex of the S. damnosum complex, was found breeding throughout rivers in the Togo-Benin Gap, as far north as 9 degrees 30'N. Its distribution changed with the season. In southern Togo there were seasonal fluctuations in the relative abundancies of the Beffa form and of S. damnosum/S.sirbanum. There was considerable temporal and regional variation in the frequencies of different colour morphs of adult flies. The flies in Benin tended to be darker. Infections with Onchocerca volvulus (Leuckart) appeared to be independent of the host's colour morph category. Larger flies harboured significantly more first stage Onchocerca larvae but no significant relations with fly size were found for second and third stage larvae. PMID:2979517

  14. The cytotaxonomy of Simulium damnosum s.l. (Diptera: Simuliidae) from the Thyolo onchocerciasis focus in Malawi and description of a new member of the complex.

    PubMed

    Vajime, C G; Tambala, P A; Krüger, A; Post, R J

    2000-04-01

    Larvae of the Simulium damnosum complex were collected in southern Malawi, in particular from the Thyolo onchocerciasis focus. Cytological identifications revealed the occurrence of S. (Edwardsellum) thyolense sp.nov., S. kilibanum Gouteux, 'Ketaketa', a new cytoform tentatively designated 'Mwamphanzi', and two unassigned specimens. Simulium thyolense sp.nov. is presumably the major vector of Onchocerca volvulus in the area, but it remains possible that the other cytospecies are secondary vectors. Simulium thyolense sp.nov. is most appropriately classified near the 'Sanje' subcomplex, whereas 'Mwamphanzi' and the unassigned specimens are members of the 'Ketaketa' subcomplex. PMID:10884873

  15. Prevalence of filariasis in symptomatic patients in Moyen Chari district, south of Chad.

    PubMed

    Bregani, Enrico Rino; Balzarini, Laura; Mbaïdoum, Narassem; Rovellini, Angelo

    2007-07-01

    Filarial parasites infect an estimated 140 million people worldwide. Wuchereria bancrofti, Onchocerca volvulus, Loa loa and Mansonella perstans are responsible for most filarial infections in sub-Saharan Africa. We describe the prevalence and the clinical characteristics of filariasis in symptomatic patients in Goundi Sanitary district:167 patients were enrolled (99 men, 68 women). M. perstans microfilariae were isolated in peripheral blood in 164 cases, while Loa loa and Wuchereria bancrofti filariasis were diagnosed in only six and three cases, respectively. The most frequent filariasis observed in our study were due to M. perstans and L. loa, while the few cases of W. bancrofti filariasis seem to have been acquired abroad. No cases of O. volvulus were observed. Microfilarial burden was not related to symptoms, but a correlation between eosinophilia and pruritus was evident. No relationship was observed between eosinophils and symptoms. The prevalence observed in symptomatic patients could reflect the real prevalence of filariasis. PMID:17716512

  16. Optimization of the Esperanza window trap for the collection of the African onchocerciasis vector Simulium damnosum sensu lato.

    PubMed

    Toé, Laurent D; Koala, Lassane; Burkett-Cadena, Nathan D; Traoré, Bizini M; Sanfo, Moussa; Kambiré, Sié Roger; Cupp, Eddie W; Traoré, Soungalo; Yameogo, Laurent; Boakye, Daniel; Rodríguez-Pérez, Mario A; Unnasch, Thomas R

    2014-09-01

    A simple inexpensive trap (Esperanza window trap) was shown recently to collect significant numbers of Simulium ochraceum sensu lato, a major vector of Onchocerca volvulus in Mesoamerica. Here, we report studies optimizing this trap for the collection of Simulium damnosum s.l., the major vector of O. volvulus in Africa. A shortened, blue and black striped version of the Esperanza window trap, when baited with a combination of CO2 and worn trousers, rivalled human landing collections in the number of S. damnosum s.l. females collected. Traps baited with a commercially available human skin lure and CO2 resulted in collections that were not significantly different than those obtained from traps baited with worn trousers and CO2. This suggests that the Esperanza window trap may offer a replacement for human landing collections for monitoring onchocerciasis transmission in Africa. PMID:24794201

  17. Social Comparison and Education.

    ERIC Educational Resources Information Center

    Levine, John M.

    The classroom environment elicits social comparison behavior in which a student uses peers' performance as a gauge for his own self-assessment. Social comparison as it relates to ability is a four phase sequential process. In phase one, stimulation of social comparison is elicited through developmentally-determined cognitive capacities and motives…

  18. The complete mitochondrial genome sequence of the filarial nematode Wuchereria bancrofti from three geographic isolates provides evidence of complex demographic history.

    PubMed

    Ramesh, Akshaya; Small, Scott T; Kloos, Zachary A; Kazura, James W; Nutman, Thomas B; Serre, David; Zimmerman, Peter A

    2012-05-01

    Mitochondrial (mt) genome sequences have enabled comparison of population genetics and evolution for numerous free-living and parasitic nematodes. Here we define the complete mt genome of Wuchereria bancrofti through analysis of isolates from Papua New Guinea, India and West Africa. Sequences were assembled for each isolate and annotated with reference to the mt genome sequence for Brugia malayi. The length of the W. bancrofti mt genome is approximately 13,637 nucleotides, contains 2 ribosomal RNAs (rrns), 22 transfer RNAs (trns), 12 protein-coding genes, and is characterized by a 74.6% AT content. The W. bancrofti mt gene order is identical to that reported for Onchocerca volvulus, Dirofilaria immitis, Setaria digitata and B. malayi. In addition to using translational start codons identified previously in the mt protein-coding genes of other filarial nematodes, W. bancrofti appears to be unique in using TGT as a translational start codon. Similarly, use of incomplete stop codons in mt protein-coding genes appears to be more common in W. bancrofti than in other human filarial parasites. The complete mt genome sequence reported here provides new genetic markers for investigating phylogenetic and geographic relationships between isolates, and assessing population diversity within endemic regions. The sequence polymorphism enables new strategies to monitor the progress of public health interventions to control and eliminate this important human parasite. We illustrate the utility of this sequence and single nucleotide polymorphisms by inferring the divergence times between the three W. bancrofti isolates, suggesting predictions into their origin and migration. PMID:22326389

  19. Acquisition of Comparison Constructions

    ERIC Educational Resources Information Center

    Hohaus, Vera; Tiemann, Sonja; Beck, Sigrid

    2014-01-01

    This article presents a study on the time course of the acquisition of comparison constructions. The order in which comparison constructions (comparatives, measure phrases, superlatives, degree questions, etc.) show up in English- and German-learning children's spontaneous speech is quite fixed. It is shown to be insufficiently determined by…

  20. Pairwise-Comparison Software

    NASA Technical Reports Server (NTRS)

    Ricks, Wendell R.

    1995-01-01

    Pairwise comparison (PWC) is computer program that collects data for psychometric scaling techniques now used in cognitive research. It applies technique of pairwise comparisons, which is one of many techniques commonly used to acquire the data necessary for analyses. PWC administers task, collects data from test subject, and formats data for analysis. Written in Turbo Pascal v6.0.

  1. Differential induction of Th2- and Th1-associated responses by filarial antigens and endosymbiotic Wolbachia in a murine model of river blindness.

    PubMed

    Gentil, K; Hoerauf, A; Pearlman, E

    2012-06-01

    Immune responses to filarial parasites like the river blindness inducing Onchocerca volvulus are obscured by combined reactions to the filarial nematodes themselves and their endosymbiont bacteria Wolbachia. Overall, infection with filarial nematodes induces a strong Th2 response characterized by IL-5 production and to a lesser degree a Th1 response and IFNγ production. Neutrophil and eosinophil infiltration into the corneal stroma are hallmark features of Onchocerca volvulus stimulation in a mouse model of river blindness. To determine the splenic and corneal response to filarial antigens in the absence of Wolbachia, C57BL/6 mice were immunized subcutaneously with either endosymbiotic Wolbachia alone, a soluble extract from the filaria Acanthocheilonema viteae that does not contain Wolbachia, or both, and injected into the corneal stroma. Neutrophil and eosinophil infiltration into the cornea was assessed by immunohistochemistry. In addition, Th1- and Th2-associated responses to filaria or Wolbachia were investigated by determining IL-5 and IFN-γ production by splenocytes. We found that A. viteae in the absence of Wolbachia induced IL-5 production and eosinophil infiltration, but not IFN-γ. Conversely, Wolbachia induced IFN-γ production and no migration of eosinophils. There was no difference in neutrophil infiltration. Together, these findings demonstrate a distinct Th-associated phenotype induced by filaria and Wolbachia. PMID:24672682

  2. Public opinion: Country comparisons

    NASA Astrophysics Data System (ADS)

    Hopkins, Debbie

    2015-11-01

    Climate change awareness, risk perception and policy support vary between and within countries. National-scale comparisons can help to explain this variability and be used to develop targeted interventions.

  3. Co-endemicity of Loiasis and Onchocerciasis in Rain Forest Communities in Southwestern Nigeria

    PubMed Central

    Ojurongbe, Olusola; Akindele, Akeem Abiodun; Adeleke, Monsuru Adebayo; Oyedeji, Matthew Oyebode; Adedokun, Samuel Adeyinka; Ojo, Josephine Folashade; Akinleye, Callistus Adewale; Bolaji, Oloyede Samuel; Adefioye, Olusegun Adelowo; Adeyeba, Oluwaseyi Adegboyega

    2015-01-01

    Background Loiasis is currently receiving attention as a disease of public health importance because of the possibility of increased risk of developing neurologic serious adverse event following mass ivermectin treatment against onchocerciasis in individual co-infected with Onchocerca volvulus and Loa loa. Methodology/Principal Findings Rapid assessment procedure for loiasis (RAPLOA) was conducted in 12 communities covering the 3 senatorial districts of Osun State, Nigeria. A total of 960 people were interviewed for history of eye worm using the WHO guidelines for rapid assessment. The survey confirmed the presence of loiasis in all the 12 communities with 4 in Osun East/Ife south senatorial district being at high risk with a prevalence of over 40%. Based on the RAPLOA results, communities within Osun East/Ife south senatorial district were selected for microfilaraemic assessment of L. loa and O. volvulus. A total of 1115 and 1091 individuals were screened for L. loa and O. volvulus microfilaria worms respectively. 160 (14.3%) had L. loa microfilaria detected in their blood with 8 (5.0%) individuals having L. loa loads above 8000 mf/ml. 166 (15.2%) subjects had O. volvulus microfilaria (range 4-504 mf/ml) detected in their skin snip. 30 (2.69%) subjects were co-infected with both L. loa and O. volvulus. There was a significant variation in the prevalence (2.1% to 33.3%) of onchocerciasis in the communities studied (p = 0.001). Five (41.7%) of the studied communities had a prevalence that is equal to or greater than 20%. Conclusions/Significance Low prevalence of onchocerciasis and loiasis co-infection in this study suggests that loiasis may not pose a serious epidemiological threat to the continuous distribution and sustainability of ivermectin for the treatment of onchocerciasis. Evaluation of the interruption of onchocerciasis transmissions in this region using all the indicators set forth by WHO is therefore suggested. PMID:25812086

  4. Fall 2013 International Comparisons

    ERIC Educational Resources Information Center

    Northwest Evaluation Association, 2014

    2014-01-01

    This Fall report is an aggregated statistical analysis of Measures of Academic Progress® (MAP®) data from international schools. The report provides a consistent means of comparisons of specific sub-groups by subject and grade, which allows partners to compare their MAP® results with other schools within their region or membership organization.…

  5. Spring 2013 International Comparisons

    ERIC Educational Resources Information Center

    Northwest Evaluation Association, 2013

    2013-01-01

    This report is an aggregated statistical analysis of Measures of Academic Progress® (MAP®) data from international schools. The report provides a consistent means of comparisons of specific sub-groups by subject and grade, which allows partners to compare their MAP® results with other schools within their region or membership organization. There…

  6. Echocardiographic speckle reduction comparison.

    PubMed

    Finn, Seán; Glavin, Martin; Jones, Edward

    2011-01-01

    In this paper, a detailed description and comparison of speckle reduction of medical ultrasound, and in particular echocardiography, is presented. Fifteen speckle reduction filters are described in a detailed fashion to facilitate implementation for research and evaluation. The filtering techniques considered include anisotropic diffusion, wavelet denoising, and local statistics. Common nomenclature and notation are adopted, to expedite comparison between approaches. Comparison of the filters is based on their application to simulated images, clinical videos, and a computational requirement analysis. The ultrasound simulation method provides a realistic model of the image acquisition process, and permits the use of a noise-free reference image for comparison. Application of objective quality metrics quantifies the preservation of image edges, overall image distortion, and improvement in image contrast. The computational analysis quantifies the number of operations required for each speckle reduction method. A speed-accuracy analysis of discretization methods for anisotropic diffusion is included. It is concluded that the optimal method is the OSRAD diffusion filter. This method is capable of strong speckle suppression, increasing the average SNRA of the simulated images by a factor of two. This method also shows favorable edge preservation and contrast improvement, and may be efficiently implemented. PMID:21244977

  7. Conventional parasitology and DNA-based diagnostic methods for onchocerciasis elimination programmes.

    PubMed

    Lloyd, Melanie M; Gilbert, Rebecca; Taha, Nathalie Tebao; Weil, Gary J; Meite, Aboulaye; Kouakou, Ilunga M M; Fischer, Peter U

    2015-06-01

    Commonly used methods for diagnosing Onchocerca volvulus infections (microscopic detection of microfilariae in skin snips and nodule palpation) are insensitive. Improved methods are needed for monitoring and evaluation of onchocerciasis elimination programmes and for clinical diagnosis of individual patients. A sensitive probe-based qPCR assay was developed for detecting O. volvulus DNA, and this was tested with samples collected from an endemic area in eastern Côte d'Ivoire. The new test was evaluated with dried skin snip pairs from 369 subjects and compared to routine skin snip microscopy and nodule palpation results from the same individuals. Onchocerciasis prevalence for these samples by qPCR, skin snip microscopy, and nodule palpation were 56.9%, 26.0%, and 37.9%, respectively. Furthermore, the combination of all three tests produced an infection prevalence of 72.9%, which was significantly higher than 53.1% detected by microscopy plus nodule palpation without qPCR. However, the qPCR assay was negative for 54 of 229 individuals with palpable nodules. qPCR could be a useful tool for detecting residual O. volvulus infections in human populations as prevalence decreases in areas following community-directed treatment with ivermectin. PMID:25818324

  8. Suppression of human lymphocyte responses to specific and non-specific stimuli in human onchocerciasis.

    PubMed Central

    Elkhalifa, M Y; Ghalib, H W; Dafa'Alla, T; Williams, J F

    1991-01-01

    Characterization of in vitro lymphocyte responsiveness was performed on selected groups of onchocerciasis patients from Sudan and Sierra Leone. These patients manifested a very broad range of clinical signs and showed widely divergent parasite infection intensities. Lymphocyte proliferative responses to soluble Onchocerca volvulus antigen (sAg) were poor in infected persons; mitogen and PPD responses were maintained in the normal range in one group of patients from southwestern Sudan, but were profoundly depressed in a group from N.E. Sudan. Proliferative responses and interferon-gamma (INF-gamma) secretion were very significantly depressed in the presence of live microfilariae of O. volvulus or secretions/excretions (S/E) from microfilariae (mf) or from female, but not male, adult parasites. Lymphocyte responses were maintained near normal when exogenous IL-2 was added to these cultures. The results indicate that O. volvulus infection and its clinical consequences are not consistently associated with systemic deficits in immune responsiveness. However, suppression of lymphocyte reactivity by mf and S/E in vitro suggests that direct parasite intervention in host cell responses could be taking place in vivo, perhaps at the local microenvironment level; mediated by effects on cytokine production. PMID:1747951

  9. A novel cyclophilin from parasitic and free-living nematodes with a unique substrate- and drug-binding domain.

    PubMed

    Ma, Dong; Nelson, Laura S; LeCoz, Krystel; Poole, Catherine; Carlow, Clotilde K S

    2002-04-26

    A highly diversified member of the cyclophilin family of peptidyl-prolyl cis-trans isomerases has been isolated from the human parasite Onchocerca volvulus (OvCYP-16). This 25-kDa cyclophilin shares 43-46% similarity to other filarial cyclophilins but does not belong to any of the groups previously defined in invertebrates or vertebrates. A homolog was also isolated from Caenorhabditis elegans (CeCYP-16). Both recombinant O. volvulus and C. elegans cyclophilins were found to possess an enzyme activity with similar substrate preference and insensitivity to cyclosporin A. They represent novel cyclophilins with important differences in the composition of the drug-binding site in particular, namely, a Glu(124) (C. elegans) or Asp(123) (O. volvulus) residue present in a critical position. Site-directed mutagenesis studies and kinetic characterization demonstrated that the single residue dictates the degree of binding to substrate and cyclosporin A. CeCYP-16::GFP-expressing lines were generated with expression in the anterior and posterior distal portions of the intestine, in all larval stages and adults. An exception was found in the dauer stage, where fluorescence was observed in both the cell bodies and processes of the ventral chord motor neurons but was absent from the intestine. These studies highlight the extensive diversification of cyclophilins in an important human parasite and a closely related model organism. PMID:11847225

  10. Onchocerciasis in Gilgel Ghibe River Valley southwest Ethiopia.

    PubMed

    Taye, A; Gebre-Michael, T; Taticheff, S

    2000-02-01

    400 people in Gilgel Ghibe, southwestern Ethiopia, were subjected to parasitological and clinical examination to determine the prevalence and intensity of onchocerciasis. Its association with entomological transmission indices such as the parous rate and annual transmission potential (ATP) were determined simultaneously. Two skin snips per person were taken and examined for microfilariae of Onchocerca volvulus. In addition, collections of adult blackfly were done from human baits seated in pairs at 4 representative sites at the riverbank and away from the riverbank. Flies were then dissected for parity and infections with O. volvulus. Among the 228 people examined, the prevalence of the disease was low (17%), being higher in males than in females (19% vs. 14%). The geometric mean of microfilarial density was 11.1 mf per skin snip. Itching and skin changes were the most common signs and symptoms of the disease. The predominant anthropophilic blackfly species was Simulium (Edwardsellum) damnosum s.l. The annual parous rate was 74.7%, while ATP was 1669.5, being higher at the riverbank than at farther sites, suggesting a greater risk of infection by the riverside. In conclusion, the low prevalence of onchocerciasis vis-a-vis the high ATP level could be caused by the possible presence of bovine onchocerciasis in the area. Further studies employing molecular techniques are needed to identify O. volvulus from other filariae in flies. PMID:10774086

  11. Retained gas inventory comparison

    SciTech Connect

    BARTON, W.B.

    1999-05-18

    Gas volume data derived from four different analytical methods were collected and analyzed for comparison to volumes originally used in the technical basis for the Basis for Interim Operations (BIO). The original volumes came from Hodgson (1996) listed in the reference section of this document. Hodgson (1996) screened all 177 single and double-shell tanks for the presence of trapped gas in waste via two analytical methods: Surface Level Rise (SLR), and Barometric Pressure Effect (BPE). More recent gas volume projections have been calculated using different analytical techniques along with updates to the parameters used as input to the SLR and BPE models. Gas volumes derived from new analytical instruments include those as measured by the Void Fraction Instrument (VFI) and Retained Gas Sampler (RGS). The results of this comparison demonstrate that the original retained gas volumes of Hodgson (1996) used as a technical basis in developing the BIO were conservative, and were conservative from a safety analysis standpoint. These results represent only comparisons to the original reported volumes using the limited set of newly acquired data that is available.

  12. NTP comparison process

    NASA Technical Reports Server (NTRS)

    Corban, Robert

    1993-01-01

    The systems engineering process for the concept definition phase of the program involves requirements definition, system definition, and consistent concept definition. The requirements definition process involves obtaining a complete understanding of the system requirements based on customer needs, mission scenarios, and nuclear thermal propulsion (NTP) operating characteristics. A system functional analysis is performed to provide a comprehensive traceability and verification of top-level requirements down to detailed system specifications and provides significant insight into the measures of system effectiveness to be utilized in system evaluation. The second key element in the process is the definition of system concepts to meet the requirements. This part of the process involves engine system and reactor contractor teams to develop alternative NTP system concepts that can be evaluated against specific attributes, as well as a reference configuration against which to compare system benefits and merits. Quality function deployment (QFD), as an excellent tool within Total Quality Management (TQM) techniques, can provide the required structure and provide a link to the voice of the customer in establishing critical system qualities and their relationships. The third element of the process is the consistent performance comparison. The comparison process involves validating developed concept data and quantifying system merits through analysis, computer modeling, simulation, and rapid prototyping of the proposed high risk NTP subsystems. The maximum amount possible of quantitative data will be developed and/or validated to be utilized in the QFD evaluation matrix. If upon evaluation of a new concept or its associated subsystems determine to have substantial merit, those features will be incorporated into the reference configuration for subsequent system definition and comparison efforts.

  13. Prevalence and risk factors for Active Convulsive Epilepsy in Kintampo, Ghana

    PubMed Central

    Ae-Ngibise, Kenneth Ayuurebobi; Akpalu, Bright; Ngugi, Anthony; Akpalu, Albert; Agbokey, Francis; Adjei, Patrick; Punguyire, Damien; Bottomley, Christian; Newton, Charles; Owusu-Agyei, Seth

    2015-01-01

    Introduction Epilepsy is common in sub-Saharan Africa, but there is little data in West Africa, to develop public health measures for epilepsy in this region. Methods We conducted a three-stage cross-sectional survey to determine the prevalence and risk factors for active convulsive epilepsy (ACE), and estimated the treatment gap in Kintampo situated in the middle of Ghana. Results 249 people with ACE were identified in a study population of 113,796 individuals. After adjusting for attrition and the sensitivity of the screening method, the prevalence of ACE was 10.1/1000 (95% Confidence Interval (95%CI) 9.5-10.7). In children aged <18 years, risk factors for ACE were: family history of seizures (OR=3.31; 95%CI: 1.83-5.96), abnormal delivery (OR=2.99; 95%CI: 1.07-8.34), problems after birth (OR=3.51; 95%CI: 1.02-12.06), and exposure to Onchocerca volvulus (OR=2.32; 95%CI: 1.12-4.78). In adults, a family history of seizures (OR=1.83; 95%CI: 1.05-3.20), never attended school (OR=11.68; 95%CI: 4.80-28.40), cassava consumption (OR=3.92; 95%CI: 1.14-13.54), pork consumption (OR=1.68; 95%CI: 1.09-2.58), history of snoring at least 3 nights per week (OR=3.40: 95%CI: 1.56-7.41), exposure to Toxoplasma gondii (OR=1.99; 95%CI: 1.15-3.45) and Onchocerca volvulus (OR=2.09: 95%CI: 1.29-3.40) were significant risk factors for the development of ACE. The self-reported treatment gap was 86.9% (95%CI: 83.5%-90.3%). Conclusion ACE is common within the middle belt of Ghana and could be reduced with improved obstetric care and prevention of parasite infestations such as Onchocerca volvulus and Toxoplasma gondii. PMID:26401223

  14. MACPEX Water Measurement Comparison

    NASA Astrophysics Data System (ADS)

    Al-Saadi, J. A.; Thornhill, A.; Alston, E. J.; Chen, G.; Fahey, D. W.; Jensen, E. J.; Mace, G. G.

    2012-12-01

    The Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) airborne field campaign was conducted in March and April 2011 to investigate cirrus cloud properties and the processes that affect their impact on radiation. In pursuit of this goal the NASA WB-57 was outfitted with dozens of in-situ instruments from government and university science teams including a wide range of water instruments. This provided an unprecedented situation to compare eight water instruments on one platform measuring water vapor (CIMS, DLH, HWV, JLH, and ULH), total water (ALIAS and FISH) and ice water content (CLH/IWC) for 14 flight days. Objective and data-driven approaches were applied to analyze the comparison data and to assess the consistency levels between the instruments and instrument uncertainties. The analysis is primarily focused on the upper tropospheric and lower stratospheric conditions, paying particular attention to water levels below 20 ppmv and between 20 - 120 ppmv depending on specific instrument data coverage. To be presented are comparison results suggesting the level of the agreement among the instrument as a function of atmospheric conditions, e.g., temperature and water vapor. Also discussed are some exploratory analyses of instrument precisions.

  15. 5) Review of the Biology and Ecology of Adult Blackflies in Relation to the Transmission of Onchocerciasis in Guatemala.

    PubMed

    Takaoka, Hiroyuki

    2015-11-01

    Recent studies on the biology and ecology of adult blackflies in relation to the transmission of human onchocerciasis in Guatemala are reviewed. First, earlier studies on the transmission of the disease since its discovery by Dr. R. Robles in 1915 are outlined. Second, eleven blackfly species caught on humans are evaluated for vector status on the basis of their natural and experimental infections with third-stage larvae of Onchocerca volvulus, and Simulium ochraceum,* S. metallicum* and S. callidum are confirmed as natural vectors of the disease in Guatemala in descending order of importance, whereas S. gonzalezi, S. haematopotum, S. veracruzanum and S. horacioi are potential vectors. Third, the migration and fate of O. volvulus microfilariae ingested by female blackflies are highlighted on the basis of the findings of the cibarial armature of S. ochraceum and physiological incompatibility of S. metallicum as main barriers against microfilariae, both of which greatly decrease the number of ingested O. volvulus microfilariae developing to the third-stage larvae per female. Fourth, among many ecological factors of female blackfly populations, geographical and altitudinal distributions, habits of blood feeding, host preferences for blood feeding, preference for human body parts, parous rates, daily and seasonal fluctuations of biting activities, in particular, of parous females, gonotrophic cycle, longevity, flight range, and annual transmission potential are reviewed, and their influences on the transmission dynamics of the disease agents are considered. Fifth, effects of air temperatures on the O. volvulus-S. ochraceum complex are examined, with a special reference to the characteristic altitudinal distributions of the disease. The importance of reliable identification of both the vector blackfly species and filarial larvae found in female blackflies is emphasized to understand the transmission of the disease. [*It is now known that these two species are actually

  16. Long History of IAM Comparisons

    SciTech Connect

    Smith, Steven J.; Clarke, Leon E.; Edmonds, James A.; Kejun, Jiang; Kriegler, Elmar; Masui, Toshihiko; Riahi, Keywan; Shukla, Priyadarshi R.; Tavoni, Massimo; Van Vuuren, Detlef; Weyant, John

    2015-04-23

    Correspondence to editor: We agree with the editors that the assumptions behind models of all types, including integrated assessment models (IAMs), should be as transparent as possible. The editors were in error, however, when they implied that the IAM community is just “now emulating the efforts of climate researchers by instigating their own model inter-comparison projects (MIPs).” In fact, model comparisons for integrated assessment and climate models followed a remarkably similar trajectory. Early General Circulation Model (GCM) comparison efforts, evolved to the first Atmospheric Model Inter-comparison Project (AMIP), which was initiated in the early 1990s. Atmospheric models evolved to coupled atmosphere-ocean models (AOGCMs) and results from the first Coupled Model Inter-Comparison Project (CMIP1) become available about a decade later. Results of first energy model comparison exercise, conducted under the auspices of the Stanford Energy Modeling Forum, were published in 1977. A summary of the first comparison focused on climate change was published in 1993. As energy models were coupled to simple economic and climate models to form IAMs, the first comparison exercise for IAMs (EMF-14) was initiated in 1994, and IAM comparison exercises have been on-going since this time.

  17. Geology orbiter comparison study

    NASA Technical Reports Server (NTRS)

    Cutts, J. A. J.; Blasius, K. R.; Davis, D. R.; Pang, K. D.; Shreve, D. C.

    1977-01-01

    Instrument requirements of planetary geology orbiters were examined with the objective of determining the feasibility of applying standard instrument designs to a host of terrestrial targets. Within the basic discipline area of geochemistry, gamma-ray, X-ray fluorescence, and atomic spectroscopy remote sensing techniques were considered. Within the discipline area of geophysics, the complementary techniques of gravimetry and radar were studied. Experiments using these techniques were analyzed for comparison at the Moon, Mercury, Mars and the Galilean satellites. On the basis of these comparative assessments, the adaptability of each sensing technique was judged as a basic technique for many targets, as a single instrument applied to many targets, as a single instrument used in different mission modes, and as an instrument capability for nongeoscience objectives.

  18. Glovebox decontamination technology comparison

    SciTech Connect

    Quintana, D.M.; Rodriguez, J.B.; Cournoyer, M.E.

    1999-09-26

    Reconfiguration of the CMR Building and TA-55 Plutonium Facility for mission requirements will require the disposal or recycle of 200--300 gloveboxes or open front hoods. These gloveboxes and open front hoods must be decontaminated to meet discharge limits for Low Level Waste. Gloveboxes and open front hoods at CMR have been painted. One of the deliverables on this project is to identify the best method for stripping the paint from large numbers of gloveboxes. Four methods being considered are the following: conventional paint stripping, dry ice pellets, strippable coatings, and high pressure water technology. The advantages of each technology will be discussed. Last, cost comparisons between the technologies will be presented.

  19. Social Comparison Processes in Organizations

    ERIC Educational Resources Information Center

    Greenberg, Jerald; Ashton-James, Claire E.; Ashkanasy, Neal M.

    2007-01-01

    We systematically analyze the role of social comparison processes in organizations. Specifically, we describe how social comparison processes have been used to explain six key areas of organizational inquiry: (1) organizational justice, (2) performance appraisal, (3) virtual work environments, (4) affective behavior in the workplace, (5) stress,…

  20. Learning a Network of Comparisons

    ERIC Educational Resources Information Center

    Moeser, Shannon D.; Tarrant, Barbara L.

    1977-01-01

    Using a network of comparisons, B. Hayes-Roth and F. Hayes-Roth found that subjects performed better on adjacent than on nonadjacent comparisons. Results suggested that such networks are processed in a manner fundamentally different from simple linear arrays. Here subjects were required to learn a similar knowledge structure. These results…

  1. Social Comparison in the Classroom: A Review

    ERIC Educational Resources Information Center

    Dijkstra, Pieternel; Kuyper, Hans; van der Werf, Greetje; Buunk, Abraham P.; van der Zee, Yvonne G.

    2008-01-01

    This article reviews research conducted on social comparison processes in the classroom since Festinger proposed his theory of social comparison. It covers the theoretical framework of social comparison theory, and it is organized around the following themes: motives for social comparison, dimensions of social comparison, direction of social…

  2. Exposure to Multiple Parasites Is Associated with the Prevalence of Active Convulsive Epilepsy in Sub-Saharan Africa

    PubMed Central

    Kamuyu, Gathoni; Bottomley, Christian; Mageto, James; Lowe, Brett; Wilkins, Patricia P.; Noh, John C.; Nutman, Thomas B.; Ngugi, Anthony K.; Odhiambo, Rachael; Wagner, Ryan G.; Kakooza-Mwesige, Angelina; Owusu-Agyei, Seth; Ae-Ngibise, Kenneth; Masanja, Honorati; Osier, Faith H. A.; Odermatt, Peter; Newton, Charles R.

    2014-01-01

    Background Epilepsy is common in developing countries, and it is often associated with parasitic infections. We investigated the relationship between exposure to parasitic infections, particularly multiple infections and active convulsive epilepsy (ACE), in five sites across sub-Saharan Africa. Methods and Findings A case-control design that matched on age and location was used. Blood samples were collected from 986 prevalent cases and 1,313 age-matched community controls and tested for presence of antibodies to Onchocerca volvulus, Toxocara canis, Toxoplasma gondii, Plasmodium falciparum, Taenia solium and HIV. Exposure (seropositivity) to Onchocerca volvulus (OR = 1.98; 95%CI: 1.52–2.58, p<0.001), Toxocara canis (OR = 1.52; 95%CI: 1.23–1.87, p<0.001), Toxoplasma gondii (OR = 1.28; 95%CI: 1.04–1.56, p = 0.018) and higher antibody levels (top tertile) to Toxocara canis (OR = 1.70; 95%CI: 1.30–2.24, p<0.001) were associated with an increased prevalence of ACE. Exposure to multiple infections was common (73.8% of cases and 65.5% of controls had been exposed to two or more infections), and for T. gondii and O. volvulus co-infection, their combined effect on the prevalence of ACE, as determined by the relative excess risk due to interaction (RERI), was more than additive (T. gondii and O. volvulus, RERI = 1.19). The prevalence of T. solium antibodies was low (2.8% of cases and 2.2% of controls) and was not associated with ACE in the study areas. Conclusion This study investigates how the degree of exposure to parasites and multiple parasitic infections are associated with ACE and may explain conflicting results obtained when only seropositivity is considered. The findings from this study should be further validated. PMID:24875312

  3. Indirect comparisons of therapeutic interventions

    PubMed Central

    Schöttker, Ben; Lühmann, Dagmar; Boulkhemair, Dalila; Raspe, Heiner

    2009-01-01

    Health political background The comparison of the effectiveness of health technologies is not only laid down in German law (Social Code Book V, § 139 and § 35b) but also constitutes a central element of clinical guidelines and decision making in health care. Tools supporting decision making (e. g. Health Technology Assessments (HTA)) are therefore in need of a valid methodological repertoire for these comparisons. Scientific background Randomised controlled head-to-head trials which directly compare the effects of different therapies are considered the gold standard methodological approach for the comparison of the efficacy of interventions. Because this type of trial is rarely found, comparisons of efficacy often need to rely on indirect comparisons whose validity is being controversially debated. Research questions Research questions for the current assessment are: Which (statistical) methods for indirect comparisons of therapeutic interventions do exist, how often are they applied and how valid are their results in comparison to the results of head-to-head trials? Methods In a systematic literature research all medical databases of the German Institute of Medical Documentation and Information (DIMDI) are searched for methodological papers as well as applications of indirect comparisons in systematic reviews. Results of the literature analysis are summarized qualitatively for the characterisation of methods and quantitatively for the frequency of their application. The validity of the results from indirect comparisons is checked by comparing them to the results from the gold standard – a direct comparison. Data sets from systematic reviews which use both direct and indirect comparisons are tested for consistency by of the z-statistic. Results 29 methodological papers and 106 applications of indirect methods in systematic reviews are being analysed. Four methods for indirect comparisons can be identified: Unadjusted indirect comparisons include, independent of

  4. {sup 129}I interlaboratory comparison

    SciTech Connect

    Roberts, M.L.; Caffee, M.W.; Proctor, L.D.

    1996-05-01

    An interlaboratory comparison exercise for {sup 129}I has been organized and conducted. A total of seven laboratories participated in the exercise to either a full or limited extent. In the comparison, a suite of 11 samples were used. This suite of standards contained both synthetic `standard type` materials(i.e., AgI) and environmental materials. The isotopic {sup 129}I/{sup 127}I ratio of the samples varied from 10{sup -8} to 10{sup -14}. Preliminary results of the comparison are presented.

