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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 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.

  4. Misidentification of Onchocerca volvulus as guinea worm.

    PubMed

    Eberhard, M L; Melemoko, G; Zee, A K; Weisskopf, M G; Ruiz-Tiben, E

    2001-12-01

    Over the past 10 years, the status of human infection with guinea worm (Dracunculus medinensis) in the Central African Republic (CAR) has been difficult to ascertain. It is unclear if indigenous cases are occurring and whether cases are migrating into the CAR from surrounding countries. A team of investigators visited the CAR in July-August 2000, to attempt to ascertain the presence of indigenous transmission. No cases of true guinea-worm infection (i.e. dracunculiasis) were detected, but three cases of human infection with Onchocerca volvulus, each of which had been misidentified as dracunculiasis, were detected. The unusual presentation of skin blisters and extraction of an intact female O. volvulus are described. As a result of this investigation, and the confusion of onchocerciasis being misidentified as dracunculiasis, the presence of endemic transmission of guinea worm in the CAR remains in question.

  5. Onchocerca volvulus Molting Inhibitors Identified through Scaffold Hopping.

    PubMed

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

    2015-05-01

    The anthelmintic closantel has shown promise in abrogating the L3 molting of Onchocerca volvulus, the causative agent of the infectious disease onchocerciasis. In our search for alternative scaffolds, we utilized a fragment replacement/modification approach to generate novel chemotypes with improved chitinase inhibitory properties. Further evaluation of the compounds unveiled the potential of urea-tropolones as potent inhibitors of O. volvulus L3 molting. PMID:27622649

  6. Angiogenic activity of an Onchocerca volvulus Ancylostoma secreted protein homologue.

    PubMed

    Higazi, Tarig B; Pearlman, Eric; Whikehart, David R; Unnasch, Thomas R

    2003-06-01

    Angiogenesis is an important step in the development of ocular onchocercaisis. In previous studies, it has been demonstrated that Onchocerca volvulus homologues of the Ancylostoma secreted protein family have pronounced angiogenic activity. The overall goal of the current study was to determine if this angiogenic effect is exerted through a direct or indirect mechanism. These studies focused on one member of this family, OvASP-2, as this protein is expressed in microfilaria, the stage of the parasite that causes ocular onchocercaisis. Clones encoding truncated and full length open reading frames were expressed as fusion proteins with Escherichia coli maltose binding protein (MBP), and angiogenic activity was compared in vitro and in vivo with MBP alone. Truncated constructs expressing only the first 105 amino acids of OvASP-2 were as active as the full length protein in inducing new blood vessel formation. The full length fusion protein did not stimulate proliferation or production of vascular endothelial growth factor in vascular endothelial cells in vitro, indicating that OvASP-2 does not directly stimulate angiogenesis. Sequence analysis demonstrated that the gene encoding OvASP-2 contained five introns. Sequence comparisons of the genomic loci from West African blinding and non-blinding strains of O. volvulus revealed that some polymorphism existed among the various isolates tested. However, none of these polymorphisms could be used to differentiate the parasite strains, suggesting that qualitative variation in OvASP-2 could not explain the difference in ocular pathogenic potential of the two parasite strains.

  7. The association of adult Onchocerca volvulus with lymphatic vessels.

    PubMed

    Mackenzie, C D; Huntington, M K; Wanji, S; Lovato, R V; Eversole, R R; Geary, T G

    2010-02-01

    Immunocytochemical examination of onchocercal nodule tissues containing adult Onchocerca volvulus using immuno-markers for blood and lymphatic vessels (vWF, D2-40, podoplanin, Prox-1, and Lyve1) shows a distinct pattern of distribution of these vessels within nodules. Blood vessels were commonly seen associated with organized lymphoid cellular aggregates in the both the outer and inner areas of the nodules. In contrast, the majority of the lymphatic vessel positivity was seen in the central zone in close apposition to the adult parasites, and the remainder usually associated with microfilariae in the outer areas of the nodule. These findings suggest an intimate relationship between adult O. volvulus and lymphatic vessels, including the likely proliferation of lymphatic endothelial cells (lymphangectasia) akin to that seen with other filariae. These findings indicate that adult O. volvulus may migrate via the lymphatic system, and that clinical manifestations of this disease that involve tissue edema may be the result of the location of these worms in the lymphatic system.

  8. Onchocerca-Simulium interactions and the population and evolutionary biology of Onchocerca volvulus.

    PubMed

    Basáñez, María-Gloria; Churcher, Thomas S; Grillet, María-Eugenia

    2009-01-01

    Parasite-vector interactions shape the population dynamics of vector-borne infections and contribute to observed epidemiological patterns. Also, parasites and their vectors may co-evolve, giving rise to locally adapted combinations or complexes with the potential to stabilise the infection. Here, we focus on Onchocerca-Simulium interactions with particular reference to the transmission dynamics of human onchocerciasis. A wide range of simuliid species may act as vectors of Onchocerca volvulus, each exerting their own influence over the local epidemiology and the feasibility of controlling/eliminating the infection. Firstly, current understanding of the processes involved in parasite acquisition by, and development within, different Simulium species in West Africa and Latin America will be reviewed. A description of how Onchocerca and Simulium exert reciprocal effects on each other's survival at various stages of the parasite's life cycle within the blackfly, and may have adapted to minimise deleterious effects on fitness and maximise transmission will be given. Second, we describe the interactions in terms of resultant (positive and negative) density-dependent processes that regulate parasite abundance, and discuss their incorporation into mathematical models that provide useful qualitative insight regarding transmission breakpoints. Finally, we examine the interactions' influence upon the evolution of anthelmintic resistance, and conclude that local adaptation of Onchocerca-Simulium complexes will influence the feasibility of eliminating the parasite reservoir in different foci.

  9. Cryopreservation of infective larvae of Onchocerca volvulus (Filarioidea: Onchocercidae).

    PubMed

    Trpis, M; Scoles, G A; Struble, R H

    1993-10-01

    Infective larvae (L3) of Onchocerca volvulus were procured in Liberia, West Africa, in the natural black fly vector, Simulium yahense. A cryobiological technique was developed to preserve L3 of O. volvulus that were fully viable after thawing. Larvae were treated before cooling with 4 cryoprotective compounds. Three compounds, dimethyl sulfoxide (DMSO), glycerol, and ethylene glycol, were prepared with distilled water. The fourth compound was DMSO prepared in different concentrations with 0.25 M sucrose. The treatment with DMSO + 0.25 M sucrose cryoprotectant resulted in the highest survival of infective larvae. Five cooling rates between 0.5 C/min and 20.0 C/min were applied. The highest survival of L3 was with the cooling rate of 1.0 C/min. Two-step cooling of L3 was applied. In the first step, L3's were frozen to 5 levels from -10.0 C to -20.0 C, -30.0 C, -40.0 C, -60 C, and -80.0 C, and in the second step, larvae were transferred into liquid nitrogen at -196 C for rapid cooling and storage. The survival was the highest when larvae were cooled to approximately -40 C prior to transfer into liquid nitrogen. Slow, gradual, and rapid thawing procedures were applied. The survival was the highest in rapid warming.

  10. 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

  11. T cell responses in coinfection with Onchocerca volvulus and the human immunodeficiency virus type 1.

    PubMed

    Sentongo, E; Rubaale, T; Büttner, D W; Brattig, N W

    1998-09-01

    Onchocerca volvulus and the human immunodeficiency virus (HIV) are two immunocompromising infectious agents of major public health concern in Uganda. To examine the effect of coinfection with O. volvulus and HIV on cellular immune responses, lymphocyte proliferative responses and cytokine production of peripheral blood mononuclear cells (PBMC) from persons infected with O. volvulus with and without HIV type 1 infection were compared. Proliferation of PBMC to PHA and tuberculin (PPD) in coinfection was less (P = 0.08, P < 0.01) than in O. volvulus infection. O. volvulus extract stimulated lymphocyte proliferation in microfilaria-negative and HIV-negative O. volvulus infection while only an inconspicuous response was observed in microfilaria-negative coinfection. After stimulation of PBMC with PPD, the production of interferon-gamma (IFN-gamma), interleukin (IL)-4 and IL-5-demonstrated in O. volvulus infection-were reduced in coinfection with HIV (P < 0.01). While both groups failed to produce IFN-gamma in response to O. volvulus extract, only O. volvulus infected persons generated pronounced IL-5 and low IL-4 levels (0.01 > P = 0.02). The cellular immune responses in coinfection suggested an HIV-related lack of specific reactivity to O. volvulus antigen and impairment of IL-4 and IL-5 production in addition to the lack of IFN-gamma response on antigenic stimulation. PMID:9767610

  12. 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

  13. 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

  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. 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.