  5. Onchocerciasis endemic in the State of Bolivar, Venezuela.

    PubMed

    Godoy, G A; Volcan, G S; Medrano, C; Guevara, R

    1989-08-01

    Microfilariae of Onchocerca volvulus were demonstrated by single shoulder-skin biopsy in 42.8% of inhabitants of seven Amerindian villages in an area of approximately 10,000 km2, near the Brasilian Roraima Territory. The highest prevalence was found among the Yanomama Indians of Chajuraña (84.6%, with a mean of 61.3 microfilariae per mg of skin). The six other communities were affected, but with lower prevalence and microfilaria skin densities. The absence of lymphoedema and the few subcutaneous nodules and eye lesions found among the infected individuals suggest a relatively recent introduction of the disease to the region. Mansonella ozzardi infections were also detected in the area. PMID:2604478

  6. THE ARTHROPOD-BORNE ONCHOCERCIASIS: IS IT DESERVED TO BE NEGLECTED?.

    PubMed

    El-Bahnasawy, Mamdouh M M; Morsy, Ayman T A; Morsy, Tosson A

    2015-12-01

    Onchocerciasis a filarial parasitic nematode, also known as river blindness and Robles disease, is a neglected tropical disease infecting more than 18 million people mainly in sub-Saharan of Africa, the Middle East, South and Central America and many other countries. Disease infectivity initiates from Onchocerca volvulus (Filarioidea: Onchocercidae) transmitted by the blackfly, Simulium sp. which introduces the infective stage larva with its saliva into the skin. Within human body, adult females (macrofilaria) produce thousands of larvae (microfilariae) which migrate in skin and eye. Infection results in severe visual impairment or blindness for about 2 million, as being the world's second-leading cause of blindness after trachoma, as well as skin onchocercomata. PMID:26939243

  7. Nodding syndrome, western Uganda, 1994.

    PubMed

    Kaiser, Christoph; Rubaale, Tom; Tukesiga, Ephraim; Kipp, Walter; Asaba, George

    2015-07-01

    Nodding syndrome (NS) is a poorly understood condition, which was delineated in 2008 as a new epilepsy syndrome. So far, confirmed cases of NS have been observed in three circumscribed African areas: southern Tanzania, southern Sudan, and northern Uganda. Case-control studies have provided evidence of an association between NS and infection with Onchocerca volvulus, but the causation of NS is still not fully clarified. We report a case of a 15-year old boy with head nodding seizures and other characteristic features of NS from an onchocerciasis endemic area in western Uganda, with no contiguity to the hitherto known areas. We suggest that the existence of NS should be systematically investigated in other areas. PMID:25918208

  8. Nodding syndrome-a new hypothesis and new direction for research.

    PubMed

    Colebunders, Robert; Hendy, Adam; Nanyunja, Miriam; Wamala, Joseph Francis; van Oijen, Marieke

    2014-10-01

    Nodding syndrome (NS) is an unexplained neurological illness that mainly affects children aged between 5 and 15 years. NS has so far been reported from South Sudan, northern Uganda, and Tanzania, but in spite of extensive investigations, the aetiology remains unknown. We hypothesize that blackflies (Diptera: Simuliidae) infected with Onchocerca volvulus microfilariae may also transmit another pathogen. This may be a novel neurotropic virus or an endosymbiont of the microfilariae, which causes not only NS, but also epilepsy without nodding. This hypothesis addresses many of the questions about NS that researchers have previously been unable to answer. An argument in favour of the hypothesis is the fact that in Uganda, the number of new NS cases decreased (with no new cases reported since 2013) after ivermectin coverage was increased and with the implementation of a programme of aerial spraying and larviciding of the large rivers where blackflies were breeding. If confirmed, our hypothesis will enable new strategies to control NS outbreaks. PMID:25181949

  9. Serine proteases of parasitic helminths.

    PubMed

    Yang, Yong; Wen, Yun jun; Cai, Ya Nan; Vallée, Isabelle; Boireau, Pascal; Liu, Ming Yuan; Cheng, Shi Peng

    2015-02-01

    Serine proteases form one of the most important families of enzymes and perform significant functions in a broad range of biological processes, such as intra- and extracellular protein metabolism, digestion, blood coagulation, regulation of development, and fertilization. A number of serine proteases have been identified in parasitic helminths that have putative roles in parasite development and nutrition, host tissues and cell invasion, anticoagulation, and immune evasion. In this review, we described the serine proteases that have been identified in parasitic helminths, including nematodes (Trichinella spiralis, T. pseudospiralis, Trichuris muris, Anisakis simplex, Ascaris suum, Onchocerca volvulus, O. lienalis, Brugia malayi, Ancylostoma caninum, and Steinernema carpocapsae), cestodes (Spirometra mansoni, Echinococcus granulosus, and Schistocephalus solidus), and trematodes (Fasciola hepatica, F. gigantica, and Schistosoma mansoni). Moreover, the possible biological functions of these serine proteases in the endogenous biological phenomena of these parasites and in the host-parasite interaction were also discussed. PMID:25748703

  10. Serosurveillance to monitor onchocerciasis elimination: the Ugandan experience.

    PubMed

    Oguttu, David; Byamukama, Edson; Katholi, Charles R; Habomugisha, Peace; Nahabwe, Christine; Ngabirano, Monica; Hassan, Hassan K; Lakwo, Thomson; Katabarwa, Moses; Richards, Frank O; Unnasch, Thomas R

    2014-02-01

    Uganda is the only African country whose onchocerciasis elimination program uses a two-pronged approach of vector control and mass drug distribution. The Ugandan program relies heavily upon the use of serosurveys of children to monitor progress toward elimination. The program has tested over 39,000 individuals from 11 foci for Onchocerca volvulus exposure, using the Ov16 ELISA test. The data show that the Ov16 ELISA is a useful operational tool to monitor onchocerciasis transmission interruption in Africa at the World Health Organization (WHO) recommended threshold of < 0.1% in children. The Ugandan experience has also resulted in a re-examination of the statistical methods used to estimate the boundary of the upper 95% confidence interval for the WHO prevalence threshold when all samples tested are negative. This has resulted in the development of Bayesian and hypergeometric statistical methods that reduce the number of individuals who must be tested to meet the WHO criterion. PMID:24343885

  11. Litomosoides sigmodontis: a jird urine metabolome study.

    PubMed

    Globisch, Daniel; Specht, Sabine; Pfarr, Kenneth M; Eubanks, Lisa M; Hoerauf, Achim; Janda, Kim D

    2015-12-15

    The neglected tropical disease onchocerciasis affects more than 35 million people worldwide with over 95% in Africa. Disease infection initiates from the filarial parasitic nematode Onchocerca volvulus, which is transmitted by the blackfly vector Simulium sp. carrying infectious L3 larvae. New treatments and diagnostics are required to eradicate this parasitic disease. Herein, we describe that a previously discovered biomarker for onchocerciasis, N-acetyltyramine-O-glucuronide (NATOG) is also present in urine samples of jirds infected with the onchocerciasis model nematode Litomosoides sigmodontis. Increased NATOG values paralleled a progressing infection and demonstrated that quantification of NATOG in this rodent model can be utilized to track its infectivity. Moreover, our findings suggest how NATOG monitoring may be used for evaluating potential drug candidates. PMID:26573416

  12. Serine protease inhibitors of parasitic helminths.

    PubMed

    Molehin, Adebayo J; Gobert, Geoffrey N; McManus, Donald P

    2012-05-01

    Serine protease inhibitors (serpins) are a superfamily of structurally conserved proteins that inhibit serine proteases and play key physiological roles in numerous biological systems such as blood coagulation, complement activation and inflammation. A number of serpins have now been identified in parasitic helminths with putative involvement in immune regulation and in parasite survival through interference with the host immune response. This review describes the serpins and smapins (small serine protease inhibitors) that have been identified in Ascaris spp., Brugia malayi, Ancylostoma caninum Onchocerca volvulus, Haemonchus contortus, Trichinella spiralis, Trichostrongylus vitrinus, Anisakis simplex, Trichuris suis, Schistosoma spp., Clonorchis sinensis, Paragonimus westermani and Echinococcus spp. and discusses their possible biological functions, including roles in host-parasite interplay and their evolutionary relationships. PMID:22310379

  13. Cutaneous onchocerciasis in Dumbu, a pastoral area in the North-West region of Cameroon: diagnostic challenge and socio-economic implications.

    PubMed

    Njim, Tsi; Ngum, Joel Mbigha; Aminde, Leopold Ndemnge

    2015-01-01

    Onchocerciasis is a severe parasitic infestation caused by Onchocerca volvulus which causes disabling skin and subcutaneous tissue changes and ultimately leads to blindness. It has a huge public health impact due to its socioeconomic burden and the vast number of people it affects in developing countries. In this case, a 60 years old woman was encountered with leopard skin like changes, rashes and pruritus on the left leg; which had been managed as cutaneous mycosis for over a period of 8 years. A diagnosis of onchocerciasis was finally made after a skin snip identified onchocercal microfilariae. The above case shows that onchocerciasis is still a neglected tropical disease (NTD) in Cameroon. This emphasizes the need for more expansive outreach programs in remote areas in Cameroon, a change in health policies to ensure the eradication of this disabling disease and health promotion amongst vulnerable populations. PMID:26966494

  14. Selective primary health care: strategies for control of disease in the developing world. VI. Onchocerciasis.

    PubMed

    Greene, B M

    1983-01-01

    Onchocerca volvulus, a major filarial parasite of humans, infects tens of millions of people and is a leading cause of blindness. It also causes disabling or disfiguring dermatitis and lymph node involvement. The infection is transmitted by the bite of female blackflies of Simulium species, which breed around freely flowing waterways. Vector control by aerial spraying of rivers and streams with larvicide has achieved some success in the Volta River Basin, but other areas are less well-suited for such an approach. Efforts to control onchocerciasis are plagued by emerging resistance of blackflies, excessive costs of spraying, and the lack of suitable chemotherapy for existing cases. Mass chemotherapy for infected persons as a means to limit the disease and its impact is not feasible because existing drug regiments are too complex, too toxic, or not effective enough. Selective chemotherapy directed at persons at high risk of complications may be a more effective means of minimizing the impact of the disease. PMID:6622890

  15. Descriptions of members of the Simulium damnosum complex (Diptera: Simuliidae) from southern Africa, Ethiopia and Tanzania.

    PubMed

    Krüger, A; Car, M; Maegga, B T A

    2005-04-01

    This paper presents cytotaxonomic details of five populations of the Simulium damnosum complex from South Africa, Swaziland and Ethiopia. The 'Nkusi SW' and 'Pienaars' forms are newly designated members of the complex from South Africa, but the taxonomic rank of an isolate indistinguishable chromosomally from the 'Nkusi' cytoform remains unclear. From Ethiopia two cytoforms were identified, one of which shares two diagnostic chromosome inversions with the cytoform 'Kisiwani' from Tanzania. The second form belongs to S. kaffaense, and is the suspected local vector of Onchocerca volvulus. In addition, a re-analysis of the cytoform 'Kibwezi' from north-eastern Tanzania provided further insights into its population subdivision, and its genetic and morphological characteristics. Cytotaxonomic similarities between 'Kibwezi', S. mengense and S. pandanophilum, along with their biogeography, indicate a relict status of each of these taxa. PMID:15829137

  16. Cytotaxonomy of the Simulium damnosum complex and description of new cytotypes in the Tukuyu focus, southwest Tanzania.

    PubMed

    Maegga, B T; Cupp, E W

    1994-06-01

    Larvae of Simulium damnosum complex collected from rivers draining Tukuyu onchocerciasis focus were chromosomally examined. Of the 970 larvae analysed, 910 were identified as Kiwira form, a newly described cytotype found in all S. damnosum larval habitats in the Tukuyu area, while 51 were classified as a new subpopulation, tentatively named as Kasyabone form. The F1 larval progeny obtained from wild caught human biting S. damnosum and reared in the laboratory were chromosomally examined. 509 F1 larvae from 70 females blood fed on human volunteers were identified as Kiwira form. As the main human-biting member of the complex in the Tukuyu area, and because some of the wild caught females had developing filarial larvae indistinguishable from those of Onchocerca volvulus, Kiwira form is thus incriminated as the local vector of onchocerciasis. These observations are discussed with respect to previous literature. PMID:7939162

  17. Serine Proteases of Parasitic Helminths

    PubMed Central

    Yang, Yong; Wen, Yun jun; Cai, Ya Nan; Vallée, Isabelle; Boireau, Pascal; Liu, Ming Yuan; Cheng, Shi Peng

    2015-01-01

    Serine proteases form one of the most important families of enzymes and perform significant functions in a broad range of biological processes, such as intra- and extracellular protein metabolism, digestion, blood coagulation, regulation of development, and fertilization. A number of serine proteases have been identified in parasitic helminths that have putative roles in parasite development and nutrition, host tissues and cell invasion, anticoagulation, and immune evasion. In this review, we described the serine proteases that have been identified in parasitic helminths, including nematodes (Trichinella spiralis, T. pseudospiralis, Trichuris muris, Anisakis simplex, Ascaris suum, Onchocerca volvulus, O. lienalis, Brugia malayi, Ancylostoma caninum, and Steinernema carpocapsae), cestodes (Spirometra mansoni, Echinococcus granulosus, and Schistocephalus solidus), and trematodes (Fasciola hepatica, F. gigantica, and Schistosoma mansoni). Moreover, the possible biological functions of these serine proteases in the endogenous biological phenomena of these parasites and in the host-parasite interaction were also discussed. PMID:25748703

  18. The onchocercal nodule: interrelationship of adult worms and blood vessels.

    PubMed

    George, G H; Palmieri, J R; Connor, D H

    1985-11-01

    This study of onchocercal nodules reveals an intimate relationship between the cuticle of Onchocerca volvulus and the capillaries of the host. Perfusion of blood vessels with India ink and other special techniques reveal a proliferation of capillaries around the worms and communication between small vessels and the spaces around the worms. The space around the worm is continuous with the central fibrin lake. These findings, together with the fact that the worm's gut contains hemosiderin, suggest that the worm subverts the vascular reaction and causes within the nodule a controlled hemorrhage that serves the worm's nutritional needs. We believe this explains, in part, how worms survive in fibrous nodules for many years. PMID:3834800

  19. Mating, blood feeding, and oviposition of Simulium damnosum Theobald in the laboratory

    PubMed Central

    Wenk, Peter; Raybould, John N.

    1972-01-01

    The development of suitable techniques for colonizing the vectors of human onchocerciasis in the laboratory would facilitate critical studies on many aspects of their biology. Progress towards this end, however, has until now been prevented by the fact that no African simuliid had been induced to mate in captivity. The main vector of human onchocerciasis in Africa is Simulium damnosum, which exists in a number of different forms, some but not all of which bite man. During the present investigations one form of S. damnosum, the “Kibwezi” form, was successfully induced to mate, to blood-feed, and to lay viable eggs in the laboratory. The methods described should be tested on other forms of S. damnosum, especially the anthropophilic forms responsible for the transmission of Onchocerca volvulus. ImagesFig. 1 PMID:4540682

  20. Ocular onchocerciasis

    PubMed Central

    Thylefors, B.

    1978-01-01

    Well over 20 million people in the world are infected with Onchocerca volvulus and it is probable that 200 000-500 000 people are blind as a result of this infection, which is the most important cause of blindness in certain areas of Africa and Latin America. Treatment of the disease is difficult and often produces serious adverse reactions in the patient. Combined use of diethylcarbamazine citrate and suramin is still the most suitable form of treatment. Screening for the early detection of cases at high risk of ocular manifestations must be organized, and their treatment undertaken, if blindness is to be avoided. Prevention of ocular onchocerciasis is feasible, using vector control methods to reduce transmission, but the procedures are costly and may have to be maintained for many years. Research is needed to improve treatment and to find a chemoprophylactic agent or a preventive vaccine. PMID:307448

  1. Vector competence of Simulium metallicum s.l. (Diptera: Simuliidae) in two endemic areas of human onchocerciasis in northern Venezuela.

    PubMed

    Grillet, M E; Botto, C; Basañez, M G; Barrera, R

    1994-02-01

    Experimental infections of Simulium metallicum s.l. with Onchocerca volvulus were carried out in two onchocerciasis foci, Altamira and Trincheras, in northern Venezuela, to determine vector competence. Wild-caught flies, fed on infected volunteers, were maintained in the laboratory for 13-15 days at 27 degrees C. Parasite development was complete but asynchronous and retarded. No differences in the vector competence of the two populations of S. metallicum s.l. were found. However, a less efficient development of the parasite occurred during the dry season at both localities. The distribution of the parasite within the vector was aggregated and also displayed seasonal variation. The seasonal susceptibility may be a consequence of a density-dependence regulation mechanism of the parasite within the vector. These results indicate a relatively low vector competence for S. metallicum s.l. in northern Venezuela. PMID:8192518

  2. Hydrogen peroxide is the most toxic oxygen species for Onchocerca cervicalis microfilariae.

    PubMed

    Callahan, H L; Crouch, R K; James, E R

    1990-06-01

    The toxicity of the active oxygen species hydrogen peroxide, superoxide radical, hydroxyl radical and singlet oxygen to microfilariae (mf) has been studied in vitro, using active oxygen-generating systems and scavengers/inhibitors. Mf viability was monitored by uptake of the radiolabel, [3H]2-deoxy-D-glucose. Hydrogen peroxide and singlet oxygen, but not superoxide radical or hydroxyl radical, are toxic for mf. Hydrogen peroxide was toxic for mf within 2 h at concentrations as low as 5 microM, an amount eosinophils have been shown to release in vitro (Weiss et al. 1986). Catalase and thiourea, but not inactivated catalase, superoxide dismutase (SOD), singlet oxygen scavengers, or hydroxyl radical scavengers, protected mf. Mf have relatively high levels of endogenous SOD but no measurable glutathione peroxidase and low levels of catalase when compared with other parasites (Callahan, Crouch & James, 1988). The low levels of hydrogen peroxide-scavenging enzymes correlate well with mf sensitivity to hydrogen peroxide and the protective effect of exogenous catalase. PMID:2163503

  3. Comparison of Artificial Compressibility Methods

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin; Housman, Jeffrey; Kwak, Dochan

    2004-01-01

    Various artificial compressibility methods for calculating the three-dimensional incompressible Navier-Stokes equations are compared. Each method is described and numerical solutions to test problems are conducted. A comparison based on convergence behavior, accuracy, and robustness is given.

  4. COMPARISON OF FRACTURED BEDROCK REMEDIATION

    EPA Science Inventory

    This report compares the technologies/approaches used at 7 Superfund sites to treat contaminated groundwater in fractured bedrock. The comparison shows how well each technology/approach met the stated goal, problems encountered, and lessons learned.

  5. Onchocerciasis in the Upper Imo River Basin, Nigeria: Prevalence and Comparative Study of Waist and Shoulder Snips from Mesoendemic Communities

    PubMed Central

    Uttah, EC

    2010-01-01

    Background Onchocerciasis is endemic in the Imo River Basin, Nigeria. This study was aimed at assessing the prevalence and intensity of microfilaria of Onchocerca volvulus in the area. Methods A cross-sectional study was carried out in the Okigwe Local Government Area, Imo State, Nigeria. Two skin snips (one from the waist and another from the shoulder) were taken from 1024 individuals examined. The survey coverage was high (91.8% of the study population). An individual was considered mf positive if either of the waist or shoulder snips or both were mf positive. The SPSS for Windows package was used for entering and analysis of data. Results Thirty-seven percentage of those examined was positive for Onchocerca volvulus microfilariae (39.2% of males and 34.9% of females). The mf prevalence increased steadily with increasing age to reach 70.4% in the oldest age group. The overall mf Geometric Mean Intensity among mf positive individuals was 16 mf/skin snip and was significantly higher among males (18 mf/skin snip) than females (14 mf/skin snip) (p<0.01). A scatter plot of microfilariae numbers in snips from the waist against numbers in snips from the shoulder of the same individuals, showed close correlation (Pearson's correlation coefficient=+0.90; p<0.01), and those with mf intensities below 10 mf/snip had a more scattering tendency away from the regression line than those with higher mf intensities. Conclusion Onchocerciasis is a public health concern in the area. Perhaps, 10 mf/snip is critical intensity threshold for reliable sampling using corneo-scleral punch. PMID:22347242

  6. Human onchocerciasis in Nigeria: isotypic responses and antigen recognition in individuals with defined cutaneous pathology.

    PubMed

    Murdoch, M E; Abiose, A; Garate, T; Hay, R J; Jones, B R; Maizels, R M; Parkhouse, R M

    1996-06-01

    Antigen (Ag)-specific isotype responses to Onchocerca volvulus Ag (OvAg) were assessed by enzyme-linked immunosorbent assay and immunoblot in 123 residents of a mesoendemic area in northern Nigeria and 16 Nigerians from a nonendemic area. Individuals from an endemic area were divided into six groups on the basis of cutaneous onchocercal pathology: acute papular onchodermatitis (APOD), chronic papular onchodermatitis (CPOD), lichenified onchodermatitis (LOD), atrophy (ATR), depigmentation (DPM) and normal skin, high microfilarial load (NSHMF). Immunoglobulin (Ig)G1-4 levels were all significantly associated with residence in an endemic area after controlling for age and sex (all P values = 0.0001). Both IgG1 and IgG3 were significantly associated with onchocercal clinical category after controlling for age, sex, and microfilarial load (P = 0.0031 and 0.0035, respectively). The IgG1 and IgG3 responses were both highest in LOD and lowest in NSHMF and ATR, respectively. A significant inverse association was found between IgG1 levels and microfilarial load after controlling for age, sex, and clinical category (P = 0.0061). On immunoblotting, 20 (44.4%) of 45 individual onchocerciasis sera contained IgG4 antibodies against a band of 29-31 kD, which was not recognized by pooled sera from individuals with other filarial infections. There was heterogeneity of antigen recognition within each of the onchocercal clinical groups, which together with the small numbers examined by immunoblotting, limits interpretation. Nevertheless, some differences in patterns of antigen recognition were found between the onchocercal groups. The LOD group demonstrated prominent immunoreactivity in IgG1 and IgG3 while a general paucity of low molecular weight reactivity was seen with NSHMF in IgG1-3 subclasses, but there was no specific banding pattern that differentiated NSHMF from those with pathology. Comparison of microfilariae-positive (mf+) and mf- individuals with onchocercal skin disease

  7. Human filarial Wolbachia lipopeptide directly activates human neutrophils in vitro.

    PubMed

    Tamarozzi, F; Wright, H L; Johnston, K L; Edwards, S W; Turner, J D; Taylor, M J

    2014-10-01

    The host inflammatory response to the Onchocerca volvulus endosymbiont, Wolbachia, is a major contributing factor in the development of chronic pathology in humans (onchocerciasis/river blindness). Recently, the toll-like pattern recognition receptor motif of the major inflammatory ligands of filarial Wolbachia, membrane-associated diacylated lipoproteins, was functionally defined in murine models of pathology, including mediation of neutrophil recruitment to the cornea. However, the extent to which human neutrophils can be activated in response to this Wolbachia pattern recognition motif is not known. Therefore, the responses of purified peripheral blood human neutrophils to a synthetic N-terminal diacylated lipopeptide (WoLP) of filarial Wolbachia peptidoglycan-associated lipoprotein (PAL) were characterized. WoLP exposure led to a dose-dependent activation of healthy, human neutrophils that included gross morphological alterations and modulation of surface expressed integrins involved in tethering, rolling and extravasation. WoLP exposure induced chemotaxis but not chemokinesis of neutrophils, and secretion of the major neutrophil chemokine, interleukin 8. WoLP also induced and primed the respiratory burst, and enhanced neutrophil survival by delay of apoptosis. These results indicate that the major inflammatory motif of filarial Wolbachia lipoproteins directly activates human neutrophils in vitro and promotes a molecular pathway by which human neutrophils are recruited to sites of Onchocerca parasitism. PMID:24909063

  8. Wolbachia and its implications for the immunopathology of filariasis.

    PubMed

    Genchi, Claudio; Kramer, Laura H; Sassera, Davide; Bandi, Claudio

    2012-03-01

    Filarial infections are characterized by immunopathological phenomena, that are responsible for the onset of often dramatic pathological outcomes, such as blindness (Onchocerca volvulus) and elephantiasis (W. bancrofti). In addition, the long-term survival (as long as 10 years) of these parasites in otherwise immunocompetent hosts indicates that these nematodes are capable of manipulating the host immune response. The ground-breaking discovery of the bacterial endosymbiont Wolbachia, which resides in most filarial nematodes causing disease, has led to increasing interest in the role it may play in immuno-modulation, pro-inflammatory pathology and other aspects of filarial infection. Indeed, Wolbachia has been shown to be responsible for exacerbating inflammation (as in river blindness), while at the same time blocking efficient elimination of parasites through the host immune response (Onchocerca ochengi). While studies aimed at identifying Wolbachia as a potential target for anti-filarial therapy are at the forefront of current research, understanding its role in the immunology of filarial infection is a fascinating field that has yet to uncover many secrets. PMID:22214329

  9. Ocular Filariasis in US Residents, Returning Travelers, and Expatriates.

    PubMed

    Diaz, James H

    2015-01-01

    Several factors acting in concert now place US residents, returning travelers, and expatriates at risks of contracting ocular filariasis including increasing seroprevalence rates of zoonotic filariasis, international travel bringing tourists to and expatriates from filariasis-endemic regions, and warming temperatures extending distribution ranges of arthropod vectors. To describe the epidemiology and outcomes of ocular filariasis and to recommend strategies for the diagnosis, management, and prevention of ocular filariasis, internet search engines were queried with the key words in order to examine case reports and series of ocular filariasis in the US and elsewhere. Descriptive epidemiological, morphological, and molecular evidence now support increasing cases of ocular filariasis in domestic and wild animals and humans, with most cases caused by filarial worms including Dirofilaria repens and other zoonotic Dirofilaria species and Onchocerca lupi and other zoonotic Onchocerca species. Clinicians should maintain early suspicion of ocular filariasis in US residents, returning travelers, and expatriates who complain of combinations of red eye, eye pain, foreign body sensation, reduced visual acuity, and migrating ocular worms, even without significant peripheral eosinophilia or microfilaremia. Microfilariae of Wuchereria bancrofti, Brugia malayi, and O. volvulus may traverse the eye, but can usually be treated medically. Mobile adult worms trapped in the subconjunctiva or anterior chamber should be removed by ophthalmologists to permit species identification, prevent posterior uveitis and iritis, and stop worm migration into the posterior chamber which could require lens removal and vitrectomy for worm extraction causing further eye damage. PMID:27159510

  10. Protein Structure Comparison and Classification

    NASA Astrophysics Data System (ADS)

    Çamoǧlu, Orhan; Singh, Ambuj K.

    The success of genome projects has generated an enormous amount of sequence data. In order to realize the full value of the data, we need to understand its functional role and its evolutionary origin. Sequence comparison methods are incredibly valuable for this task. However, for sequences falling in the twilight zone (usually between 20 and 35% sequence similarity), we need to resort to structural alignment and comparison for a meaningful analysis. Such a structural approach can be used for classification of proteins, isolation of structural motifs, and discovery of drug targets.

  11. Inhibition in Dot Comparison Tasks

    ERIC Educational Resources Information Center

    Clayton, Sarah; Gilmore, Camilla

    2015-01-01

    Dot comparison tasks are commonly used to index an individual's Approximate Number System (ANS) acuity, but the cognitive processes involved in completing these tasks are poorly understood. Here, we investigated how factors including numerosity ratio, set size and visual cues influence task performance. Forty-four children aged 7-9 years completed…

  12. Matrixed business support comparison study.

    SciTech Connect

    Parsons, Josh D.

    2004-11-01

    The Matrixed Business Support Comparison Study reviewed the current matrixed Chief Financial Officer (CFO) division staff models at Sandia National Laboratories. There were two primary drivers of this analysis: (1) the increasing number of financial staff matrixed to mission customers and (2) the desire to further understand the matrix process and the opportunities and challenges it creates.

  13. Characteristics of Multiple Comparison Procedures.

    ERIC Educational Resources Information Center

    Yusuf, Mian Muhammad; And Others

    Multiple comparison procedures (MCPs), in the context of analysis of variance, are becoming more popular than the overall F tests. An attempt is made to clarify confusion among the different MCPs by systematically comparing and contrasting the procedures in terms of their purposes, restrictions, robustness to assumptions, and other special…

  14. [Individual difference in making temporal comparisons: development of Temporal Comparison Orientation Scale].

    PubMed

    Namikawa, Tsutomu

    2011-02-01

    This study developed the Temporal Comparison Orientation Scale and investigated its reliability and validity. Study 1 (N = 481) examined the factor structure and correlations with other related scales (self-consciousness scale; revaluation tendency scale; self-esteem scale; depression scale; social comparison orientation scale). The results suggested that the Temporal Comparison Orientation Scale had good reliability and validity. Study 2 examined the relationship between temporal comparison orientation and affect generated by temporal comparisons. The results showed that individuals high in temporal comparison orientation experienced more negative affect after upward and downward comparisons than individuals low in temporal comparison orientation. The possible uses and limitations of the scale were discussed. PMID:21400863

  15. The status of Simulium oyapockense and S. limbatum as vectors of human onchocerciasis in Brazilian Amazonia.

    PubMed

    Shelley, A J; Dias, A P; Moraes, M A; Procunier, W S

    1987-07-01

    In an attempt to explain the current distribution of onchocerciasis in the forests of northern Brazil (Moraes et al., 1979, 1986), and its potential for dispersal to other areas, this study compares the vector status of Simulium oyapockense Floch and Abonnenc, 1946 in both a hypoendemic and an onchocerciasis free area with that of S. limbatum Knab, 1915 in the latter area. Both species allowed the full development of Onchocerca volvulus (Leuckart) to the infective L3 stage after experimental infection with microfilariae. Their vector competence was significantly lower than for other efficient vector species in South America and Africa because of the lethal effect of the cibarial armature on ingested microfilariae. The low vector capacity of S. oyapockense, together with the low prevalence and intensity of infection of O. volvulus, probably explains why onchocerciasis has not significantly increased in intensity over the last 10 years in the hypoendemic part of the Amazonian focus. Omnipresence of both vector species in the adjacent savanna region, however, could facilitate the spread of onchocerciasis if human population movements continue from the hyperendemic part of the onchocerciasis focus. PMID:2979535

  16. Onchocerciasis transmission levels and Simulium damnosum complex biting activity at riverside and rice field sites in Sierra Leone.

    PubMed

    Davies, J B; Beech-Garwood, P A; Thomson, M C; McMahon, J E

    1988-10-01

    Biting densities of the Simulium damnosum Theobald complex of blackflies and their levels of parasitism by Onchocerca volvulus (Leuckart) were compared at two ecologically contrasted sites in the Southern Province of Sierre Leone, West Africa: by the Tabe riverside close to Gbaiima village where onchocerciasis is hyperendemic (63.1% positive skin-snips) and in open rice fields 2 km from the mesoendemic (54.9%) village of Senehun. Using a combination of morphometric and enzyme electrophoresis techniques, the primary vector was found to belong to the S.sanctipauli subcomplex and was most probably S.soubrense 'B' (sensu Post, 1986). In the wet season biting activity took place throughout the day at the village, but had morning and evening peaks in the rice fields. Transmission of O.volvulus was detected at the village in all months except February-April, while in the rice fields it was detected only during September-November and May at one tenth the level of the village. There was a significant difference between the two sites in the proportion of parous flies carrying third stage larvae in the head, but not of other larval stages. PMID:2980195

  17. Density-Dependent Mortality of the Human Host in Onchocerciasis: Relationships between Microfilarial Load and Excess Mortality

    PubMed Central

    Wagner, Karen S.; Soumbey-Alley, Edoh W.; Boatin, Boakye A.; Basáñez, María-Gloria

    2012-01-01

    Background The parasite Onchocerca volvulus has, until recently, been regarded as the cause of a chronic yet non-fatal condition. Recent analyses, however, have indicated that in addition to blindness, the parasite can also be directly associated with human mortality. Such analyses also suggested that the relationship between microfilarial load and excess mortality might be non-linear. Determining the functional form of such relationship would contribute to quantify the population impact of mass microfilaricidal treatment. Methodology/Principal Findings Data from the Onchocerciasis Control Programme in West Africa (OCP) collected from 1974 through 2001 were used to determine functional relationships between microfilarial load and excess mortality of the human host. The goodness-of-fit of three candidate functional forms (a (log-) linear model and two saturating functions) were explored and a saturating (log-) sigmoid function was deemed to be statistically the best fit. The excess mortality associated with microfilarial load was also found to be greater in younger hosts. The attributable mortality risk due to onchocerciasis was estimated to be 5.9%. Conclusions/Significance Incorporation of this non-linear functional relationship between microfilarial load and excess mortality into mathematical models for the transmission and control of onchocerciasis will have important implications for our understanding of the population biology of O. volvulus, its impact on human populations, the global burden of disease due to onchocerciasis, and the projected benefits of control programmes in both human and economic terms. PMID:22479660

  18. Filariasis in Africa--treatment challenges and prospects.

    PubMed

    Hoerauf, A; Pfarr, K; Mand, S; Debrah, A Y; Specht, S

    2011-07-01

    Lymphatic filariasis (LF) and onchocerciasis are parasitic nematode infections that are responsible for a major disease burden in the African continent. Disease symptoms are induced by the immune reactions of the host, with lymphoedema and hydrocoele in LF, and dermatitis and ocular inflammation in onchocerciasis. Wuchereria bancrofti and Onchocerca volvulus, the species causing LF and onchocerciasis in Africa, live in mutual symbiosis with Wolbachia endobacteria, which cause a major part of the inflammation leading to symptoms and are antibiotic targets for treatment. The standard microfilaricidal drugs ivermectin and albendazole are used in mass drug administration programmes, with the aim of interrupting transmission, with a consequent reduction in the burden of infection and, in some situations, leading to regional elimination of LF and onchocerciasis. Co-endemicity of Loa loa with W. bancrofti or O. volvulus is an impediment to mass drug administration with ivermectin and albendazole, owing to the risk of encephalopathy being encountered upon administration of ivermectin. Research into new treatment options is exploring several improved delivery strategies for the classic drugs or new antibiotic treatment regimens for anti-wolbachial chemotherapy. PMID:21722251

  19. New records of Mansonella ozzardi: a parasite that is spreading from the state of Amazonas to previously uninfected areas of the state of Acre in the Purus River region.

    PubMed

    Adami, Yara Leite; Rodrigues, Gabriel; Alves, Marilene Costa; Moraes, Mario Augusto Pinto; Banic, Dalma Maria; Maia-Herzog, Marilza

    2014-02-01

    Mansonella ozzardi infections are common in the riverside communities along the Solimões, Negro and Purus Rivers in the state of Amazonas (AM). However, little is known about the presence of this parasite in communities located in regions bordering AM and the state of Acre. The prevalence rate of M. ozzardi infections was determined in blood samples from volunteers according to the Knott method. A total of 355 volunteers from six riverine communities were enrolled in the study and 65 (18.3%) were found to be infected with M. ozzardi. As expected, most of the infections (25%) occurred in individuals involved in agriculture, cattle rearing and fishing and an age/sex group analysis revealed that the prevalence increased beginning in the 40-50-years-of-age group and reached 33% in both sexes in individuals over 50 years of age. Based on the described symptomatology, articular pain and headache were found to be significantly higher among infected individuals (56 and 65% prevalence, respectively, p < 0.05). Sera from volunteers were subjected to ELISA using a cocktail of recombinant proteins from Onchocerca volvulus to evaluate the specificity of the test in an endemic M. ozzardi region. No cross-reactions between M. ozzardi-infected individuals and recombinant O. volvulus proteins were detected, thus providing information on the secure use of this particular cocktail in areas where these parasites are sympatric. PMID:24141966

  20. Supergroup C Wolbachia, mutualist symbionts of filarial nematodes, have a distinct genome structure.

    PubMed

    Comandatore, Francesco; Cordaux, Richard; Bandi, Claudio; Blaxter, Mark; Darby, Alistair; Makepeace, Benjamin L; Montagna, Matteo; Sassera, Davide

    2015-12-01

    Wolbachia pipientis is possibly the most widespread endosymbiont of arthropods and nematodes. While all Wolbachia strains have historically been defined as a single species, 16 monophyletic clusters of diversity (called supergroups) have been described. Different supergroups have distinct host ranges and symbiotic relationships, ranging from mutualism to reproductive manipulation. In filarial nematodes, which include parasites responsible for major diseases of humans (such as Onchocerca volvulus, agent of river blindness) and companion animals (Dirofilaria immitis, the dog heartworm), Wolbachia has an obligate mutualist role and is the target of new treatment regimens. Here, we compare the genomes of eight Wolbachia strains, spanning the diversity of the major supergroups (A-F), analysing synteny, transposable element content, GC skew and gene loss or gain. We detected genomic features that differ between Wolbachia supergroups, most notably in the C and D clades from filarial nematodes. In particular, strains from supergroup C (symbionts of O. volvulus and D. immitis) present a pattern of GC skew, conserved synteny and lack of transposable elements, unique in the Wolbachia genus. These features could be the consequence of a distinct symbiotic relationship between C Wolbachia strains and their hosts, highlighting underappreciated differences between the mutualistic supergroups found within filarial nematodes. PMID:26631376

  1. Some unsolved problems in the epidemiology of onchocerciasis.

    PubMed

    Southgate, B A

    1987-01-01

    The descriptive epidemiology of onchocerciasis is well understood in the major foci of infection; a great stimulus to epidemiological research has been the implementation of the first control programme, which led to the eradication of infection in Kenya and, more recently, the vast Onchocerciasis Control Programme in the Volta River Basin of West Africa. However, there are still significant gaps in epidemiological knowledge which hamper the planning of future control programmes and the evaluation of current programmes. The four most important unsolved problems are: the refinement of field diagnostic techniques to identify skin microfilariae at the ultra-low densities that will become common in the late stages of vector-control campaigns; the definitive identification of Onchocerca volvulus infective larvae in Simulium species; strain analysis in the field of microfilariae from humans and of developing stages from Simulium, to determine their potential for ocular pathogenicity; determination of the lifespan, or maximum fecundity span, of adult female O. volvulus after the interruption of transmission. Three other unsolved problems are of enormous interest epidemiologically, although less urgent in practical importance. They are the identification of factors causing severe disease as opposed to heavy infection; the effects of seasonal as opposed to perennial transmission; and the importance of transplacental transmission of microfilariae or soluble antigens. PMID:3297559

  2. Supergroup C Wolbachia, mutualist symbionts of filarial nematodes, have a distinct genome structure

    PubMed Central

    Comandatore, Francesco; Cordaux, Richard; Bandi, Claudio; Blaxter, Mark; Darby, Alistair; Makepeace, Benjamin L.; Montagna, Matteo; Sassera, Davide

    2015-01-01

    Wolbachia pipientis is possibly the most widespread endosymbiont of arthropods and nematodes. While all Wolbachia strains have historically been defined as a single species, 16 monophyletic clusters of diversity (called supergroups) have been described. Different supergroups have distinct host ranges and symbiotic relationships, ranging from mutualism to reproductive manipulation. In filarial nematodes, which include parasites responsible for major diseases of humans (such as Onchocerca volvulus, agent of river blindness) and companion animals (Dirofilaria immitis, the dog heartworm), Wolbachia has an obligate mutualist role and is the target of new treatment regimens. Here, we compare the genomes of eight Wolbachia strains, spanning the diversity of the major supergroups (A–F), analysing synteny, transposable element content, GC skew and gene loss or gain. We detected genomic features that differ between Wolbachia supergroups, most notably in the C and D clades from filarial nematodes. In particular, strains from supergroup C (symbionts of O. volvulus and D. immitis) present a pattern of GC skew, conserved synteny and lack of transposable elements, unique in the Wolbachia genus. These features could be the consequence of a distinct symbiotic relationship between C Wolbachia strains and their hosts, highlighting underappreciated differences between the mutualistic supergroups found within filarial nematodes. PMID:26631376

  3. Ocular onchocerciasis and intensity of infection in the community. II. West African rainforest foci of the vector Simulium yahense.

    PubMed

    Dadzie, K Y; Remme, J; Rolland, A; Thylefors, B

    1989-09-01

    A novel method of analysis was used to describe community patterns of ocular onchocerciasis in relation to the intensity of infection in West African forest villages where S. yahense is the sole vector. The pattern is completely different from that found in the savanna, even after correction for the intensity of infection as measured by the Community Microfilarial Load (CMFL). Lesions of the anterior segment of the eye as well as onchocercal blindness either do not occur or occur only sporadically with increasing CMFL in the Yahense forest whilst a steep linear relation exists between the prevalence of these lesions and the CMFL in the savanna. Lesions of the posterior segment of the eye are also less common in the Yahense forest. For a given skin microfilarial load, the ocular microfilarial load is lower in the Yahense forest. For a given ocular microfilarial load, a lower prevalence of eye lesions is found in the Yahense forest compared to the savanna. It is concluded that microfilariae of Onchocerca volvulus in the Yahense forest are less eye invasive than microfilariae from the savanna. Furthermore, they appear to be also less pathogenic to the eye. These findings explain why ocular onchocerciasis is relatively mild in the Yahense forest, in spite of the high intensities of O. volvulus infection in the community. PMID:2559472

  4. The current status of onchocerciasis in the forest/savanna transition zone of Côte d'Ivoire.

    PubMed

    Adjami, A G; Toé, L; Bissan, Y; Bugri, S; Yaméogo, L; Kone, M; Katholi, C R; Unnasch, T R

    2004-04-01

    Onchocerca volvulus exists in at least two strains in West Africa, while its black-fly vectors consist of sibling species, dwelling in the savanna and forest/transition zones. In transition and degraded forest zones both parasite strains and different sibling species of the vector can be sympatric. The strain of parasite in infected humans and in vector black-flies was determined in two bioclimes along the Bandama river of Côte d'Ivoire. The upper Bandama is located in the savanna bioclime while the Middle Bandama is located in a degraded forest zone. At both sites, savanna-dwelling sibling species of the Simulium damnosum sensu lato species complex predominated. The severe-strain of O. volvulus was the predominant strain at both sites. However, severe-strain parasites represented a significantly larger proportion of those found in the vector population than in the human population in the degraded forest of the Middle Bandama. These data suggest that in degraded forest areas recently invaded by savanna-dwelling species of S. damnosunz s.l. transmission of the severe-strain of the parasite might be more efficient than transmission of the mild-strain. PMID:15151146

  5. Differential Evolutionary Selection and Natural Evolvability Observed in ALT Proteins of Human Filarial Parasites

    PubMed Central

    Devoe, Neil C.; Corbett, Ian J.; Barker, Linsey; Chang, Robert; Gudis, Polyxeni; Mullen, Nathan; Perez, Kailey; Raposo, Hugo; Scholz, John; May, Meghan

    2016-01-01

    The abundant larval transcript (ALT-2) protein is present in all members of the Filarioidea, and has been reported as a potential candidate antigen for a subunit vaccine against lymphatic filariasis. To assess the potential for vaccine escape or heterologous protection, we examined the evolutionary selection acting on ALT-2. The ratios of nonsynonymous (K(a)) to synonymous (K(s)) mutation frequencies (ω) were calculated for the alt-2 genes of the lymphatic filariasis agents Brugia malayi and Wuchereria bancrofti and the agents of river blindness and African eyeworm disease Onchocerca volvulus and Loa loa. Two distinct Bayesian models of sequence evolution showed that ALT-2 of W. bancrofti and L. loa were under significant (P<0.05; P < 0.001) diversifying selection, while ALT-2 of B. malayi and O. volvulus were under neutral to stabilizing selection. Diversifying selection as measured by ω values was notably strongest on the region of ALT-2 encoding the signal peptide of L. loa and was elevated in the variable acidic domain of L. loa and W. bancrofti. Phylogenetic analysis indicated that the ALT-2 consensus sequences formed three clades: the first consisting of B. malayi, the second consisting of W. bancrofti, and the third containing both O. volvulus and L. loa. ALT-2 selection was therefore not predictable by phylogeny or pathology, as the two species parasitizing the eye were selected differently, as were the two species parasitizing the lymphatic system. The most immunogenic regions of L. loa and W. bancrofti ALT-2 sequence as modeled by antigenicity prediction analysis did not correspond with elevated levels of diversifying selection, and were not selected differently than predicted antigenic epitopes in B. malayi and O. volvulus. Measurements of ALT-2 evolvability made by χ2 analysis between alleles that were stable (O. volvulus and B. malayi) and those that were under diversifying selection (W. bancrofti and L. loa) indicated significant (P<0

  6. Differential Evolutionary Selection and Natural Evolvability Observed in ALT Proteins of Human Filarial Parasites.

    PubMed

    Devoe, Neil C; Corbett, Ian J; Barker, Linsey; Chang, Robert; Gudis, Polyxeni; Mullen, Nathan; Perez, Kailey; Raposo, Hugo; Scholz, John; May, Meghan

    2016-01-01

    The abundant larval transcript (ALT-2) protein is present in all members of the Filarioidea, and has been reported as a potential candidate antigen for a subunit vaccine against lymphatic filariasis. To assess the potential for vaccine escape or heterologous protection, we examined the evolutionary selection acting on ALT-2. The ratios of nonsynonymous (K(a)) to synonymous (K(s)) mutation frequencies (ω) were calculated for the alt-2 genes of the lymphatic filariasis agents Brugia malayi and Wuchereria bancrofti and the agents of river blindness and African eyeworm disease Onchocerca volvulus and Loa loa. Two distinct Bayesian models of sequence evolution showed that ALT-2 of W. bancrofti and L. loa were under significant (P<0.05; P < 0.001) diversifying selection, while ALT-2 of B. malayi and O. volvulus were under neutral to stabilizing selection. Diversifying selection as measured by ω values was notably strongest on the region of ALT-2 encoding the signal peptide of L. loa and was elevated in the variable acidic domain of L. loa and W. bancrofti. Phylogenetic analysis indicated that the ALT-2 consensus sequences formed three clades: the first consisting of B. malayi, the second consisting of W. bancrofti, and the third containing both O. volvulus and L. loa. ALT-2 selection was therefore not predictable by phylogeny or pathology, as the two species parasitizing the eye were selected differently, as were the two species parasitizing the lymphatic system. The most immunogenic regions of L. loa and W. bancrofti ALT-2 sequence as modeled by antigenicity prediction analysis did not correspond with elevated levels of diversifying selection, and were not selected differently than predicted antigenic epitopes in B. malayi and O. volvulus. Measurements of ALT-2 evolvability made by χ2 analysis between alleles that were stable (O. volvulus and B. malayi) and those that were under diversifying selection (W. bancrofti and L. loa) indicated significant (P<0

  7. Onchocerciasis Transmission in Ghana: Persistence under Different Control Strategies and the Role of the Simuliid Vectors

    PubMed Central

    Lamberton, Poppy H. L.; Cheke, Robert A.; Winskill, Peter; Tirados, Iñaki; Walker, Martin; Osei-Atweneboana, Mike Y.; Biritwum, Nana-Kwadwo; Tetteh-Kumah, Anthony; Boakye, Daniel A.; Wilson, Michael D.; Post, Rory J.; Basañez, María-Gloria

    2015-01-01

    Background The World Health Organization (WHO) aims at eliminating onchocerciasis by 2020 in selected African countries. Current control focuses on community-directed treatment with ivermectin (CDTI). In Ghana, persistent transmission has been reported despite long-term control. We present spatial and temporal patterns of onchocerciasis transmission in relation to ivermectin treatment history. Methodology/Principal Findings Host-seeking and ovipositing blackflies were collected from seven villages in four regions of Ghana with 3–24 years of CDTI at the time of sampling. A total of 16,443 flies was analysed for infection; 5,812 (35.3%) were dissected for parity (26.9% parous). Heads and thoraces of 12,196 flies were dissected for Onchocerca spp. and DNA from 11,122 abdomens was amplified using Onchocerca primers. A total of 463 larvae (0.03 larvae/fly) from 97 (0.6%) infected and 62 (0.4%) infective flies was recorded; 258 abdomens (2.3%) were positive for Onchocerca DNA. Infections (all were O. volvulus) were more likely to be detected in ovipositing flies. Transmission occurred, mostly in the wet season, at Gyankobaa and Bosomase, with transmission potentials of, respectively, 86 and 422 L3/person/month after 3 and 6 years of CDTI. The numbers of L3/1,000 parous flies at these villages were over 100 times the WHO threshold of one L3/1,000 for transmission control. Vector species influenced transmission parameters. At Asubende, the number of L3/1,000 ovipositing flies (1.4, 95% CI = 0–4) also just exceeded the threshold despite extensive vector control and 24 years of ivermectin distribution, but there were no infective larvae in host-seeking flies. Conclusions/Significance Despite repeated ivermectin treatment, evidence of O. volvulus transmission was documented in all seven villages and above the WHO threshold in two. Vector species influences transmission through biting and parous rates and vector competence, and should be included in transmission models

  8. Performance Comparison: Superbeams, Beta Beams, Neutrino Factory

    SciTech Connect

    Winter, Walter

    2011-10-06

    In this talk, the performance comparison among superbeams (SB), beta beams (BB), and the Neutrino Factory (NF) is discussed. The ingredients to such a comparison are described, and the optimization and status of BB and NF are addressed. Finally, one example for the performance comparison is shown.

  9. Comparison of Artificial Compressibility Methods

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin; Housman, Jeffrey; Kwak, Dochan

    2003-01-01

    Various artificial compressibility methods for calculating three-dimensional, steady and unsteady, laminar and turbulent, incompressible Navier-Stokes equations are compared in this work. Each method is described in detail along with appropriate physical and numerical boundary conditions. Analysis of well-posedness and numerical solutions to test problems for each method are provided. A comparison based on convergence behavior, accuracy, stability and robustness is used to establish the relative positive and negative characteristics of each method.

  10. High pressure rinsing system comparison

    SciTech Connect

    D. Sertore; M. Fusetti; P. Michelato; Carlo Pagani; Toshiyasu Higo; Jin-Seok Hong; K. Saito; G. Ciovati; T. Rothgeb

    2007-06-01

    High pressure rinsing (HPR) is a key process for the surface preparation of high field superconducting cavities. A portable apparatus for the water jet characterization, based on the transferred momentum between the water jet and a load cell, has been used in different laboratories. This apparatus allows to collected quantitative parameters that characterize the HPR water jet. In this paper, we present a quantitative comparison of the different water jet produced by various nozzles routinely used in different laboratories for the HPR process

  11. Inverter performance comparison at PVUSA

    NASA Astrophysics Data System (ADS)

    Farmer, Brian K.; Stolte, Walter J.; Reyes, Antonio B.

    1996-01-01

    The paper is a summary of the Photovoltaics for Utility Scale Applications (PVUSA) Project's experience with procurement, testing, operation and maintenance of photovoltaic (PV) power conditioning units (PCUs) at the PVUSA Davis and Kerman sites. Brief descriptions of each of five different PCU models are included to explain tests and operational characteristics. A comparison of the PCUs' performances is presented, and conclusions are offered. Further details are in a forthcoming PVUSA report on PCUs and Power Quality [1].

  12. Artificial feeding of Simulium vectors of human and bovine onchocerciasis*

    PubMed Central

    McMahon, J. P.

    1968-01-01

    A technique for feeding simuliids artificially in a feeding-tube containing blood covered by a membrane has been developed with a view to studying the development of Onchocerca volvulus of man and O. gutturosa of cattle in their respective vectors. A number of different kinds of membranes were tested, but skin from 2-day-old chicks was found to be most satisfactory. S. ornatum, the vector of O. gutturosa in England, fed readily on human and ox blood. The trials were carried out in a constant-temperature room with artificial lighting supplied by 60- or 100-watt clear blue-glass lamps illuminating the feeding-tube with 20 lumens per ft2. Ultraviolet illumination was not satisfactory but light filtered through coloured screens gave good results in the middle of the spectrum. The flies fed well up to a temperature of 21°C (70°F) and a relative humidity of 65%-75%. The over-all feeding rate was 24.5%. The work was extended to trials with the vectors of human onchocerciasis at Kumba in West Cameroon and Amani in Tanzania. Successful membrane-feeding was achieved with the anthropophilic strains of S. damnosum from West and East Africa and with S. woodi, the main vector of O. volvulus in the Amani region. S. vorax, which is a good laboratory host for O. volvulus also, fed readily. S. nyasalandicum could be induced, but not readily, to feed through membranes. Once again, skin from 2-day-old chicks was the best membrane and human or ox blood, defibrinated or heparinized, either fresh or deep-frozen, was accepted by the flies. Wild and laboratory-bred S. damnosum also fed on a chimpanzee in a dark-room with artificial illumination at Kumba. PMID:5303668

  13. 5) Review of the Biology and Ecology of Adult Blackflies in Relation to the Transmission of Onchocerciasis in Guatemala

    PubMed Central

    2015-01-01

    Recent studies on the biology and ecology of adult blackflies in relation to the transmission of human onchocerciasis in Guatemala are reviewed. First, earlier studies on the transmission of the disease since its discovery by Dr. R. Robles in 1915 are outlined. Second, eleven blackfly species caught on humans are evaluated for vector status on the basis of their natural and experimental infections with third-stage larvae of Onchocerca volvulus, and Simulium ochraceum,* S. metallicum* and S. callidum are confirmed as natural vectors of the disease in Guatemala in descending order of importance, whereas S. gonzalezi, S. haematopotum, S. veracruzanum and S. horacioi are potential vectors. Third, the migration and fate of O. volvulus microfilariae ingested by female blackflies are highlighted on the basis of the findings of the cibarial armature of S. ochraceum and physiological incompatibility of S. metallicum as main barriers against microfilariae, both of which greatly decrease the number of ingested O. volvulus microfilariae developing to the third-stage larvae per female. Fourth, among many ecological factors of female blackfly populations, geographical and altitudinal distributions, habits of blood feeding, host preferences for blood feeding, preference for human body parts, parous rates, daily and seasonal fluctuations of biting activities, in particular, of parous females, gonotrophic cycle, longevity, flight range, and annual transmission potential are reviewed, and their influences on the transmission dynamics of the disease agents are considered. Fifth, effects of air temperatures on the O. volvulus–S. ochraceum complex are examined, with a special reference to the characteristic altitudinal distributions of the disease. The importance of reliable identification of both the vector blackfly species and filarial larvae found in female blackflies is emphasized to understand the transmission of the disease. [*It is now known that these two species are actually

  14. Identification of Human Semiochemicals Attractive to the Major Vectors of Onchocerciasis

    PubMed Central

    Young, Ryan M.; Burkett-Cadena, Nathan D.; McGaha, Tommy W.; Rodriguez-Perez, Mario A.; Toé, Laurent D.; Adeleke, Monsuru A.; Sanfo, Moussa; Soungalo, Traore; Katholi, Charles R.; Noblet, Raymond; Fadamiro, Henry; Torres-Estrada, Jose L.; Salinas-Carmona, Mario C.; Baker, Bill; Unnasch, Thomas R.; Cupp, Eddie W.

    2015-01-01

    Background Entomological indicators are considered key metrics to document the interruption of transmission of Onchocerca volvulus, the etiological agent of human onchocerciasis. Human landing collection is the standard employed for collection of the vectors for this parasite. Recent studies reported the development of traps that have the potential for replacing humans for surveillance of O. volvulus in the vector population. However, the key chemical components of human odor that are attractive to vector black flies have not been identified. Methodology/Principal Findings Human sweat compounds were analyzed using GC-MS analysis and compounds common to three individuals identified. These common compounds, with others previously identified as attractive to other hematophagous arthropods were evaluated for their ability to stimulate and attract the major onchocerciasis vectors in Africa (Simulium damnosum sensu lato) and Latin America (Simulium ochraceum s. l.) using electroantennography and a Y tube binary choice assay. Medium chain length carboxylic acids and aldehydes were neurostimulatory for S. damnosum s.l. while S. ochraceum s.l. was stimulated by short chain aliphatic alcohols and aldehydes. Both species were attracted to ammonium bicarbonate and acetophenone. The compounds were shown to be attractive to the relevant vector species in field studies, when incorporated into a formulation that permitted a continuous release of the compound over time and used in concert with previously developed trap platforms. Conclusions/Significance The identification of compounds attractive to the major vectors of O. volvulus will permit the development of optimized traps. Such traps may replace the use of human vector collectors for monitoring the effectiveness of onchocerciasis elimination programs and could find use as a contributing component in an integrated vector control/drug program aimed at eliminating river blindness in Africa. PMID:25569240

  15. Community-directed delivery of doxycycline for the treatment of onchocerciasis in areas of co-endemicity with loiasis in Cameroon

    PubMed Central

    Wanji, Samuel; Tendongfor, Nicholas; Nji, Theolbald; Esum, Mathias; Che, Julious N; Nkwescheu, Armand; Alassa, Fifen; Kamnang, Geremy; Enyong, Peter A; Taylor, Mark J; Hoerauf, Achim; Taylor, David W

    2009-01-01

    Background Severe side effects following ivermectin treatment of onchocerciasis in areas of co-endemicity with loaisis have been an impediment for the work of the African Programme for Onchocerciasis Control (APOC) in forested regions of several countries. Doxycycline has been shown to be effective in the treatment of onchocerciasis and has the added advantages of killing adult Onchocerca volvulus but neither adult Loa loa nor their microfilariae. This drug therefore offers great potential for the treatment of onchocerciasis in areas of co-endemicity with loiasis. The limitation of use of this drug is the duration of treatment that may pose a potential problem with therapeutic coverage and compliance with treatment. To benefit from the advantages that doxycycline offers in the treatment of onchocerciasis, it will be necessary to establish an effective distribution system that can access remote communities. This study assessed the feasibility of a large-scale distribution of doxycycline for the treatment of onchocerciasis in areas of co-endemicity with loiasis using a community-directed approach. Methods The study was carried out in 5 health areas co-endemic for Onchocerca volvulus and Loa loa which had no prior experience of the Community Directed Treatment with Ivermectin (CDTI). The community-directed delivery process was introduced using a cascade mechanism from the central health system that passed through the regional health delegation, health district and the health areas. Community health implementers (CHIs) were trained to deliver doxycycline to community members and, under the supervision of the health system, to monitor and document drug intake and side effects. Results The community members adhered massively to the process. Of the 21355 individuals counted, 17519 were eligible for treatment and 12936 were treated with doxycycline; giving a therapeutic coverage of eligible population of 73.8%. Of the 12936 who started the treatment, 97.5% complied by the

  16. How collective comparisons emerge without individual comparisons of the options.

    PubMed

    Robinson, Elva J H; Feinerman, Ofer; Franks, Nigel R

    2014-07-22

    Collective decisions in animal groups emerge from the actions of individuals who are unlikely to have global information. Comparative assessment of options can be valuable in decision-making. Ant colonies are excellent collective decision-makers, for example when selecting a new nest-site. Here, we test the dependency of this cooperative process on comparisons conducted by individual ants. We presented ant colonies with a choice between new nests: one good and one poor. Using individually radio-tagged ants and an automated system of doors, we manipulated individual-level access to information: ants visiting the good nest were barred from visiting the poor one and vice versa. Thus, no ant could individually compare the available options. Despite this, colonies still emigrated quickly and accurately when comparisons were prevented. Individual-level rules facilitated this behavioural robustness: ants allowed to experience only the poor nest subsequently searched more. Intriguingly, some ants appeared particularly discriminating across emigrations under both treatments, suggesting they had stable, high nest acceptance thresholds. Overall, our results show how a colony of ants, as a cognitive entity, can compare two options that are not both accessible by any individual ant. Our findings illustrate a collective decision process that is robust to differences in individual access to information. PMID:24920474

  17. Comparison of automatic control systems

    NASA Technical Reports Server (NTRS)

    Oppelt, W

    1941-01-01

    This report deals with a reciprocal comparison of an automatic pressure control, an automatic rpm control, an automatic temperature control, and an automatic directional control. It shows the difference between the "faultproof" regulator and the actual regulator which is subject to faults, and develops this difference as far as possible in a parallel manner with regard to the control systems under consideration. Such as analysis affords, particularly in its extension to the faults of the actual regulator, a deep insight into the mechanism of the regulator process.

  18. Comparison of ASGARD and UFOCapture

    NASA Technical Reports Server (NTRS)

    Blaauw, Rhiannon C.; Cruse, Katherine S.

    2011-01-01

    The Meteoroid Environment Office is undertaking a comparison between UFOCapture/Analyzer and ASGARD (All Sky and Guided Automatic Realtime Detection). To accomplish this, video output from a Watec video camera on a 17 mm Schneider lens (25 degree field of view) was split and input into the two different meteor detection softwares. The purpose of this study is to compare the sensitivity of the two systems, false alarm rates and trajectory information, among other quantities. The important components of each software will be highlighted and comments made about the detection/rejection algorithms and the amount of user-labor required for each system.

  19. RISKIND verification and benchmark comparisons

    SciTech Connect

    Biwer, B.M.; Arnish, J.J.; Chen, S.Y.; Kamboj, S.

    1997-08-01

    This report presents verification calculations and benchmark comparisons for RISKIND, a computer code designed to estimate potential radiological consequences and health risks to individuals and the population from exposures associated with the transportation of spent nuclear fuel and other radioactive materials. Spreadsheet calculations were performed to verify the proper operation of the major options and calculational steps in RISKIND. The program is unique in that it combines a variety of well-established models into a comprehensive treatment for assessing risks from the transportation of radioactive materials. Benchmark comparisons with other validated codes that incorporate similar models were also performed. For instance, the external gamma and neutron dose rate curves for a shipping package estimated by RISKIND were compared with those estimated by using the RADTRAN 4 code and NUREG-0170 methodology. Atmospheric dispersion of released material and dose estimates from the GENII and CAP88-PC codes. Verification results have shown the program to be performing its intended function correctly. The benchmark results indicate that the predictions made by RISKIND are within acceptable limits when compared with predictions from similar existing models.

  20. Comparisons of gyrofluid and gyrokinetic simulations

    SciTech Connect

    Parker, S.E.; Dorland, W.; Santoro, R.A.; Beer, M.A.; Liu, Q.P.; Lee, W.W.; Hammett, G.W.

    1994-03-01

    The gyrokinetic and gyrofluid models show the most promise for large scale simulations of tokamak microturbulence. This paper discusses detailed comparisons of these two complementary approaches. Past comparisons with linear theory have been fairly good, therefore the emphasis here is on nonlinear comparisons. Simulations include simple two dimensional slab test cases, turbulent three dimensional slab cases, and toroidal cases, each modeling the nonlinear evolution of the ion temperature gradient instability. There is good agreement in both turbulent and coherent nonlinear slab comparisons in terms of the ion heat flux, both in magnitude and scaling with magnetic shear. However, the nonlinear saturation level for {vert_bar}{Phi}{vert_bar} in the slab comparisons show differences of approximately 40%. Preliminary toroidal comparisons show agreement within 50%, in terms of ion heat flux and saturation level.

  1. Computational Chemistry Comparison and Benchmark Database

    National Institute of Standards and Technology Data Gateway

    SRD 101 NIST Computational Chemistry Comparison and Benchmark Database (Web, free access)   The NIST Computational Chemistry Comparison and Benchmark Database is a collection of experimental and ab initio thermochemical properties for a selected set of molecules. The goals are to provide a benchmark set of molecules for the evaluation of ab initio computational methods and allow the comparison between different ab initio computational methods for the prediction of thermochemical properties.

  2. European Measurement Comparisons of Environmental Radioactivity

    SciTech Connect

    Waetjen, Uwe

    2008-08-14

    The scheme of European measurement comparisons to verify radioactivity monitoring in the European Union is briefly explained. After a review of comparisons conducted during the years 1990, the approach of IRMM organising these comparisons since 2003 is presented. IRMM is providing comparison samples with a reference value traceable to the SI units and which is fully documented to all participants and national authorities after completion of the comparison. The sample preparation and determination of traceable reference values at IRMM, the sample treatment and measurement in the participating laboratories, as well as the evaluation of comparison results are described in some detail using the example of an air filter comparison. The results of a comparison to determine metabolised {sup 40}K, {sup 90}Sr and {sup 137}Cs in milk powder are presented as well. The necessary improvements in the estimation of measurement uncertainty by the participating laboratories are discussed. The performance of individual laboratories which have participated in at least four comparison exercises over the years is studied in terms of observable trends.

  3. European Measurement Comparisons of Environmental Radioactivity

    NASA Astrophysics Data System (ADS)

    Wätjen, Uwe

    2008-08-01

    The scheme of European measurement comparisons to verify radioactivity monitoring in the European Union is briefly explained. After a review of comparisons conducted during the years 1990, the approach of IRMM organising these comparisons since 2003 is presented. IRMM is providing comparison samples with a reference value traceable to the SI units and which is fully documented to all participants and national authorities after completion of the comparison. The sample preparation and determination of traceable reference values at IRMM, the sample treatment and measurement in the participating laboratories, as well as the evaluation of comparison results are described in some detail using the example of an air filter comparison. The results of a comparison to determine metabolised 40K, 90Sr and 137Cs in milk powder are presented as well. The necessary improvements in the estimation of measurement uncertainty by the participating laboratories are discussed. The performance of individual laboratories which have participated in at least four comparison exercises over the years is studied in terms of observable trends.

  4. The neural correlates of beauty comparison

    PubMed Central

    Mussweiler, Thomas; Mullins, Paul; Linden, David E. J.

    2014-01-01

    Beauty is in the eye of the beholder. How attractive someone is perceived to be depends on the individual or cultural standards to which this person is compared. But although comparisons play a central role in the way people judge the appearance of others, the brain processes underlying attractiveness comparisons remain unknown. In the present experiment, we tested the hypothesis that attractiveness comparisons rely on the same cognitive and neural mechanisms as comparisons of simple nonsocial magnitudes such as size. We recorded brain activity with functional magnetic resonance imaging (fMRI) while participants compared the beauty or height of two women or two dogs. Our data support the hypothesis of a common process underlying these different types of comparisons. First, we demonstrate that the distance effect characteristic of nonsocial comparisons also holds for attractiveness comparisons. Behavioral results indicated, for all our comparisons, longer response times for near than far distances. Second, the neural correlates of these distance effects overlapped in a frontoparietal network known for its involvement in processing simple nonsocial quantities. These results provide evidence for overlapping processes in the comparison of physical attractiveness and nonsocial magnitudes. PMID:23508477

  5. The neural correlates of beauty comparison.

    PubMed

    Kedia, Gayannée; Mussweiler, Thomas; Mullins, Paul; Linden, David E J

    2014-05-01

    Beauty is in the eye of the beholder. How attractive someone is perceived to be depends on the individual or cultural standards to which this person is compared. But although comparisons play a central role in the way people judge the appearance of others, the brain processes underlying attractiveness comparisons remain unknown. In the present experiment, we tested the hypothesis that attractiveness comparisons rely on the same cognitive and neural mechanisms as comparisons of simple nonsocial magnitudes such as size. We recorded brain activity with functional magnetic resonance imaging (fMRI) while participants compared the beauty or height of two women or two dogs. Our data support the hypothesis of a common process underlying these different types of comparisons. First, we demonstrate that the distance effect characteristic of nonsocial comparisons also holds for attractiveness comparisons. Behavioral results indicated, for all our comparisons, longer response times for near than far distances. Second, the neural correlates of these distance effects overlapped in a frontoparietal network known for its involvement in processing simple nonsocial quantities. These results provide evidence for overlapping processes in the comparison of physical attractiveness and nonsocial magnitudes. PMID:23508477

  6. Colon volvulus displaced into the chest – right-sided posttraumatic hernia or congenital malformation?

    PubMed Central

    Dębek, Wojciech; Matuszczak, Ewa

    2016-01-01

    We present the case of a 13.5-year-old girl who was admitted to the Pediatric Surgery Department from the Pediatric Department of a district hospital, where she stayed because of stomachache and vomiting. Interview revealed blunt injury of the epigastrium a week ago. Chest X-ray revealed a loss of the right diaphragmatic outline, irregular radiolucency on the right side of the chest, collapsed right lung and mediastinal displacement to the left. The patient was operated on, and the surgery revealed herniation of the intestines and half of the stomach into the defect of the right dome of the diaphragm. The patient made an uneventful postoperative recovery. A small innate defect of the diaphragm can remain asymptomatic and undiagnosed as long as there is no herniation of the abdominal organs into the chest.

  7. Plasma lactate concentration as a prognostic biomarker in dogs with gastric dilation and volvulus.

    PubMed

    Mooney, Erin; Raw, Cameron; Hughes, Dez

    2014-09-01

    Initial and serial plasma lactate concentrations can be used to guide decision making in individual dogs with GDV but care is necessary in phrasing conversations with owners. Published data suggests that survival is more likely and the chance of complications less in dogs with an initial plasma lactate of <4 mmol/L. An initial lactate >6 mmol/L makes gastric necrosis and greater expense more likely. However, because of the overlap between groups and the good overall survival rates, exploratory laparotomy should always be recommended irrespective of the plasma lactate concentration. Falls in plasma lactate of greater than ~40% after fluid resuscitation are likely to indicate better survival. If the initial plasma lactate concentration is moderately to severely increased (5->10 mmol/L) and a sustained increase in plasma lactate occurs after fluid resuscitation, the cause should be aggressively pursued. Many dogs with persistent hyperlactatemia over 24-48 hours do not survive. PMID:25496924

  8. Comparison Direction and Comparison Dimension among Disabled Individuals: Toward a Refined Conceptualization of Social Comparison under Stress.

    ERIC Educational Resources Information Center

    Buunk, Bram P.

    1995-01-01

    Illuminates the nature and direction of social comparison research using a sample of 168 Dutch individuals. Some of the findings revealed uncertainty and frustration related to a need for social comparison, a desire more for information than affiliation about similar others, and the influence of health problems in evaluating one's situation. (RJM)

  9. MCNPX Model/Table Comparison

    SciTech Connect

    J.S. Hendricks

    2003-03-03

    MCNPX is a Monte Carlo N-Particle radiation transport code extending the capabilities of MCNP4C. As with MCNP, MCNPX uses nuclear data tables to transport neutrons, photons, and electrons. Unlike MCNP, MCNPX also uses (1) nuclear data tables to transport protons; (2) physics models to transport 30 additional particle types (deuterons, tritons, alphas, pions, muons, etc.); and (3) physics models to transport neutrons and protons when no tabular data are available or when the data are above the energy range (20 to 150 MeV) where the data tables end. MCNPX can mix and match data tables and physics models throughout a problem. For example, MCNPX can model neutron transport in a bismuth germinate (BGO) particle detector by using data tables for bismuth and oxygen and using physics models for germanium. Also, MCNPX can model neutron transport in UO{sub 2}, making the best use of physics models and data tables: below 20 MeV, data tables are used; above 150 MeV, physics models are used; between 20 and 150 MeV, data tables are used for oxygen and models are used for uranium. The mix-and-match capability became available with MCNPX2.5.b (November 2002). For the first time, we present here comparisons that calculate radiation transport in materials with various combinations of data charts and model physics. The physics models are poor at low energies (<150 MeV); thus, data tables should be used when available. Our comparisons demonstrate the importance of the mix-and-match capability and indicate how well physics models work in the absence of data tables.

  10. Affective and Behavioral Consequences of Social Comparison.

    ERIC Educational Resources Information Center

    Testa, Maria N.; Major, Brenda

    Considerable attention in recent years has focused on the consequences of social comparisons and has suggested that learning that one's outcomes or abilities compare unfavorably to others' is an unpleasant, if not painful experience. Indeed, upward comparisons have been shown to result in negative affect, loss of self-esteem, stress symptoms, and…

  11. Adaptive sequential testing for multiple comparisons.

    PubMed

    Gao, Ping; Liu, Lingyun; Mehta, Cyrus

    2014-01-01

    We propose a Markov process theory-based adaptive sequential testing procedure for multiple comparisons. The procedure can be used for confirmative trials involving multi-comparisons, including dose selection or population enrichment. Dose or subpopulation selection and sample size modification can be made at any interim analysis. Type I error control is exact. PMID:24926848

  12. Comparison of Two Cryogenic Radiometers at NIST

    PubMed Central

    Houston, Jeanne M.; Livigni, David J.

    2001-01-01

    Two cryogenic radiometers from NIST, one from the Optical Technology Division and the other from the Optoelectronics Division, were compared at three visible laser wavelengths. For this comparison, each radiometer calibrated two photodiode trap detectors for spectral responsivity. The calibration values for the two trap detectors agreed within the expanded (k = 2) uncertainties. This paper describes the measurement and results of this comparison.

  13. Comparison of debris flux models

    NASA Astrophysics Data System (ADS)

    Sdunnus, H.; Beltrami, P.; Klinkrad, H.; Matney, M.; Nazarenko, A.; Wegener, P.

    The availability of models to estimate the impact risk from the man-made space debris and the natural meteoroid environment is essential for both, manned and unmanned satellite missions. Various independent tools based on different approaches have been developed in the past years. Due to an increased knowledge of the debris environment and its sources e.g. from improved measurement capabilities, these models could be updated regularly, providing more detailed and more reliable simulations. This paper addresses an in-depth, quantitative comparison of widely distributed debris flux models which were recently updated, namely ESA's MASTER 2001 model, NASA's ORDEM 2000 and the Russian SDPA 2000 model. The comparison was performed in the frame of the work of the 20t h Interagency Debris Coordination (IADC) meeting held in Surrey, UK. ORDEM 2000ORDEM 2000 uses careful empirical estimates of the orbit populations based onthree primary data sources - the US Space Command Catalog, the H ystackaRadar, and the Long Duration Exposure Facility spacecraft returned surfaces.Further data (e.g. HAX and Goldstone radars, impacts on Shuttle windows andradiators, and others) were used to adjust these populations for regions in time,size, and space not covered by the primary data sets. Some interpolation andextrapolation to regions with no data (such as projections into the future) wasprovided by the EVOLVE model. MASTER 2001The ESA MASTER model offers a full three dimensional description of theterrestrial debris distribution reaching from LEO up to the GEO region. Fluxresults relative to an orbiting target or to an inertial volume can be resolved intosource terms, impactor characteristics and orbit, as well as impact velocity anddirection. All relevant debris source terms are considered by the MASTERmodel. For each simulated source, a corresponding debris generation model interms of mass/diameter distribution, additional velocities, and directionalspreading has been developed. A

  14. Microphone interlaboratory comparison in the Americas

    NASA Astrophysics Data System (ADS)

    Wong, George S. K.; Wu, Lixue

    2002-11-01

    The final results of a Sistema Interamericano de Metrologia (SIM) interlaboratory comparison on microphone calibration are presented. Initially the comparison involved NORAMET countries: USA, Canada, and Mexico. Later, the comparison was extended to include Argentina and Brazil, resulting in a SIM AUV.A-K1 microphone interlaboratory comparison. The National Metrology Institutes (NMIs) of the five American countries that participated were the Institute for National Measurement Standards (INMS--Canada), National Institute of Standards and Technology (NIST--USA), Centro Nacional de Metrologia (CENAM--Mexico), Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (INMETRO--Brazil) and Unidad Tecnica Acustica, (INTI--Argentina). INMS, Canada was the pilot laboratory that provided the data for the final report. The maximum rms deviation for the two LS1P laboratory standard microphones measured by the above participants is 0.037 dB that may be considered as the key comparison reference value.

  15. Risk comparisons, conflict, and risk acceptability claims.

    PubMed

    Johnson, Branden B

    2004-02-01

    Despite many claims for and against the use of risk comparisons in risk communication, few empirical studies have explored their effect. Even fewer have examined the public's relative preferences among different kinds of risk comparisons. Two studies, published in this journal in 1990 and 2003, used seven measures of "acceptability" to examine public reaction to 14 examples of risk comparisons, as used by a hypothetical factory manager to explain risks of his ethylene oxide plant. This study examined the effect on preferences of scenarios involving low or high conflict between the factory manager and residents of the hypothetical town (as had the 2003 study), and inclusion of a claim that the comparison demonstrated the risks' acceptability. It also tested the Finucane et al. (2000) affect hypothesis that information emphasizing low risks-as in these risk comparisons-would raise benefits estimates without changing risk estimates. Using similar but revised scenarios, risk comparison examples (10 instead of 14), and evaluation measures, an opportunity sample of 303 New Jersey residents rated the comparisons, and the risks and benefits of the factory. On average, all comparisons received positive ratings on all evaluation measures in all conditions. Direct and indirect measures showed that the conflict manipulation worked; overall, No-Conflict and Conflict scenarios evoked scores that were not significantly different. The attachment to each risk comparison of a risk acceptability claim ("So our factory's risks should be acceptable to you.") did not worsen ratings relative to conditions lacking this claim. Readers who did or did not see this claim were equally likely to infer an attempt to persuade them to accept the risk from the comparison. As in the 2003 article, there was great individual variability in inferred rankings of the risk comparisons. However, exposure to the risk comparisons did not reduce risk estimates significantly (while raising benefit estimates

  16. RTU Comparison Calculator Enhancement Plan

    SciTech Connect

    Miller, James D.; Wang, Weimin; Katipamula, Srinivas

    2015-07-01

    Over the past two years, Department of Energy’s Building Technologies Office (BTO) has been investigating ways to increase the operating efficiency of the packaged rooftop units (RTUs) in the field. First, by issuing a challenge to the RTU manufactures to increase the integrated energy efficiency ratio (IEER) by 60% over the existing ASHRAE 90.1-2010 standard. Second, by evaluating the performance of an advanced RTU controller that reduces the energy consumption by over 40%. BTO has previously also funded development of a RTU comparison calculator (RTUCC). RTUCC is a web-based tool that provides the user a way to compare energy and cost savings for two units with different efficiencies. However, the RTUCC currently cannot compare savings associated with either the RTU Challenge unit or the advanced RTU controls retrofit. Therefore, BTO has asked PNNL to enhance the tool so building owners can compare energy and savings associated with this new class of products. This document provides the details of the enhancements that are required to support estimating energy savings from use of RTU challenge units or advanced controls on existing RTUs.

  17. Performance Comparison of CGM Systems

    PubMed Central

    Kirchsteiger, Harald; Heinemann, Lutz; Freckmann, Guido; Lodwig, Volker; Schmelzeisen-Redeker, Günther; Schoemaker, Michael; del Re, Luigi

    2015-01-01

    Background: The ongoing progress of continuous glucose monitoring (CGM) systems results in an increasing interest in comparing their performance, in particular in terms of accuracy, that is, matching CGM readings with reference values measured at the same time. Most often accuracy is evaluated by the mean absolute relative difference (MARD). It is frequently overseen that MARD does not only reflect accuracy, but also the study protocol and evaluation procedure, making a cross-study comparison problematic. Methods: We evaluate the effect of several factors on the MARD statistical properties: number of paired reference and CGM values, distribution of the paired values, accuracy of the reference measurement device itself and the time delay between data pairs. All analysis is done using clinical data from 12 patients wearing 6 sensors each. Results: We have found that a few paired points can have a potentially high impact on MARD. Leaving out those points for evaluation thus reduces the MARD. Similarly, accuracy of the reference measurements greatly affects the MARD as numerical and graphical data show. Results also show that a log-normal distribution of the paired references provides a significantly different MARD than, for example, a uniform distribution. Conclusions: MARD is a reasonable parameter to characterize the performance of CGM systems when keeping its limitations in mind. To support clinicians and patients in selecting which CGM system to use in a clinical setting, care should be taken to make MARD more comparable by employing a standardized evaluation procedure. PMID:26330485

  18. Distributed Wind Policy Comparison Tool

    SciTech Connect

    2011-12-01

    Power through Policy: 'Best Practices' for Cost-Effective Distributed Wind is a U.S. Department of Energy (DOE)-funded project to identify distributed wind technology policy best practices and to help policymakers, utilities, advocates, and consumers examine their effectiveness using a pro forma model. Incorporating a customized feed from the Database of State Incentives for Renewables and Efficiency (DSIRE), the Web-based Distributed Wind Policy Comparison Tool (Policy Tool) is designed to assist state, local, and utility officials in understanding the financial impacts of different policy options to help reduce the cost of distributed wind technologies. The Policy Tool can be used to evaluate the ways that a variety of federal and state policies and incentives impact the economics of distributed wind (and subsequently its expected market growth). It also allows policymakers to determine the impact of policy options, addressing market challenges identified in the U.S. DOE’s '20% Wind Energy by 2030' report and helping to meet COE targets.

  19. Comparison theorems for causal diamonds

    NASA Astrophysics Data System (ADS)

    Berthiere, Clément; Gibbons, Gary; Solodukhin, Sergey N.