  16. 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

  17. 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

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

    PubMed Central

    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

  20. Onchocerca volvulus DNA probe classification correlates with epidemiologic patterns of blindness.

    PubMed

    Zimmerman, P A; Dadzie, K Y; De Sole, G; Remme, J; Alley, E S; Unnasch, T R

    1992-05-01

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

  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. [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.

  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. Interruption of Transmission of Onchocerca volvulus in the Southern Chiapas Focus, México

    PubMed Central

    Rodríguez-Pérez, Mario A.; Domínguez-Vázquez, Alfredo; Unnasch, Thomas R.; Hassan, Hassan K.; Arredondo-Jiménez, Juan I.; Orozco-Algarra, María Eugenia; Rodríguez-Morales, Kristel B.; Rodríguez-Luna, Isabel C.; Prado-Velasco, Francisco Gibert

    2013-01-01

    Background The Southern Chiapas focus of onchocerciasis in Southern Mexico represents one of the major onchocerciasis foci in Latin America. All 559 endemic communities of this focus have undergone semi-annual mass treatment with ivermectin since 1998. In 50 communities of this focus, ivermectin frequency shifted from twice to four times a year in 2003; an additional 113 communities were added to the quarterly treatment regimen in 2009 to achieve a rapid suppression of transmission. Methodology/Principal findings In-depth epidemiologic and entomologic assessments were performed in six sentinel communities (which had undergone 2 rounds of ivermectin treatment per year) and three extra-sentinel communities (which had undergone 4 rounds of ivermectin treatment per year). None of the 67,924 Simulium ochraceum s.l. collected from this focus during the dry season of 2011 were found to contain parasite DNA when tested by polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA), resulting in an upper bound of the 95% confidence interval (95%-ULCI) of the infective rate in the vectors of 0.06/2,000 flies examined. Serological assays testing for Onchocerca volvulus exposure conducted on 4,230 children 5 years of age and under (of a total population of 10,280 in this age group) revealed that 2/4,230 individuals were exposed to O. volvulus (0.05%; one sided 95% confidence interval = 0.08%). Conclusions/Significance The in-depth epidemiological and entomological findings from the Southern Chiapas focus meet the criteria for interruption of transmission developed by the international community. PMID:23556018

  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. 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

  8. 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

  9. The Onchocerca volvulus micro- and macrofilarial responses in onchocerciasis patients to increased dosage of diethylcarbamazine.

    PubMed

    Langham, M E; Beltranena, F

    1985-09-01

    The response of 45 severely infected onchocerciasis patients to relatively high doses of diethylcarbamazine citrate (DEC-C) has been determined. The treatment comprised two sequential phases; the first phase comprised the topical applications of a DEC-C lotion and of the anti-inflammatory steroid betamethasone. The second phase comprised the daily oral administration of high doses of DEC-C (30 mg/kg body wt) for seven days. Onchocerca volvulus microfilarial (o.v.mf.) counts in skin snips of the 45 patients decreased by 96 +/- 1.5% after 5 days of treatment with topical DEC-C lotion. Following the administration of oral DEC, the average O.v.mf. counts in the skin snips at days 51, 97, and 143 remained decreased by 85 to 93%. The mean O.v.mf. counts in 10 nodules excised from 5 treated patients at day 77 had decreased by 93% compared to the mean O.v.mf. counts in 11 nodules taken from 5 untreated patients with similar initial O.v.mf. infection. No visual loss resulted from the treatment.

  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.

  11. 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

  12. 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

  13. 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

  14. 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

  15. Onchocerca gutturosa and O. volvulus: studies on the viability and drug responses of cryopreserved adult worms in vitro.

    PubMed

    Townson, S; Shay, K E; Dobinson, A R; Connelly, C; Comley, J C; Zea-Flores, G

    1989-01-01

    The viability and drug responses of cryopreserved adult Onchocerca have been examined in vitro. Male worms were cryopreserved in liquid nitrogen (-196 degrees C) using ethanediol as a cryoprotectant in a 2-step incubation procedure. After thawing, 85-90% of O. gutturosa males were normally motile. These motile worms were evaluated for viability using 4 measurements (long-term motility/survival in culture; [U-14C]adenine uptake and leakage; glucose utilization; MTT-formazan colorimetry) and were no different from unfrozen controls. Subsequent experiments demonstrated that the motility responses of cryopreserved worms exposed to the antifilarial drugs ivermectin, CGP 6140 and levamisole were virtually identical to unfrozen controls. Some success was also obtained with this technique in cryopreserving O. volvulus males, with 2 thawed specimens surviving in culture for 93 and 106 d respectively. Following collagenase isolation, female worms were cryopreserved in medium +10% serum without protectant at -79 degrees C. A batch of 8 female O. gutturosa were all motile when thawed 14 d later, with a mean survival time (based on 5 specimens) of 71 d (range 60-90). However, a batch of worms transferred from -79 degrees C to -196 degrees C were badly damaged when thawed. Female O. volvulus were cryopreserved at -79 degrees C in Guatemala and sent by air freight on solid CO2 to the UK. Most specimens were active when thawed. Survival of motile specimens ranged from 7 to 272 d in culture. It is concluded that these techniques are of practical value for the storage and transportation of adult Onchocerca.

  16. 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

  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. Rapid suppression of Onchocerca volvulus transmission in two communities of the Southern Chiapas focus, Mexico, achieved by quarterly treatments with Mectizan.

    PubMed

    Rodríguez-Pérez, Mario A; Lutzow-Steiner, Miguel A; Segura-Cabrera, Aldo; Lizarazo-Ortega, Cristian; Domínguez-Vázquez, Alfredo; Sauerbrey, Mauricio; Richards, Frank; Unnasch, Thomas R; Hassan, Hassan K; Hernández-Hernández, Raymundo

    2008-08-01

    The impact of quarterly Mectizan (ivermectin) treatments on transmission, microfiladermia, and ocular lesions was evaluated in two formerly hyperendemic communities (Las Golondrinas and Las Nubes II) located in the main endemic focus for onchocerciasis in Southern Chiapas, Mexico. The data suggest that Onchocerca volvulus transmission has been suppressed after elimination of microfiladermia in these two communities. Increasing the frequency of Mectizan treatment to four times per year appears to have resulted in the rapid suppression of transmission in communities with residual transmission.

  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. 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

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

    PubMed Central

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

    2015-01-01

    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. 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

  3. Development of Onchocerca volvulus (Filarioidea: Onchocercidae) in the West African black fly Simulium yahense (Diptera: Simuliidae) in Liberia.

    PubMed

    Trpis, M; Wergin, W P; Murphy, C A

    2001-12-01

    Simulium yahense black flies infected with microfilaria of Onchocerca volvulus were kept in a defined insectary environment in Liberia, West Africa. A daily sample of infected flies was dissected for larvae developing in the thoracic muscles and examined for growth in stadial development. Microfilariae ingested by black flies transformed to the L1 larval stage without molting. Successive larval development included molting to the L2 stage and, finally, to the L3 stage, which was infective in humans. The cephalic cap, consisting of a laterally located hook and central stoma, occurs in the first larval stage. The caudal appendix and the laterally located anal opening are apparent in the L1 larva. In the L2 stage, the cephalic cap is lost and the large circular stoma becomes surrounded with elevated flaps. The caudal appendix was lost after larvae molted to the L3 stage, and in its place, 3 terminal papillae developed. Sense organs, such as 2 opposing phasmids and 8 papillae that were arranged into 2 circles, developed in the cephalic region of the L3 larva. The evidence of pathological consequences due to the presence of the L3 larva in the fly host are illustrated and discussed. PMID:11780809

  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. Ivermectin effect on microfilariae of Onchocerca volvulus after a single oral dose in humans.