    2015-09-01

    We formulate certain inequalities for the geometric quantities characterizing causal diamonds in curved and Minkowski spacetimes. These inequalities involve the redshift factor which, as we show explicitly in the spherically symmetric case, is monotonic in the radial direction, and it takes its maximal value at the center. As a by-product of our discussion we rederive Bishop's inequality without assuming the positivity of the spatial Ricci tensor. We then generalize our considerations to arbitrary, static and not necessarily spherically symmetric, asymptotically flat spacetimes. In the case of spacetimes with a horizon our generalization involves the so-called domain of dependence. The respective volume, expressed in terms of the duration measured by a distant observer compared with the volume of the domain in Minkowski spacetime, exhibits behaviors which differ if d =4 or d >4 . This peculiarity of four dimensions is due to the logarithmic subleading term in the asymptotic expansion of the metric near infinity. In terms of the invariant duration measured by a comoving observer associated with the diamond we establish an inequality which is universal for all d . We suggest some possible applications of our results including comparison theorems for entanglement entropy, causal set theory, and fundamental limits on computation.

  20. Statistical comparison of dissolution profiles.

    PubMed

    Wang, Yifan; Snee, Ronald D; Keyvan, Golshid; Muzzio, Fernando J

    2016-05-01

    Statistical methods to assess similarity of dissolution profiles are introduced. Sixteen groups of dissolution profiles from a full factorial design were used to demonstrate implementation details. Variables in the design include drug strength, tablet stability time, and dissolution testing condition. The 16 groups were considered similar when compared using the similarity factor f2 (f2 > 50). However, multivariate ANOVA (MANOVA) repeated measures suggested statistical differences. A modified principal component analysis (PCA) was used to describe the dissolution curves in terms of level and shape. The advantage of the modified PCA approach is that the calculated shape principal components will not be confounded by level effect. Effect size test using omega-squared was also used for dissolution comparisons. Effects indicated by omega-squared are independent of sample size and are a necessary supplement to p value reported from the MANOVA table. Methods to compare multiple groups show that product strength and dissolution testing condition had significant effects on both level and shape. For pairwise analysis, a post-hoc analysis using Tukey's method categorized three similar groups, and was consistent with level-shape analysis. All these methods provide valuable information that is missed using f2 method alone to compare average profiles. The improved statistical analysis approach introduced here enables one to better ascertain both statistical significance and clinical relevance, supporting more objective regulatory decisions. PMID:26294289

  1. Attractor comparisons based on density

    SciTech Connect

    Carroll, T. L.

    2015-01-15

    Recognizing a chaotic attractor can be seen as a problem in pattern recognition. Some feature vector must be extracted from the attractor and used to compare to other attractors. The field of machine learning has many methods for extracting feature vectors, including clustering methods, decision trees, support vector machines, and many others. In this work, feature vectors are created by representing the attractor as a density in phase space and creating polynomials based on this density. Density is useful in itself because it is a one dimensional function of phase space position, but representing an attractor as a density is also a way to reduce the size of a large data set before analyzing it with graph theory methods, which can be computationally intensive. The density computation in this paper is also fast to execute. In this paper, as a demonstration of the usefulness of density, the density is used directly to construct phase space polynomials for comparing attractors. Comparisons between attractors could be useful for tracking changes in an experiment when the underlying equations are too complicated for vector field modeling.

  2. RTU Comparison Calculator Enhancement Plan

    SciTech Connect

    Miller, James D.; Wang, Weimin; Katipamula, Srinivas

    2014-03-31

    Over the past two years, Department of Energy’s Building Technologies Office (BTO) has been investigating ways to increase the operating efficiency of the packaged rooftop units (RTUs) in the field. First, by issuing a challenge to the RTU manufactures to increase the integrated energy efficiency ratio (IEER) by 60% over the existing ASHRAE 90.1-2010 standard. Second, by evaluating the performance of an advanced RTU controller that reduces the energy consumption by over 40%. BTO has previously also funded development of a RTU comparison calculator (RTUCC). RTUCC is a web-based tool that provides the user a way to compare energy and cost savings for two units with different efficiencies. However, the RTUCC currently cannot compare savings associated with either the RTU Challenge unit or the advanced RTU controls retrofit. Therefore, BTO has asked PNNL to enhance the tool so building owners can compare energy and savings associated with this new class of products. This document provides the details of the enhancements that are required to support estimating energy savings from use of RTU challenge units or advanced controls on existing RTUs.

  3. Epidemiology and psycho-social aspects of onchocercal skin diseases in northeastern Nigeria

    PubMed Central

    Okoye, Ikem Chris; Onwuliri, Celestine OE

    2007-01-01

    Background Observations were made on the prevalence of onchocerciasis and Onchocercal Skin Diseases (OSD); frequency of occurrence and anatomical distribution of OSD in the Hawal River Valley, an established onchocerciasis endemic focus in north-eastern Nigeria. Methods Symptoms of OSD were diagnosed in 5 844 subjects using Rapid Assessment Method (RAM) while 1 479 of the subjects chosen from alternate households had their skin biopsies examined for active microfilariae of Onchocerca volvulus. Also, Focal Group Discussions (FGD) were conducted at the Health District levels. Results O. volvulus was recorded in (19.0%) and OSD in (43.8%) of the subjects. The Mantel-Haenszel test for linear association showed a close agreement between onchocerciasis prevalence and the rate of OSD (χ2 = 3.93; p < 0.05). The various forms of OSD occurred in the order: CPOD (17.7%), APOD (9.9%), DPM (9.0%), LOD (7.0%) and ATR (3.1%). The overall frequency of occurrence of various symptoms of OSD on different anatomical locations showed the locations in descending order of occurrence as lower limbs (24.6%), upper limbs (21.3%), buttocks (19.9%), shoulder & neck (19.1%), abdomen and trunk (11.3%), backside (10.6), and 'other' sites (7.5%). The Focal Group Discussion (FGD) revealed the most worrisome consequences of OSD as social isolation of victims (31.3%), shame and low self esteem (22.7%) and high cost of medication (15.6%). Conclusion It is recommended that Onchocerciasis control programmes in the Hawal River Valley and any other focus with high incidence of OSD should incorporate an aspect that would address the anxiety and depression caused by various OSD lesions since they carry lots of psycho-social implications. This would increase acceptance and compliance of the target population. The classification criteria of onchocerciasis endemicity should be based on either or both of the O. volvulus and onchocercal skin disease burden of any community and no longer on O. volvulus

  4. Localization of a filarial phosphate permease that is up-regulated in response to depletion of essential Wolbachia endobacteria.

    PubMed

    Arumugam, Sridhar; Hoerauf, Achim; Pfarr, Kenneth M

    2014-03-01

    Wolbachia of filarial nematodes are essential, obligate endobacteria. When depleted by doxycycline worm embryogenesis, larval development and worm survival are inhibited. The molecular basis governing the endosymbiosis between Wolbachia and their filarial host is still being deciphered. In rodent filarial nematode Litomosoides sigmodontis, a nematode encoded phosphate permease gene (Ls-ppe-1) was up-regulated at the mRNA level in response to Wolbachia depletion and this gene promises to have an important role in Wolbachia-nematode endosymbiosis. To further characterize this gene, the regulation of phosphate permease during Wolbachia depletion was studied at the protein level in L. sigmodontis and in the human filaria Onchocerca volvulus. And the localization of phosphate permease (PPE) and Wolbachia in L. sigmodontis and O. volvulus was investigated in untreated and antibiotic treated worms. Depletion of Wolbachia by tetracycline (Tet) resulted in up-regulation of Ls-ppe-1 in L. sigmodontis. On day 36 of Tet treatment, compared to controls (Con), >98% of Wolbachia were depleted with a 3-fold increase in mRNA levels of Ls-ppe-1. Anti-Ls-PPE serum used in Western blots showed up-regulation of Ls-PPE at the protein level in Tet worms on day 15 and 36 of treatment. Immunohistology revealed the localization of Wolbachia and Ls-PPE in the embryos, microfilariae and hypodermis of L. sigmodontis female worms and up-regulation of Ls-PPE in response to Wolbachia depletion. Expression of O. volvulus phosphate permease (Ov-PPE) studied using anti-Ov-PPE serum, showed up-regulation of Ov-PPE at the protein level in doxycycline treated Wolbachia depleted O. volvulus worms and immunohistology revealed localization of Ov-PPE and Wolbachia and up-regulation of Ov-PPE in the hypodermis and embryos of doxycycline treated worms. Ls-PPE and Ov-PPE are upregulated upon Wolbachia depletion in same tissues and regions where Wolbachia are located in untreated worms, reinforcing a link

  5. Uav Photogrammetry: Block Triangulation Comparisons

    NASA Astrophysics Data System (ADS)

    Gini, R.; Pagliari, D.; Passoni, D.; Pinto, L.; Sona, G.; Dosso, P.

    2013-08-01

    UAVs systems represent a flexible technology able to collect a big amount of high resolution information, both for metric and interpretation uses. In the frame of experimental tests carried out at Dept. ICA of Politecnico di Milano to validate vector-sensor systems and to assess metric accuracies of images acquired by UAVs, a block of photos taken by a fixed wing system is triangulated with several software. The test field is a rural area included in an Italian Park ("Parco Adda Nord"), useful to study flight and imagery performances on buildings, roads, cultivated and uncultivated vegetation. The UAV SenseFly, equipped with a camera Canon Ixus 220HS, flew autonomously over the area at a height of 130 m yielding a block of 49 images divided in 5 strips. Sixteen pre-signalized Ground Control Points, surveyed in the area through GPS (NRTK survey), allowed the referencing of the block and accuracy analyses. Approximate values for exterior orientation parameters (positions and attitudes) were recorded by the flight control system. The block was processed with several software: Erdas-LPS, EyeDEA (Univ. of Parma), Agisoft Photoscan, Pix4UAV, in assisted or automatic way. Results comparisons are given in terms of differences among digital surface models, differences in orientation parameters and accuracies, when available. Moreover, image and ground point coordinates obtained by the various software were independently used as initial values in a comparative adjustment made by scientific in-house software, which can apply constraints to evaluate the effectiveness of different methods of point extraction and accuracies on ground check points.

  6. CCN Cloud Processing Interhemispheric Comparisons

    NASA Astrophysics Data System (ADS)

    Tabor, S. S.; Noble, S. R., Jr.; Hudson, J. G.

    2014-12-01

    Cloud processing of CCN spectra is described by Hudson and Noble (2014) and Noble and Hudson (2014). Bimodal CCN spectra have also been observed in 4 Southern Hemisphere (SH) cloud research projects: SOCEX1, July 1993 and 2, Jan-Feb, 1995 and ACE1, Nov-Dec, 1995 all off Tasmania and INDOEX, Feb-Mar, 1999 Indian Ocean (Fig.). However, as in the Northern Hemisphere (NH) bimodal CCN spectra are interspersed with monomodal spectra, which indicates that cloudy boundary layers are not as well-mixed as conventional wisdom. Hoppel minima between the modes provide estimates of cloud effective supersaturations (Seff). Unlike DMA measurements particle composition/hygroscopicity (κ) is not needed for these Seff estimate because CCN are measured in terms of S. However, these Hoppel Seff often tend to be lower than Seff obtained by comparing below cloud CCN spectra with nearby cloud droplet concentrations (Nc). These Seff differences may be due to less cloud processing by smaller cloud droplets. However, this may be a smaller issue in the SH due to larger droplets in cleaner air masses. Furthermore, SH Seff may also tend to be higher for the same reason. This might reduce the Seff differences of the two types of estimates compared to the more polluted NH. SH/NH comparisons of detailed differential CCN spectra can provide an important baseline for preindustrial aerosol. Relative differences between the contribution of chemical and physical cloud processing between hemispheres also provide important baseline characteristics. Chemical processing enhance the indirect aerosol effect (IAE) by moving CCN to lower critical S (Sc), which increases droplet concentrations (Nc) whereas physical processing reduces IAE by inherently reducing CCN (Noble and Hudson 2014). The extent of cloud processing is as important as CCN sources. Hudson and Noble 2014, this meeting. Noble and Hudson 2014, this meeting.

  7. An ecological momentary assessment of comparison target as a moderator of the effects of appearance-focused social comparisons.

    PubMed

    Leahey, Tricia M; Crowther, Janis H

    2008-09-01

    This research examined whether comparison target moderates the effects of naturally occurring appearance-focused social comparisons on women's affect, appearance esteem, and dieting thoughts. During daily activities, body-satisfied (BS) women and body-dissatisfied (BD) women recorded their comparison targets and reactions to comparison information. For BS women, upward comparisons with peers were associated with more positive affect (PA) and appearance esteem and less guilt than upward comparisons with media images and downward comparisons with peers were associated with less PA than downward comparisons with media images. For BD women, upward comparisons with peers were associated with more appearance esteem and diet thoughts than upward comparisons with media images and downward comparisons with peers were associated with less PA, appearance esteem, and diet thoughts and more guilt than downward comparisons with media images. PMID:18585108

  8. STS-134 Launch Composite Video Comparison

    NASA Video Gallery

    A side-by-side comparison video shows a one-camera view of the STS-134 launch (left) with the six-camera composited view (right). Imaging experts funded by the Space Shuttle Program and located at ...

  9. Doctoral Program Selection Using Pairwise Comparisons.

    ERIC Educational Resources Information Center

    Tadisina, Suresh K.; Bhasin, Vijay

    1989-01-01

    The application of a pairwise comparison methodology (Saaty's Analytic Hierarchy Process) to the doctoral program selection process is illustrated. A hierarchy for structuring and facilitating the doctoral program selection decision is described. (Author/MLW)

  10. OpenMP Experiences and Comparisons

    NASA Technical Reports Server (NTRS)

    Nelson, Terry; Thigpen, William W. (Technical Monitor)

    2002-01-01

    The document discusses message passage interfaces (MPI), open message passage issues and parallelization. A comparison of the two vector platforms, C90 and SVlex is presented. Sections of the document are written in computer code.

  11. Pairwise Multiple Comparisons: New Yardstick, New Results.

    ERIC Educational Resources Information Center

    Cribbie, Robert A.

    2003-01-01

    Monte Carlo study results show that recently proposed multiple comparison procedures (MCPs) that are not intended to control the familywise error rate had consistently larger true model rates than did familywise error controlling MCPs. (SLD)

  12. Comparison of LASSO and GPS time transfers

    NASA Technical Reports Server (NTRS)

    Lewandowski, W.; Petit, G.; Baumont, F.; Fridelance, P.; Gaignebet, J.; Grudler, P.; Veillet, C.; Wiant, J.; Klepczynski, W. J.

    1994-01-01

    The LASSO is a technique which should allow the comparison of remote atomic clocks with sub-nanosecond precision and accuracy. The first successful time transfer using LASSO has been carried out between the Observatoire de la Cote d'Azur in France and the McDonald Observatory in Texas, United States. This paper presents a preliminary comparison of LASSO time transfer with GPS common-view time transfer.

  13. Rankings, Standards, and Competition: Task vs. Scale Comparisons

    ERIC Educational Resources Information Center

    Garcia, Stephen M.; Tor, Avishalom

    2007-01-01

    Research showing how upward social comparison breeds competitive behavior has so far conflated local comparisons in "task" performance (e.g. a test score) with comparisons on a more general "scale" (i.e. an underlying skill). Using a ranking methodology (Garcia, Tor, & Gonzalez, 2006) to separate task and scale comparisons, Studies 1-2 reveal that…

  14. Differential Item Functioning Detection across Two Methods of Defining Group Comparisons: Pairwise and Composite Group Comparisons

    ERIC Educational Resources Information Center

    Sari, Halil Ibrahim; Huggins, Anne Corinne

    2015-01-01

    This study compares two methods of defining groups for the detection of differential item functioning (DIF): (a) pairwise comparisons and (b) composite group comparisons. We aim to emphasize and empirically support the notion that the choice of pairwise versus composite group definitions in DIF is a reflection of how one defines fairness in DIF…

  15. 16 CFR 233.2 - Retail price comparisons; comparable value comparisons.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... GUIDES AGAINST DECEPTIVE PRICING § 233.2 Retail price comparisons; comparable value comparisons. (a... fountain pens at $10, it is not dishonest for retailer Doe to advertise: “Brand X Pens, Price Elsewhere $10... here would be deceptive, since the price charged by the small suburban outlets would have no...

  16. Interprovincial Comparisons of University Financing. Eleventh Report of the Tripartite Committee on Interprovincial Comparisons.

    ERIC Educational Resources Information Center

    Council of Ontario Universities, Toronto.

    This report presents comparisons of Canadian university financing on a province by province basis. An introductory section describes the project through which the study was undertaken, explains the indicators used, and discusses structural problems encountered in making comparisons. The central portion of the report is a tabulation of these…

  17. Interprovincial Comparisons of University Financing. Fourth Report of the Tripartite Committee on Interprovincial Comparisons.

    ERIC Educational Resources Information Center

    Council of Ontario Universities, Toronto.

    Eight indicators used to make interprovincial comparisons of university financing in Canada are outlined and the values of these indicators are presented for 1974-1975 to 1980-1981. The Tripartite Committee on Interprovincial Comparisons has directed attention to how much financial support is provided to universities, how university financing fits…

  18. Sonic Boom Prediction Exercise: Experimental Comparisons

    NASA Technical Reports Server (NTRS)

    Tu, Eugene; Cheung, Samson; Edwards, Thomas

    1999-01-01

    The success of a future High Speed Civil Transport (HSCT) depends on the ability to accurately assess and, possibly, modify the sonic boom signatures of potential designs. In 1992, the Sonic Boom Steering Committee initiated a prediction exercise to assess the current computational capabilities for the accurate and efficient prediction of sonic boom signatures and loudness levels. A progress report of this effort was given at the Sonic Boom Workshop held at NASA Ames Research Center in 1993 where predictions from CFD and Modified Linear Theory (MLT) methods were given. Comparisons between the methods were made at near-, mid- and far-field locations. However, at that time, experimental data from wind-tunnel tests were not available. The current paper presents a comparison of computational results with the now available experimental data. Further comparisons between the computational methods and analyses of the discrepancies in the results are presented.

  19. Real medical benefit assessed by indirect comparison.

    PubMed

    Falissard, Bruno; Zylberman, Myriam; Cucherat, Michel; Izard, Valérie; Meyer, François

    2009-01-01

    Frequently, in data packages submitted for Marketing Approval to the CHMP, there is a lack of relevant head-to-head comparisons of medicinal products that could enable national authorities responsible for the approval of reimbursement to assess the Added Therapeutic Value (ASMR) of new clinical entities or line extensions of existing therapies.Indirect or mixed treatment comparisons (MTC) are methods stemming from the field of meta-analysis that have been designed to tackle this problem. Adjusted indirect comparisons, meta-regressions, mixed models, Bayesian network analyses pool results of randomised controlled trials (RCTs), enabling a quantitative synthesis.The REAL procedure, recently developed by the HAS (French National Authority for Health), is a mixture of an MTC and effect model based on expert opinions. It is intended to translate the efficacy observed in the trials into effectiveness expected in day-to-day clinical practice in France. PMID:19671436

  20. Photon/Electron Benchmarks for Intercode Comparisons

    SciTech Connect

    Hughes, Henry Grady III; Sweezy, Jeremy Ed; Lemaire, Sebastien

    2015-07-21

    The goal of this work was to improve accuracy and efficiency of two Monte-Carlo transport codes (MCNP and DIANE) with an emphasis on γ+electron physics. The approach involved intercode comparisons + measurements for gamma/e- energy deposition in a cylinder with a photon source and different materials (C, Pb) and the bombardment of 15-MeV electrons on thick targets (Al, Be, Pb). Comparisons of the codes DIANE and MCNP6 showed good agreement (differences < 3%) for gamma-electron energy deposition in a 2D cylinder, except for the first 0.1 μm of lead (difference < 10%). Comparisons with measurements showed generally good agreement, often better than 10%; best-performing codes/options are problem-dependent; and single-event discrepancies are in active use in reviewing electron elastic scattering.

  1. Key comparison of liquid density standards

    NASA Astrophysics Data System (ADS)

    Buchner, Christian; Zelenka, Zoltan; Kajastie, Heikki; Madec, Tanguy; Wolf, Henning; Vámossy, Csilla; Lorefice, Salvatore; Garberg, Torgunn; Lenard, Elżbieta; Spohr, Isabel; Mares, Gabriela; Spurný, Robert; Lumbreras, Angel; Medina, Nieves; Y Akçadağ, Ümit; Perkin, Michael

    2015-01-01

    Hydrostatic density determination for liquids is mainly performed by laboratories to provide means for calibrating liquid density measuring instruments such as oscillation-type density meters. From 2002 to 2005 the CIPM key comparison CCM.D-K2 'comparison of liquid density standards' was carried out piloted by the PTB. The aim was to compare the results of the density determination by the participating laboratories to support entries to the CMC tables in this sub-field. To provide further laboratories the possibility to support their entries to the CMC tables at the meeting of the EUROMET Working Group on Density in 2007 this comparison was agreed on. BEV (Austria) organized the comparison supported by the PTB (Germany). For the comparison samples of pentadecane, water, tetrachloroethylene and of an oil of high viscosity were measured in the temperature range from 5 °C to 60 °C at atmospheric pressure by hydrostatic weighing. The measurements were completed in 2008. The reference values of the first reports based on the draft of the CCM.D-K2. After the official publication of the CCM.D-K2 the reference values were recalculated and the report was finalised in 2015. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  2. Infrared spectral normal emittance/emissivity comparison

    NASA Astrophysics Data System (ADS)

    Hanssen, L.; Wilthan, B.; Filtz, J.-R.; Hameury, J.; Girard, F.; Battuello, M.; Ishii, J.; Hollandt, J.; Monte, C.

    2016-01-01

    The National Measurement Institutes (NMIs) of the United States, Germany, France, Italy and Japan, have joined in an inter-laboratory comparison of their infrared spectral emittance scales. This action is part of a series of supplementary inter-laboratory comparisons (including thermal conductivity and thermal diffusivity) sponsored by the Consultative Committee on Thermometry (CCT) Task Group on Thermophysical Quantities (TG-ThQ). The objective of this collaborative work is to strengthen the major operative National Measurement Institutes' infrared spectral emittance scales and consequently the consistency of radiative properties measurements carried out worldwide. The comparison has been performed over a spectral range of 2 μm to 14 μm, and a temperature range from 23 °C to 800 °C. Artefacts included in the comparison are potential standards: oxidized Inconel, boron nitride, and silicon carbide. The measurement instrumentation and techniques used for emittance scales are unique for each NMI, including the temperature ranges covered as well as the artefact sizes required. For example, all three common types of spectral instruments are represented: dispersive grating monochromator, Fourier transform and filter-based spectrometers. More than 2000 data points (combinations of material, wavelength and temperature) were compared. Ninety-eight percent (98%) of the data points were in agreement, with differences to weighted mean values less than the expanded uncertainties calculated from the individual NMI uncertainties and uncertainties related to the comparison process. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  3. Systematic Comparison of Operating Reserve Methodologies: Preprint

    SciTech Connect

    Ibanez, E.; Krad, I.; Ela, E.

    2014-04-01

    Operating reserve requirements are a key component of modern power systems, and they contribute to maintaining reliable operations with minimum economic impact. No universal method exists for determining reserve requirements, thus there is a need for a thorough study and performance comparison of the different existing methodologies. Increasing penetrations of variable generation (VG) on electric power systems are posed to increase system uncertainty and variability, thus the need for additional reserve also increases. This paper presents background information on operating reserve and its relationship to VG. A consistent comparison of three methodologies to calculate regulating and flexibility reserve in systems with VG is performed.

  4. Metrics for comparison of crystallographic maps

    SciTech Connect

    Urzhumtsev, Alexandre; Afonine, Pavel V.; Lunin, Vladimir Y.; Terwilliger, Thomas C.; Adams, Paul D.

    2014-10-01

    Numerical comparison of crystallographic contour maps is used extensively in structure solution and model refinement, analysis and validation. However, traditional metrics such as the map correlation coefficient (map CC, real-space CC or RSCC) sometimes contradict the results of visual assessment of the corresponding maps. This article explains such apparent contradictions and suggests new metrics and tools to compare crystallographic contour maps. The key to the new methods is rank scaling of the Fourier syntheses. The new metrics are complementary to the usual map CC and can be more helpful in map comparison, in particular when only some of their aspects, such as regions of high density, are of interest.

  5. Performance comparison of electronic radon monitors.

    PubMed

    Lin, Chi-Feng; Wang, Jeng-Jong; Lin, Shih-Jung; Lin, Chien-Kung

    2013-11-01

    The electronic radon monitors are noted for their convenience and acceptable accuracy. Even so, it is necessary to reassure their data quality regularly. We utilized a performance comparison system for this purpose. The instruments in our laboratories (Alphaguard, RAD7, RTM-2100 and Safety Siren) were tested via the comparison experiments. We conclude that by utilizing this system with the concept of calibration factor, it can be helpful to decide whether to send the monitors back to the original manufacturers for adjustment. PMID:23566805

  6. Quantum private comparison over noisy channels

    NASA Astrophysics Data System (ADS)

    Siddhu, Vikesh; Arvind

    2015-08-01

    Quantum private comparison (QPC) allows us to protect private information during its comparison. In the past, various three-party quantum protocols have been proposed that claim to work well under noisy conditions. Here, we tackle the problem of QPC under noise. We analyze the EPR-based protocol under depolarizing noise, bit flip and phase flip noise. We show how noise affects the robustness of the EPR-based protocol. We then present a straightforward protocol based on CSS codes to perform QPC which is robust against noise and secure under general attacks.

  7. On relative distortion in fingerprint comparison.

    PubMed

    Kalka, Nathan D; Hicklin, R Austin

    2014-11-01

    When fingerprints are deposited, non-uniform pressure in conjunction with the inherent elasticity of friction ridge skin often causes linear and non-linear distortions in the ridge and valley structure. The effects of these distortions must be considered during analysis of fingerprint images. Even when individual prints are not notably distorted, relative distortion between two prints can have a serious impact on comparison. In this paper we discuss several metrics for quantifying and visualizing linear and non-linear fingerprint deformations, and software tools to assist examiners in accounting for distortion in fingerprint comparisons. PMID:25216456

  8. Molecular phylogenetic studies on filarial parasites based on 5S ribosomal spacer sequences.

    PubMed

    Xie, H; Bain, O; Williams, S A

    1994-06-01

    This paper is the first large-scale molecular phylogenetic study on filarial parasites (family Onchocercidae) which includes 16 species of 6 genera: Brugia beaveri Ash et Little, 1962, B. buckleyi Dissanaike et Paramananthan, 1961; B. malayi (Brug, 1927) Buckley, 1960; B. pahangi (Buckley et Edeson, 1956) Buckley, 1960; B. patei (Buckley, Nelson et Heisch, 1958) Buckley, 1960; B. timori Partono et al, 1977; Wuchereria bancrofti (Cobbold, 1877) Seurat, 1921: W. kalimantani Palmieri. Purnomo, Dennis and Marwoto, 1980: Mansonella perstans (Manson, 1891) Eberhard et Orihel, 1984; loa loc, Stiles, 1905; Onchocerca volvulus (Leuckart, 1983) Railliet er Henry, 1910; O. ochengi Bwangamoi, 1969; O. gutturosa Neumann, 1910; Dirofilaria immitis (Leidy, 1856) Railliet e Henry, 1911; Acanthocheilonema viteae (Krepkogorskaya, 1933) Bain, Baker et Chabaud, 1982 and Litomosoides sigmodontis Chandler, 1931. 5S rRNA gene spacer region sequence data were collected by PCR, cloning and dideoxy sequencing. The 5S rRNA gene spacer region sequences were aligned and analyzed by maximum parsimony algorithms, distance methods and maximum likelihood methods to construct phylogenetic trees. Bootstrap analysis was used to test the robustness of the different phylogenetic reconstructions. The data indicated that 5S spacer region sequences are highly conserved within species yet differ significantly between species. Spliced leader sequences were observed in all of the 5S rDNA spacers with no sequence variation, although flanking region sequence and length heterogeneity was observed even within species. All of the various tree-building methods gave very similar results. This study identified four clades which are strongly supported by bootstrap analysis the Brugia clade; the Wuchereria clade; the Brugia-Wuchereria clade and the Onchocerca clade. The analyses indicated that L. sigmodontis and A. viteae may be the most primitive among the 16 species studied. The data did not show any close

  9. Inter-comparison of subglacial hydrological models

    NASA Astrophysics Data System (ADS)

    de Fleurian, Basile; Werder, Mauro

    2016-04-01

    The recent emergence of a number of subglacial hydrological models allows us to obtain theoretical insights on basal processes; for instance on the coupling between water pressure and the sliding of glaciers. In ice-flow models, it is relatively clear what the simulated physics ought to be. Conversely, the physical processes incorporated into subglacial hydrology models are diverse as it is yet unclear which ones are of relevance for a particular setting. An inter-comparison of hydrology models will therefore need a somewhat different approach to the one used in the many ice-flow model inter-comparisons (EISMINT, ISMIP, etc.). Here, we present a set of experiments that will allow the comparison of the behavior of different hydrology models. The design of the benchmark aims at allowing the participation of a wide range of models based on different physical approaches. We aim at evaluating the models with a focus on the effective pressure which has the most impact on the dynamics of glaciers. The aim of this inter-comparison is to provide modellers with the necessary data to make an informed decision on which subglacial hydrology model to use for a particular study.

  10. Immediacy bias in social-emotional comparisons.

    PubMed

    White, Katherine; Van Boven, Leaf

    2012-08-01

    In seven studies of naturally occurring, "real-world" emotional events, people demonstrated an immediacy bias in social-emotional comparisons, perceiving their own current or recent emotional reactions as more intense compared with others' emotional reactions to the same events. The events examined include crossing a scary bridge (study 1a), a national tragedy (study 1b), terrorist attacks (studies 2a and 3b), a natural disaster (study 2b), and a presidential election (study 3b). These perceived differences between one's own and others' emotions declined over time, as relatively immediate and recent emotions subsided, a pattern that people were not intuitively aware of (study 2c). This immediacy bias in social-emotional comparisons emerged for both explicit comparisons (studies 1a, 1b, and 3b), and for absolute judgments of emotional intensity (studies 2a, 2b, and 3a). Finally, the immediacy bias in social-emotional comparisons was reduced when people were reminded that emotional display norms might lead others' appearances to understate emotional intensity (studies 3a and 3b). Implications of these findings for social-emotional phenomena are discussed. PMID:22148998

  11. COMPARISONS AND CONTRASTS AMONG DIFFERENT SCALED ASSESSMENTS

    EPA Science Inventory

    A comparison of a regional (multi-state) and local (multi-county) scale assessment was done to evaluate similarities and differences in the collection, analysis, and interpretation of landscape data. The study areas included EP A Region 3 a11d a sub-region spanning North and Sout...

  12. Social Comparison of Pay and Inequity Theory.

    ERIC Educational Resources Information Center

    Judd, Ben

    Inequity theory differs from social exchange theory in its analysis of a worker's reaction to pay by asserting that effects on work performance caused by high or low pay are due to social comparison of fairness rather than principles of direct exchange, such as reciprocity and power. The present experiment held piece-rate pay constant at two…

  13. Comparison of Classical and Quantum Mechanical Uncertainties.

    ERIC Educational Resources Information Center

    Peslak, John, Jr.

    1979-01-01

    Comparisons are made for the particle-in-a-box, the harmonic oscillator, and the one-electron atom. A classical uncertainty principle is derived and compared with its quantum-mechanical counterpart. The results are discussed in terms of the statistical interpretation of the uncertainty principle. (Author/BB)

  14. On the comparison of fundamental numerical ephemerides

    NASA Astrophysics Data System (ADS)

    Tkachuk, V. V.; Choliy, V. Ya.

    2013-12-01

    We present the results of our comparison of three main numerical ephemerides (DELE, INPOP, EPM) for the determination of precision and errors of their dynamical coordinate systems. It was shown that all of them have comparable levels of precision, however the EPM demonstrates an unusual shift of the coordinate origin. Systematic errors were estimated as well, and mutual shifts of coordinate centres were found.

  15. International Comparisons and Sensitivity to Instruction

    ERIC Educational Resources Information Center

    Wiliam, Dylan

    2008-01-01

    While international comparisons such as those provided by PISA may be meaningful in terms of overall judgements about the performance of educational systems, caution is needed in terms of more fine-grained judgements. In particular it is argued that the results of PISA to draw conclusions about the quality of instruction in different systems is…

  16. Do Young Children Understand Relative Value Comparisons?

    PubMed Central

    Benenson, Joyce F.; Markovits, Henry; Whitmore, Bjorn; Van, Christophe; Margolius, Sara; Wrangham, Richard W.

    2015-01-01

    Many forms of judgments, such as those used in economic games or measures of social comparison, require understanding relative value, as well as the more complex ability to make comparisons between relative values. To examine whether young children can accurately compare relative values, we presented children 4 to 7 years with simple judgments of relative value in two scenarios. Children then were asked to compare the relative values in the two scenarios. Results show that even the youngest children downgraded evaluations of a reward when another has a larger amount, indicating the ability to make relative value judgments. When asked to compare relative values however, only the oldest children were able to make these comparisons consistently. We then extended this analysis to economic game performance. Specifically, previous results using economic games suggest that younger children are more generous than older ones. We replicate this result, and then show that a simple change in procedure, based on the initial study, is sufficient to change young children’s choices. Our results strongly suggest that conclusions regarding young children’s pro-social motives based on relative value comparisons should be viewed cautiously. PMID:25875949

  17. Multiple Comparison Procedures when Population Variances Differ.

    ERIC Educational Resources Information Center

    Olejnik, Stephen; Lee, JaeShin

    A review of the literature on multiple comparison procedures suggests several alternative approaches for comparing means when population variances differ. These include: (1) the approach of P. A. Games and J. F. Howell (1976); (2) C. W. Dunnett's C confidence interval (1980); and (3) Dunnett's T3 solution (1980). These procedures control the…

  18. International Comparisons of Vocational Education and Training.

    ERIC Educational Resources Information Center

    Freeland, Brett

    This report, which is based primarily on figures released by the Organisation for Economic Cooperation and Development (OECD), reviews the indicators available for international comparisons of vocational education and training (VET) to clarify the following issues: the kinds of comparability problems that exit, their extent and severity, their…

  19. Measurement of Social Development: An International Comparison

    ERIC Educational Resources Information Center

    Ray, Amal Kanti

    2008-01-01

    PQLI and HDI are the two most popular measures of development, besides per capita income. Over the years, PQLI appears to be not much in use for regional comparisons, especially after the introduction of HDI. While PQLI considers only the physical variables--adult literacy, life expectancy at birth and infant survival rate, HDI has life expectancy…

  20. ABL and BAM Friction Analysis Comparison

    DOE PAGESBeta

    Warner, Kirstin F.; Sandstrom, Mary M.; Brown, Geoffrey W.; Remmers, Daniel L.; Phillips, Jason J.; Shelley, Timothy J.; Reyes, Jose A.; Hsu, Peter C.; Reynolds, John G.

    2014-12-29

    Here, the Integrated Data Collection Analysis (IDCA) program has conducted a proficiency study for Small-Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here is a comparison of the Alleghany Ballistic Laboratory (ABL) friction data and Bundesanstalt fur Materialforschung und -prufung (BAM) friction data for 19 HEM and military standard explosives.

  1. "Units of Comparison" across Languages, across Time

    ERIC Educational Resources Information Center

    Thomas, Margaret

    2009-01-01

    Lardiere's keynote article adverts to a succession of "units of comparison" that have been employed in the study of cross-linguistic differences, including mid-twentieth-century structural patterns, generative grammar's parameters, and (within contemporary Minimalism) features. This commentary expands on the idea of units of cross-linguistic…

  2. A comparison of Monte Carlo generators

    NASA Astrophysics Data System (ADS)

    Golan, Tomasz

    2015-05-01

    A comparison of GENIE, NEUT, NUANCE, and NuWro Monte Carlo neutrino event generators is presented using a set of four observables: protons multiplicity, total visible energy, most energetic proton momentum, and π+ two-dimensional energy vs cosine distribution.

  3. The discovery and comparison of symbolic magnitudes.

    PubMed

    Chen, Dawn; Lu, Hongjing; Holyoak, Keith J

    2014-06-01

    Humans and other primates are able to make relative magnitude comparisons, both with perceptual stimuli and with symbolic inputs that convey magnitude information. Although numerous models of magnitude comparison have been proposed, the basic question of how symbolic magnitudes (e.g., size or intelligence of animals) are derived and represented in memory has received little attention. We argue that symbolic magnitudes often will not correspond directly to elementary features of individual concepts. Rather, magnitudes may be formed in working memory based on computations over more basic features stored in long-term memory. We present a model of how magnitudes can be acquired and compared based on BARTlet, a representationally simpler version of Bayesian Analogy with Relational Transformations (BART; Lu, Chen, & Holyoak, 2012). BARTlet operates on distributions of magnitude variables created by applying dimension-specific weights (learned with the aid of empirical priors derived from pre-categorical comparisons) to more primitive features of objects. The resulting magnitude distributions, formed and maintained in working memory, are sensitive to contextual influences such as the range of stimuli and polarity of the question. By incorporating psychological reference points that control the precision of magnitudes in working memory and applying the tools of signal detection theory, BARTlet is able to account for a wide range of empirical phenomena involving magnitude comparisons, including the symbolic distance effect and the semantic congruity effect. We discuss the role of reference points in cognitive and social decision-making, and implications for the evolution of relational representations. PMID:24531498

  4. A comparison of Monte Carlo generators

    SciTech Connect

    Golan, Tomasz

    2015-05-15

    A comparison of GENIE, NEUT, NUANCE, and NuWro Monte Carlo neutrino event generators is presented using a set of four observables: protons multiplicity, total visible energy, most energetic proton momentum, and π{sup +} two-dimensional energy vs cosine distribution.

  5. Cross-Cultural Comparisons: The Validity of Assessment by Indices of Factor Comparison.

    ERIC Educational Resources Information Center

    Eysenck, Hans J.