    PubMed

    Soboslay, P T; Newland, H S; White, A T; Erttmann, K D; Albiez, E J; Taylor, H R; Williams, P N; Greene, B M

    1987-03-01

    Ivermectin is a broad spectrum anti-helminthic agent which is currently being tested for use in human onchocerciasis. Its activity is believed to result from its effect on GABA-mediated neurotransmission. We examined the effects of ivermectin on motility of microfilariae of O. volvulus following administration to humans. When ivermectin was given in dosages of 100, 150 and 200 mcg/kg on day 1 there was a clear reduction in motility of microfilariae obtained on day 3 when compared to microfilariae from the placebo group. The mean motility scores in microfilariae from ivermectin recipients were 3.1, 2.3, and 2.2 at 0, 12, and 24 hours of incubation compared to 3.3, 2.9, and 2.5, respectively, in microfilariae from placebo recipients (p less than 0.003, p less than 0.005, and p less than 0.012, respectively). Examination of the effect according to dose suggested a dose-response relationship. Microfilariae in the anterior chamber of the eye 2 days after a single oral dose of ivermectin showed abnormal and reduced winding and coiling. Microfilariae in 50% of ivermectin recipients showed abnormal motility compared to no such effects in subjects examined concurrently who received oral DEC, DEC lotion or placebo. These observations indicate that ivermectin has an effect on motility of microfilariae of O. volvulus following administration to humans.

  6. Rapid Suppression of Onchocerca volvulus Transmission in Two Communities of the Southern Chiapas Focus, Mexico, Achieved by Quarterly Treatments with Mectizan

    PubMed Central

    Rodríguez-Pérez, Mario A.; Lutzow-Steiner, Miguel A.; Segura-Cabrera, Aldo; Lizarazo-Ortega, Cristian; Domínguez-Vázquez, Alfredo; Sauerbrey, Mauricio; Richards, Frank; Unnasch, Thomas R.; Hassan, Hassan K.; Hernández-Hernández, Raymundo

    2008-01-01

    The impact of quarterly Mectizan (ivermectin) treatments on transmission, microfiladermia, and ocular lesions was evaluated in two formerly hyperendemic communities (Las Golondrinas and Las Nubes II) located in the main endemic focus for onchocerciasis in Southern Chiapas, Mexico. The data suggest that Onchocerca volvulus transmission has been suppressed after elimination of microfiladermia in these two communities. Increasing the frequency of Mectizan treatment to four times per year appears to have resulted in the rapid suppression of transmission in communities with residual transmission. PMID:18689630

  7. Dynamics of Onchocerca volvulus Microfilarial Densities after Ivermectin Treatment in an Ivermectin-naïve and a Multiply Treated Population from Cameroon

    PubMed Central

    Pion, Sébastien D. S.; Nana-Djeunga, Hugues C.; Kamgno, Joseph; Tendongfor, Nicholas; Wanji, Samuel; Njiokou, Flobert; Prichard, Roger K.; Boussinesq, Michel

    2013-01-01

    Background/Objective Ivermectin has been the keystone of onchocerciasis control for the last 25 years. Sub-optimal responses to the drug have been reported in Ghanaian communities under long-term treatment. We assessed, in two Cameroonian foci, whether the microfilaricidal and/or embryostatic effects of ivermectin on Onchocerca volvulus have been altered after several years of drug pressure. Methods We compared the dynamics of O. volvulus skin microfilarial densities after ivermectin treatment in two cohorts with contrasting exposure to this drug: one received repeated treatment for 13 years whereas the other had no history of large-scale treatments (referred to as controls). Microfilarial densities were assessed 15, 80 and 180 days after ivermectin in 122 multiply treated and 127 ivermectin-naïve individuals. Comparisons were adjusted for individual factors related to microfilarial density: age and number of nodules. Findings Two weeks post ivermectin, microfilarial density dropped equally (98% reduction) in the ivermectin-naïve and multiply treated groups. Between 15 and 180 days post ivermectin, the proportion of individuals with skin microfilariae doubled (from 30.8% to 67.8%) in controls and quadrupled (from 19.8% to 76.9%) in multiply treated individuals but the mean densities remained low in both sites. In fact, between 15 and 80 days, the repopulation rate was significantly higher in the multiply treated individuals than in the controls but no such difference was demonstrated when extending the follow-up to 180 days. The repopulation rate by microfilariae was associated with host factors: negatively with age and positively with the number of nodules. Conclusion These observations may indicate that the worms from the multi-treated area recover mf productivity earlier but would be less productive than the worms from the ivermectin-naïve area between 80 and 180 days after ivermectin. Moreover, they do not support the operation of a strong cumulative effect

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

    PubMed

    Omar, M S; Prost, A; Marshall, T F

    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.

  9. 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

  10. 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.

  11. Infection rates and parasitic loads of Onchocerca volvulus, and other filariae, in Simulium sanctipauli s.l. and S. yahense in a rain-forest area of Liberia.

    PubMed

    Garms, R

    1987-09-01

    Simulium sanctipauli s.l. and S. yahense are common and widespread in the rain-forest zone of Liberia, but differ with regard to their biting densities and contribution to the transmission of Onchocerca volvulus. Although, in a study area on the St. Pauli River, S. sanctipauli s.l. (presumably S. soubrense in the sense of Post) was the predominant ma-biting species (74.3% of 30,855 females examined), S. yahense was shown to be the important vector. While 1000 biting females of S. yahense carried 96 3rd stage larvae indistinguishable from O. volvulus, only 14 were found per 1000 females of S. sanctipauli s.l. Of the parous females (3135 S. sanctipauli s.l./1621 S. yahense) 23.8/39.9% harboured 1st and/or 2nd stage filarial larvae and 1.9/9.4% 3rd stage larvae of O. volvulus. Animal filariae of unknown origin, indicative of zoophily, were very common in S. sanctipauli s.l. (13.8%) but practically absent from S. yahense (0.5%). In spite of its poorer vectorial performance S. sanctipauli s.l. cannot be neglected as a vector because it may occur in high biting densities and contribute considerably to the transmission, in particular in the vicinity of the St. Paul River. The interplay of two vector species, which develop in different types of water-courses explains the overall high endemicity of onchocerciasis in the study area.

  12. 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

  13. Epitopes of the Onchocerca volvulus RAL1 antigen, a member of the calreticulin family of proteins, recognized by sera from patients with onchocerciasis.

    PubMed Central

    Rokeach, L A; Zimmerman, P A; Unnasch, T R

    1994-01-01

    RAL1 is an antigen (Ag) encoded by the filarial nematode Onchocerca volvulus, the parasite causing onchocerciasis (river blindness). RAL1 shares 64.4% identity with the autoantigen calreticulin. The striking similarity of the parasite Ag and the human autoantigen has led to the hypothesis that RAL1 may induce a cross-reactive immune response to calreticulin, which in turn may be involved in the pathogenesis of onchocerciasis. To test this hypothesis, we explored the immune response to RAL1 recombinant Ag (RAL1 rAg) and human calreticulin in patients with O. volvulus infection. A total of 86% of the O. volvulus-infected individuals produced antibodies recognizing RAL1 rAg. Antibody reactivity to RAL1 rAg in patient sera was confined primarily to the central and carboxyl-terminal parts of the molecule. No significant correlations were found to associate recognition of RAL1 rAg, or any particular portion thereof, with a particular disease state. Antibodies against RAL1 thus appear to be produced as a general immune reaction to O. volvulus infection and do not necessarily lead to a cross-reacting response with the host protein. In contrast, 33% of the patient sera tested bound recombinant human calreticulin. All of these sera also recognized a polypeptide encompassing the carboxyl-terminal portion of the RAL1 rAg. These results suggest that recognition of an epitope encoded in the carboxyl-terminal portion of RAL1 is at least in part responsible for inducing a cross-reacting immune response to the host protein. Images PMID:7520419

  14. 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

  15. 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

  16. Nested PCR to detect and distinguish the sympatric filarial species Onchocerca volvulus, Mansonella ozzardi and Mansonella perstans in the Amazon Region.