    1986-01-01

    Considers the cross-cultural consistency of personality inventories, concluding that it is justifiable to use the scale of the Eysenck Personality Questionnaire for comparisons within and between different countries. (Author/LHW)

  6. Therapeutic Efficacy and Macrofilaricidal Activity of Doxycycline for the Treatment of River Blindness

    PubMed Central

    Walker, Martin; Specht, Sabine; Churcher, Thomas S.; Hoerauf, Achim; Taylor, Mark J.; Basáñez, María-Gloria

    2015-01-01

    Background. Onchocerca volvulus and lymphatic filariae, causing river blindness and elephantiasis, depend on endosymbiotic Wolbachia bacteria for growth, development, fertility, and survival. Clinical trials have shown that doxycycline treatment eliminates Wolbachia, causing long-term sterilization of adult female filariae and effecting potent macrofilaricidal activity. The continual reinfection by drug-naive worms that occurs in these trial settings dilutes observable anti-Wolbachia and antifilarial effects, making it difficult to estimate therapeutic efficacy and compare different doxycycline regimens, evaluated at different times after treatment. Methods. A meta-analytical modeling framework is developed to link all usable data collected from clinical trials measuring the Wolbachia status and viability of individual female adult worms collected at various times after treatment with 4, 5, or 6 weeks of daily 100 or 200 mg oral doxycycline. The framework is used to estimate efficacy parameters that are not directly measurable as trial outcomes. Results. The estimated efficacy of doxycycline (the maximum proportional reduction in the percentage of adult female O. volvulus positive for Wolbachia) is 91%–94% on average, irrespective of the treatment regimen. Efficacy is >95% in the majority of trial participants. The life span of Wolbachia-depleted worms is reduced by 70%–80%, from approximately 10 years to 2–3 years. Conclusions. The efficacy parameters are pertinent to the prospects of using doxycycline on a “test and treat” basis for onchocerciasis control and confirm doxycycline as a potent macrofilaricidal therapy. The modeling approach is more generally relevant to the design and evaluation of clinical trials for antifilarial drugs conducted in endemic settings. PMID:25537873

  7. An Integrated Multiomics Approach to Identify Candidate Antigens for Serodiagnosis of Human Onchocerciasis*

    PubMed Central

    McNulty, Samantha N.; Rosa, Bruce A.; Fischer, Peter U.; Rumsey, Jeanne M.; Erdmann-Gilmore, Petra; Curtis, Kurt C.; Specht, Sabine; Townsend, R. Reid; Weil, Gary J.; Mitreva, Makedonka

    2015-01-01

    Improved diagnostic methods are needed to support ongoing efforts to eliminate onchocerciasis (river blindness). This study used an integrated approach to identify adult female Onchocerca volvulus antigens that can be explored for developing serodiagnostic tests. The first step was to develop a detailed multi-omics database of all O. volvulus proteins deduced from the genome, gene transcription data for different stages of the parasite including eight individual female worms (providing gene expression information for 94.8% of all protein coding genes), and the adult female worm proteome (detecting 2126 proteins). Next, female worm proteins were purified with IgG antibodies from onchocerciasis patients and identified using LC-MS with a high-resolution hybrid quadrupole-time-of-flight mass spectrometer. A total of 241 immunoreactive proteins were identified among those bound by IgG from infected individuals but not IgG from uninfected controls. These included most of the major diagnostic antigens described over the past 25 years plus many new candidates. Proteins of interest were prioritized for further study based on a lack of conservation with orthologs in the human host and other helminthes, their expression pattern across the life cycle, and their consistent expression among individual female worms. Based on these criteria, we selected 33 proteins that should be carried forward for testing as serodiagnostic antigens to supplement existing diagnostic tools. These candidates, together with the extensive pan-omics dataset generated in this study are available to the community (http://nematode.net) to facilitate basic and translational research on onchocerciasis. PMID:26472727

  8. Genome Filtering for New DNA Biomarkers of Loa loa Infection Suitable for Loop-Mediated Isothermal Amplification

    PubMed Central

    Poole, Catherine B.; Ettwiller, Laurence; Tanner, Nathan A.; Evans, Thomas C.; Wanji, Samuel; Carlow, Clotilde K. S.

    2015-01-01

    Loa loa infections have emerged as a serious public health problem in patients co-infected with Onchocerca volvulus or Wuchereria bancrofti because of severe adverse neurological reactions after treatment with ivermectin. Accurate diagnostic tests are needed for careful mapping in regions where mass drug administration is underway. Loop-mediated isothermal amplification (LAMP) has become a widely adopted screening method because of its operational simplicity, rapidity and versatility of visual detection readout options. Here, we present a multi-step bioinformatic pipeline to generate diagnostic candidates suitable for LAMP and experimentally validate this approach using one of the identified candidates to develop a species-specific LAMP assay for L. loa. The pipeline identified ~140 new L. loa specific DNA repeat families as putative biomarkers of infection. The consensus sequence of one family, repeat family 4 (RF4), was compiled from ~ 350 sequences dispersed throughout the L. loa genome and maps to a L. loa-specific region of the long terminal repeats found at the boundaries of Bel/Pao retrotransposons. PCR and LAMP primer sets targeting RF4 specifically amplified L. loa but not W. bancrofti, O. volvulus, Brugia malayi, human or mosquito DNA. RF4 LAMP detects the DNA equivalent of one microfilaria (100 pg) in 25–30 minutes and as little as 0.060 pg of L. loa DNA (~1/1600th of a microfilaria) purified from spiked blood samples in approximately 50 minutes. In summary, we have successfully employed a bioinformatic approach to mine the L. loa genome for species-specific repeat families that can serve as new DNA biomarkers for LAMP. The RF4 LAMP assay shows promise as a field tool for the implementation and management of mass drug administration programs and warrants further testing on clinical samples as the next stage in development towards this goal. PMID:26414073

  9. Immunoepidemiological profiling of onchocerciasis patients reveals associations with microfilaria loads and ivermectin intake on both individual and community levels.

    PubMed

    Arndts, Kathrin; Specht, Sabine; Debrah, Alexander Y; Tamarozzi, Francesca; Klarmann Schulz, Ute; Mand, Sabine; Batsa, Linda; Kwarteng, Alexander; Taylor, Mark; Adjei, Ohene; Martin, Coralie; Layland, Laura E; Hoerauf, Achim

    2014-02-01

    Mass drug administration (MDA) programmes against Onchocerca volvulus use ivermectin (IVM) which targets microfilariae (MF), the worm's offspring. Most infected individuals are hyporesponsive and present regulated immune responses despite high parasite burden. Recently, with MDA programmes, the existence of amicrofilaridermic (a-MF) individuals has become apparent but little is known about their immune responses. Within this immunoepidemiological study, we compared parasitology, pathology and immune profiles in infection-free volunteers and infected individuals that were MF(+) or a-MF. The latter stemmed from villages in either Central or Ashanti regions of Ghana which, at the time of the study, had received up to eight or only one round of MDA respectively. Interestingly, a-MF patients had fewer nodules and decreased IL-10 responses to all tested stimuli. On the other hand, this patient group displayed contrary IL-5 profiles following in vitro stimulation or in plasma and the dampened response in the latter correlated to reduced eosinophils and associated factors but elevated neutrophils. Furthermore, multivariable regression analysis with covariates MF, IVM or the region (Central vs. Ashanti) revealed that immune responses were associated with different covariates: whereas O. volvulus-specific IL-5 responses were primarily associated with MF, IL-10 secretion had a negative correlation with times of individual IVM therapy (IIT). All plasma parameters (eosinophil cationic protein, IL-5, eosinophils and neutrophils) were highly associated with MF. With regards to IL-17 secretion, although no differences were observed between the groups to filarial-specific or bystander stimuli, these responses were highly associated with the region. These data indicate that immune responses are affected by both, IIT and the rounds of IVM MDA within the community. Consequently, it appears that a lowered infection pressure due to IVM MDA may affect the immune profile of community

  10. Analysis of gene expression from the Wolbachia genome of a filarial nematode supports both metabolic and defensive roles within the symbiosis.

    PubMed

    Darby, Alistair C; Armstrong, Stuart D; Bah, Germanus S; Kaur, Gaganjot; Hughes, Margaret A; Kay, Suzanne M; Koldkjær, Pia; Rainbow, Lucille; Radford, Alan D; Blaxter, Mark L; Tanya, Vincent N; Trees, Alexander J; Cordaux, Richard; Wastling, Jonathan M; Makepeace, Benjamin L

    2012-12-01

    The α-proteobacterium Wolbachia is probably the most prevalent, vertically transmitted symbiont on Earth. In contrast with its wide distribution in arthropods, Wolbachia is restricted to one family of animal-parasitic nematodes, the Onchocercidae. This includes filarial pathogens such as Onchocerca volvulus, the cause of human onchocerciasis, or river blindness. The symbiosis between filariae and Wolbachia is obligate, although the basis of this dependency is not fully understood. Previous studies suggested that Wolbachia may provision metabolites (e.g., haem, riboflavin, and nucleotides) and/or contribute to immune defense. Importantly, Wolbachia is restricted to somatic tissues in adult male worms, whereas females also harbor bacteria in the germline. We sought to characterize the nature of the symbiosis between Wolbachia and O. ochengi, a bovine parasite representing the closest relative of O. volvulus. First, we sequenced the complete genome of Wolbachia strain wOo, which revealed an inability to synthesize riboflavin de novo. Using RNA-seq, we also generated endobacterial transcriptomes from male soma and female germline. In the soma, transcripts for membrane transport and respiration were up-regulated, while the gonad exhibited enrichment for DNA replication and translation. The most abundant Wolbachia proteins, as determined by geLC-MS, included ligands for mammalian Toll-like receptors. Enzymes involved in nucleotide synthesis were dominant among metabolism-related proteins, whereas the haem biosynthetic pathway was poorly represented. We conclude that Wolbachia may have a mitochondrion-like function in the soma, generating ATP for its host. Moreover, the abundance of immunogenic proteins in wOo suggests a role in diverting the immune system toward an ineffective antibacterial response. PMID:22919073

  11. An Integrated Multiomics Approach to Identify Candidate Antigens for Serodiagnosis of Human Onchocerciasis.

    PubMed

    McNulty, Samantha N; Rosa, Bruce A; Fischer, Peter U; Rumsey, Jeanne M; Erdmann-Gilmore, Petra; Curtis, Kurt C; Specht, Sabine; Townsend, R Reid; Weil, Gary J; Mitreva, Makedonka

    2015-12-01

    Improved diagnostic methods are needed to support ongoing efforts to eliminate onchocerciasis (river blindness). This study used an integrated approach to identify adult female Onchocerca volvulus antigens that can be explored for developing serodiagnostic tests. The first step was to develop a detailed multi-omics database of all O. volvulus proteins deduced from the genome, gene transcription data for different stages of the parasite including eight individual female worms (providing gene expression information for 94.8% of all protein coding genes), and the adult female worm proteome (detecting 2126 proteins). Next, female worm proteins were purified with IgG antibodies from onchocerciasis patients and identified using LC-MS with a high-resolution hybrid quadrupole-time-of-flight mass spectrometer. A total of 241 immunoreactive proteins were identified among those bound by IgG from infected individuals but not IgG from uninfected controls. These included most of the major diagnostic antigens described over the past 25 years plus many new candidates. Proteins of interest were prioritized for further study based on a lack of conservation with orthologs in the human host and other helminthes, their expression pattern across the life cycle, and their consistent expression among individual female worms. Based on these criteria, we selected 33 proteins that should be carried forward for testing as serodiagnostic antigens to supplement existing diagnostic tools. These candidates, together with the extensive pan-omics dataset generated in this study are available to the community (http://nematode.net) to facilitate basic and translational research on onchocerciasis. PMID:26472727

  12. Enhanced humoral response to influenza vaccine in aged mice with a novel adjuvant, rOv-ASP-1.

    PubMed

    Jiang, Jiu; Fisher, Erin M; Concannon, Mark; Lustigman, Sara; Shen, Hao; Murasko, Donna M

    2016-02-10

    Immunization is the best way to prevent seasonal epidemics and pandemics of influenza. There are two kinds of influenza vaccines available in the United States: an inactivated vaccine (TIV) and an attenuated vaccine; however, only TIV is approved for immunization of the elderly population. While the aged population has the highest rate of influenza vaccination, the protective efficacy is low as evidenced by elderly individuals having the highest mortality associated with influenza. Recently, we reported that an adjuvant derived from the helminth parasite Onchocerca volvulus, named O. volvulus activation-associated secreted protein-1 (Ov-ASP-1), can significantly enhance the protective efficacy of an inactivated vaccine (TIV) in young adult mice. In the current study, we examined whether this recombinant Ov-ASP-1 (rOv-ASP-1) can enhance the efficacy of TIV in aged mice as well. While primary immunization with TIV alone produced only a low level of influenza-specific antibodies (total IgG, IgG1, and IgG2c) in aged mice, the antibody levels were significantly increased after immunization with TIV+rOv-ASP-1. More importantly, the level of the total IgG in aged mice administered TIV+rOv-ASP-1 was comparable to that of young adult mice immunized with TIV alone. Co-administration of rOv-ASP-1 induced a low level of cross-reactive antibody and enhanced the protective efficacy of TIV in aged mice, reflected by significantly increased survival after challenge with a heterologous influenza virus. rOv-ASP-1 was also superior to the conventional adjuvant alum in inducing specific IgG after TIV immunization in aged mice, and in conferring protection after challenge. These results demonstrate that rOv-ASP-1 may serve as a potential adjuvant for influenza vaccine to improve the efficacy of protection in the elderly. PMID:26795365

  13. Interruption of Infection Transmission in the Onchocerciasis Focus of Ecuador Leading to the Cessation of Ivermectin Distribution

    PubMed Central

    Lovato, Raquel; Guevara, Angel; Guderian, Ronald; Proaño, Roberto; Unnasch, Thomas; Criollo, Hipatia; Hassan, Hassan K.; Mackenzie, Charles D.

    2014-01-01

    Introduction: A clinically significant endemic focus of onchocerciasis existing in Esmeraldas Province, coastal Ecuador has been under an ivermectin mass drug administration program since 1991. The main transmitting vector in this area is the voracious blackfly, Simulium exiguum. This paper describes the assessments made that support the decision to cease mass treatment. Methodology and Principle Findings: Thirty-five rounds of ivermectin treatment occurred between 1991–2009 with 29 of these carrying >85% coverage. Following the guidelines set by WHO for ceasing ivermectin distribution the impact on parasite transmission was measured in the two vector species by an O-150 PCR technique standard for assessing for the presence of Onchocerca volvulus. Up to seven collection sites in three major river systems were tested on four occasions between 1995 and 2008. The infectivity rates of 65.0 (CI 39–101) and 72.7 (CI 42–116) in 1995 dropped to zero at all seven collection sites by 2008. Assessment for the presence of antibodies against O. volvulus was made in 2001, 2006, 2007 and 2008 using standard ELISA assays for detecting anti-Ov16 antibodies. None of total of 1810 children aged 1–15 years (between 82 and 98% of children present in the surveyed villages) tested in the above years were found to be carrying antibodies to this antigen. These findings were the basis for the cessation of mass drug treatment with ivermectin in 2009. Significance: This fulfillment of the criteria for cessation of mass distribution of ivermectin in the only known endemic zone of onchocerciasis in Ecuador moves the country into the surveillance phase of official verification for national elimination of transmission of infection. These findings indicate that ivermectin given twice a year with greater than 85% of the community can move a program to the final stages of verification of transmission interruption. PMID:24853587

  14. Analysis of gene expression from the Wolbachia genome of a filarial nematode supports both metabolic and defensive roles within the symbiosis

    PubMed Central

    Darby, Alistair C.; Armstrong, Stuart D.; Bah, Germanus S.; Kaur, Gaganjot; Hughes, Margaret A.; Kay, Suzanne M.; Koldkjær, Pia; Rainbow, Lucille; Radford, Alan D.; Blaxter, Mark L.; Tanya, Vincent N.; Trees, Alexander J.; Cordaux, Richard; Wastling, Jonathan M.; Makepeace, Benjamin L.

    2012-01-01

    The α-proteobacterium Wolbachia is probably the most prevalent, vertically transmitted symbiont on Earth. In contrast with its wide distribution in arthropods, Wolbachia is restricted to one family of animal-parasitic nematodes, the Onchocercidae. This includes filarial pathogens such as Onchocerca volvulus, the cause of human onchocerciasis, or river blindness. The symbiosis between filariae and Wolbachia is obligate, although the basis of this dependency is not fully understood. Previous studies suggested that Wolbachia may provision metabolites (e.g., haem, riboflavin, and nucleotides) and/or contribute to immune defense. Importantly, Wolbachia is restricted to somatic tissues in adult male worms, whereas females also harbor bacteria in the germline. We sought to characterize the nature of the symbiosis between Wolbachia and O. ochengi, a bovine parasite representing the closest relative of O. volvulus. First, we sequenced the complete genome of Wolbachia strain wOo, which revealed an inability to synthesize riboflavin de novo. Using RNA-seq, we also generated endobacterial transcriptomes from male soma and female germline. In the soma, transcripts for membrane transport and respiration were up-regulated, while the gonad exhibited enrichment for DNA replication and translation. The most abundant Wolbachia proteins, as determined by geLC-MS, included ligands for mammalian Toll-like receptors. Enzymes involved in nucleotide synthesis were dominant among metabolism-related proteins, whereas the haem biosynthetic pathway was poorly represented. We conclude that Wolbachia may have a mitochondrion-like function in the soma, generating ATP for its host. Moreover, the abundance of immunogenic proteins in wOo suggests a role in diverting the immune system toward an ineffective antibacterial response. PMID:22919073

  15. Genome Filtering for New DNA Biomarkers of Loa loa Infection Suitable for Loop-Mediated Isothermal Amplification.

    PubMed

    Poole, Catherine B; Ettwiller, Laurence; Tanner, Nathan A; Evans, Thomas C; Wanji, Samuel; Carlow, Clotilde K S

    2015-01-01

    Loa loa infections have emerged as a serious public health problem in patients co-infected with Onchocerca volvulus or Wuchereria bancrofti because of severe adverse neurological reactions after treatment with ivermectin. Accurate diagnostic tests are needed for careful mapping in regions where mass drug administration is underway. Loop-mediated isothermal amplification (LAMP) has become a widely adopted screening method because of its operational simplicity, rapidity and versatility of visual detection readout options. Here, we present a multi-step bioinformatic pipeline to generate diagnostic candidates suitable for LAMP and experimentally validate this approach using one of the identified candidates to develop a species-specific LAMP assay for L. loa. The pipeline identified ~140 new L. loa specific DNA repeat families as putative biomarkers of infection. The consensus sequence of one family, repeat family 4 (RF4), was compiled from ~ 350 sequences dispersed throughout the L. loa genome and maps to a L. loa-specific region of the long terminal repeats found at the boundaries of Bel/Pao retrotransposons. PCR and LAMP primer sets targeting RF4 specifically amplified L. loa but not W. bancrofti, O. volvulus, Brugia malayi, human or mosquito DNA. RF4 LAMP detects the DNA equivalent of one microfilaria (100 pg) in 25-30 minutes and as little as 0.060 pg of L. loa DNA (~1/1600th of a microfilaria) purified from spiked blood samples in approximately 50 minutes. In summary, we have successfully employed a bioinformatic approach to mine the L. loa genome for species-specific repeat families that can serve as new DNA biomarkers for LAMP. The RF4 LAMP assay shows promise as a field tool for the implementation and management of mass drug administration programs and warrants further testing on clinical samples as the next stage in development towards this goal. PMID:26414073

  16. Inflammatory reactions in onchocerciasis: a report on current knowledge and recommendations for further study*

    PubMed Central

    Henson, P. M.; Mackenzie, C. D.; Spector, W. G.

    1979-01-01

    This report concerns the host's reactions to the presence of the parasite both in the course of the natural disease and during drug treatment. The various stages of Onchocerca volvulus are discussed in terms of the type of tissue reaction seen. The discussion then turns to basic hypotheses concerning the etiology of these reactions, emphasis being placed on the fact that while pathological changes are considerable in some locations there is a remarkable lack of reaction in others. Some of the mechanisms possibly involved in this apparent absence of host response are discussed, including anti-complement factors, poor antigenicity, acquisition of host antigen, immune tolerance, and blocking antibodies. In any study of the inflammatory response it is recommended that critical evaluations be made of histological material, haematological studies, the definition of the antigenic nature of O. volvulus, characterization of immunological reactivity of patients, and the definition of the migratory pathways of the parasite. The marked host reactions seen following chemotherapy, especially those related to the interaction of the drug diethylcarbamazine with microfilariae, are discussed at some length. The etiology of these reactions is considered and recommendations are made for the experimental elucidation of the mechanisms involved. Emphasis is placed on the necessity for detailed sequential histopathological and immunopathological studies in the definition of the tissue lesions found in onchocerciasis. Characterization of these lesions will assist greatly the approach to control of the adverse reactions seen during treatment. The use of anti-inflammatory agents in clinical trials is discussed and comments are made concerning the most suitable clinical situations for testing drugs and the types of drug that should be tested. PMID:396050

  17. Does Increasing Treatment Frequency Address Suboptimal Responses to Ivermectin for the Control and Elimination of River Blindness?

    PubMed Central

    Frempong, Kwadwo K.; Walker, Martin; Cheke, Robert A.; Tetevi, Edward Jenner; Gyan, Ernest Tawiah; Owusu, Ebenezer O.; Wilson, Michael D.; Boakye, Daniel A.; Taylor, Mark J.; Biritwum, Nana-Kwadwo; Osei-Atweneboana, Mike; Basáñez, María-Gloria

    2016-01-01

    Background. Several African countries have adopted a biannual ivermectin distribution strategy in some foci to control and eliminate onchocerciasis. In 2010, the Ghana Health Service started biannual distribution to combat transmission hotspots and suboptimal responses to treatment. We assessed the epidemiological impact of the first 3 years of this strategy and quantified responses to ivermectin over 2 consecutive rounds of treatment in 10 sentinel communities. Methods. We evaluated Onchocerca volvulus community microfilarial intensity and prevalence in persons aged ≥20 years before the first, second, and fifth (or sixth) biannual treatment rounds using skin snip data from 956 participants. We used longitudinal regression modeling to estimate rates of microfilarial repopulation of the skin in a cohort of 217 participants who were followed up over the first 2 rounds of biannual treatment. Results. Biannual treatment has had a positive impact, with substantial reductions in infection intensity after 4 or 5 rounds in most communities. We identified 3 communities—all having been previously recognized as responding suboptimally to ivermectin—with statistically significantly high microfilarial repopulation rates. We did not find any clear association between microfilarial repopulation rate and the number of years of prior intervention, coverage, or the community level of infection. Conclusions. The strategy of biannual ivermectin treatment in Ghana has reduced O. volvulus microfilarial intensity and prevalence, but suboptimal responses to treatment remain evident in a number of previously and consistently implicated communities. Whether increasing the frequency of treatment will be sufficient to meet the World Health Organization's 2020 elimination goals remains uncertain. PMID:27001801

  18. A guide to the Simulium damnosum complex (Diptera: Simuliidae) in Nigeria, with a cytotaxonomic key for the identification of the sibling species

    PubMed Central

    Post, R J; Onyenwe, E; Somiari, S A E; Mafuyai, H B; Crainey, J L; Ubachukwu, P O

    2011-01-01

    Although approximately 40% of all the people blinded by Onchocerca volvulus are Nigerians, almost nothing was known about the various cytospecies of the blackfly vectors present in Nigeria until 1981. The activation of the Nigerian National Onchocerciasis Control Programme in 1986 (and that programme’s initiation of mass distributions of ivermectin in 1991) provided a significant stimulus to understand the biology of the Nigerian vectors but the exploration of any possible differences between the cytospecies has been hampered by a lack of accessible taxonomic information. This review attempts to satisfy that need. There are nine different cytoforms reliably recorded from Nigeria (Simulium damnosum s.s. Nile form, S. damnosum s.s. Volta form, S. sirbanum Sirba form, S. sirbanum Sudanense form, S. soubrense Beffa form, S. squamosum A, S. squamosum B, S. squamosum C and S. yahense typical form), and three more are known from surrounding countries and might be reasonably expected to occur in Nigeria. All of these cytospecies are presumed to be vectors, although there have been almost no identifications of the vectors of O. volvulus in Nigeria. The biogeographical distribution of the cytoforms is broadly similar to that known in other parts of West Africa (although many of the cytoforms remain insufficiently studied). The physico–chemical hydrology of the Nigerian breeding sites of the cytospecies does not, however, correspond to that seen elsewhere in West Africa, and it is not clear whether this might be related to differences in the cytoforms. An illustrated cytotaxonomic key is presented to facilitate and encourage future studies. PMID:21871165

  19. The relationships between the burden of adult parasites, host age and the microfilarial density in human onchocerciasis.

    PubMed

    Duerr, H P; Dietz, K; Schulz-Key, H; Büttner, D W; Eichner, M

    2004-03-29

    We investigate the relationship between the microfilarial density in the skin and the burden of adult female Onchocerca volvulus by analysing pre-control nodulectomy data which allow for a direct approach, independent of exposure. The data of 169 patients in Burkina Faso and 182 patients in Liberia represent savannah and forest onchocerciasis in West Africa, respectively. Whereas in Burkina Faso, a saturating relationship between microfilarial density and worm burden suggests the operation of density-dependent processes within human hosts, the Liberian data show a linear relationship implying no density dependence. The differences may derive from differences between both parasite strains, i.e. the savannah or the forest strain of O. volvulus. Consistently for both parasite strains and independent of the worm burden, the microfilarial density increases with host age emphasising the concept of the acquisition of immunological tolerance. In male hosts in Liberia, the microfilarial density increases stronger with the worm burden than in female hosts, whereas such sex-specific differences cannot be found in Burkina Faso. In the methodological part of this investigation, we suggest the beta-distribution to be most appropriate for describing variability in microfilarial densities and we present an approach to consider the uncertainty in the adult parasite burden which cannot be determined precisely in helminth infections. Implications of density dependence are discussed with respect to immunological processes in the human host and with respect to the success of control programs. The relationships described show that regulatory processes between the parasite and the human host are multi-dimensional, operating within a high degree of biological variability. PMID:15013736

  20. SUPPLEMENTARY COMPARISON: Final report on COOMET.L-S6: Comparison of standards of evolvent surface

    NASA Astrophysics Data System (ADS)

    Vladimir Semenovich, Kupko

    2010-01-01

    TThe COOMET Project No 314/UA/04, 'Comparison of the involute surface standards', KCDB Reference COOMET.L-S6, was organized by TC 1.5 'Length and Angle' of COOMET. This supplementary comparison started in September 2004 and finished in July 2007. It was piloted by the National Scientific Centre 'Institute of Metrology', Kharkov, Ukraine, and VNIIMS, Russia, participated in the comparison. The comparison standard of NSC 'Institute of Metrology' was carried to the place of the comparison (VNIIMS) by NCS IM attendant specialists as personal baggage, where it was measured by reference to the VNIIMS measuring instrument of parameters of evolvent surfaces, VNIIMS ZMC-550. The pilot laboratory processed the data for estimating measurement result differences between the measuring instruments of NSC IM and VNIIMS. The following parameters were determined: deviation from profile form, deviation from profile position and full profile error. The conclusion is that the equivalence of the reference installations for parameter measurements of involute surfaces of NSC 'Institute of Metrology', Ukraine, and of VNIIMS, Russia, is sufficient and constitutes an appropriate basis for mutual recognition of measurement results. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by COOMET, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  1. 16 CFR 233.1 - Former price comparisons.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... DECEPTIVE PRICING § 233.1 Former price comparisons. (a) One of the most commonly used forms of bargain..., not for the purpose of establishing a fictitious higher price on which a deceptive comparison might...

  2. Supplement to photographic catalog of selected planetary size comparisons

    NASA Technical Reports Server (NTRS)

    Meszaros, Stephen Paul

    1991-01-01

    This document updates and extends the photographic catalog of selected planetary size comparisons. It utilizes photographs taken by NASA spacecraft to illustrate size comparisons of planets and moons of the solar system. Global views are depicted at the same scale, within each comparison, allowing size relationships to be studied visually.

  3. The Performance versus Ability Distinction Following Social Comparison Feedback

    ERIC Educational Resources Information Center

    Buckingham, Justin T.; LeBeau, Lavonia Smith; Klein, William M. P.

    2011-01-01

    Previous research suggests that self-evaluations can be influenced by social comparison feedback. The present study tested whether social comparison feedback has stronger effects on self-evaluations of performance than ability. Participants received social comparison feedback indicating that they had performed above or below average. In addition…

  4. Learning through Case Comparisons: A Meta-Analytic Review

    ERIC Educational Resources Information Center

    Alfieri, Louis; Nokes-Malach, Timothy J.; Schunn, Christian D.

    2013-01-01

    Over the past 20 years, there has been much research on how people learn from case comparisons. This work has implemented comparison activities in a variety of different ways across a wide range of laboratory and classroom contexts. In an effort to assess the overall effectiveness of case comparisons across this diversity of implementation and…

  5. Comparison versus Contrast: Task Specifics Affect Category Acquisition

    ERIC Educational Resources Information Center

    Ankowski, Amber A.; Vlach, Haley A.; Sandhofer, Catherine M.

    2013-01-01

    A large literature has documented that comparison and contrast lead to better performance in a variety of tasks. However, studies of comparison and contrast present contradictory conclusions as to when and how these processes benefit learners. Across four studies, we examined how the specifics of the comparison and contrast task affect performance…

  6. 30 CFR 1206.155 - Accounting for comparison.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Accounting for comparison. 1206.155 Section... INTERIOR Natural Resources Revenue PRODUCT VALUATION Federal Gas § 1206.155 Accounting for comparison. (a... with § 1206.152 of this subpart. (b) The requirement for accounting for comparison contained in...

  7. Investigation criteria for dosimetry results comparisons

    SciTech Connect

    Hough, E.G. )

    1984-01-01

    This paper reports that the Oconee Nuclear Station, like most nuclear facilities, monitors its personnel with two types of dosimeters: a thermoluminescent dosimeter (TLD), which is normally used for determining the official dose equivalent, and a pocket ionization chamber (PIC), which is used to estimate exposure for control purposes. At Oconee, the results obtained from the two types of dosimeters are compared on a monthly basis as a part of the routine exchange and processing of worker TLDs. Each worker's TLD result is compared to the sum of the PIC dose estimates for the month that the TLD was used. The TLD result is accepted as the official dose equivalent for the month if the comparison results are within the tolerance limits specified by the criteria. An out-of-tolerance comparison requires investigation, which consists of performance tests of the dosimetry involved and reviews of exposure records. Adjustments to a worker's official dose equivalent are made when warranted by an investigation.

  8. Robot Trajectories Comparison: A Statistical Approach

    PubMed Central

    Ansuategui, A.; Arruti, A.; Susperregi, L.; Yurramendi, Y.; Jauregi, E.; Lazkano, E.; Sierra, B.

    2014-01-01

    The task of planning a collision-free trajectory from a start to a goal position is fundamental for an autonomous mobile robot. Although path planning has been extensively investigated since the beginning of robotics, there is no agreement on how to measure the performance of a motion algorithm. This paper presents a new approach to perform robot trajectories comparison that could be applied to any kind of trajectories and in both simulated and real environments. Given an initial set of features, it automatically selects the most significant ones and performs a statistical comparison using them. Additionally, a graphical data visualization named polygraph which helps to better understand the obtained results is provided. The proposed method has been applied, as an example, to compare two different motion planners, FM2 and WaveFront, using different environments, robots, and local planners. PMID:25525618

  9. 33alloy: comparison between experiment and simulation

    SciTech Connect

    Kramer, M J; Mendelev, M I; Asta, M

    2014-04-22

    We report data on the structure of liquid Al and an Al67Mg33 alloy obtained from state-of-the-art X-ray diffraction experiments and ab initio molecular dynamics (AIMD) simulations. To facilitate a direct comparison between these data, we develop a method to elongate the AIMD pair correlation function in order to obtain reliable AIMD structure factors. The comparison reveals an appreciable level of discrepancy between experimental and AIMD liquid structures, with the latter being consistently more ordered than the former at the same temperature. The discrepancy noted in this study is estimated to have significant implications for simulation-based calculations of liquid transport properties and solid–liquid interface kinetic properties.

  10. Metrics for comparison of crystallographic maps

    DOE PAGESBeta

    Urzhumtsev, Alexandre; Afonine, Pavel V.; Lunin, Vladimir Y.; Terwilliger, Thomas C.; Adams, Paul D.

    2014-10-01

    Numerical comparison of crystallographic contour maps is used extensively in structure solution and model refinement, analysis and validation. However, traditional metrics such as the map correlation coefficient (map CC, real-space CC or RSCC) sometimes contradict the results of visual assessment of the corresponding maps. This article explains such apparent contradictions and suggests new metrics and tools to compare crystallographic contour maps. The key to the new methods is rank scaling of the Fourier syntheses. The new metrics are complementary to the usual map CC and can be more helpful in map comparison, in particular when only some of their aspects,more » such as regions of high density, are of interest.« less

  11. Robot trajectories comparison: a statistical approach.

    PubMed

    Ansuategui, A; Arruti, A; Susperregi, L; Yurramendi, Y; Jauregi, E; Lazkano, E; Sierra, B

    2014-01-01

    The task of planning a collision-free trajectory from a start to a goal position is fundamental for an autonomous mobile robot. Although path planning has been extensively investigated since the beginning of robotics, there is no agreement on how to measure the performance of a motion algorithm. This paper presents a new approach to perform robot trajectories comparison that could be applied to any kind of trajectories and in both simulated and real environments. Given an initial set of features, it automatically selects the most significant ones and performs a statistical comparison using them. Additionally, a graphical data visualization named polygraph which helps to better understand the obtained results is provided. The proposed method has been applied, as an example, to compare two different motion planners, FM(2) and WaveFront, using different environments, robots, and local planners. PMID:25525618

  12. Comparisons of activity measurements with radionuclide calibrators.

    PubMed

    Oropesa, P; Hernández, A T; Serra, R; Martínez, E; Varela, C

    2003-01-01

    The correct administration to a patient of the prescribed activity of a radiopharmaceutical is an important factor to ensure the confidence in the diagnosis or the therapeutic efficiency, while at the same time keeping the unnecessary human exposure as low as possible. Comparisons of activity measurements for 131I, 201Tl and 99mTc with radionuclide calibrators were organized the first time in Cuba during 2002 with the aim of obtaining information about the quality of administration of radiopharmaceuticals. Ten Cuban nuclear medicine departments and the laboratories involved in the production of these kinds of compounds participated in the comparison runs. The results presented in this paper facilitated the identification of several problems and initiated corrective actions. In addition, they indicate the necessity of establishing Quality Systems in nuclear medicine in Cuba. PMID:14622940

  13. Comparison of interventions to reduce sun exposure.

    PubMed

    Roberts, Dawn C; Black, Danielle

    2009-01-01

    Exposure to ultraviolet (UV) light is the leading behavioral cause of skin cancer. This study evaluated the efficacy of 2 interventions to reduce UV exposure in college students prior to an opportunity for high-intensity exposure. Participants of 1 college campus were assigned randomly to 1 of 2 interventions prior to their spring holiday spent in a warm, sunny location: (1) a community-based informational campaign, or (2) a combination of the campaign and a cognitive-behavioral small group intervention. Participants of a second college campus served as a comparison group. The cognitive-behavioral group exhibited increased knowledge, more positive attitudes toward UV protection, greater advancement through stages of change, and greater protective clothing use relative to the comparison or community-education groups. The informational campaign had little apparent impact in this study. PMID:19433378

  14. Inter-species comparisons of carcinogenicity.

    PubMed Central

    Purchase, I. F.

    1980-01-01

    The carcinogenicity of 250 chemicals in 2 species, usually the rat and the mouse, was obtained from the published literature through 3 independent sources. Of the 250 compounds listed, 38% were non-carcinogenic in both rats and mice, and 44% were carcinogenic in both species. A total of 43 compounds had different results in the two species, 21 (8%) being carcinogenic in mice only, 17 (7%) in rats only and 5 (2%) having differing results from other species. A comparison of the major target organs affected by chemicals carcinogenic in both species revealed that 64% of the chemicals studied produced cancer at the same site. This comparison of carcinogenic activity in 2 species suggests that extrapolation from results in a single-animal study to man may be subject to substantial errors. PMID:7387835

  15. Visual comparison testing of automotive paint simulation

    NASA Astrophysics Data System (ADS)

    Meyer, Gary; Fan, Hua-Tzu; Seubert, Christopher; Evey, Curtis; Meseth, Jan; Schnackenberg, Ryan

    2015-03-01

    An experiment was performed to determine whether typical industrial automotive color paint comparisons made using real physical samples could also be carried out using a digital simulation displayed on a calibrated color television monitor. A special light booth, designed to facilitate evaluation of the car paint color with reflectance angle, was employed in both the real and virtual color comparisons. Paint samples were measured using a multi-angle spectrophotometer and were simulated using a commercially available software package. Subjects performed the test quicker using the computer graphic simulation, and results indicate that there is only a small difference between the decisions made using the light booth and the computer monitor. This outcome demonstrates the potential of employing simulations to replace some of the time consuming work with real physical samples that still characterizes material appearance work in industry.

  16. Bayesian hypothesis testing for key comparisons

    NASA Astrophysics Data System (ADS)

    Wübbeler, Gerd; Bodnar, Olha; Elster, Clemens

    2016-08-01

    Unilateral degrees of equivalence are the key result in the analysis of key comparison data and they are used to approve, or disapprove, calibration and measurement capabilities of the participating laboratories. To this end, it is checked whether a degree of equivalence differs significantly from zero. Proceeding in such a way can be viewed as carrying out a classical hypothesis test. We develop a Bayesian counterpart to this approach which has the advantage that it can include prior assessment of the corresponding Consultative Committee about the calibration and measurement capabilities of the participating laboratories. Simple expressions are derived and their implementation is provided in terms of MATLAB® and R programs. The novel procedure is illustrated by its application to two recent key comparisons CCL-K1 and CCM.FF-K4.1.2011.

  17. Comparison results for ignition in conjugate systems

    NASA Technical Reports Server (NTRS)

    Pushpavanam, S.; Narayanan, R.

    1988-01-01

    The exothermic reaction of an arbitrarily shaped solid in a well-mixed continuous flow of constant density and velocity is investigated analytically, with a focus on a zeroth-order reaction in a pellet. Comparison theorems for the basic problem and the eigenvalue problem of ignition are derived, and the domain dependence of the bifurcation point is explored using the method of Joseph (1976). Some typical analytical results are presented in tables and compared with published values obtained using numerical methods.

  18. Comparison of two dissimilar modal identification techniques

    NASA Technical Reports Server (NTRS)

    Pappa, Richard S.; Schenk, Axel; Niedbal, Norbert; Klusowski, Erhard

    1992-01-01

    Recent laboratory results using a refined phase resonance method and the eigensystem realization algorithm on the same test structure are reported. These methods are dissimilar modal identification techniques suitable for future large spacecraft. The theory, application approach, and results obtained for each technique are summarized and compared. Although both methods worked well in this investigation, significant differences occurred in some identified mode shapes. Comparison of independently derived modal parameters provides the means for disclosing such discrepancies in flight projects.

  19. Spectral comparisons of sunlight and different lamps

    NASA Technical Reports Server (NTRS)

    Deitzer, Gerald

    1994-01-01

    The tables in this report were compiled to characterize the spectra of available lamp types and provide comparison to the spectra of sunlight. Table 1 reports the spectral distributions for various lamp sources and compares them to those measured for sunlight. Table 2 provides the amount of energy in Wm(exp -2) relative to the number of photons of PAR (photosynthetically active radiation) (400-700 nm) for each light source.

  20. KEY COMPARISON: Final report on CCQM-K69 key comparison: Testosterone glucuronide in human urine

    NASA Astrophysics Data System (ADS)

    Liu, Fong-Ha; Mackay, Lindsey; Murby, John

    2010-01-01

    The CCQM-K69 key comparison of testosterone glucuronide in human urine was organized under the auspices of the CCQM Organic Analysis Working Group (OAWG). The National Measurement Institute Australia (NMIA) acted as the coordinating laboratory for the comparison. The samples distributed for the key comparison were prepared at NMIA with funding from the World Anti-Doping Agency (WADA). WADA granted the approval for this material to be used for the intercomparison provided the distribution and handling of the material were strictly controlled. Three national metrology institutes (NMIs)/designated institutes (DIs) developed reference methods and submitted data for the key comparison along with two other laboratories who participated in the parallel pilot study. A good selection of analytical methods and sample workup procedures was displayed in the results submitted considering the complexities of the matrix involved. The comparability of measurement results was successfully demonstrated by the participating NMIs. Only the key comparison data were used to estimate the key comparison reference value (KCRV), using the arithmetic mean approach. The reported expanded uncertainties for results ranged from 3.7% to 6.7% at the 95% level of confidence and all results agreed within the expanded uncertainty of the KCRV. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  1. AERICOMP: an aerial photo comparison system

    NASA Astrophysics Data System (ADS)

    Grewe, Lynne L.; Rowe, Neil; Baer, Wolfgang

    2000-08-01

    This paper describes a system, which compares aerial photographs of the same terrain taken at different times and tires to recognize straight-edged cultural features that have changed. This work is intended to be highly robust, handling very different lighting conditions, weather, times of year, camera, and film between the images to be compared. Our system AERICOMP is designed to facilitate battlefield terrain modeling by permitting automatic updates form new images. AERICOMP does coarse registration, image correction, feature detection, automatic refined registration, feature difference detection and reduction, feature difference presentation and operator acceptance, difference identification, and database update. It emphasizes line segments for comparisons because differences in them are more robust for photometric changes between terrain images. In addition, line segment comparisons require less computation than pixel comparisons and are more compatible with identification tasks. For our intended application of battlefield terrain modeling, detecting changes in man-made structures is of much greater importance than changes in vegetation, and line segments are the key to identifying such structures. We show results involving change analysis between color IR and black/white USGS photographs of the same area six years apart. Even a mostly automatic system benefits form user interacting at key points. AERICOMP exploits user judgements at the beginning and end of its processing to assist in coarse registration and to approve the significance of any differences found. AERICOMP is currently under development at the Naval Postgraduate School, and is supported by the TENCAPS project under the US Navy.

  2. Hydraulic fracture model comparison study: Complete results

    SciTech Connect

    Warpinski, N.R.; Abou-Sayed, I.S.; Moschovidis, Z.; Parker, C.

    1993-02-01

    Large quantities of natural gas exist in low permeability reservoirs throughout the US. Characteristics of these reservoirs, however, make production difficult and often economic and stimulation is required. Because of the diversity of application, hydraulic fracture design models must be able to account for widely varying rock properties, reservoir properties, in situ stresses, fracturing fluids, and proppant loads. As a result, fracture simulation has emerged as a highly complex endeavor that must be able to describe many different physical processes. The objective of this study was to develop a comparative study of hydraulic-fracture simulators in order to provide stimulation engineers with the necessary information to make rational decisions on the type of models most suited for their needs. This report compares the fracture modeling results of twelve different simulators, some of them run in different modes for eight separate design cases. Comparisons of length, width, height, net pressure, maximum width at the wellbore, average width at the wellbore, and average width in the fracture have been made, both for the final geometry and as a function of time. For the models in this study, differences in fracture length, height and width are often greater than a factor of two. In addition, several comparisons of the same model with different options show a large variability in model output depending upon the options chosen. Two comparisons were made of the same model run by different companies; in both cases the agreement was good. 41 refs., 54 figs., 83 tabs.

  3. Goals and Social Comparisons Promote Walking Behavior.

    PubMed

    Chapman, Gretchen B; Colby, Helen; Convery, Kimberly; Coups, Elliot J

    2016-05-01

    The effectiveness of a pedometer intervention was affected by manipulating the goals given to participants and by providing social comparison feedback about how participants' performance compared with others. In study 1 (n= 148), university staff members received a low, medium, or high walking goal (10%, 50%, or 100% increase over baseline walking). Participants walked 1358 more steps per day (95% confidence interval [CI], 729, 1985), when receiving a high goal than when receiving a medium goal, but a medium goal did not increase walking relative to a low goal (554 more steps; 95% CI, -71,1179). In study 2 (n= 64), participants received individual feedback only or individual plus social comparison feedback. Participants walked 1120 more steps per day (95% CI, 538, 1703) when receiving social comparison feedback than when receiving only individual feedback. Goals and the performance of others act as reference points and influence the effect that pedometer feedback has on walking behavior, illustrating the applicability of the principles of behavioral economics and social psychology to the design of health behavior interventions. PMID:26139447

  4. Multiple comparisons in complex clinical trial designs.

    PubMed

    Hung, H M James; Wang, Sue-Jane

    2013-05-01

    Multiple comparisons have drawn a great deal of attention in evaluation of statistical evidence in clinical trials for regulatory applications. As the clinical trial methodology is increasingly more complex to properly take into consideration many practical factors, the multiple testing paradigm widely employed for regulatory applications may not suffice to interpret the results of an individual trial and of multiple trials. In a large outcome trial, an increasing need of studying more than one dose complicates a proper application of multiple comparison procedures. Additional challenges surface when a special endpoint, such as mortality, may need to be tested with multiple clinical trials combined, especially under group sequential designs. Another interesting question is how to study mortality or morbidity endpoints together with symptomatic endpoints in an efficient way, where the former type of endpoints are often studied in only one single trial but the latter type of endpoints are usually studied in at least two independent trials. This article is devoted to discussion of insufficiency of such a widely used paradigm applying only per-trial based multiple comparison procedures and to expand the utility of the procedures to such complex trial designs. A number of viable expanded strategies are stipulated. PMID:23620458

  5. KEY COMPARISON: Final report on international comparison COOMET.QM-K23b: Natural gas

    NASA Astrophysics Data System (ADS)

    Konopelko, L. A.; Kustikov, Y. A.; Gromova, E. V.; Rozhnov, M. S.; Mironchik, A. M.; Kluchits, A. S.; Heine, H.-J.; Valkova, M.; Musil, S.; Tichy, J.

    2010-01-01

    The composition of natural gas is one of the significant objects for comparison study. Since 2000 three key comparisons of natural gas within CCQM have been implemented: CCQM-K1e-g, CCQM-K16a-b and CCQM-K23a-c. In 2007 VNIIM offered to organize within COOMET a key comparison of natural gas linked to CCQM-K23b. There were five NMIs that decided to take part in COOMET.QM-K23b in order to claim new or improve present CMCs: Ukrmetrteststandard (Ukraine), BelGIM (Belarus), BAM (Germany), SMU (Slovak Republic) and CMI (Czech Republic). Most of the NMIs (VNIIM, BAM, SMU, CMI) participated in CCQM-K23b; BelGIM and Ukrmetrteststandard participated in a comparison of natural gas for the first time. The gas mixtures for study contained nitrogen, carbon dioxide, ethane, propane, iso-butane, n-butane and methane. The key comparison reference value (KCRV) was based on the gravimetric preparation for all components. In order to determine the link between COOMET.QM-K23b and CCQM-K23b the uncertainty of degrees of equivalence of all the participants included the degree of equivalence of VNIIM in CCQM-K23b. The agreement of the results in this key comparison is very good. Most of the results agree with the KCRV within 0.5% relative. BelGIM and Ukrmetrteststandard participated in a comparison of natural gas for the first time, and both laboratories performed well in this key comparison. CMI obtained better results than in CCQM-K23b. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  6. Economic comparison of nuclear and coal-fired generation. [Monograph

    SciTech Connect

    Corey, G.R.

    1980-01-01

    This paper compares the current and historic operating performance of 12 large nuclear and coal-fired units now operated by Commonwealth Edison Co., and provides specific comparisons of busbar costs of electricity generated by those units in recent years. It also provides cost comparisons for future nuclear and coal-fired units, and attempts to deal realistically with the effect of future inflation upon these comparisons. The paper deals with the problem of uncertainty, the effect of future developments on present-day comparisons, and how published comparisons have varied over the past four or five years. 9 tables.

  7. On the role of code comparisons in verification and validation.

    SciTech Connect

    Oberkampf, William Louis; Trucano, Timothy Guy; Pilch, Martin M.

    2003-08-01

    This report presents a perspective on the role of code comparison activities in verification and validation. We formally define the act of code comparison as the Code Comparison Principle (CCP) and investigate its application in both verification and validation. One of our primary conclusions is that the use of code comparisons for validation is improper and dangerous. We also conclude that while code comparisons may be argued to provide a beneficial component in code verification activities, there are higher quality code verification tasks that should take precedence. Finally, we provide a process for application of the CCP that we believe is minimal for achieving benefit in verification processes.

  8. KEY COMPARISON: Final report of International Comparison EUROMET.QM-K1c: Comparison of measurements of nitrogen monoxide in nitrogen

    NASA Astrophysics Data System (ADS)

    van der Veen, A. M. H.; Nieuwenkamp, G.; Oudwater, R.; Wessel, R. M.; Novak, J.; Perrochet, J.-F.; Ackermann, A.; Rakowska, A.; Cortez, L.; Dias, F.; Konopelko, L.; Kustikov, Y.; Sutour, C.; Masé, T.; Milton, M. J. T.; Uprichard, I. J.; Woods, P. T.; Walden, J.; Lopez Esteban, M. T.

    2005-01-01

    Following-up the key comparison CCQM-K1c, EUROMET organized a regional key comparison involving ten laboratories. The objectives of this EUROMET key comparison were essentially the same as for the CCQM-K1c comparison: to compare the measurement capabilities of national metrological institutes (NMIs) in measuring amount of substance fractions of nitrogen monoxide in nitrogen. The nominal amount of substance fraction of the standards used for the comparison was 100 µmol/mol. The pilot laboratory in this key comparison also piloted the CCQM key comparison and has long-term experience in the behaviour of these mixtures and the technical challenges in preparing batches of very similar mixtures. Most participants used chemiluminescence as the measurement method; two participants used UV techniques and one ND-IR. The degrees of equivalence between this comparison and CCQM-K1c were calculated; four laboratories participated in both key comparisons, thus providing sufficient data for demonstrating the comparability. Main text. To reach the main text of this paper, click on Final Report. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the Mutual Recognition Arrangement (MRA).

  9. Comparisons and perceived deprivation in ethnic minority settings.

    PubMed

    Zagefka, Hanna; Brown, Rupert

    2005-04-01

    Two studies investigated comparison choices among ethnic minorities and majorities. The perceived status of the self vis-á-vis different comparison targets also was assessed. Antecedents and consequences of comparisons and relative deprivation were examined. Predictions were derived from social comparison, stigma, social identity, and relative deprivation research. Two surveys were conducted, one in London with mainly Asian participants (N = 235) and one in Germany with Turkish and Aussiedler participants (N = 166) and German majority members (N = 351). Participants preferred intragroup and temporal comparisons (with other ingroup members and with the self in the past) to various types of cross-group comparisons (with outgroup members). Perceived similarity and contact with a target positively predicted interest in comparing with this target, and perceived higher status of the target was a negative predictor. Some evidence was found that feelings of deprivation depend on comparison choices. Deprivation negatively predicted self-esteem and life satisfaction. Deprivation and group identification were negatively correlated. PMID:15743982

  10. Social comparisons in novel situations: finding inspiration during life transitions.

    PubMed

    Lockwood, Penelope; Shaughnessy, Sarah C; Fortune, Jennifer L; Tong, Man-On

    2012-08-01

    The authors propose that individuals transitioning to a novel environment will prefer upward comparisons, particularly those made with individuals who have experienced a similar transition. Such comparisons help to reduce uncertainty and demonstrate that future success is possible. Study 1 found that individuals facing transitions to unfamiliar situations seek upward comparisons as a result of their uncertainty. Study 2 demonstrated that individuals who perceive themselves to be making a significant life transition are especially motivated by upward comparisons. Study 3 provided evidence that upward comparisons are especially inspiring to individuals making a transition to a novel cultural environment. Study 4 provided experimental evidence that individuals in a novel cultural environment are particularly inspired by upward comparisons with other newcomers. These studies suggest that upward comparisons with individuals who have experienced a similar transition enhance individuals' sense of control over future outcomes and play a key role during adjustment to novel environments. PMID:22825208

  11. Physical appearance comparisons in ethnically diverse college women.

    PubMed

    Schaefer, Lauren M; Thibodaux, Lia K; Krenik, Daniel; Arnold, Elysse; Thompson, J Kevin

    2015-09-01

    Research demonstrates ethnic differences in rates of body dissatisfaction and disordered eating. Appearance comparison frequency is related to these outcomes, however, research has not examined possible ethnic differences in levels of appearance comparisons nor their relation to body dissatisfaction and disordered eating. The current study examined the frequency of appearance comparisons and the strength of the relationships between appearance comparisons, appearance evaluation, and disordered eating among White, Black, and Hispanic women. Measures of appearance comparison, appearance evaluation, and disordered eating were administered to 895 college women. Compared with White and Hispanic women, Black women reported fewer appearance comparisons, more positive appearance evaluation, and lower levels of disordered eating. Associations between examined variables were generally weaker among Black women. Results suggest that the reduced frequency and impact of appearance comparisons may contribute to more positive appearance evaluation and reduced levels of disordered eating among Black women. PMID:26453998

  12. Comparison of FMS versus TDMS applications

    SciTech Connect

    Werner, N.E.

    1983-01-01

    A business application which uses forms management is described. The screen format, data dictionary, dataflow diagrams, minispecs, and structured design chart are included to provide the description of this application. It is implemented using TDMS and FMS in separate applications. Examples of code are included showing both methods of implementation. Finally, a comparison of FMS features and TDMS features is done, indicating that the nature of the application and also the environment under which the application will be used and maintained dictates which form product would be more suitable.

  13. Comparison of Ridges on Triton and Europa

    NASA Technical Reports Server (NTRS)

    Prockter, L. M.; Pappalardo, R. .

    2003-01-01

    Triton and Europa each display a variety of ridges and associated troughs. The resemblance of double ridges on these two satellites has been previously noted [R. Kirk, pers. comm.], but as yet, the similarities and differences between these feature types have not been examined in any detail. Triton s ridges, and Europa s, exhibit an evolutionary sequence ranging from isolated troughs, through doublet ridges, to complex ridge swaths [1, 2]. Comparison of ridges on Europa to those on Triton may provide insight into their formation on both satellites, and thereby have implications for the satellites' histories.

  14. Comparison of Shallow Survey 2012 Multibeam Datasets

    NASA Astrophysics Data System (ADS)

    Ramirez, T. M.

    2012-12-01

    The purpose of the Shallow Survey common dataset is a comparison of the different technologies utilized for data acquisition in the shallow survey marine environment. The common dataset consists of a series of surveys conducted over a common area of seabed using a variety of systems. It provides equipment manufacturers the opportunity to showcase their latest systems while giving hydrographic researchers and scientists a chance to test their latest algorithms on the dataset so that rigorous comparisons can be made. Five companies collected data for the Common Dataset in the Wellington Harbor area in New Zealand between May 2010 and May 2011; including Kongsberg, Reson, R2Sonic, GeoAcoustics, and Applied Acoustics. The Wellington harbor and surrounding coastal area was selected since it has a number of well-defined features, including the HMNZS South Seas and HMNZS Wellington wrecks, an armored seawall constructed of Tetrapods and Akmons, aquifers, wharves and marinas. The seabed inside the harbor basin is largely fine-grained sediment, with gravel and reefs around the coast. The area outside the harbor on the southern coast is an active environment, with moving sand and exposed reefs. A marine reserve is also in this area. For consistency between datasets, the coastal research vessel R/V Ikatere and crew were used for all surveys conducted for the common dataset. Using Triton's Perspective processing software multibeam datasets collected for the Shallow Survey were processed for detail analysis. Datasets from each sonar manufacturer were processed using the CUBE algorithm developed by the Center for Coastal and Ocean Mapping/Joint Hydrographic Center (CCOM/JHC). Each dataset was gridded at 0.5 and 1.0 meter resolutions for cross comparison and compliance with International Hydrographic Organization (IHO) requirements. Detailed comparisons were made of equipment specifications (transmit frequency, number of beams, beam width), data density, total uncertainty, and

  15. Comparison of erosion and channel characteristics

    USGS Publications Warehouse

    Parker, Gene W.

    1998-01-01

    Erosion was observed at 33 percent of 22,495 bridge sites in nine States. Among sites with erosion, 56 percent were associated with skewed flows, curved channels, or a combination of these two conditions, and at 18 percent of the sites, channels were straight with steep bank angles. The remaining 26 percent are sites with observable erosion at piers or abutments on straight channels. Comparison of the sites with erosion to channel bed-material indicate that 44 percent of the single-span sites had gravel-size or smaller bed material and 70 percent of the multiple-span sites had gravel-size or smaller bed material.

  16. Interior structure of Neptune - Comparison with Uranus

    NASA Technical Reports Server (NTRS)

    Hubbard, W. B.; Nellis, W. J.; Mitchell, A. C.; Holmes, N. C.; Mccandless, P. C.; Limaye, S. S.

    1991-01-01

    Measurements of rotation rates and gravitational harmonics of Neptune made with the Voyager 2 spacecraft allow tighter constraints on models of the planet's interior. Shock measurements of material that may match the composition of Neptune, the so-called planetary 'ice', have been carried out to pressures exceeding 200 gigapascals (2 megabars). Comparison of shock data with inferred pressure-density profiles for both Uranus and Neptune shows substantial similarity through most of the mass of both planets. Analysis of the effect of Neptune's strong differential rotation on its gravitational harmonics indicates that differential rotation involves only the outermost few percent of Neptune's mass.

  17. Comparison of RESRAD with hand calculations

    SciTech Connect

    Rittmann, P.D.

    1995-09-01

    This report is a continuation of an earlier comparison done with two other computer programs, GENII and PATHRAE. The dose calculations by the two programs were compared with each other and with hand calculations. These band calculations have now been compared with RESRAD Version 5.41 to examine the use of standard models and parameters in this computer program. The hand calculations disclosed a significant computational error in RESRAD. The Pu-241 ingestion doses are five orders of magnitude too small. In addition, the external doses from some nuclides differ greatly from expected values. Both of these deficiencies have been corrected in later versions of RESRAD.

  18. An architectural comparison of dataflow systems

    SciTech Connect

    Srini, V.P.

    1986-03-01

    A Distributed Computer System, or DCS, based on the dataflow model of computation has the potential to concurrently execute a large number of tasks employing potentially thousands of processors. Since control has to be distributed and asynchronous in such a DCS, several new challenges appear in the design of processors, momory, and interconnection networks. Some of the challenges in the design of processors is presented in this article. An architectural comparison of seven dataflow processors based on sixteen criteria forms the major part of the article.

  19. A comparison of thermal zone aggregation methods

    SciTech Connect

    Dobbs, Justin R.; Hencey, Brandon M.

    2012-12-10

    The impact of increasing energy prices on building operation budgets has fueled demand for more energy-efficient structures. Existing building energy simulation tools generate an immense amount of data yet comparatively little knowledge. This paper introduces a framework that allows aggregation-based model reduction to operate on geometric building information models. The resulting aggregation sequence provides designers with faster simulations and affords insight into complex multi-scale thermal interactions. A comparison of the trade-off between simulation speed and accuracy for three hierarchical cluster partitioning methods concludes the discussion.

  20. A comparison of RISKIND and RADTRAN 4

    SciTech Connect

    Brumburgh, G.P.; Alesso, H.P.

    1993-11-01

    Our objective in this paper is to provide preliminary comparisons between the two computer codes RISKIND and RADTRAN 4. These codes have utility in evaluating radiological consequences during the transportation of radioactive materials. We reviewed the codes to three criteria: (1) the code`s evaluation capability for accident sequences, frequencies, and environmental consequences, (2) the code`s ``user friendliness`` (as well as how much specific technical expertise the user needed to apply to it), and (3) compatibility with other code output or modules.

  1. Classifications and comparisons of multilocus recombination distributions

    PubMed Central

    Karlin, Samuel; Liberman, Uri

    1978-01-01

    Various classifications and representations of multilocus recombination structures are delineated based on generalized notions of linkage values and recombination rates. An important class of recombination distributions (called the count-location chiasma process) is parameterized by a distribution of the number of crossover events and, for each such crossover count, by a conditional distribution of crossover locations. A number of properties of this recombination structure are developed. A multilocus definition of a “natural” recombination range is set forth. Orderings among recombination distributions in the multilocus setting are also discussed. Comparisons are made in terms of complete linkage, free assortment and noninterference schemes serving as standards. PMID:16592601

  2. Comparison of CALPUFF with ISC3

    SciTech Connect

    Coulter, C.T.; Eckhoff, P.A.

    1998-12-01

    In the report, a comparison is made of two different dispersion models, CALPUFF and ISC3. CALPUFF is a Lagrangian puff model which simulates continuous puffs of pollutants released into the ambient flow, whereas ISC3 is a Gaussian plume model that treats emissions from a source as a contiguous mass. CALPUFF may be configured to treat emissions as integrated puffs or as slugs. ISC3 is currently recommended for routine use in assessing source impacts involving transport distances of less than 50km. The report is being released to establish part of the basis for review of the consequences resulting from use of CALPUFF in routine dispersion modeling of air pollution impacts.

  3. A simple method for global sequence comparison.

    PubMed Central

    Pizzi, E; Attimonelli, M; Liuni, S; Frontali, C; Saccone, C

    1992-01-01

    A simple method of sequence comparison, based on a correlation analysis of oligonucleotide frequency distributions, is here shown to be a reliable test of overall sequence similarity. The method does not involve sequence alignment procedures and permits the rapid screening of large amounts of sequence data. It identifies those sequences which deserve more careful analysis of sequence similarity at the level of resolution of the single nucleotide. It uses observed quantities only and does not involve the adoption of any theoretical model. PMID:1738591

  4. Cray 1 v. Cyber 205: some comparisons

    SciTech Connect

    Temperton, C.

    1983-04-01

    The author has been able to work on two of the world's fastest computers, the Cray-1 (at the European Centre for Medium Range Weather Forecasts) and the Cyber 205 (at the UK Meteorological Office). A comparison between the two machines is of interest not only to poential users but also to a more general audience. The author points out some of the differences between the two machines, and the impact these differences have on the way in which certain problems should be formulated and programmed.

  5. Preference Learning and Ranking by Pairwise Comparison

    NASA Astrophysics Data System (ADS)

    Fürnkranz, Johannes; Hüllermeier, Eyke

    This chapter provides an overview of recent work on preference learning and ranking via pairwise classification. The learning by pairwise comparison (LPC) paradigm is the natural machine learning counterpart to the relational approach to preference modeling and decision making. From a machine learning point of view, LPC is especially appealing as it decomposes a possibly complex prediction problem into a certain number of learning problems of the simplest type, namely binary classification. We explain how to approach different preference learning problems, such as label and instance ranking, within the framework of LPC. We primarily focus on methodological aspects, but also address theoretical questions as well as algorithmic and complexity issues.

  6. Intercode comparison of gyrokinetic global electromagnetic modes

    NASA Astrophysics Data System (ADS)

    Görler, T.; Tronko, N.; Hornsby, W. A.; Bottino, A.; Kleiber, R.; Norscini, C.; Grandgirard, V.; Jenko, F.; Sonnendrücker, E.

    2016-07-01

    Aiming to fill a corresponding lack of sophisticated test cases for global electromagnetic gyrokinetic codes, a new hierarchical benchmark is proposed. Starting from established test sets with adiabatic electrons, fully gyrokinetic electrons, and electrostatic fluctuations are taken into account before finally studying the global electromagnetic micro-instabilities. Results from up to five codes involving representatives from different numerical approaches as particle-in-cell methods, Eulerian and Semi-Lagrangian are shown. By means of spectrally resolved growth rates and frequencies and mode structure comparisons, agreement can be confirmed on ion-gyro-radius scales, thus providing confidence in the correct implementation of the underlying equations.

  7. Rooftop Unit Comparison Calculator User Manual

    SciTech Connect

    Miller, James D.

    2015-04-30

    This document serves as a user manual for the Packaged rooftop air conditioners and heat pump units comparison calculator (RTUCC) and is an aggregation of the calculator’s website documentation. Content ranges from new-user guide material like the “Quick Start” to the more technical/algorithmic descriptions of the “Methods Pages.” There is also a section listing all the context-help topics that support the features on the “Controls” page. The appendix has a discussion of the EnergyPlus runs that supported the development of the building-response models.

  8. Interior structure of Neptune: Comparison with Uranus

    SciTech Connect

    Hubbard, W.B. ); Nellis, W.J.; Mitchell, A.C.; Holmes, N.C.; McCandless, P.C. ); Limaye, S.S. )

    1991-08-09

    Measurements of rotation rates and gravitational harmonics of Neptune made with the Voyager 2 spacecraft allow tighter constraints on models of the planet's interior. Shock measurements of material that may match the composition of Neptune, the so-called planetary ice, have been carried out to pressures exceeding 200 gigapascals (2 megabars). Comparison of shock data with inferred pressure-density profiles for both Uranus and Neptune shows substantial similarity through most of the mass of both planets. Analysis of the effect of Neptune's strong differential rotation on its gravitational harmonics indicates that differential rotation involves only the outermost few percent of Neptune's mass.

  9. Comparison of hyperbolic and hyperboloid conductor electrostatics

    NASA Astrophysics Data System (ADS)

    Lekner, John

    2006-01-01

    The potentials and fields of hyperbolic and hyperboloidal conductors are available analytically. A detailed comparison of the two-dimensional and three-dimensional problems shows strong similarities, but also interesting differences. The electric field near a hyperboloidal needle is stronger (ceteris paribus) than near a hyperbolic blade, and dies off faster. The field at the hyperbolic conductor varies as the 1/3 power of the local curvature. At the hyperboloid conductor the field varies as the 1/4 power of the local Gaussian curvature (which is the product of the two principal curvatures).

  10. Case-control Studies on the Relationship between Onchocerciasis and Epilepsy: Systematic Review and Meta-analysis

    PubMed Central

    Kaiser, Christoph; Pion, Sébastien D. S.; Boussinesq, Michel

    2013-01-01

    Objective A systematic review and meta-analysis of all available case-control studies on the relationship between onchocerciasis and epilepsy. Because age and level of onchocerciasis endemicity in the area of residence are major determinants for infection, an additional analysis was performed, restricted to studies achieving control of these confounding factors. Data sources Medical databases, the “African Neurology Database, Institute of Neuroepidemiology and Tropical Neurology, Limoges,” reference lists of relevant articles, commercial search engines, up to May 2012. Methods We searched for studies examining infection status with Onchocerca volvulus in persons with epilepsy (PWE) and without epilepsy (PWOE) providing data suitable for the calculation of pooled odds ratios (ORp) and/or standardized mean differences (SMD) using random-effects models. Results Eleven studies providing data of qualitative skin biopsies for diagnosis of onchocerciasis were identified. Combined analysis on the total sample of 876 PWE and 4712 PWOE resulted in an ORp of 2.49 (95% confidence interval (95%CI): 1.61–3.86, p<0.001). When this analysis was restricted to those studies achieving control for age, residence and sex (367 PWE, 624 PWOE), an ORp of 1.29 (95% CI: 0.93–1.79; p = 0.139) was found. Presence of nodules for diagnosis of onchocerciasis was analyzed in four studies (225 PWE, 189 PWOE; ORp 1.74; 95%CI: 0.94–3.20; p<0.076), including two studies of the restricted analysis (106 PWE, 106 PWOE; ORp 2.81; 95%CI: 1.57–5.00; p<0.001). One study examined quantitative microfilariae counts in patients without preceding microfilaricidal treatment and demonstrated significantly higher counts in PWE than in PWOE. Interpretation Our results strengthen the hypothesis that, in onchocerciasis foci, epilepsy and infection with O. volvulus are associated. Analysis of indicators giving information on infection intensity, namely nodule palpation and quantitative microfilaria

  11. Brain potentials in outcome evaluation: when social comparison takes effect.

    PubMed

    Wu, Yan; Zhang, Dexuan; Elieson, Bill; Zhou, Xiaolin

    2012-08-01

    Social comparison, in which people evaluate their opinions and abilities by comparing them with the opinions and abilities of others, is a central feature of human social life. Previous work has highlighted the importance of social comparison in reward processing. However, the time-course of the social comparison effect in outcome evaluation remains largely unknown. The purpose of this study was to explore to what extent brain activity is modulated by social comparison between an individual and their anonymous partner. Event-related potentials (ERPs) were measured while the participants viewed their own and their partner's gain and loss outcomes based on their performance in a dot estimation task. Analysis of ERPs revealed that the feedback-related negativity (FRN) amplitude differences between gains and losses were not modulated by social comparison. In contrast, the P300 was larger for gains and showed an effect of social comparison independent of feedback valence. A late component, the late positive potential (LPP), was also modulated by social comparison, but it was insensitive to feedback valence. The data suggest that social comparison modulates outcome evaluation at several points in the information processing stream. Social comparison has no effect on the early coarse evaluation stage, but modulates the late cognitive/affective appraisal and re-appraisal processes. These findings provide neurophysiological evidence for the importance of social comparisons in outcome evaluations by the human brain. PMID:22705168

  12. KEY COMPARISON: Report on bilateral comparison COOMET.AUV.A-K1.1

    NASA Astrophysics Data System (ADS)

    Fedtke, Thomas

    2009-01-01

    A bilateral comparison of primary standards for sound in air, COOMET.AUV.A-K1.1 was conducted in 2004 between the DNDI (Ukraine) and the PTB (Germany) with PTB acting as the linking laboratory to the previous COOMET.AUV.A-K1 comparison. A similar protocol was followed, and although measurements were made at 23 acoustic frequencies, the results were analysed in terms of degrees of equivalence only at the recommended frequencies of the CCAUV.A-K1 comparison so that the appropriate links could be made. The results were approved by CCAUV in October 2008 are in agreement with all the linked results within the uncertainties. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCAUV, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  13. KEY COMPARISON International comparison CCQM-K46: Ammonia in nitrogen

    NASA Astrophysics Data System (ADS)

    van der Veen, Adriaan M. H.; Nieuwenkamp, Gerard; Wessel, Rob M.; Maruyama, Masaaki; Heo, Gwi Suk; Kim, Yong-doo; Moon, Dong Min; Niederhauser, Bernhard; Quintilii, Manuela; Milton, Martin J. T.; Cox, Maurice G.; Harris, Peter M.; Guenther, Franklin R.; Rhoderick, George C.; Konopelko, L. A.; Kustikov, Y. A.; Pankratov, V. V.; Selukov, D. N.; Petrov, V. A.; Gromova, E. V.

    2010-01-01

    Ammonia is an important compound in the chemical industry. It is widely used and is the basis for producing other compounds containing nitrogen. Ammonia is also very hazardous, and consequently emissions of ammonia need be controlled and monitored. In the past years, several national metrology institutes have developed facilities for the preparation of Primary Standard gas Mixtures (PSMs), dynamically generated ammonia mixtures and facilities for comparing and certifying gas mixtures containing ammonia. The amount-of-substance fraction level of ammonia chosen for this key comparison is 30-50 µmol/mol. The results of this key comparison revealed that there is at present no consensus among static and dynamic techniques for gas mixture preparation for this component in this range. As key comparison reference value (KCRV), the mean of the three methods is used. In its uncertainty, no allowance is made for the observed biases. With respect to the KCRV, only two laboratories report consistent results. When grouped in accordance with the employed methods, the results are consistent. Further experimental work is needed. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  14. Neuropsychological comparison of children with heavy prenatal alcohol exposure and an IQ-matched comparison group.

    PubMed

    Vaurio, Linnea; Riley, Edward P; Mattson, Sarah N

    2011-05-01

    An objective in current research on children with fetal alcohol spectrum disorders (FASD) is to determine neurobehavioral profiles to identify affected individuals. Deficits observed when children with FASD are compared to typically developing controls may be confounded by lower IQ scores in the subjects with FASD. To determine if prenatal alcohol exposure is associated with neurobehavioral deficits after controlling for IQ differences, multivariate analyses were conducted to compare alcohol-exposed (ALC) subjects to a comparison group closely matched on IQ (IQC). The initial analysis included a broad neuropsychological battery with measures of language, executive function, visual-motor integration, motor ability, and academic achievement. Additional, in depth comparisons focused on visual sustained attention, verbal learning and memory and parent/guardian-reported behavior problems. Group differences (ALC < IQC) were found on verbal learning and parent-rated behavior problems. Group differences were marginally significant (measures within the broad neuropsychological comparison) or not significant (visual attention, retention of verbal material) on the remaining comparisons. Therefore, some deficits (e.g., verbal learning and behavior problems) in children with heavy prenatal alcohol exposure cannot be explained by the lower FSIQ observed in the population. These areas of relative weakness could be useful in distinguishing children with FASD from other children with lowered IQ. PMID:21349236

  15. Comparison of State Unemployment Insurance Laws. Comparison Revision, Number 1, August 6, 1978.

    ERIC Educational Resources Information Center

    Employment and Training Administration (DOL), Washington, DC. Unemployment Insurance Service.

    To inform the public about details of the employment security program and how it functions, this comparison of state unemployment insurance laws is presented. The report is based primarily on an analysis of state statutes. It examines state by state the types of workers and employers that are covered under the state law, the methods of financing…

  16. Interprovincial Comparisons of University Financing. Eighth Report of the Tripartite Committee on Interprovincial Comparisons.

    ERIC Educational Resources Information Center

    Council of Ontario Universities, Toronto.

    Eight indicators used to make interprovincial comparisons of university financing in Canada are outlined and the amounts for these indicators for each of the 10 provinces are presented for 1974-1975 to 1984-1985. The eight indicators are as follows: provincial operating grants per student, provincial operating grants per capita, provincial…

  17. Interprovincial Comparisons of University Financing. Ninth Report of the Tripartite Committee on Interprovincial Comparisons.

    ERIC Educational Resources Information Center

    Council of Ontario Universities, Toronto.

    Expenditures on universities by each of Canada's provinces are compared. An introductory section describes the project through which the study is undertaken, explains the indicators used, and discusses structural problems encountered in making comparisons. The central portion of the report is a tabulation of these indicators for each province and…

  18. A Comparison of Type I Error Rates of Alpha-Max with Established Multiple Comparison Procedures.

    ERIC Educational Resources Information Center

    Barnette, J. Jackson; McLean, James E.

    J. Barnette and J. McLean (1996) proposed a method of controlling Type I error in pairwise multiple comparisons after a significant omnibus F test. This procedure, called Alpha-Max, is based on a sequential cumulative probability accounting procedure in line with Bonferroni inequality. A missing element in the discussion of Alpha-Max was the…

  19. The interpretation of shoeprint comparison class correspondences.

    PubMed

    Hancock, Sheida; Morgan-Smith, Rian; Buckleton, John

    2012-12-01

    The underlying principles involved in the interpretation of shoeprint comparisons have become a topical subject due to criticisms in the 2009 National Academy of Science (NAS) report on forensic sciences [1]. Difficulties in the application and understanding of these principles were also highlighted in a recent court ruling [2-5]. We report here a survey that may inform some aspects of this interpretation and discuss the implications of findings from this survey in the light of that court ruling and more importantly the NAS report. Five hundred shoeprints taken from student volunteers in Auckland, New Zealand were compared against each other for the presence of any pattern correspondences. Comparisons were undertaken of the full outsole and of smaller portions of the more common patterns. Of the 500 shoe impressions collected 488 (97.6%) were ultimately represented only once in the survey. The greatest number of corresponding patterns was for the most common brand of shoe (Converse Chuck Taylor All Star) and occurred in 3 of 500 observations. No instances of an imitation brand matching the authentic brand were found. Smaller sections of the common patterns showed a greater number of corresponding prints. However, the greatest number of matching partial patterns was again for the most common brand of shoe (Converse Chuck Taylor All Star) and occurred in 29 of 500 observations. We conclude that pattern match alone is of considerable evidential value even when the print is partial. PMID:23068775

  20. PROCAIN: protein profile comparison with assisting information

    PubMed Central

    Wang, Yong; Sadreyev, Ruslan I.; Grishin, Nick V.