    PubMed

    Tang, Thuy-Huong Ta; López-Vélez, Rogelio; Lanza, Marta; Shelley, Anthony John; Rubio, Jose Miguel; Luz, Sérgio Luiz Bessa

    2010-09-01

    We present filaria-nested polymerase chain reaction (PCR), which is based on amplification of first internal transcribed spacer rDNA to distinguish three parasitic filarial species (Onchocerca volvulus, Mansonella ozzardi and Mansonella perstans) that can be found in the Amazon Region. Nested PCR-based identifications yielded the same results as those utilizing morphological characters. Nested PCR is highly sensitive and specific and it detects low-level infections in both humans and vectors. No cross-amplifications were observed with various other blood parasites and no false-positive results were obtained with the nested PCR. The method works efficiently with whole-blood, blood-spot and skin biopsy samples. Our method may thus be suitable for assessing the efficacy of filaria control programmes in Amazonia by recording parasite infections in both the human host and the vector. By specifically differentiating the major sympatric species of filaria, this technique could also enhance epidemiological research in the region. PMID:20945000

  17. 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

  18. Quantitative studies on the transmission of Onchocerca volvulus by Simulium damnosum s.l. in the Tukuyu Valley, South West Tanzania.

    PubMed

    Pedersen, E M; Maegga, B T

    1985-12-01

    A survey of the Simulium breeding and the transmission of Onchocerca volvulus was carried out in and around the Tukuyu valley, S.W. Tanzania, S. damnosum s.l. was found breeding in the midstretches of the main rivers in the valley and their bigger tributaries, and also in the boundary river to Malawi and the most northerly of the three rivers draining the Livingstone Mts. to Lake Nyasa (L. Malawi). A total of 19,500 S. damnosum s.l. females was caught and 13,200 dissected. The annual biting rate varied between 2,000 and 23,800. 7.6% of all the flies were infected with O. volvulus and 1.5% carried infective larvae in the head capsule, on average 2.7 per fly. The transmission was mainly in the dry season and the annual transmission potential varied between 0 and 1,120. The entomological data showed many similarities to those from the Mahenge Mts., Tanzania, and correlation of places with comparable transmission potentials suggests a similarity in the relationship parasite-human host between the West African rain forest and the two Tanzanian foci.

  19. 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

  20. Characterization of a novel filarial serine protease inhibitor, Ov-SPI-1, from Onchocerca volvulus, with potential multifunctional roles during development of the parasite.

    PubMed

    Ford, Louise; Guiliano, David B; Oksov, Yelena; Debnath, Asim K; Liu, Jing; Williams, Steven A; Blaxter, Mark L; Lustigman, Sara

    2005-12-01

    A novel filarial serine protease inhibitor (SPI) from the human parasitic nematode Onchocerca volvulus, Ov-SPI-1, was identified through the analysis of a molting third-stage larvae expressed sequence tag dataset. Subsequent analysis of the expressed sequence tag datasets of O. volvulus and other filariae identified four other members of this family. These proteins are related to the low molecular weight SPIs originally isolated from Ascaris suum where they are believed to protect the parasite from host intestinal proteases. The two Ov-spi transcripts are up-regulated in the molting larvae and adult stages of the development of the parasite. Recombinant Ov-SPI-1 is an active inhibitor of serine proteases, specifically elastase, chymotrypsin, and cathepsin G. Immunolocalization of the Ov-SPI proteins demonstrates that the endogenous proteins are localized to the basal layer of the cuticle of third-stage, molting third-stage, and fourth-stage larvae, the body channels and multivesicular bodies of third-stage larvae and the processed material found between the two cuticles during molting. In O. volvulus adult worms the Ov-SPI proteins are localized to the sperm and to eggshells surrounding the developing embryos. RNA interference targeting the Ov-spi genes resulted in the specific knockdown of the transcript levels of both Ov-spi-1 and Ov-spi-2, a loss of native proteins, and a significant reduction in both molting and viability of third-stage larvae. We suggest the Ov-SPI proteins play a vital role in nematode molting by controlling the activity of an endogenous serine protease(s). The localization data in adults also indicate that these inhibitors may be involved in other processes such as embryogenesis and spermatogenesis.

  1. 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.

  2. Reproductive Status of Onchocerca volvulus after Ivermectin Treatment in an Ivermectin-Naïve and a Frequently Treated Population from Cameroon

    PubMed Central

    Bopda, Jean; Kengne-Ouafo, Jonas A.; Njiokou, Flobert; Prichard, Roger K.; Wanji, Samuel; Kamgno, Joseph; Boussinesq, Michel

    2014-01-01

    Background For two decades, onchocerciasis control has been based on mass treatment with ivermectin (IVM), repeated annually or six-monthly. This drug kills Onchocerca volvulus microfilariae (mf) present in the skin and the eyes (microfilaricidal effect) and prevents for 3–4 months the release of new mf by adult female worms (embryostatic effect). In some Ghanaian communities, the long-term use of IVM was associated with a more rapid than expected skin repopulation by mf after treatment. Here, we assessed whether the embryostatic effect of IVM on O. volvulus has been altered following frequent treatment in Cameroonian patients. Methodology Onchocercal nodules were surgically removed just before (D0) and 80 days (D80) after a standard dose of IVM in two cohorts with different treatment histories: a group who had received repeated doses of IVM over 13 years, and a control group with no history of large-scale treatments. Excised nodules were digested with collagenase to isolate adult worms. Embryograms were prepared with females for the evaluation of their reproductive capacities. Principal Findings Oocyte production was not affected by IVM. The mean number of intermediate embryos (morulae and coiled mf) decreased similarly in the two groups between D0 and D80. In contrast, an accumulation of stretched mf, either viable or degenerating, was observed at D80. However, it was observed that the increase in number of degenerating mf between D0 and D80 was much lower in the frequently treated group than in the control one (Incidence Rate Ratio: 0.25; 95% CI: 0.10–0.63; p = 0.003), which may indicate a reduced sequestration of mf in the worms from the frequently treated group. Conclusion/Significance IVM still had an embryostatic effect on O. volvulus, but the effect was reduced in the frequently treated cohort compared with the control population. PMID:24762816

  3. 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

  4. 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.

  5. Retarded Onchocerca volvulus L1 to L3 larval development in the Simulium damnosum vector after anti-wolbachial treatment of the human host

    PubMed Central

    2012-01-01

    Background The human parasite Onchocerca volvulus harbours Wolbachia endosymbionts essential for worm embryogenesis, larval development and adult survival. In this study, the development of Wolbachia-depleted microfilariae (first stage larvae) to infective third stage larvae (L3) in the insect vector Simulium damnosum was analysed. Methods Infected volunteers in Cameroon were randomly and blindly allocated into doxycycline (200 mg/day for 6 weeks) or placebo treatment groups. After treatment, blackflies were allowed to take a blood meal on the volunteers, captured and dissected for larval counting and DNA extraction for quantitative real-time PCR analysis. Results PCR results showed a clear reduction in Wolbachia DNA after doxycycline treatment in microfilariae from human skin biopsies with > 50% reduction at one month post-treatment, eventually reaching a reduction of > 80%. Larval stages recovered from the insect vector had similar levels of reduction of endosymbiotic bacteria. Larval recoveries were analysed longitudinally after treatment to follow the kinetics of larval development. Beginning at three months post-treatment, significantly fewer L3 were seen in the blackflies that had fed on doxycycline treated volunteers. Concomitant with this, the proportion of second stage larvae (L2) was significantly increased in this group. Conclusions Doxycycline treatment and the resulting decline of Wolbachia endobacteria from the microfilaria resulted in retarded development of larvae in the insect vector. Thus, anti-wolbachial treatment could have an additive effect for interrupting transmission by reducing the number of L3 that can be transmitted by blackflies. PMID:22236497

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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.

  11. Contribution of migrant coffee labourers infected with Onchocerca volvulus to the maintenance of the microfilarial reservoir in an ivermectin-treated area of Mexico

    PubMed Central

    Rodríguez-Pérez, Mario A; Cabrera, Aldo Segura; Ortega, Cristian Lizarazo; Basáñez, María-Gloria; Davies, John B

    2007-01-01

    Background Since 1991, in Mexico, ivermectin has been administered twice a year to all residents in the onchocerciasis endemic foci which are mainly located in the coffee growing areas. However, the presence of a potentially infected itinerant seasonal labour force which is not treated regularly could jeopardise the attainment of the 85% coverage which is the present target for elimination of the disease. Methods The prevalence and intensity of Onchocerca volvulus microfilariae (mf), as well as their transmission from humans to vectors, were assessed during the coffee planting-clearing and harvesting seasons of 1997–1998, and 1998–1999 in two localities (I and II) of Southern Chiapas, Mexico, which regularly receive an influx of untreated migrant coffee labourers. Results Localities I and II had, respectively, an average of 391 (± 32) and 358 (± 14) resident inhabitants, and 70 (± 52) and 498 (± 289) temporary labourers. The ratio of migrants to residents ranged from 0.1:1 in locality I to 2.4:1 in locality II. The proportion of infected Simulium ochraceum s.l. parous flies was significantly lower in locality I than in locality II, and significantly higher during the stay of the migrants than before their arrival or after their departure. Parity and infection were higher in May-July than in November-February (in contrast with the latter being typically considered as the peak onchocerciasis transmission season by S. ochraceum s.l.). Conclusion The presence of significant numbers of untreated and potentially infected migrants may contribute to ongoing transmission, and their incorporation into ivermectin programmes should be beneficial for the attainment of the elimination goals of the regional initiative. However, the possibility that the results also reflect transmission patterns for the area cannot be excluded and these should be analyzed further. PMID:18088423

  12. Effects of high doses of diethylcarbamazine on adult Onchocerca volvulus examined by the collagenase technique and by histology.

    PubMed

    Albiez, E J; Walter, G; Kaiser, A; Newland, H S; White, A T; Greene, B M; Taylor, H R; Büttner, D W

    1988-06-01

    Thirty adult male nodule carriers from a hyperendemic onchocerciasis area in the Liberian rain forest were treated with high doses of diethylcarbamazine (30 mg/kg/d) over one week. Another ten patients received placebo tablets and served as a control. All detectable nodules were removed from half of the patients at two months and from the remaining patients at ten months after chemotherapy. The adult worms in the nodules were examined for pathological alterations by the collagenase technique including embryogram, and by histology. No macrofilaricidal effect was observed at either time, and no significant reduction of microfilariae in the uteri of the female worms or in the tissue of the nodules was seen. Two months after the therapy there was a significant increase of degenerated stretched intrauterine microfilariae but this effect was no longer observed after ten months. No pathological effect was seen on the intrauterine coiled microfilariae. On the contrary, their number had significantly increased after ten months which could mean a stimulation of the embryogenesis. No effect on spermatogenesis was observed. Both techniques, the collagenase digestion and the histological examination of the nodules, provided similar results to demonstrate that there was no marked long lasting effect on O. volvulus after a treatment with high doses of diethylcarbamazine.

  13. 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

  14. 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

  15. Induction of protection against divergent H5N1 influenza viruses using a recombinant fusion protein linking influenza M2e to Onchocerca volvulus activation associated protein-1 (ASP-1) adjuvant.

    PubMed

    Zhao, Guangyu; Du, Lanying; Xiao, Wenjun; Sun, Shihui; Lin, Yongping; Chen, Min; Kou, Zhihua; He, Yuxian; Lustigman, Sara; Jiang, Shibo; Zheng, Bo-Jian; Zhou, Yusen

    2010-10-18

    Our previous studies have shown the adjuvanticity of an Onchocerca volvulus recombinant protein, Ov-ASP-1 (ASP-1), when administered in an aqueous formulation with bystander vaccine antigens or commercial vaccines. In this study, we reported a novel formulation that took advantage of the protein nature of the ASP-1 adjuvant by creating recombinant fusion protein vaccines linking the highly conserved extracellular domain of M2 protein (M2e) consensus sequence of H5N1 influenza viruses with the ASP-1 adjuvant. Two recombinant fusion proteins designated M2e-ASP-1 and M2e3-ASP-1 were studied, in which ASP-1 was fused with one or three tandem copies of the M2e antigen. Our results show that these novel recombinant influenza vaccines, particularly M2e3-ASP-1, induced strong anti-M2e-specific humoral and cellular immune responses in the established mouse model. Furthermore, M2e3-ASP-1 was able to provide significant cross-clade protection against divergent H5N1 viruses. Consequently, this study has demonstrated a potential novel vaccine formulation that could provide a complementary prophylactic strategy in preventing the threat of future influenza outbreak resulting from rapid evolution of the H5N1 virus and co-circulation of multiple antigenic variants in various regions.

  16. Evaluation of recombinant Onchocerca volvulus activation associated protein-1 (ASP-1) as a potent Th1-biased adjuvant with a panel of protein or peptide-based antigens and commercial inactivated vaccines.

    PubMed

    Xiao, Wenjun; Du, Lanying; Liang, Chao; Guan, Jie; Jiang, Shibo; Lustigman, Sara; He, Yuxian; Zhou, Yusen

    2008-09-15

    Alum, the only adjuvant approved for clinical applications, can induce strong humoral (Th2) but weak cellular (Th1) immune responses. It is necessary to develop safe and effective adjuvants capable of inducing both humoral and cellular immune responses. We previously showed that activation-associated protein-1 (ASP-1) derived from Onchocerca volvulus has potent adjuvant activity. In this study, we have further evaluated the adjuvanticity of recombinant ASP-1 using a panel of recombinant proteins or synthetic peptide-based antigens, including ovalbumin (OVA), synthetic HIV peptide (HIV-p), recombinant HIV gp41 (rgp41) and HBV HBsAg, as well as three commercially available inactivated vaccines against haemorrhagic fever with renal syndrome (HFRS), Influenza and Rabies. Our results indicate that ASP-1 induced significantly higher IgG1 (Th2-associated) and IgG2a (Th1-associated) responses than alum adjuvant against OVA antigen, HIV-p, and rgp41. Consistently, it induced similar level of IgG1 responses as alum but higher level of IgG2a and IFN-gamma-producing T cell responses than alum adjuvant against HBsAg. Further, ASP-1 improved both IgG1 and IgG2a responses to three commercial inactivated vaccines when used separately or in combination. In conclusion, the recombinant ASP-1, unlike alum adjuvant, is able to induce both Th1 and Th2-associated humoral responses and Th1 cellular responses, suggesting that it can be further developed as a promising adjuvant for subunit-based and inactivated vaccines. PMID:18675867

  17. Resistance to Onchocerca lienalis microfilariae in mice conferred by egg antigens of homologous and heterologous Onchocerca species.