    2009-01-01

    Detection of remote sequence homology is essential for the accurate inference of protein structure, function and evolution. The most sensitive detection methods involve the comparison of evolutionary patterns reflected in multiple sequence alignments (MSAs) of protein families. We present PROCAIN, a new method for MSA comparison based on the combination of ‘vertical’ MSA context (substitution constraints at individual sequence positions) and ‘horizontal’ context (patterns of residue content at multiple positions). Based on a simple and tractable profile methodology and primitive measures for the similarity of horizontal MSA patterns, the method achieves the quality of homology detection comparable to a more complex advanced method employing hidden Markov models (HMMs) and secondary structure (SS) prediction. Adding SS information further improves PROCAIN performance beyond the capabilities of current state-of-the-art tools. The potential value of the method for structure/function predictions is illustrated by the detection of subtle homology between evolutionary distant yet structurally similar protein domains. ProCAIn, relevant databases and tools can be downloaded from: http://prodata.swmed.edu/procain/download. The web server can be accessed at http://prodata.swmed.edu/procain/procain.php. PMID:19357092

  1. PROCAIN: protein profile comparison with assisting information.

    PubMed

    Wang, Yong; Sadreyev, Ruslan I; Grishin, Nick V

    2009-06-01

    Detection of remote sequence homology is essential for the accurate inference of protein structure, function and evolution. The most sensitive detection methods involve the comparison of evolutionary patterns reflected in multiple sequence alignments (MSAs) of protein families. We present PROCAIN, a new method for MSA comparison based on the combination of 'vertical' MSA context (substitution constraints at individual sequence positions) and 'horizontal' context (patterns of residue content at multiple positions). Based on a simple and tractable profile methodology and primitive measures for the similarity of horizontal MSA patterns, the method achieves the quality of homology detection comparable to a more complex advanced method employing hidden Markov models (HMMs) and secondary structure (SS) prediction. Adding SS information further improves PROCAIN performance beyond the capabilities of current state-of-the-art tools. The potential value of the method for structure/function predictions is illustrated by the detection of subtle homology between evolutionary distant yet structurally similar protein domains. ProCAIn, relevant databases and tools can be downloaded from: http://prodata.swmed.edu/procain/download. The web server can be accessed at http://prodata.swmed.edu/procain/procain.php. PMID:19357092

  2. Comparison of radar data versus rainfall data.

    PubMed

    Espinosa, B; Hromadka, T V; Perez, R

    2015-01-01

    Doppler radar data are increasingly used in rainfall-runoff synthesis studies, perhaps due to radar data availability, among other factors. However, the veracity of the radar data are often a topic of concern. In this paper, three Doppler radar outcomes developed by the United States National Weather Service at three radar sites are examined and compared to actual rain gage data for two separate severe storm events in order to assess accuracy in the published radar estimates of rainfall. Because the subject storms were very intense rainfall events lasting approximately one hour in duration, direct comparisons between the three radar gages themselves can be made, as well as a comparison to rain gage data at a rain gage location subjected to the same storm cells. It is shown that topographic interference with the radar outcomes can be a significant factor leading to differences between radar and rain gage readings, and that care is needed in calibrating radar outcomes using available rain gage data in order to interpolate rainfall estimates between rain gages using the spatial variation observed in the radar readings. The paper establishes and describes•the need for "ground-truthing" of radar data, and•possible errors due to topographic interference. PMID:26649276

  3. Solar Sail GN and C Model Comparisons

    NASA Technical Reports Server (NTRS)

    Heaton, Andrew F.

    2004-01-01

    The Solar Sail Propulsion project is engaged in an ambitious program to raise the Technology Readiness Level of solar sails and prepare for a validation flight via a series of hardware ground demonstrations and development of a number of high fidelity simulations and models. Guidance, navigation, and control of solar sails is a key part of this effort. The large flexible structure and optical nature of solar sails create a considerable challenge for attitude control, thrust modeling, and navigation. In this paper, we present an overview and comparison of two recently delivered prototype solar sail guidance, navigation, and control software tools currently funded by the Solar Sail Propulsion project. The results of some key test cases are presented. Where possible, we also make comparisons to other software tools. We discuss the implications of the results of these comparative studies to the future direction and scope of development efforts for guidance, navigation and control software for solar sails, including the relationship to hardware test efforts such as the Thrust Vector Control Authority Demonstration.

  4. Bilateral Comparison in Chemosensory-Mediated Foraging

    NASA Astrophysics Data System (ADS)

    Webster, D. R.; Rahman, S.; Dasi, L. P.

    2000-11-01

    Motivation is drawn from the need to determine the sensory cues that animals such as blue crabs and lobsters use to track chemical odor plumes to locate food or mates. Major steps forward with this difficult problem can only be achieved through an appreciation of the spatial and temporal variation of concentration fields and the information content available to a forager in the plume. Here we discuss the usefulness of bilateral comparison to an animal tracking a turbulent plume. Instantaneous concentration fields of a chemical plume diffusing in a fully-developed turbulent open channel flow are measured using planar laser-induced fluorescence (PLIF). The plume is released iso-kinetically 25 mm above the smooth bed (z+ = 90), thus transport is mainly due to advection and ambient turbulence. A spatial correlation function in the spanwise direction is a dramatic indicator of the relative position of the centerline and distance from the source. The relative direction of the plume centerline can be estimated from an instantaneous bilateral comparison provided the sensors are separated by a distance that is relatively large compared to the spanwise integral length scale based on the spatial correlation function.

  5. Water gun vs air gun: A comparison

    USGS Publications Warehouse

    Hutchinson, D.R.; Detrick, R. S.

    1984-01-01

    The water gun is a relatively new marine seismic sound source that produces an acoustic signal by an implosive rather than explosive mechanism. A comparison of the source characteristics of two different-sized water guns with those of conventional air guns shows the the water gun signature is cleaner and much shorter than that of a comparable-sized air gun: about 60-100 milliseconds (ms) for an 80-in3. (1.31-liter (I)) water gun compared with several hundred ms for an 80-in3. (1.31-1) air gun. The source spectra of water guns are richer in high frequencies (>200 Hz) than are those of air guns, but they also have less energy than those of air guns at low frequencies. A comparison between water gun and air gun reflection profiles in both shallow (Long Island Sound)-and deep (western Bermuda Rise)-water settings suggests that the water gun offers a good compromise between very high resolution, limited penetration systems (e.g. 3.5-kHz profilers and sparkers) and the large volume air guns and tuned air gun arrays generally used where significant penetration is required. ?? 1984 D. Reidel Publishing Company.

  6. Cirrus Parcel Model Comparison Project. Phase 1

    NASA Technical Reports Server (NTRS)

    Lin, Ruei-Fong; Starr, David O'C.; DeMott, Paul J.; Cotton, Richard; Jensen, Eric; Sassen, Kenneth

    2000-01-01

    The Cirrus Parcel Model Comparison (CPMC) is a project of the GEWEX Cloud System Study Working Group on Cirrus Cloud Systems (GCSS WG2). The primary goal of this project is to identify cirrus model sensitivities to the state of our knowledge of nucleation and microphysics. Furthermore, the common ground of the findings may provide guidelines for models with simpler cirrus microphysics modules. We focus on the nucleation regimes of the warm (parcel starting at -40 C and 340 hPa) and cold (-60 C and 170 hPa) cases studied in the GCSS WG2 Idealized Cirrus Model Comparison Project. Nucleation and ice crystal growth were forced through an externally imposed rate of lift and consequent adiabatic cooling. The background haze particles are assumed to be lognormally-distributed H2SO4 particles. Only the homogeneous nucleation mode is allowed to form ice crystals in the HN-ONLY runs; all nucleation modes are switched on in the ALL-MODE runs. Participants were asked to run the HN-lambda-fixed runs by setting lambda = 2 (lambda is further discussed in section 2) or tailoring the nucleation rate calculation in agreement with lambda = 2 (exp 1). The depth of parcel lift (800 m) was set to assure that parcels underwent complete transition through the nucleation regime to a stage of approximate equilibrium between ice mass growth and vapor supplied by the specified updrafts.

  7. Comparison of radar data versus rainfall data

    PubMed Central

    Espinosa, B.; Hromadka, T.V.; Perez, R.

    2015-01-01

    Doppler radar data are increasingly used in rainfall-runoff synthesis studies, perhaps due to radar data availability, among other factors. However, the veracity of the radar data are often a topic of concern. In this paper, three Doppler radar outcomes developed by the United States National Weather Service at three radar sites are examined and compared to actual rain gage data for two separate severe storm events in order to assess accuracy in the published radar estimates of rainfall. Because the subject storms were very intense rainfall events lasting approximately one hour in duration, direct comparisons between the three radar gages themselves can be made, as well as a comparison to rain gage data at a rain gage location subjected to the same storm cells. It is shown that topographic interference with the radar outcomes can be a significant factor leading to differences between radar and rain gage readings, and that care is needed in calibrating radar outcomes using available rain gage data in order to interpolate rainfall estimates between rain gages using the spatial variation observed in the radar readings. The paper establishes and describes•the need for “ground-truthing” of radar data, and•possible errors due to topographic interference. PMID:26649276

  8. Alternate Propulsion Subsystem Concepts Tripropellant Comparison Study

    NASA Technical Reports Server (NTRS)

    Levack, Daniel

    1995-01-01

    A study was conducted under MSFC contract NAS8-39210 to compare tripropellant and bipropellant engine configurations for the SSTO mission. The objective was to produce an 'apples-to-apples' comparison to isolate the effects of design implementation, designing company, year of design, or technologies included from the basic tripropellant/bipropellant comparison. Consequently, identical technologies were included (e.g., jet pumps) and the same design groundrules and practices were used. Engine power cycles were examined as were turbomachinery/preburner arrangements for each cycle. The bipropellant approach and two tripropellant approaches were separately optimized in terms of operating parameters: exit pressures, mixture ratios, thrust splits, etc. This briefing presents the results of the study including engine weights for both tripropellant and bipropellant engines; dry vehicle weight performance for a range of engine chamber pressures; discusses the basis for the results; examines vehicle performance due to engine cycles and the margin characteristics of various cycles; and identifies technologies with significant payoffs for this application.

  9. Final report on CCM key comparison CCM.D-K2: Comparison of liquid density standards

    NASA Astrophysics Data System (ADS)

    Bettin, Horst; Jacques, Claude; Zelenka, Zoltán; Fujii, Ken-ichi; Kuramoto, Naoki; Chang, Kyung-Ho; Lee, Yong Jae; Becerra, Luis Omar; Domostroeva, Natalia

    2013-01-01

    The results are presented of the key comparison CCM.D-K2 that covered the density measurements of four liquids: the density of water at 20 °C, of pentadecane at 15 °C, 20 °C, 40 °C and 60°C, of tetrachloroethlyene at 5 °C and 20 °C and of a viscous oil at 20 °C. Seven national metrology institutes measured the densities at atmospheric pressure by hydrostatic weighing of solid density standards in the time interval from 27 April 2004 to 28 June 2004. Since the participants were asked not to include components for a possible drift or inhomogeneity of the liquid in their uncertainty budget, these uncertainty contributions are investigated for the final evaluation of the data. For this purpose, results of stability and homogeneity measurements of the pilot laboratory are used. The participants decided not to include a possible drift of the liquid's density since no significant drift could be detected, and the influence of the drift and its uncertainty are negligible. Similarly, the inhomogeneity of the water and pentadecane samples is not significant and has no influence on the evaluation. Thus, it was neglected. Only the inhomogeneities of tetrachloroethylene and of the viscous oil were significant. Consequently, they were included in the evaluation. With one or two exceptions, the results show good agreement among the participants. Only in the case of water are the results clearly discrepant. The key comparison reference values were calculated by the weighted mean (taking into account a small correlation between two participants) in the case of consistent results. Otherwise the Procedure B of Cox was used. The expanded uncertainties of all reference densities are below 1 × 10-5 in relative terms. This satisfies the needs of all customers who wish to calibrate or check liquid density measuring instruments such as oscillation-type density meters. The comparison fully supports the calibration measurement capabilities table in the BIPM key comparison database

  10. SUPPLEMENTARY COMPARISON: EUROMET.L-S10 Comparison of squareness measurements

    NASA Astrophysics Data System (ADS)

    Mokros, Jiri

    2005-01-01

    The idea of performing a comparison of squareness resulted from the need to review the MRA Appendix C, Category 90° square. At its meeting in October 1999 (in Prague) it was decided upon a first comparison of squareness measurements in the framework of EUROMET, numbered #570, starting in 2000, with the Slovak Institute of Metrology (SMU) as the pilot laboratory. During the preparation stage of the project, it was agreed that it should be submitted as a EUROMET supplementary comparison in the framework of the Mutual Recognition Arrangement (MRA) of the Metre Convention and would boost confidence in calibration and measurement certificates issued by the participating national metrology institutes. The aim of the comparison of squareness measurement was to compare and verify the declared calibration measurement capabilities of participating laboratories and to investigate the effect of systematic influences in the measurement process and their elimination. Eleven NMIs from the EUROMET region carried out this project. Two standards were calibrated: granite squareness standard of rectangular shape, cylindrical squareness standard of steel with marked positions for the profile lines. The following parameters had to be calibrated: granite squareness standard: interior angle γB between two lines AB and AC (envelope - LS regression) fitted through the measured profiles, and/or granite squareness standard: interior angle γLS between two LS regression lines AB and AC fitted through the measured profiles, cylindrical squareness standard: interior angles γ0°, γ90°, γ180°, γ270° between the LS regression line fitted through the measurement profiles at 0°, 90°, 180°, 270° and the envelope plane of the basis (resting on a surface plate), local LS straightness deviation for all measured profiles (2 and 4) of both standards. The results of the comparison are the deviations of profiles and angles measured by the individual NMIs from the reference values. These resulted

  11. SUPPLEMENTARY COMPARISON: Final report on CCL-S3 supplementary line scale comparison Nano3

    NASA Astrophysics Data System (ADS)

    Bosse, Harald; Häßler-Grohne, Wolfgang; Flügge, Jens; Köning, Rainer

    2003-01-01

    This report describes the results of the international line scale comparison Nano3, which was carried out between 2000 and 2003 and which was accepted as supplementary comparison CCL-S3. This comparison was initiated by the BIPM working group on nanometrology as one of five international comparisons in the field of dimensional nanometrology. Two high quality line scales, one made of Zerodur and one made of fused silica (quartz), with 280 mm main graduation length and additional smaller graduations of only a few mm were chosen as transfer standards. These scales were produced using advanced and optimized lithography and processing technologies by the Dr Johannes Heidenhain GmbH, Germany. A considerable number of characterizations of the graduations were performed in order to ensure an optimized line edge quality of the scales used in the comparison. Moreover, it was decided to have long gauge blocks manufactured out of the same piece of substrate material as was used for the scales. In this way, it was possible to independently determine important substrate material parameters like thermal expansion, compressibility and to investigate the long-term stability of the substrate materials. The Zerodur line scale standard revealed a small length reduction of about (-7 +/- 4)×10-8/a, which was confirmed by the measurements on the long gauge blocks. This length change of the Zerodur line scale could be taken into account for the comparison of participant's data by the application of a linear drift model. On the quartz samples and linescales no comparable effects were observed. The line scales were measured by 13 national metrology institutes from four different metrology regions. Two institutes decided to withdraw from Nano3 after the measurements were performed, but before Draft A was circulated. The measurement uncertainties that were evaluated by the participants over the 280 mm length of the graduations showed a variation from about 300 nm down to 30 nm. The good line

  12. Incorporating multiple interventions in meta-analysis: an evaluation of the mixed treatment comparison with the adjusted indirect comparison

    PubMed Central

    O'Regan, Christopher; Ghement, Isabella; Eyawo, Oghenowede; Guyatt, Gordon H; Mills, Edward J

    2009-01-01

    Background Comparing the effectiveness of interventions is now a requirement for regulatory approval in several countries. It also aids in clinical and public health decision-making. However, in the absence of head-to-head randomized trials (RCTs), determining the relative effectiveness of interventions is challenging. Several methodological options are now available. We aimed to determine the comparative validity of the adjusted indirect comparisons of RCTs with the mixed treatment comparison approach. Methods Using systematic searching, we identified all meta-analyses evaluating more than 3 interventions for a similar disease state with binary outcomes. We abstracted data on each clinical trial including population n and outcomes. We conducted fixed effects meta-analysis of each intervention versus mutual comparator and then applied the adjusted indirect comparison. We conducted a mixed treatment meta-analysis on all trials and compared the point estimates and 95% confidence/credible intervals (CIs/CrIs) to determine important differences. Results We included data from 7 reviews that met our inclusion criteria, allowing a total of 51 comparisons. According to the a priori consistency rule, we found 2 examples where the analytic comparisons were statistically significant using the mixed treatment comparison over the adjusted indirect comparisons and 1 example where this was vice versa. We found 6 examples where the direction of effect differed according to the indirect comparison method chosen and we found 9 examples where the confidence intervals were importantly different between approaches. Conclusion In most analyses, the adjusted indirect comparison yields estimates of relative effectiveness equal to the mixed treatment comparison. In less complex indirect comparisons, where all studies share a mutual comparator, both approaches yield similar benefits. As comparisons become more complex, the mixed treatment comparison may be favoured. PMID:19772573

  13. How Social Neuroscience Can Inform Theories of Social Comparison

    PubMed Central

    Swencionis, Jillian K.; Fiske, Susan T.

    2016-01-01

    Social comparison pervades our interactions with others, informing us of our standing and motivating improvement, but producing negative emotional and behavioral consequences that can harm relationships and lead to poor health outcomes. Social neuroscience research has begun to illuminate some mechanisms by which status divides lead to interpersonal consequences. This review integrates core findings on the neuroscience of social comparison processes, showing the effects of comparing the self to relevant others on dimensions of competence and warmth. The literature converges to suggest that relative status divides initiate social comparison processes, that upward and downward comparisons initiate pain- and pleasure- related neural responses, and that these responses can predict people's kindly or aggressive intentions toward one another. Across different types of comparisons, brain regions involved in mentalizing are also sometimes involved. Along with future work, the research reviewed here may inform efforts to mitigate negative outcomes of constant social comparisons. PMID:24486767

  14. Prevalence, geographical distribution and clinical manifestations of onchocerciasis on the Island of Bioko (Equatorial Guinea).

    PubMed

    Mas, J; Yumbe, A; Solé, N; Capote, R; Cremades, T

    1995-03-01

    A survey for the prevalence, geographical distribution and clinical manifestations of onchocerciasis was conducted on the Island of Bioko (formerly Fernando Póo), Equatorial Guinea, between 1987-89. The whole population (1799 inhabitants) of thirteen villages distributed around the island was surveyed. Identification data, physical examination and Snellen "E" test for visual acuity were performed. Skin snips were taken from both iliac crests and right scapula and calf. Differential diagnosis between Onchocerca volvulus and Mansonella streptocerca was carried out in both fresh and Giemsa stained preparations. The overall prevalence (+ skin snips) and mean microfilarial density were 75.2% (range 51.9% to 87.1%) and 32.2 mf/snip respectively. Skin snips showed a higher microfilarial density from iliac crests. The following clinical manifestations were found: 560 (31.2%) with nodules; 518 (28.8%) with dermatitis, pigmentation changes and cutaneous atrophy; 753 (41.9%) with lymphoadenopathy and lymphoedema. Blindness due to different causes was registered in 13 cases (0.8%). The results showed that onchocerciasis is hyperendemic and widespread over the island. It is estimated that almost the whole population (62,000) is at risk of infection. PMID:7631122

  15. Occurrence and diagnosis of Mansonella streptocerca in Uganda.

    PubMed

    Fischer, P; Bamuhiiga, J; Büttner, D W

    1997-01-01

    During filaria surveys Mansonella streptocerca was found for the first time in Uganda, in 12 widely scattered villages in the Bundibugyo district between the Ruwenzori mountains and the Ituri forest, an area not endemic for Onchocerca volvulus. The crude prevalence in 806 examined adult persons ranged from 5 to 89% with an average of 61%. In 148 children the prevalence was 36%. The geometric mean of microfilaria (mf) densities in adult mf carriers was 1.7 mf/mg skin and the community microfilarial loads ranged from 1.0 to 13.7 mf/skin snip. In 476 persons skin snips from the shoulder contained mf in 58% and those from the buttocks in 48%. Skin snips from 68 persons digested with collagenase showed that only 30-37% of the mf emerged during 24 h incubation at 30 degrees C in isotonic salt solution. An itching acute or more often chronic papular dermatitis, predominantly on the upper parts of the body, was the typical skin lesion observed in 24% of 177 M. streptocerca mf carriers. PMID:9083584

  16. An 18S ribosomal DNA barcode for the study of Isomermis lairdi, a parasite of the blackfly Simulium damnosum s.l.

    PubMed

    Crainey, J L; Wilson, M D; Post, R J

    2009-09-01

    The mermithid parasite, Isomermis lairdi Mondet, Poinar & Bernadou (Nematoda: Mermithidae), is known to have a major impact on populations of Simulium damnosum s.l. Theobald (Diptera: Simuliidae) and on their efficiency as vectors of Onchocerca volvulus (Leuckart) (Nematoda: Filarioidea). However, the value of I. lairdi and other mermithid parasites as potential means of integrated vector control has not been fully realized. This is partly because traditional taxonomic approaches have been insufficient for describing and analysing important aspects of their biology and host range. In total, rDNA barcode sequences have been obtained from over 70 I. lairdi mermithids found parasitizing S. damnosum s.l. larvae in three different rivers. No two sequences were found to vary by more than 0.5%, and cytospecies identification of mermithid hosts revealed that I. lairdi with identical rDNA barcodes can parasitize multiple cytoforms of the S. damnosum complex, including S. squamosum (Enderlein). Phylogenetic analysis using a partial sequence from the 18S ribosomal DNA barcode, grouped I. lairdi in a monophyletic group with Gastromermis viridis Welch (Nematoda: Mermithidae) and Isomermis wisconsinensis Welch (Nematoda: Mermithidae). PMID:19712154

  17. Biting behaviour and potential vector status of anthropophilic blackflies in a new focus of human onchocerciasis at Minaçu, central Brazil.

    PubMed

    Shelley, A J; Maia-Herzog, M; Dias, A P; Camargo, M; Costa, E G; Garritano, P; Lowry, C A

    2001-03-01

    Monthly collections were made of man-biting female blackflies: Simulium auripellitum Enderlein, S. guianense Wise, S. minusculum Lutz and S. nigrimanum Macquart (Diptera: Simuliidae) from four catching stations in the newly discovered focus of human onchocerciasis at Minaçu (13 degrees 35 minutes S 48 degrees 18 minutes W), 300 km north of Brasília in Goiás State. These provided baseline data on biting habits, population density and seasonal prevalence during the year before completion of the Serra da Mesa hydroelectric dam on the Rio Tocantins near Minaçu, in a project investigating the effect of dam construction on onchocerciasis transmission in the area. All four simuliid species were most abundant during the dry season, and only bit in low numbers (S. auripellitum S. minusculum, S. nigrimanum) or were absent (S. guianense) in the wet season. Simulium minusculum was the predominant species at all catching stations, being particularly abundant by the large River Tocantins. The other three species were mainly associated with smaller rivers. In the dry season, biting rhythms of S. minusculum varied with catching site, while S. nigrimanum showed peaks of activity in early morning and during the afternoon. Experimental infection with Onchocerca volvulus (Leuckart) (Nematoda: Onchocercidae), from a human volunteer, showed that this parasite could develop fully in the four simuliid species, which are all considered to be potential vectors in the area. PMID:11297099

  18. An insight into the sialome of Simulium guianense (DIPTERA:SIMulIIDAE), the main vector of River Blindness Disease in Brazil

    PubMed Central

    2011-01-01

    Background Little is known about the composition and function of the saliva in black flies such as Simulium guianense, the main vector of river blindness disease in Brazil. The complex salivary potion of hematophagous arthropods counteracts their host's hemostasis, inflammation, and immunity. Results Transcriptome analysis revealed ubiquitous salivary protein families--such as the Antigen-5, Yellow, Kunitz domain, and serine proteases--in the S. guianense sialotranscriptome. Insect-specific families were also found. About 63.4% of all secreted products revealed protein families found only in Simulium. Additionally, we found a novel peptide similar to kunitoxin with a structure distantly related to serine protease inhibitors. This study revealed a relative increase of transcripts of the SVEP protein family when compared with Simulium vittatum and S. nigrimanum sialotranscriptomes. We were able to extract coding sequences from 164 proteins associated with blood and sugar feeding, the majority of which were confirmed by proteome analysis. Conclusions Our results contribute to understanding the role of Simulium saliva in transmission of Onchocerca volvulus and evolution of salivary proteins in black flies. It also consists of a platform for mining novel anti-hemostatic compounds, vaccine candidates against filariasis, and immuno-epidemiologic markers of vector exposure. PMID:22182526

  19. Identifying sub-optimal responses to ivermectin in the treatment of River Blindness

    PubMed Central

    Churcher, Thomas S.; Pion, Sébastien D. S.; Osei-Atweneboana, Mike Y.; Prichard, Roger K.; Awadzi, Kwablah; Boussinesq, Michel; Collins, Richard C.; Whitworth, James A.; Basáñez, María-Gloria

    2009-01-01

    Identification of drug resistance before it becomes a public health concern requires a clear distinction between what constitutes a normal and a suboptimal treatment response. A novel method of analyzing drug efficacy studies in human helminthiases is proposed and used to investigate recent claims of atypical responses to ivermectin in the treatment of River Blindness. The variability in the rate at which Onchocerca volvulus microfilariae repopulate host's skin following ivermectin treatment is quantified using an individual-based onchocerciasis mathematical model. The model estimates a single skin repopulation rate for every host sampled, allowing reports of suboptimal responses to be statistically compared with responses from populations with no prior exposure to ivermectin. Statistically faster rates of skin repopulation were observed in 3 Ghanaian villages (treated 12–17 times), despite the wide variability in repopulation rates observed in ivermectin-naïve populations. Another village previously thought to have high rates of skin repopulation was shown to be indistinguishable from the normal treatment response. The model is used to generate testable hypotheses to identify whether atypical rates of skin repopulation by microfilariae could result from low treatment coverage alone or provide evidence of decreased ivermectin efficacy. Further work linking phenotypic poor responses to treatment with parasite molecular genetics markers will be required to confirm drug resistance. Limitations of the skin-snipping method for estimating parasite load indicates that changes in the distribution of microfilarial repopulation rates, rather than their absolute values, maybe a more sensitive indicator of emerging ivermectin resistance. PMID:19805362

  20. Long-term assessment of insecticides treatments in West Africa: aquatic entomofauna.

    PubMed

    Yaméogo, L; Crosa, G; Samman, J; Nabé, K; Kondé, F; Tholley, D; Calamari, D

    2001-09-01

    For the control of the Onchocerca volvulus vector in West Africa, up to 18,000 km of rivers from 1975 and up to 50,000 km from 1989 had been partly sprayed weekly with insecticides as part of the Onchocerciasis Control Programme (OCP). To evaluate the possible short-term and long-term effects of the application of insecticides on the non-target fauna, an aquatic monitoring programme was set up during the initial phase of the programme. By analysing the invertebrate data, which were collected using various sampling strategies from four different countries between 1977 and 1996, this paper evaluates the long-term changes of the invertebrate populations with respect to their taxonomic composition as well as their trophic structures. The discussed results of the applied numerical analysis strategy suggest that neither the taxonomic nor the trophic structures are greatly altered from the range of biological, flow-related variation that normally occurs in the studied river systems. This allows us to conclude that the biological variation found here is ecologically acceptable. PMID:11534907

  1. Toward molecular parasitologic diagnosis: enhanced diagnostic sensitivity for filarial infections in mobile populations.

    PubMed

    Fink, Doran L; Fahle, Gary A; Fischer, Steven; Fedorko, Daniel F; Nutman, Thomas B

    2011-01-01

    The diagnosis of filarial infections among individuals residing in areas where the disease is not endemic requires both strong clinical suspicion and expert training in infrequently practiced parasitological methods. Recently developed filarial molecular diagnostic assays are highly sensitive and specific but have limited availability and have not been closely evaluated for clinical use outside populations residing in areas of endemicity. In this study, we assessed the performance of a panel of real-time PCR assays for the four most common human filarial pathogens among blood and tissue samples collected from a cohort of patients undergoing evaluation for suspected filarial infections. Compared to blood filtration, real-time PCR was equally sensitive for the detection of microfilaremia due to Wuchereria bancrofti (2 of 46 samples positive by both blood filtration and PCR with no discordant results) and Loa loa (24 of 208 samples positive by both blood filtration and PCR, 4 samples positive by PCR only, and 3 samples positive by blood filtration only). Real-time PCR of skin snip samples was significantly more sensitive than microscopic examination for the detection of Onchocerca volvulus microfiladermia (2 of 218 samples positive by both microscopy and PCR and 12 samples positive by PCR only). The molecular assays required smaller amounts of blood and tissue than conventional methods and could be performed by laboratory personnel without specialized parasitology training. Taken together, these data demonstrate the utility of the molecular diagnosis of filarial infections in mobile populations. PMID:20980560

  2. Towards novel antifilarial drugs: challenges and recent developments.

    PubMed

    Singh, Prashant Kumar; Ajay, Arya; Kushwaha, Susheela; Tripathi, Rama Pati; Misra-Bhattacharya, Shailja

    2010-02-01

    Filariasis is caused by thread-like nematode worms, classified according to their presence in the vertebrate host. The cutaneous group includes Onchocerca volvulus, Loa loa and Mansonella streptocerca; the lymphatic group includes Wuchereria bancrofti, Brugia malayi and Brugia timori and the body cavity group includes Mansonella perstans and Mansonella ozzardi. Lymphatic filariasis, a mosquito-borne disease, is one of the most prevalent diseases in tropical and subtropical countries and is accompanied by a number of pathological conditions. In recent years, there has been rapid progress in filariasis research, which has provided new insights into the pathogenesis of filarial disease, diagnosis, chemotherapy, the host-parasite relationship and the genomics of the parasite. Together, these insights are assisting the identification of novel drug targets and the discovery of antifilarial agents and candidate vaccine molecules. This review discusses the antifilarial activity of various chemical entities, the merits and demerits of antifilarial drugs currently in use, their mechanisms of action, in addition to antifilarial drug targets and their validation. PMID:21426193

  3. Loa loa-does it deserve to be neglected?

    PubMed

    Metzger, Wolfram Gottfried; Mordmüller, Benjamin

    2014-04-01

    More than 10 million people in western and central Africa are estimated to be infected with Loa loa filarial nematodes. Like most other infectious diseases, L loa filariasis (loiasis) covers a wide range of symptoms. Severe complications have been reported; however, most observations are anecdotal, typically in travellers. The widespread use of filaricidal drugs within eradication programmes of Onchocerca volvulus and Wuchereria bancrofti led to the observation that concomitant L loa infection increases the risk of severe treatment-associated, life-threatening complications. Initiatives were therefore launched to map the risk of loiasis. Insight about the epidemiology of L loa has advanced notably; however, its effect on the individual as well as on the community level has not been well studied. In the absence of appropriate studies, L loa is commonly judged a harmless nematode, and loiasis as a separate entity does not belong to the list of neglected tropical diseases to be controlled or eradicated in worldwide campaigns. We advocate reorientation of research efforts towards a patient-centric view of loiasis and, as a first step, to establish the disease burden in disability-adjusted life-years of this chronic infection, and to answer the question of whether loiasis should be included in future control programmes. PMID:24332895

  4. Future prospects and challenges of vaccines against filariasis.

    PubMed

    Babayan, Simon A; Allen, J E; Taylor, D W

    2012-05-01

    Filarial infections remain a major public health and socio-economic problem across the tropics, despite considerable effort to reduce disease burden or regionally eliminate the infection with mass drug administration programmes. The sustainability of these programmes is now open to question owing to a range of issues, not least of which is emerging evidence for drug resistance. Vaccination, if developed appropriately, remains the most cost-effective means of long-term disease control. The rationale for the feasibility of vaccination against filarial parasites including onchocerciasis (river blindness, Onchocerca volvulus) and lymphatic filariasis (Wuchereria bancrofti or Brugia malayi) is founded on evidence from both humans and animal models for the development of protective immunity. Nonetheless, enormous challenges need to be faced in terms of overcoming parasite-induced suppression without inducing pathology as well as the need to both recognize and tackle evolutionary and ecological obstacles to successful vaccine development. Nonetheless, new technological advances in addition to systems biology approaches offer hope that optimal immune responses can be induced that will prevent infection, disease and/or transmission. PMID:22150082

  5. Introduction to the alpha-proteobacteria: Wolbachia and Bartonella, Rickettsia, Brucella, Ehrlichia, and Anaplasma.

    PubMed

    Bowman, Dwight D

    2011-11-01

    Wolbachia is an obligate intracellular endosymbiont and likely mutualist living within the heartworm Dirofilaria immitis and a number of other filarial nematodes in the family Onchocercidae. The bacterial infection is passed from worm to worm transovarially; the organisms are in ovarian cells, the developing microfilariae, and multiply and persist in all later developmental stages through the mosquito and into the next host. Besides being present in the ovaries of the adult worms, they also are present in large numbers within the hypodermal tissues of the nematode. It is now know that these bacteria that were first observed in heartworms more than 30 years ago are actually related to similar Wolbachia bacteria that are found in arthropods. Wolbachia is an alpha-proteobacteria, and this group includes a number of important arthropod-transmitted bacterial agents of dogs and cats: Rickettsia rickettsii, R. felis, Anaplasma platys, Ehrlichia canis, E. chaffeensis, and E. ewingii. Alpha-proteobacteria are also important as obligate intracellular mutualists in plants in which they are responsible for nitrogen fixation. Recent work on the treatment of heartworms in dogs with doxycycline stems from related work with the human filarial nematode Onchocerca volvulus that causes river blindness in people. PMID:22152604

  6. Plasmodium vivax and Mansonella ozzardi co-infection in north-western Argentina.

    PubMed

    Dantur Juri, María J; Veggiani Aybar, Cecilia A; Ortega, Eugenia S; Galante, Guillermina B; Zaidenberg, Mario O

    2013-01-01

    A case of co-infection with Plasmodium vivax and Mansonella ozzardi was detected in a blood sample from a person who had shown symptoms of malaria and lived in a city that was close to the Argentina/Bolivia border. The case was detected during a random revision of thick and thin smears from patients diagnosed with malaria from various towns and cities located in north-western Argentina between 1983 and 2001. Trophozoites of P. vivax were observed in the thin blood smear along with M. ozzardi microfilaria (larval form), which presented a long, slender, pointed anucleate tail and the absence of the sheath. This last characteristic is shared with Mansonella perstans, Mansonella streptocerca and Onchocerca volvulus. More rigorously controlled studies to detect other co-infection cases in the area as well as the possibility of importation from Bolivia into Argentina are currently ongoing. The relationship between the malaria parasite and microfilaria, the potential effect of malaria treatment on the development of M. ozzardi, and the possible impact of this microfilaria on the immunity of a person against P. vivax are all still unknown. This contribution constitutes a point of focus for future studies involving the interaction between the parasites and the potential risk that humans are exposed to. PMID:23866313

  7. Progress toward elimination of onchocerciasis in the Americas - 1993-2012.

    PubMed

    2013-05-24

    Onchocerciasis (river blindness) is caused by the parasitic worm Onchocerca volvulus, transmitted to humans by the bite of infected black flies of the genus Simulium, and is characterized by chronic skin disease, severe itching, and eye lesions that can progress to complete blindness. Currently, among approximately 123 million persons at risk for infection in 38 endemic countries, at least 25.7 million are infected, and 1 million are blinded or have severe visual impairment. Periodic, communitywide mass drug administration (MDA) with ivermectin (Mectizan, Merck) prevents eye and skin disease and might interrupt transmission of the infection, depending on the coverage, duration, and frequency of MDA. The Onchocerciasis Elimination Program for the Americas (OEPA) was launched in response to a 1991 resolution of the Pan American Health Organization (PAHO) calling for the elimination of onchocerciasis from the Americas. By the end of 2012, transmission of the infection, judged by surveys following World Health Organization (WHO) guidelines, had been interrupted or eliminated in four of the six endemic countries in the WHO Americas Region. Thus, in 2013, only 4% (23,378) of the 560,911 persons originally at risk in the Americas will be under ivermectin MDA. Active transmission currently is limited to two foci among Yanomami indigenes in adjacent border areas of Venezuela and Brazil. PMID:23698606

  8. Hyperreactive onchocerciasis is characterized by a combination of Th17-Th2 immune responses and reduced regulatory T cells.

    PubMed

    Katawa, Gnatoulma; Layland, Laura E; Debrah, Alex Y; von Horn, Charlotte; Batsa, Linda; Kwarteng, Alexander; Arriens, Sandra; W Taylor, David; Specht, Sabine; Hoerauf, Achim; Adjobimey, Tomabu

    2015-01-01

    Clinical manifestations in onchocerciasis range from generalized onchocerciasis (GEO) to the rare but severe hyperreactive (HO)/sowda form. Since disease pathogenesis is associated with host inflammatory reactions, we investigated whether Th17 responses could be related to aggravated pathology in HO. Using flow cytometry, filarial-specific cytokine responses and PCR arrays, we compared the immune cell profiles, including Th subsets, in individuals presenting the two polar forms of infection and endemic normals (EN). In addition to elevated frequencies of memory CD4+ T cells, individuals with HO showed accentuated Th17 and Th2 profiles but decreased CD4+CD25hiFoxp3+ regulatory T cells. These profiles included increased IL-17A+, IL-4+, RORC2+ and GATA3+CD4+ T cell populations. Flow cytometry data was further confirmed using a PCR array since Th17-related genes (IL-17 family members, IL-6, IL-1β and IL-22) and Th2-related (IL-4, IL-13, STAT6) genes were all significantly up-regulated in HO individuals. In addition, stronger Onchocerca volvulus-specific Th2 responses, especially IL-13, were observed in vitro in hyperreactive individuals when compared to GEO or EN groups. This study provides initial evidence that elevated frequencies of Th17 and Th2 cells form part of the immune network instigating the development of severe onchocerciasis. PMID:25569210

  9. Diagnosis of brugian filariasis by loop-mediated isothermal amplification.

    PubMed

    Poole, Catherine B; Tanner, Nathan A; Zhang, Yinhua; Evans, Thomas C; Carlow, Clotilde K S

    2012-01-01

    In this study we developed and evaluated a Brugia Hha I repeat loop-mediated isothermal amplification (LAMP) assay for the rapid detection of Brugia genomic DNA. Amplification was detected using turbidity or fluorescence as readouts. Reactions generated a turbidity threshold value or a clear visual positive within 30 minutes using purified genomic DNA equivalent to one microfilaria. Similar results were obtained using DNA isolated from blood samples containing B. malayi microfilariae. Amplification was specific to B. malayi and B. timori, as no turbidity was observed using DNA from the related filarial parasites Wuchereria bancrofti, Onchocerca volvulus or Dirofilaria immitis, or from human or mosquito. Furthermore, the assay was most robust using a new strand-displacing DNA polymerase termed Bst 2.0 compared to wild-type Bst DNA polymerase, large fragment. The results indicate that the Brugia Hha I repeat LAMP assay is rapid, sensitive and Brugia-specific with the potential to be developed further as a field tool for diagnosis and mapping of brugian filariasis. PMID:23272258

  10. Potential effects of warmer worms and vectors on onchocerciasis transmission in West Africa.

    PubMed

    Cheke, Robert A; Basáñez, Maria-Gloria; Perry, Malorie; White, Michael T; Garms, Rolf; Obuobie, Emmanuel; Lamberton, Poppy H L; Young, Stephen; Osei-Atweneboana, Mike Y; Intsiful, Joseph; Shen, Mingwang; Boakye, Daniel A; Wilson, Michael D

    2015-04-01

    Development times of eggs, larvae and pupae of vectors of onchocerciasis (Simulium spp.) and of Onchocerca volvulus larvae within the adult females of the vectors decrease with increasing temperature. At and above 25°C, the parasite could reach its infective stage in less than 7 days when vectors could transmit after only two gonotrophic cycles. After incorporating exponential functions for vector development into a novel blackfly population model, it was predicted that fly numbers in Liberia and Ghana would peak at air temperatures of 29°C and 34°C, about 3°C and 7°C above current monthly averages, respectively; parous rates of forest flies (Liberia) would peak at 29°C and of savannah flies (Ghana) at 30°C. Small temperature increases (less than 2°C) might lead to changes in geographical distributions of different vector taxa. When the new model was linked to an existing framework for the population dynamics of onchocerciasis in humans and vectors, transmission rates and worm loads were projected to increase with temperature to at least 33°C. By contrast, analyses of field data on forest flies in Liberia and savannah flies in Ghana, in relation to regional climate change predictions, suggested, on the basis of simple regressions, that 13-41% decreases in fly numbers would be expected between the present and before 2040. Further research is needed to reconcile these conflicting conclusions. PMID:25688018

  11. Outstanding insecurities concerning the use of an Ov16-based ELISA in the Amazonia onchocerciasis focus.

    PubMed

    Luz, Sérgio Luiz Bessa; Crainey, James Lee; Shelley, Anthony John; Rubio, Miguel

    2014-07-01

    In a recent issue of Memórias do Instituto Oswaldo Cruz, published in Rio de Janeiro in February 2014 (109: 87-92), Adami et al. have published a survey reporting Mansonella parasite prevalence in the Amazon Region. This report makes a useful contribution to the existing knowledge of filarial parasite distribution within the Amazon area, parasite prevalence rates in relation to age and occupation and provides observations on the possible clinical impact of Mansonella ozzardi. Their publication also provides an account of what appears to be a novel ELISA that has recently been used in the Simuliidae and Onchocerciasis Laboratory of the Oswaldo Cruz Institute, Rio de Janeiro, Brazil. We are concerned that the publication of this ELISA may have created an excessively positive impression of the effectiveness of the onchocerciasis recrudescence serological surveillance tools that are presently available for use in the Amazonia onchocerciasis focus. In this letter we have, thus, sought to highlight some of the limitations of this ELISA and suggest how continuing insecurities concerning the detection of antibodies to Onchocerca volvulus within the Amazonia onchocerciasis focus might be minimised. PMID:25075790

  12. A truncated fragment of Ov-ASP-1 consisting of the core pathogenesis-related-1 (PR-1) domain maintains adjuvanticity as the full-length protein.

    PubMed

    Guo, Jingjing; Yang, Yi; Xiao, Wenjun; Sun, Weilai; Yu, Hong; Du, Lanying; Lustigman, Sara; Jiang, Shibo; Kou, Zhihua; Zhou, Yusen

    2015-04-15

    The Onchocerca volvulus activation-associated secreted protein-1 (Ov-ASP-1) has good adjuvanticity for a variety of antigens and vaccines, probably due to its ability activate antigen-processing cells (APCs). However, the functional domain of Ov-ASP-1 as an adjuvant is not clearly defined. Based on the structural prediction of this protein family, we constructed a 16-kDa recombinant protein of Ov-ASP-1 that contains only the core pathogenesis-related-1 (PR-1) domain (residues 10-153), designated ASPPR. We found that ASPPR exhibits adjuvanticity similar to that of the full-length Ov-ASP-1 (residues 10-220) for various antigens, including ovalbumin (OVA), HBsAg protein antigen, and the HIV peptide 5 (Pep5) antigen, but it is more suitable for vaccine design in ASPPR-antigen fusion proteins, and more stable in PBS than Ov-ASP-1 stored at -70 °C. These results suggest that ASPPR might be the functional region of Ov-ASP-1 as an adjuvant, and therefore could be developed as an adjuvant for human use. PMID:25736195

  13. Iron necessity: the secret of Wolbachia's success?

    PubMed

    Gill, Alessandra Christina; Darby, Alistair C; Makepeace, Benjamin L

    2014-10-01

    The bacterium Wolbachia (order Rickettsiales) is probably the world's most successful vertically-transmitted symbiont, distributed among a staggering 40% of terrestrial arthropod species. Wolbachia has great potential in vector control due to its ability to manipulate its hosts' reproduction and to impede the replication and dissemination of arboviruses and other pathogens within haematophagous arthropods. In addition, the unexpected presence of Wolbachia in filarial nematodes of medical and veterinary importance has provided an opportunity to target the adult worms of Wuchereria bancrofti, Onchocerca volvulus, and Dirofilaria immitis with safe drugs such as doxycycline. A striking feature of Wolbachia is its phenotypic plasticity between (and sometimes within) hosts, which may be underpinned by its ability to integrate itself into several key processes within eukaryotic cells: oxidative stress, autophagy, and apoptosis. Importantly, despite significant differences in the genomes of arthropod and filarial Wolbachia strains, these nexuses appear to lie on a continuum in different hosts. Here, we consider how iron metabolism may represent a fundamental aspect of host homeostasis that is impacted by Wolbachia infection, connecting disparate pathways ranging from the provision of haem and ATP to programmed cell death, aging, and the recycling of intracellular resources. Depending on how Wolbachia and host cells interact across networks that depend on iron, the gradient between parasitism and mutualism may shift dynamically in some systems, or alternatively, stabilise on one or the other end of the spectrum. PMID:25329055

  14. Iron Necessity: The Secret of Wolbachia's Success?

    PubMed Central

    Gill, Alessandra Christina; Darby, Alistair C.; Makepeace, Benjamin L.

    2014-01-01

    The bacterium Wolbachia (order Rickettsiales) is probably the world's most successful vertically-transmitted symbiont, distributed among a staggering 40% of terrestrial arthropod species. Wolbachia has great potential in vector control due to its ability to manipulate its hosts' reproduction and to impede the replication and dissemination of arboviruses and other pathogens within haematophagous arthropods. In addition, the unexpected presence of Wolbachia in filarial nematodes of medical and veterinary importance has provided an opportunity to target the adult worms of Wuchereria bancrofti, Onchocerca volvulus, and Dirofilaria immitis with safe drugs such as doxycycline. A striking feature of Wolbachia is its phenotypic plasticity between (and sometimes within) hosts, which may be underpinned by its ability to integrate itself into several key processes within eukaryotic cells: oxidative stress, autophagy, and apoptosis. Importantly, despite significant differences in the genomes of arthropod and filarial Wolbachia strains, these nexuses appear to lie on a continuum in different hosts. Here, we consider how iron metabolism may represent a fundamental aspect of host homeostasis that is impacted by Wolbachia infection, connecting disparate pathways ranging from the provision of haem and ATP to programmed cell death, aging, and the recycling of intracellular resources. Depending on how Wolbachia and host cells interact across networks that depend on iron, the gradient between parasitism and mutualism may shift dynamically in some systems, or alternatively, stabilise on one or the other end of the spectrum. PMID:25329055

  15. Onchocerciasis in Ecuador: evolution of chorioretinopathy after amocarzine treatment.

    PubMed Central

    Cooper, P J; Proaño, R; Beltran, C; Anselmi, M; Guderian, R H

    1996-01-01

    AIMS: To investigate the impact of the macrofilaricidal drug, amocarzine, on the evolution of chorioretinopathy in onchocerciasis. METHODS: A prospective uncontrolled cohort study was performed using subjects infected with Onchocerca volvulus in a hyperendemic onchocerciasis focus in Esmeraldas Province in Ecuador. Study subjects were recruited into four cohorts in which ophthalmic and parasitological data were collected for 2, 3, 4, and 5 years respectively. RESULTS: Complete ophthalmic follow up was obtained for 294 individuals in the four cohorts. The incidence of retinal pigment epithelial atrophy tended to remain constant between cohorts while that of chorioretinal scarring with a greater observation period. The incidence rate of cases with new or extending chorioretinal lesions was greater with an increasing period of follow up. An association was seen between the cumulative microfilarial loads in the skin and the development of new chorioretinal lesions (p < 0.05). No relation was noted between cumulative microfilarial loads and the progression of existing disease. CONCLUSION: Amocarzine therapy did not prevent the natural evolution of chorioretinal disease. It was suggested that ocular microfilariae were necessary for the induction of chorioretinopathy in previously unaffected eyes and that extension of existing disease might also be related to the presence of ocular microfilariae or to other immunological mechanisms. PMID:8703886

  16. Immunoregulation in onchocerciasis. Functional and phenotypic abnormalities of lymphocyte subsets and changes with therapy.

    PubMed Central

    Freedman, D O; Lujan-Trangay, A; Steel, C; Gonzalez-Peralta, C; Nutman, T B

    1991-01-01

    To help define the immunoregulatory defects in patients with onchocerciasis, flow cytometric analysis of circulating lymphocyte subpopulations was performed in parallel with functional assays. No significant differences in CD4/CD8 ratios were seen when microfilariae-positive individuals from Guatemala were compared with Guatemalan controls. However, the infected individuals had significantly increased numbers of circulating CD4+CD45RA+ lymphocytes (mean 38.3%) when compared with controls (mean 16.0%). Coexpression of the activation marker HLA-DR was significantly increased on CD4+ cells from infected individuals. In contrast, no up-regulation of HLA-DR was seen on CD8+ or CD19+ cells. At 1 year after initiation of treatment with semiannual doses of the microfilaricide ivermectin, there were significant increases (P less than 0.05) in the percentage of CD4+CD45RA- cells, the percentage of CD4+HLA-DR+ cells, and mitogen-induced lymphokine production (IL-2, IL-4). Despite these changes, parasite-specific IL-2 and IL-4 production which had been undetectable before treatment did not manifest itself even by the 2-yr follow-up. Defects in the T-cell activation pathway in Onchocerca volvulus-infected individuals may thus exist at several independent points; a state of parasite antigen-specific tolerance appears to remain even after the relative reversal of other generalized immunoregulatory defects. PMID:1829096

  17. Community-based treatment of onchocerciasis with ivermectin: acceptability and early adverse reactions.

    PubMed Central

    Pacque, M. C.; Dukuly, Z.; Greene, B. M.; Munoz, B.; Keyvan-Larijani, E.; Williams, P. N.; Taylor, H. R.

    1989-01-01

    A study of community-based treatment of onchocerciasis with ivermectin was undertaken in a rain forest area of Liberia to investigate the possible occurrence of serious adverse effects. The total population was 13,704, the microfilarial load was 5.35 mf/mg skin, and the prevalence of Onchocerca volvulus infection was 50% at 9 years of age and over 80% among those aged 15 years and older. Certain groups (like pregnant women and young children) were excluded from treatment. Out of the 7956 people eligible for treatment, 7699 (97%) accepted the ivermectin. Data on possible adverse reactions were collected by four different methods, including systematic house-by-house follow-up visits three days after treatment, biweekly population surveillance, and monitoring of both mobile clinic records and hospital records. No severe adverse reactions were noted, and no deaths could be related to ivermectin treatment; only 1.3% of the persons treated had a moderate adverse reaction of the Mazzotti type, presumably related to the killing of microfilariae. The study showed good acceptance by the population, and that mass treatment campaigns with ivermectin are feasible. PMID:2633887

  18. A survey of Simulium control in Africa.

    PubMed

    BROWN, A W

    1962-01-01

    It has become possible to control or even eradicate the Simulium fly vectors of Onchocerca volvulus, the causative organism of onchocerciasis. There are two vectors in Africa-namely, S. damnosum, characteristic of the rivers of West Africa, and S. neavei, which breeds on the carapaces of crabs in the streams of East Africa. The use of DDT applied to the water at a concentration as low as 0.1 p.p.m. for 30 minutes eliminates the larvae of Simulium. Such larvicidal methods have eradicated S. neavei from western Kenya and virtually eradicated S. damnosum from the Victoria Nile in Uganda. Excellent control sufficient to render the transmission of onchocerciasis almost negligible has been obtained at Léopoldville (Republic of the Congo) and in circumscribed areas in southern Chad, Northern Nigeria, and Sierra Leone. The following survey describes operational research on Simulium control carried out in Kenya, Uganda, the Congo, Chad, Nigeria, Ghana, Upper Volta and Sierra Leone. PMID:14015908

  19. Studies on the dynamics of transmission of onchocerciasis in a Sudan-savanna area of North Cameroon V. What is a tolerable level of Annual Transmission Potential?

    PubMed

    Renz, A; Wenk, P; Anderson, J; Fuglsang, H

    1987-06-01

    The prevalence and intensity of infection with Onchocerca volvulus were assessed in population surveys in nine villages, situated at different distances from Simulium damnosum s.l. breeding sites. The prevalence varied from 48 to 89%, the arithmetic mean densities of microfilariae per skin snip were between 16 and 109, and severe ocular lesions were found in from 1 to 22% of patients. Annual Transmission Potentials (ATP) were measured for up to three years in the near vicinity of nine villages at several fly-catching sites. Weighted means of the ATP over the three years, and of the sojourn times of the human population, were calculated at three of the villages, where the prevalence of onchocerciasis was 51, 61 and 89%. An average ATP of 100 larvae or less in the head, thorax and abdomen of the flies was associated with an onchocerciasis prevalence of 50 to 60%, a mean microfilarial density below 40 microfilariae per skin-snip, less than 5% of ocular lesions, and no onchocercal blindness. This value might therefore be considered to be an indication of the level to which the transmission must be reduced in the savanna in order to prevent the occurrence of severe ocular lesions or blindness. It is lower than the present level accepted by the Onchocerciasis Control Programme in the Volta River Basin. PMID:3662668

  20. Studies on the reinvasion of the Onchocerciasis Control Programme in the Volta River Basin by Simulium damnosum s.I. with emphasis on the south-western areas.

    PubMed

    Garms, R; Walsh, J F; Davies, J B

    1979-09-01

    The aerial larvicidng operation of the Onchocerciasis Control Programme of the World Health Organization which began in February 1975 resulted in a sharp reduction in Simulium damnosum numbers. However, at the onset of the rainy season the fly population increased in certain areas. Detailed surveys both on the ground and by helicopter did not reveal any significant failures of treatments that could account for the fly densities observed, and it was concluded that the flies must originate from sources outside the controlled zone. This reinvasion proved to be an annual occurrence which has been studied in detail between 1975 and 1978 in the south-western parts of the control zone. The methods used included full day catches by vector collectors carried out every day throughout the season, cytotaxonomic determination of larvae, detailed morphological examination of reared and biting adults and treatment of suspected source rivers with insecticide. The results indicate that the invasion takes place in a SW-NE direction across country for distances of 300 km or more along the track of the monsoon winds. It involves mainly the savanna cytospecies S. damnosum s. str. and S. sirbanum. The invading populations are composed of older parous flies, many of which carry infective 3rd stage larvae indistinguishable from those of Onchocerca volvulus. These females tend to bite close to the rivers and do not disperse as far as normal populations with a higher proportion of younger flies. PMID:575581

  1. Can ivermectin mass treatments eliminate onchocerciasis in Africa?

    PubMed Central

    Winnen, M.; Plaisier, A. P.; Alley, E. S.; Nagelkerke, N. J. D.; van Oortmarssen, G.; Boatin, B. A.; Habbema, J. D. F.

    2002-01-01

    OBJECTIVE: To elucidate the conditions in which mass treatment with ivermectin reduces the transmission of Onchocerca volvulus sufficiently to eliminate infection from an African community. METHODS: ONCHOSIM, a microsimulation model for onchocerciasis transmission, was used to explore the implications of different treatment intervals, coverage levels and precontrol endemicities for the likelihood of elimination. FINDINGS: Simulations suggested that control strategies based exclusively on ivermectin mass treatments could eliminate onchocerciasis. The duration of treatment required to eliminate infection depended heavily on the treatment programme and precontrol endemicity. In areas with medium to high levels of infection, annual mass treatments with 65% coverage for at least 25 years were necessary. Model predictions suggested that durations exceeding 35 years would be required if there were much heterogeneity in exposure to vector bites and, consequently, wide individual variation in microfilaria counts. If the treatment interval were reduced from 12 to 6 months the time for completion of the programme could be more than halved and elimination could be accomplished in areas of hyperendemicity, provided that the effects of each treatment would be the same as with annual treatments. However, it was doubtful whether high coverage levels could be sustained long enough to achieve worldwide eradication. CONCLUSION: Elimination of onchocerciasis from most endemic foci in Africa appears to be possible. However, the requirements in terms of duration, coverage, and frequency of treatment may be prohibitive in highly endemic areas. PMID:12077614

  2. Diagnosis of Brugian Filariasis by Loop-Mediated Isothermal Amplification

    PubMed Central

    Poole, Catherine B.; Tanner, Nathan A.; Zhang, Yinhua; Evans, Thomas C.; Carlow, Clotilde K. S.

    2012-01-01

    In this study we developed and evaluated a Brugia Hha I repeat loop-mediated isothermal amplification (LAMP) assay for the rapid detection of Brugia genomic DNA. Amplification was detected using turbidity or fluorescence as readouts. Reactions generated a turbidity threshold value or a clear visual positive within 30 minutes using purified genomic DNA equivalent to one microfilaria. Similar results were obtained using DNA isolated from blood samples containing B. malayi microfilariae. Amplification was specific to B. malayi and B. timori, as no turbidity was observed using DNA from the related filarial parasites Wuchereria bancrofti, Onchocerca volvulus or Dirofilaria immitis, or from human or mosquito. Furthermore, the assay was most robust using a new strand-displacing DNA polymerase termed Bst 2.0 compared to wild-type Bst DNA polymerase, large fragment. The results indicate that the Brugia Hha I repeat LAMP assay is rapid, sensitive and Brugia-specific with the potential to be developed further as a field tool for diagnosis and mapping of brugian filariasis. PMID:23272258

  3. Cloning and characterization of the Cu/Zn superoxide dismutase of Trichinella pseudospiralis.

    PubMed

    Wu, W K; Mak, C H; Ko, R C

    2006-03-01

    Copper/zinc (Cu/Zn) superoxide dismutase (SOD) activity was identified for the first time in both crude somatic extracts (CE) and excretory/secretory (E/S) products of Trichinella pseudospiralis. It was the dominant SOD in infective-stage larvae. Native polyacrylamide gel electrophoresis of CE and E/S products yielded a prominent band, which was cyanide-sensitive and was partly inhibited by hydrogen peroxide in SOD assay. Cytosolic Cu/Zn SOD was cloned. The 471-bp full-length cDNA sequence contained an open reading frame of 157 amino acids. The gene contained three introns. Quantitative reverse transcription-polymerase chain reaction indicated that the expression of cytosolic Cu/Zn SOD was substantially higher in infective-stage larvae than in adult worms. Cluster analysis showed that the sequence of the Cu/Zn SOD of T. pseudospiralis, an adenophorean nematode, is related to those of Brugia pahangi, Acanthocheilonema viteae, Onchocerca volvulus, and Haemonchus contortus (all belonging to the sercenentean group). PMID:16341881

  4. A survey of Simulium control in Africa

    PubMed Central

    Brown, A. W. A.

    1962-01-01

    It has become possible to control or even eradicate the Simulium fly vectors of Onchocerca volvulus, the causative organism of onchocerciasis. There are two vectors in Africa—namely, S. damnosum, characteristic of the rivers of West Africa, and S. neavei, which breeds on the carapaces of crabs in the streams of East Africa. The use of DDT applied to the water at a concentration as low as 0.1 p.p.m. for 30 minutes eliminates the larvae of Simulium. Such larvicidal methods have eradicated S. neavei from western Kenya and virtually eradicated S. damnosum from the Victoria Nile in Uganda. Excellent control sufficient to render the transmission of onchocerciasis almost negligible has been obtained at Léopoldville (Republic of the Congo) and in circumscribed areas in southern Chad, Northern Nigeria, and Sierra Leone. The following survey describes operational research on Simulium control carried out in Kenya, Uganda, the Congo, Chad, Nigeria, Ghana, Upper Volta and Sierra Leone. PMID:14015908

  5. Onchocerciasis: the Role of Wolbachia Bacterial Endosymbionts in Parasite Biology, Disease Pathogenesis, and Treatment

    PubMed Central

    Tamarozzi, Francesca; Halliday, Alice; Gentil, Katrin; Hoerauf, Achim; Pearlman, Eric; Taylor, Mark J.

    2011-01-01

    Summary: The discovery of Wolbachia intracellular bacteria within filarial nematodes, including Onchocerca volvulus, the causative agent of onchocerciasis or “river blindness,” has delivered a paradigm shift in our understanding of the parasite's biology, to where we now know that the bacterial endosymbionts are essential for normal development of larvae and embryos and may support the long-term survival of adult worms. The apparent mutualistic dependency has also offered a novel approach to the treatment of onchocerciasis through the use of antibiotics to eliminate Wolbachia, delivering for the first time a treatment which has significant macrofilaricidal efficacy. Studies with other filarial nematode species have also highlighted a role for Wolbachia in transmission and infection of the mammalian host through a fascinating manipulation of mast cell-mediated vasodilation to enhance infectivity of vector-borne larvae. Wolbachia has also been identified as the principal driver of innate and adaptive Th1 inflammatory immunity, which can either contribute to disease pathogenesis or, with the Wolbachia-mediated recruitment of mast cells, enhance infectivity. The Wolbachia activation of innate inflammation also drives inflammatory adverse events in response to chemotherapy with either diethylcarbamazine (DEC) or ivermectin. In this review we summarize the experimental and field trial data which have uncovered the importance of Wolbachia symbiosis in onchocerciasis. PMID:21734243

  6. Potential effects of warmer worms and vectors on onchocerciasis transmission in West Africa

    PubMed Central

    Cheke, Robert A.; Basáñez, Maria-Gloria; Perry, Malorie; White, Michael T.; Garms, Rolf; Obuobie, Emmanuel; Lamberton, Poppy H. L.; Young, Stephen; Osei-Atweneboana, Mike Y.; Intsiful, Joseph; Shen, Mingwang; Boakye, Daniel A.; Wilson, Michael D.

    2015-01-01

    Development times of eggs, larvae and pupae of vectors of onchocerciasis (Simulium spp.) and of Onchocerca volvulus larvae within the adult females of the vectors decrease with increasing temperature. At and above 25°C, the parasite could reach its infective stage in less than 7 days when vectors could transmit after only two gonotrophic cycles. After incorporating exponential functions for vector development into a novel blackfly population model, it was predicted that fly numbers in Liberia and Ghana would peak at air temperatures of 29°C and 34°C, about 3°C and 7°C above current monthly averages, respectively; parous rates of forest flies (Liberia) would peak at 29°C and of savannah flies (Ghana) at 30°C. Small temperature increases (less than 2°C) might lead to changes in geographical distributions of different vector taxa. When the new model was linked to an existing framework for the population dynamics of onchocerciasis in humans and vectors, transmission rates and worm loads were projected to increase with temperature to at least 33°C. By contrast, analyses of field data on forest flies in Liberia and savannah flies in Ghana, in relation to regional climate change predictions, suggested, on the basis of simple regressions, that 13–41% decreases in fly numbers would be expected between the present and before 2040. Further research is needed to reconcile these conflicting conclusions. PMID:25688018

  7. Plasmodium vivax and Mansonella ozzardi co-infection in north-western Argentina

    PubMed Central

    2013-01-01

    A case of co-infection with Plasmodium vivax and Mansonella ozzardi was detected in a blood sample from a person who had shown symptoms of malaria and lived in a city that was close to the Argentina/Bolivia border. The case was detected during a random revision of thick and thin smears from patients diagnosed with malaria from various towns and cities located in north-western Argentina between 1983 and 2001. Trophozoites of P. vivax were observed in the thin blood smear along with M. ozzardi microfilaria (larval form), which presented a long, slender, pointed anucleate tail and the absence of the sheath. This last characteristic is shared with Mansonella perstans, Mansonella streptocerca and Onchocerca volvulus. More rigorously controlled studies to detect other co-infection cases in the area as well as the possibility of importation from Bolivia into Argentina are currently ongoing. The relationship between the malaria parasite and microfilaria, the potential effect of malaria treatment on the development of M. ozzardi, and the possible impact of this microfilaria on the immunity of a person against P. vivax are all still unknown. This contribution constitutes a point of focus for future studies involving the interaction between the parasites and the potential risk that humans are exposed to. PMID:23866313

  8. A new insight into the pathogenesis of filarial disease.

    PubMed

    Taylor, Mark J

    2002-05-01

    Filariasis is a major public health problem throughout many regions of the tropics. The disease is caused by several species of filarial nematode including Wuchereria bancrofti and Brugia malayi, the agents of lymphatic filariasis, and Onchocerca volvulus, the cause of 'riverblindness'. Disease caused by these worms varies depending on the tissue location of the parasite, and is associated with episodes of acute and chronic inflammation. These pathologies, including elephantiasis and blindness, rank among the most disabling in the world. Studies aimed at characterizing the molecular nature of the inflammatory stimuli derived from filarial nematodes uncovered a long forgotten secret, their symbiont Wolbachia. LPS-like molecules from these intracellular bacteria are responsible for potent inflammatory responses from macrophages and in animal models of filarial disease. Wolbachia has also been associated with severe inflammatory reactions to filarial chemotherapy, being released into the blood following the death of the parasite. Recent studies in animal models even implicate Wolbachia in the onset of lymphodema and blindness. Taken together these studies suggest a major role for Wolbachia in the pathogenesis of filarial disease. It may be possible, through the use of antibiotic therapy, to clear worms of their bacteria, in the hope that this will prevent the onset and development of filarial pathology. PMID:12041732

  9. Ocular onchocerciasis and intensity of infection in the community. III. West African rainforest foci of the vector Simulium sanctipauli.

    PubMed

    Dadzie, K Y; Remme, J; Baker, R H; Rolland, A; Thylefors, B

    1990-12-01

    The community pattern of ocular onchocerciasis is described for 11 villages from the forest area in Côte d'Ivoire where S. sanctipauli is the princial vector. An analytical method is applied which relates indices of ocular onchocerciasis with the Community Microfilarial Load (CMFL) and compares the results with the ocular onchocerciasis pattern found in the West African savanna. In spite of high transmission levels as estimated by entomological indices, the CMFLs were relatively low which complicated the characterization of the ocular disease pattern. Nevertheless, it could be shown that ocular onchocerciasis is less severe in the Sanctipauli forest than in the savanna, even after correction for differences in CMFL. The prevalence of onchocercal eye lesions and blindness were low and advanced sclerosing keratitis was completely absent. The differences are explained by presuming strain differences of the parasite Onchocerca volvulus. For given CMFLs the mean microfilarial loads in the eye were significantly lower than in the savanna which suggests that the parasite strain in the Sanctipauli forest is less invasive to the eye. Ocular microfilarial loads were too low to determine if the parasite is also less pathogenic to the eye, as has been concluded previously for foci of S. yahense, but this possibility cannot be excluded. PMID:1963702

  10. Remote and Ground Truth Spectral Measurement Comparisons

    NASA Technical Reports Server (NTRS)

    Abercromby, Kira Jorgensen; Hamada, Kris; Guyote, Michael; Okada, Jennifer; Barker, Edwin

    2007-01-01

    FORMOSAT III are a set of six research satellites from Taiwan that were launched in April 2006. The satellites are in 800 km, 71 degree inclination orbits and separated by 24 degrees in ascending node. Ground truth spectral measurements were taken of outer surface materials on FORMOSAT III. From those measurements, a computer model was built to predict the spectral reflectance, which included phase angle and orientation of the spacecraft relative to the observer. However, materials exposed to the space environment have exhibited spectral changes including a darkening and a reddening of the spectra. This reddening was seen as an increase in slope of the reflectance as the wavelength increases. Therefore, the model of pristine materials was augmented to include the space weathering effects. Remote data were collected on two of the six FORMOSAT satellites using the 1.6 meter telescope at AMOS (Air Force Maui Optical and Supercomputing) site with the Spica spectrometer. Due to the separation in ascending node, observations were made on whichever one of the six satellites was visible on that specific night. Three nights of data were collected using the red (6000 9500 angstroms) filter and two nights of data were collected using the blue (3200 -6600 angstroms) filter. A comparison of the data showed a good match to the pristine model for the blue filter region. The absorption feature near 5500 angstroms due to the copper colored Kapton multi-layer insulation (MLI) was very apparent in the remote samples and a good fit to the data was seen in both satellites observed. The features in the red filter regime agreed with the pristine model up through 7000 angstroms where the reddening begins and the slope of the remote sample increases. A comparison of the two satellites showed similar features in the red and blue filter regions, i.e. the satellites were aging at the same rate. A comparison of the pristine model to the first month of remote measurements showed the amount by

  11. Adaptive seeds tame genomic sequence comparison.

    PubMed

    Kiełbasa, Szymon M; Wan, Raymond; Sato, Kengo; Horton, Paul; Frith, Martin C

    2011-03-01

    The main way of analyzing biological sequences is by comparing and aligning them to each other. It remains difficult, however, to compare modern multi-billionbase DNA data sets. The difficulty is caused by the nonuniform (oligo)nucleotide composition of these sequences, rather than their size per se. To solve this problem, we modified the standard seed-and-extend approach (e.g., BLAST) to use adaptive seeds. Adaptive seeds are matches that are chosen based on their rareness, instead of using fixed-length matches. This method guarantees that the number of matches, and thus the running time, increases linearly, instead of quadratically, with sequence length. LAST, our open source implementation of adaptive seeds, enables fast and sensitive comparison of large sequences with arbitrarily nonuniform composition. PMID:21209072

  12. Quality of life: an international comparison

    SciTech Connect

    Hopkinson, J.; Anderson, C.F.; Liu, B.C.

    1980-04-01

    Dissatisfaction with gross national product (GNP) as a realistic yardstick for comparing the well-being of societies has led to a quality of life (QOL) concept which considers the environment in which people live. QOL includes both the economic and noneconomic factors affecting an individual's happiness. An international comparison of energy, GNP, and QOL in 50 countries considers five major categories (social, economic, health and education, environmental, and national vitality and security) and 12 subcategories. The study indicates that substantial increases in energy consumption will be needed to raise the living standards of developing countries. QOL appears to decline beyond a certain level of GNP, while continuing a direct relationship to per capita energy consumption and electricity production. 12 references. (DCK)

  13. GCSS Idealized Cirrus Model Comparison Project

    NASA Technical Reports Server (NTRS)

    Starr, David OC.; Benedetti, Angela; Boehm, Matt; Brown, Philip R. A.; Gierens, Klaus; Girard, Eric; Giraud, Vincent; Jakob, Christian; Jensen, Eric; Khvorostyanov, Vitaly; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The GCSS Working Group on Cirrus Cloud Systems (WG2) is conducting a systematic comparison and evaluation of cirrus cloud models. This fundamental activity seeks to support the improvement of models used for climate simulation and numerical weather prediction through assessment and improvement of the "process" models underlying parametric treatments of cirrus cloud processes in large-scale models. The WG2 Idealized Cirrus Model Comparison Project is an initial comparison of cirrus cloud simulations by a variety of cloud models for a series of idealized situations with relatively simple initial conditions and forcing. The models (16) represent the state-of-the-art and include 3-dimensional large eddy simulation (LES) models, two-dimensional cloud resolving models (CRMs), and single column model (SCM) versions of GCMs. The model microphysical components are similarly varied, ranging from single-moment bulk (relative humidity) schemes to fully size-resolved (bin) treatments where ice crystal growth is explicitly calculated. Radiative processes are included in the physics package of each model. The baseline simulations include "warm" and "cold" cirrus cases where cloud top initially occurs at about -47C and -66C, respectively. All simulations are for nighttime conditions (no solar radiation) where the cloud is generated in an ice supersaturated layer, about 1 km in depth, with an ice pseudoadiabatic thermal stratification (neutral). Continuing cloud formation is forced via an imposed diabatic cooling representing a 3 cm/s uplift over a 4-hour time span followed by a 2-hour dissipation stage with no cooling. Variations of these baseline cases include no-radiation and stable-thermal-stratification cases. Preliminary results indicated the great importance of ice crystal fallout in determining even the gross cloud characteristics, such as average vertically-integrated ice water path (IWP). Significant inter-model differences were found. Ice water fall speed is directly

  14. Comparison Measurements of Silicon Carbide Temperature Monitors

    SciTech Connect

    J. L. Rempe; K. G. Condie; D. L. Knudson; L. L. Snead

    2010-06-01

    As part of the efforts initiated through the Advanced Test Reactor (ATR) National Scientific User Facility (NSUF) program to make Silicon Carbide (SiC) temperature monitors available, a capability was developed at the Idaho National Laboratory (INL) to complete post-irradiation evaluations of these monitors. INL selected the resistance measurement approach for detecting peak irradiation temperature from SiC temperature monitors. To demonstrate this new capability, comparison measurements were completed by INL and Oak Ridge National Laboratory (ORNL) on identical samples subjected to identical irradiation conditions. Results reported in this paper indicate that the resistance measurement approach can yield similar peak irradiation temperatures if appropriate equipment is used and appropriate procedures are followed.

  15. Critical comparison of 3D imaging approaches

    SciTech Connect

    Bennett, C L

    1999-06-03

    Currently three imaging spectrometer architectures, tunable filter, dispersive, and Fourier transform, are viable for imaging the universe in three dimensions. There are domains of greatest utility for each of these architectures. The optimum choice among the various alternative architectures is dependent on the nature of the desired observations, the maturity of the relevant technology, and the character of the backgrounds. The domain appropriate for each of the alternatives is delineated; both for instruments having ideal performance as well as for instrumentation based on currently available technology. The environment and science objectives for the Next Generation Space Telescope will be used as a specific representative case to provide a basis for comparison of the various alternatives.

  16. Comparison of select reference management tools.

    PubMed

    Zhang, Yingting

    2012-01-01

    Bibliographic management tools have been widely used by researchers to store, organize, and manage their references for research papers, theses, dissertations, journal articles, and other publications. There are a number of reference management tools available. In order for users to decide which tool is best for their needs, it is important to know each tool's strengths and weaknesses. This article compares four reference management tools, one of which is licensed by University of Medicine and Dentistry of New Jersey libraries and the other three are open source and freely available. They were chosen based on their functionality, ease of use, availability to library users, and popularity. These four tools are EndNote/EndNote Web, Zotero, Connotea, and Mendeley Desktop/Mendeley Web. Each tool is analyzed in terms of the following features: accessing, collecting, organizing, collaborating, and citing/formatting. A comparison table is included to summarize the key features of these tools. PMID:22289095

  17. Poultry litter toxicity comparison from various bioassays

    SciTech Connect

    Gupta, G.; Kelly, P. )

    1992-01-01

    Poultry litter contains many toxic chemicals including Cu, As, Pb, Cd, Hg, Se and PCBs. Poultry litter leachate has been shown to be more toxic to marine luminescent organisms (Photobacterium phosphoreum) than other farm animal manures. A comparison of toxicity of the poultry litter leachate was undertaken using various bioassays. The EC{sub 50} (or LC{sub 50}) value for the leachate with the Microtox and Daphnia bioassays was 2.9 g/L/ Nitrobacter and Pseudomonas bioassays were not useful in determining the leachate toxicity because of the nutritional properties of the litter. Poultry litter leachate was found to be mutagenic to strains TA 97, TA 98, TA 100 and TA 102 using the Ames Test.

  18. Objective comparison of particle tracking methods.

    PubMed

    Chenouard, Nicolas; Smal, Ihor; de Chaumont, Fabrice; Maška, Martin; Sbalzarini, Ivo F; Gong, Yuanhao; Cardinale, Janick; Carthel, Craig; Coraluppi, Stefano; Winter, Mark; Cohen, Andrew R; Godinez, William J; Rohr, Karl; Kalaidzidis, Yannis; Liang, Liang; Duncan, James; Shen, Hongying; Xu, Yingke; Magnusson, Klas E G; Jaldén, Joakim; Blau, Helen M; Paul-Gilloteaux, Perrine; Roudot, Philippe; Kervrann, Charles; Waharte, François; Tinevez, Jean-Yves; Shorte, Spencer L; Willemse, Joost; Celler, Katherine; van Wezel, Gilles P; Dan, Han-Wei; Tsai, Yuh-Show; Ortiz de Solórzano, Carlos; Olivo-Marin, Jean-Christophe; Meijering, Erik

    2014-03-01

    Particle tracking is of key importance for quantitative analysis of intracellular dynamic processes from time-lapse microscopy image data. Because manually detecting and following large numbers of individual particles is not feasible, automated computational methods have been developed for these tasks by many groups. Aiming to perform an objective comparison of methods, we gathered the community and organized an open competition in which participating teams applied their own methods independently to a commonly defined data set including diverse scenarios. Performance was assessed using commonly defined measures. Although no single method performed best across all scenarios, the results revealed clear differences between the various approaches, leading to notable practical conclusions for users and developers. PMID:24441936

  19. Comparison of Recent Total Irradiance Measurements

    NASA Astrophysics Data System (ADS)

    Helizon, R.; Pap, J.

    2002-12-01

    Total solar irradiance has been measured since 1978 from various satellites. Since the absolute accuracy of the current irradiance measurements is about 0.2%, one needs to compile composite irradiance time series to study long-term changes and to establish whether there are any secular variations over the last two and half decades. In this paper we compare the UARS/ACRIM II and SOHO/VIRGO total irradiance data as well as the SOHO/VIRGO and ACRIM III total irradiance. Our main goal is to validate the newly processed ACRIM II total irradiance. Comparison of the SOHO/VIRGO and ACRIM III data will also help to establish whether the high total irradiance values for the maximum of solar cycle 23 represent real solar, rather than, instrumental events.

  20. An agreement coefficient for image comparison

    USGS Publications Warehouse

    Ji, L.; Gallo, K.

    2006-01-01

    Combination of datasets acquired from different sensor systems is necessary to construct a long time-series dataset for remotely sensed land-surface variables. Assessment of the agreement of the data derived from various sources is an important issue in understanding the data continuity through the time-series. Some traditional measures, including correlation coefficient, coefficient of determination, mean absolute error, and root mean square error, are not always optimal for evaluating the data agreement. For this reason, we developed a new agreement coefficient for comparing two different images. The agreement coefficient has the following properties: non-dimensional, bounded, symmetric, and distinguishable between systematic and unsystematic differences. The paper provides examples of agreement analyses for hypothetical data and actual remotely sensed data. The results demonstrate that the agreement coefficient does include the above properties, and therefore is a useful tool for image comparison. ?? 2006 American Society for Photogrammetry and Remote Sensing.