    PubMed

    Carlow, C K; Bianco, A E

    1987-06-01

    Embryonic stages of various Onchocerca species have been used to stimulate resistance in CBA mice to challenge injections with the microfilariae of Onchocerca lienalis. Comparable levels of resistance to challenge (29-37% reductions) were conferred by living, freeze-killed, or sonicated organisms administered with Freunds' Complete Adjuvant (FCA). Antigens extracted in saline, or with the detergent sodium deoxycholate, were also protective. Adjuvants enhanced the protective effect, particularly FCA (78% reduction), Freunds' Incomplete Adjuvant (74% reduction), aluminum hydroxide (70% reduction) and Bordetella pertussis (70% reduction). Detergent extracts prepared from intact embryos with n-octyl glucoside also stimulated significant levels of protection against microfilarial challenge when given with FCA (37-45% reductions). Levels of resistance induced by immunizations with intact organisms were greatest following subcutaneous (s.c.) injection over the neck or by intramuscular inoculation. Soluble extracts were also particially effective given by s.c. inguinal or intraperitoneal injection. A time-interval of greater than 3 weeks between the completion of immunization and challenge was required for the expression of immunity. Cross-protection against challenge with O. lienalis microfilariae was also afforded to mice by immunization with intact embryos or detergent extracts of Onchocerca gutturosa (45 and 34% reductions), Onchocerca gibsoni (66 and 47% reductions) or Onchocerca volvulus (58 and 41% reductions). It is concluded that the embryonic stages of both human and animal parasites provide a source of cross-protective antigens of value in studies on resistance to Onchocerca microfilariae in experimental hosts.

  18. 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

  19. Management of colonic volvulus.

    PubMed

    Gingold, Daniel; Murrell, Zuri

    2012-12-01

    Colonic volvulus is a common cause of large bowel obstruction worldwide. It can affect all parts of the colon, but most commonly occurs in the sigmoid and cecal areas. This disease has been described for centuries, and was studied by Hippocrates himself. Currently, colonic volvulus is the third most common cause of large bowel obstruction worldwide, and is responsible for ∼15% of large bowel obstructions in the United States. This article will discuss the history of colonic volvulus, and the predisposing factors that lead to this disease. Moreover, the epidemiology and diagnosis of each type of colonic volvulus, along with the various treatment options will be reviewed. PMID:24294126

  20. 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

  1. 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

  2. Detection and comparison of nitric oxide in clinically healthy horses and those with naturally acquired strangulating large colon volvulus

    PubMed Central

    2005-01-01

    Abstract The objective of the study was to determine whether nitric oxide (NO) is present in clinically healthy horses (control) under basal conditions, and if it increases secondary to naturally acquired strangulating large colon volvulus (affected). Eleven affected horses and 10 controls were studied. Jugular venous blood, abdominal fluid, and urine were collected. The NO concentrations were standardized to the creatinine concentration in the respective samples. A biopsy specimen collected from the large colon pelvic flexure at surgery was divided into subsections for processing for inducible nitric synthase (iNOS) and nitrotyrosine (NT) immunohistochemical staining and reduced nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase histochemical staining. There were no significant differences in plasma, abdominal fluid, or urine NO concentrations between affected and control horses. There was a significant decrease in submucosal arteriolar and venular endothelium, submucosal plexus, mucosal leukocyte, mucosal and musclaris vasculature, and myenteric plexus NADPH diaphorase staining in affected versus control horses. There was a significant increase in iNOS staining in mucosal leukocytes and vasculature in affected versus control horses. Other than a greater number of positively stained mucosal leukocytes in affected horses, there were no significant differences between affected and control horses for NT staining. The presence of NADPH diaphorase staining in the endothelium and submucosal neurons suggests endothelial and neuronal NOS are present under basal conditions in the large colon of horses. Increased iNOS and NT staining in mucosal leukocytes of affected horses suggests involvement of the NO pathway in large colon volvulus. The reasons for the lack of a significant difference in plasma, abdominal fluid, and urine NO concentrations between affected and control horses are unknown. PMID:15971674

  3. 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

  4. 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

  5. Onchocerca spp: a "family" of secreted acidic proteins expressed by infective larvae in blackflies.

    PubMed

    Bianco, A E; Wu, Y; Jenkins, R E

    1995-11-01

    Biosynthetic labeling of developing larvae of Onchocerca in blackflies has been used to characterize a group of stage-specific, secreted proteins produced by vector-stage parasites. These are highly acidic molecules (pI 4.4-5.1) present in at least three members of the genus (O. volvulus, O. lienalis, O. ochengi) that exhibit minor heterogeneity among species in apparent molecular mass (between 18 and 23 kDa). In O. volvulus, there are two polypeptides that run as a doublet of 18 and 20 kDa. In O. lienalis and O. ochengi, single polypeptides of 23 and 20 kDa were detected. The processes of synthesis and secretion appear to be temperature-sensitive and dissociated events. Experiments with O. volvulus in Simulium damnosum sl revealed that synthesis is initiated in second stage larvae and increases in infective-stage parasites: Secretion occurs when larvae leave the vector and enter the phase of development associated with the vertebrate host. Third-stage larvae of O. lienalis were shown to continue to express and accumulate the 23-kDa protein with age. The primary organ of secretion, as indicated by dissection, was the glandular esophagus. These data point to an important biological role for this group of molecules and suggest that they may belong to a family of related products. Because they have the distinctive characteristics of being secreted larval acidic proteins, we propose the acronym SLAP pending further insights into their functional properties.

  6. [Volvulus in pregnancy: a case report].

    PubMed

    Aguayo-Macías, Eduardo; Rodríguez-Valle, Antonio Joel; Gonzalez-Habib, Roberto; Reyes-Sepúlveda, Hernán

    2012-03-01

    There are several etiologies of abdominal pain during pregnancy, including an extremely rare: the intestinal volvulus. Have been reported about 78 cases in the literature of intestinal volvulus complicating pregnancy, we reported this case occurred in our hospital and to assess the difficult diagnosis of intestinal volvulus in pregnancy.

  7. 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

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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

  13. [Malrotation with or without volvulus].

    PubMed

    Heidsma, Charlotte M; Hulsker, Caroline C C; van der Zee, David; Kramer, William H

    2015-01-01

    Malrotation occurs when there is a failure in the intestinal rotation leading to abnormal fixation to the abdominal wall and a mesentery with a short root. Volvulus is a life-threatening complication of malrotation. It can lead to irreversible intestinal necrosis and requires immediate attention. Early recognition of malrotation and surgical correction could prevent the onset of volvulus. We describe 3 cases of children with a malrotation. Case A involves a 2-year-old boy who suffered from repeated episodes of vomiting. Case B, a 1-month-old female, was taken to the general practitioner after acute onset of crying and flexing of the legs. Case C, a 5-year-old-boy with no medical history, had started vomiting hourly. In presenting these 3 cases, we highlight the dangers of untreated malrotation and make recommendations on how to manage a patient suspected of having this congenital abnormality.

  14. 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

  15. 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

  16. 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

  17. 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.

  18. Anti-Onchocerca activity and phytochemical analysis of an essential oil from Cyperus articulatus L

    PubMed Central

    2014-01-01

    Background The lack of a safe and effective adult worm drug and the emergence of resistant animal parasite strains to the only recommended drug, the microfilaricide, ivermectin put many at risk of the devastating effects of the onchocerciasis. The present study was undertaken to investigate the acclaimed anti-Onchocerca activity of the roots/rhizomes of Cyperus articulatus in the traditional treatment of onchocerciasis in North Western Cameroon and to assess the plant as a new source of potential filaricidal lead compounds. Methods Crude extracts were prepared from the dried plant parts using hexane, methylene chloride and methanol. 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. The viabilities of microfilariae and adult male worms were determined based on motility reduction, while for the adult female worms the viability was based on the standard MTT/formazan assay. Cytotoxicity of the active extract was assessed on monkey kidney epithelial cells in vitro and the selectivity indices (SI) were determined. Acute toxicity of the promising extract was investigated in mice. Chemical composition of the active extract was unraveled by GC/MS analysis. Results Only the hexane extract, an essential oil exhibited anti-Onchocerca activity. The oil killed both the microfilariae and adult worms of O. ochengi in a dose manner dependently, with IC50s of 23.4 μg/ml on the Mfs, 23.4 μg/ml on adult male worms and 31.25 μg/ml on the adult female worms. Selectivity indices were 4, 4, and 2.99 for Mfs, adult males and adult females, respectively. At a single limit dose of 2000 mg/kg body weight, none of 6 mice that received the essential oil by gavage died. GC/MS analysis revealed the presence of terpenoids, hydrocarbons and fatty acids or fatty acid derivatives as components of the oil. Conclusions The essential oil from the roots/rhizomes of Cyperus

  19. An interesting rare case of double volvulus.

    PubMed

    Chittal, R; Harris, D; Patel, A; Goodyear, S; Parkianathan, V

    2011-02-23

    A 71-year-old female presented with recurrent sigmoid volvulus. In the current admission, her symptoms were not settling on conservative measures and subsequently went on to have laparotomy. During laparotomy, along with the sigmoid volvulus, there was associated gallbladder torsion. About 500 cases of gallbladder volvulus have been published in literature, however, in our literature search, the authors did not find any similar published case presenting with volvulus involving the gallbladder and the sigmoid colon at the same time. This patient went onto have cholecystectomy and sigmoid colectomy and had a good postoperative recovery and was discharged on the tenth postoperative day. At 6-week postoperative follow-up, she was doing well with no specific concerns.

  20. 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

  1. Morphological identification of simulium sanctipauli and S. yahense in Liberia and comparison of results with those of enzyme electrophoresis.

    PubMed

    Garms, R; Zillmann, U

    1984-12-01

    Simulium sanctipauli and S. yahense have been incriminated as the main vectors of Onchocerca volvulus in the rain-forest zone of Liberia. An accurate identification of the females of the two species which breed in different types of water-courses but are morphologically similar is essential for a proper study of their epidemiological importance and the planning of control measures. Various external characters were examined for their diagnostic value by the comparison of identifications using these characters and those based on enzyme electrophoresis (phosphoglucomutase, trehalase). It was shown that the females of the two species can be separated reliably by the use of external morphological characters. The occasional finding in the same fly of phosphoglucomutase variants typical for each species indicated the possible occurrence of natural hybridization between S. sanctipauli and S. yahense.

  2. Cecal volvulus following laparoscopic nephrectomy and renal transplantation.

    PubMed

    Eng, Mary; Ravindra, Kadiyala

    2009-01-01

    Cecal volvulus is a rare cause of bowel obstruction that carries a high mortality. Recent surgery is known to be a risk factor for the development of cecal volvulus. We present a case of cecal volvulus following laparoscopic nephrectomy and renal transplantation.

  3. 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

  4. Eosinophils contribute to killing of adult Onchocerca ochengi within onchocercomata following elimination of Wolbachia.

    PubMed

    Nfon, Charles K; Makepeace, Benjamin L; Njongmeta, Leo M; Tanya, Vincent N; Bain, Odile; Trees, Alexander J

    2006-10-01

    Many filarial nematodes, including Onchocerca volvulus (the cause of human 'River Blindness'), have a mutually dependent relationship with Wolbachia bacteria. There has been much interest in Wolbachia as a chemotherapeutic target, since there are no macrofilaricidal drugs (i.e., lethal to adult worms) of low toxicity. Using the bovine parasite O. ochengi, we previously demonstrated that combined intensive and intermittent (COM) oxytetracycline treatment induces a sustained depletion of Wolbachia and is macrofilaricidal, whereas a short intensive regimen (SIR) is non-macrofilaricidal. To understand how targeting Wolbachia with oxytetracycline can lead to worm death, O. ochengi nodules (onchocercomata) were sequentially excised from cattle administered COM or SIR therapy, and cell infiltrates were microscopically quantified. Pre-treatment, worms were surrounded by neutrophils, with eosinophils rare or absent. At 8-12weeks after either regimen, eosinophils increased around worms and were observed degranulating on the cuticle. However, with the SIR treatment, neutrophils returned to predominance by 48weeks, while in the COM group, eosinophilia persisted. These observations suggest that accumulation of degranulating eosinophils over a prolonged period is a cause rather than an effect of parasite death, and the macrofilaricidal mechanism of antibiotics may relate to facilitation of eosinophil infiltration around worms by ablation of Wolbachia-mediated neutrophilia.

  5. Cicatrical cecal volvulus following laparoscopic cholecystectomy.

    PubMed

    Morris, Michael W; Barker, Andrea K; Harrison, James M; Anderson, Andrew J; Vanderlan, Wesley B

    2013-01-01

    Laparoscopic cholecystectomy is the procedure of choice for the treatment of symptomatic biliary disease. There is currently no agreement on the management of spilled gallstones, which commonly occurs during laparoscopic cholecystectomy and may produce significant morbidity. We present a case of spilled gallstones causing cicatrical cecal volvulus and also provide a review of pertinent literature. PMID:23925032

  6. Ocular Zoonotic Onchocerca Infection in a Resident of Oregon

    PubMed Central

    Eberhard, Mark L.; Sims, Annette C.; Bishop, Henry S.; Mathison, Blaine A.; Hoffman, Richard S.

    2012-01-01

    A long, slender filarial nematode was removed from the left anterior chamber of a resident of Oregon after several days of pain and blurred vision. The worm was identified as an Onchocerca, but it could not be further identified. This worm is the third zoonotic Onchocerca removed from the anterior chamber and the second case reported from the United States. Cases of zoonotic onchocerciasis continue to garner attention, and those cases affecting the eye are of particular interest. PMID:23109373

  7. 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

  8. Geographical distribution of the prevalence of nodules of Onchocerca volvulus in Guatemala over the last four decades.

    PubMed

    Yamagata, Y; Suzuki, T; Garcia Manzo, G A

    1986-03-01

    In Guatemala a national nodulectomy campaign has been carried out since 1935 in three operational areas, namely the Eastern, Central and Western endemic zones. The prevalence of nodules was calculated in each 1 km grid square in these zones in each decade and plotted on mesh maps. A total of nine foci of high endemicity, three in each operational area, was found in the decade 1940-49. Nodule prevalence was concentric in each endemic focus; high in the centre and gradually falling towards periphery. The foci were found mainly on Tertiary or Quaternary-Tertiary volcanic rocks in the Eastern and Central zones, or on non-carbonate sedimentary rocks in the Western zone. Nodule carriers were found at altitudes from 220 to 2200 m above sea level. The altitude of the foci of high endemicity varied, being low in the Eastern zone, medium in the Central zone and high in the Western zone. The nodule prevalence declined from the decade 1940-49 to the decade 1970-79 in most of the grid squares. The Santa Rosa focus in the Eastern zone virtually disappeared before 1970. The extent of endemic area having a nodule prevalence of 1% or higher decreased from 2384 km2 in the decade 1940-49 to 1424 km2 in the decade 1970-79. The area recommended for vector control operation against Simulium ochraceum was estimated at 803 km2.

  9. [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

  10. 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

  11. 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.

  12. 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

  13. 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

  14. 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

  15. 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

  16. [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.

  17. 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

  18. Volvulus of ileum: a rare cause of small bowel obstruction.

    PubMed

    Islam, Shariful; Hosein, Devin; Dan, Dilip; Naraynsingh, Vijay

    2016-01-01

    Small bowel volvulus is a rare but life-threatening surgical emergency. Owing to its rarity, it is seldom entertained as a differential for small bowel obstruction. The aetiology may be either primary or secondary, with secondary being more common in the Western world. Prompt diagnosis and urgent surgical treatment is required if bowel necrosis is to be prevented, which is associated with increased mortality. We present a case of primary ileal volvulus with a gangrenous segment and a brief overview of the current literature. PMID:27646320

  19. 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

  20. Volvulus of ileum: a rare cause of small bowel obstruction.

    PubMed

    Islam, Shariful; Hosein, Devin; Dan, Dilip; Naraynsingh, Vijay

    2016-09-19

    Small bowel volvulus is a rare but life-threatening surgical emergency. Owing to its rarity, it is seldom entertained as a differential for small bowel obstruction. The aetiology may be either primary or secondary, with secondary being more common in the Western world. Prompt diagnosis and urgent surgical treatment is required if bowel necrosis is to be prevented, which is associated with increased mortality. We present a case of primary ileal volvulus with a gangrenous segment and a brief overview of the current literature.

  1. Onchocerca sweetae (Nematoda: Filarioidea): notes on the intermediate host.

    PubMed

    Spratt, D M; Dyce, A L; Standfast, H A

    1978-03-01

    Microfilariae of Onchocerca sweetae are broadly distributed in the superficial layers of the dermis of the water buffalo (Bubalus bubalis). A total of 2855 insects representing 20 species were collected from O. sweetae-infected bait buffaloes. Only one species, Culicoides sp. "M", ingested microfilariae from buffalo skin. Larval development of O. sweetae was observed in the thorax of this species. Atotal of 829 insects, representing 7 species and including 749 parous Culicoides spp. were collected from light and Manitoba traps. Developing filarioid larvae were observed only in Culicoides sp. "M". It is concluded that Culicoides sp. "M" is a natural intermediate host of O. sweetae in the Northern Territory of Australia.

  2. [Primary small bowel volvulus in a young adult].

    PubMed

    Pastor, J; Adámek, S; Polanecký, O

    2014-06-01

    The authors present a rare case of a young male patient with primary small bowel volvulus. They show the main points to be considered in clinical diagnosis of this kind of acute abdomen and the importance of CT scan in such cases.

  3. 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

  4. Gastric volvulus and associated gastro-oesophageal reflux.

    PubMed Central

    Samuel, M; Burge, D M; Griffiths, D M

    1995-01-01

    Between 1984 and 1994, 10 neurologically normal children between 2 and 24 months were diagnosed as having gastric volvulus with associated gastro-oesophageal reflux (GOR). The common features at presentation were episodic colicky abdominal pain, non-bilious vomiting, upper abdominal distension, haematemesis, and failure to thrive. Anterior gastropexy and conservative management of GOR was curative. Images Figure 2 PMID:8554369

  5. [Primary volvulus of the small intestine: vascular-like acute abdomen].

    PubMed

    Damiani, S; Ruscazio, M; Ciulla, A; Miceli, G; Tomasello, G

    1998-01-01

    The Authors discuss etiology, clinical picture, diagnostic and therapeutic possibilities of intestinal volvulus, an uncommon disease in Europe, thinking of a case of primitive small intestine volvulus, recently observed, and considering the literature. The Authors have come to the conclusion that in all the cases of intestinal occlusion, in emergency hospitalization, it is important to suspect the intestinal volvulus and to operate on the patient urgently to avoid the raise of postoperative mortality in all the cases complicated with intestinal gangrene.

  6. 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

  7. Image diagnosis of zoonotic onchocercosis by Onchocerca lupi.

    PubMed

    Franchini, Delia; Giannelli, Alessio; Di Paola, Giancarlo; Cortes, Helder; Cardoso, Luís; Lia, Riccardo Paolo; Campbell, Bronwyn Evelyn; Dantas-Torres, Filipe; Lenoci, Diana; Assad, Eyad Abu; Ricciardi, Mario; Valastro, Carmela; Cavaliere, Leonardo; Di Bello, Antonio; Otranto, Domenico

    2014-06-16

    Onchocerca lupi, a zoonotic nematode infecting the eyes of carnivores, has been increasingly reported in dogs from Europe and the USA. In order to improve the current status of knowledge on this neglected filarioid, diagnostic imaging tools (i.e., ultrasound scan, computed tomography and magnetic resonance imaging) are herein used to diagnose canine onchocercosis in two dogs, which scored positive for O. lupi microfilariae at the skin snip test and to assess the anatomical location of the nematode within the ocular apparatus. Results indicate that ultrasound tools are useful to address the diagnosis of O. lupi in dogs and to evaluate the localization of nodules or cysts containing the adult nematode. PMID:24685021

  8. 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

  9. Congenital diaphragmatic hernia with recurrent gastric volvulus and pulmonary sequestration: A “chance” combination

    PubMed Central

    Kumar, Kashish; Khanna, Vikram; Dhua, Anjan Kumar; Bhatnagar, Veereshwar

    2016-01-01

    Congenital diaphragmatic hernia (CDH) is a known cause of secondary gastric volvulus. It is also known that bronchopulmonary sequestration (BPS) may be associated with CDH. An extremely rare case of BPS associated with gastric volvulus in a girl with left sided CDH is being reported. PMID:26862295

  10. A rare case of acute on chronic gastric volvulus with Borchardt's triad.

    PubMed

    Senior, Andrew; Hari, Churunal

    2014-01-01

    Gastric volvulus is a rare condition with two forms of presentation, either acute or chronic. Since its discovery, there have been no cases of acute on chronic volvulus discussed in the literature. Its vague presentation makes diagnosis and subsequent management difficult. The diagnosis of acute gastric volvulus is made on clinical grounds via Borchardt's triad; however, barium swallow and oesophagogastroduodenoscopy have been shown to play a role. We describe a case of a 95-year-old Caucasian woman who presented with worsening dysphagia, epigastric pain, retching without vomiting and hiccups of 5 months. Initially diagnosed as a hiatus hernia, the patient subsequently died following an acute on chronic gastric volvulus. This rare, life-threatening diagnosis provides an opportunity to discuss characteristics of gastric volvulus and the difficulties in management. PMID:25413999

  11. Sigmoid Volvulus Complicating Pregnancy Managed by Resection and Primary Anastomosis: Case report with literature review.

    PubMed

    Machado, Norman O; Machado, Lovina S M

    2009-04-01

    Sigmoid volvulus is an extremely rare cause of intestinal obstruction in pregnancy. The rarity of the condition and the fact that pregnancy itself clouds the clinical picture invariably leads to a delay in diagnosis with an increased risk of gangrene of the gut. The majority of these patients would then require resection and colostomy. However, an early diagnosis and intervention as in our patient, which would require a high index of clinical suspicion, could significantly improve the outcome of the foetus and the mother. A case of sigmoid volvulus in pregnancy is reported which was managed by resection and primary anastomosis. A review of literature revealed no previous reports of sigmoid volvulus in pregnancy managed by primary anastomosis following resection of the sigmoid volvulus. The literature is also reviewed regarding predisposing factors, management options and the outcome of sigmoid volvulus complicating pregnancy.

  12. Laparoscopic repair of hiatal hernia with mesenterioaxial volvulus of the stomach.

    PubMed

    Inaba, Kazuki; Sakurai, Yoichi; Isogaki, Jun; Komori, Yoshiyuki; Uyama, Ichiro

    2011-04-21

    Although mesenterioaxial gastric volvulus is an uncommon entity characterized by rotation at the transverse axis of the stomach, laparoscopic repair procedures have still been controversial. We reported a case of mesenterioaxial intrathoracic gastric volvulus, which was successfully treated with laparoscopic repair of the diaphragmatic hiatal defect using a polytetrafluoroethylene mesh associated with Toupet fundoplication. A 70-year-old Japanese woman was admitted to our hospital because of sudden onset of upper abdominal pain. An upper gastrointestinal series revealed an incarcerated intrathoracic mesenterioaxial volvulus of the distal portion of the stomach and the duodenum. The complete laparoscopic approach was used to repair the volvulus. The laparoscopic procedures involved the repair of the hiatal hernia using polytetrafluoroethylene mesh and Toupet fundoplication. This case highlights the feasibility and effectiveness of the laparoscopic procedure, and laparoscopic repair of the hiatal defect using a polytetrafluoroethylene mesh associated with Toupet fundoplication may be useful for preventing postoperative recurrence of hiatal hernia, volvulus, and gastroesophageal reflux.

  13. 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

  14. 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

  15. [Entomology of onchocerciasis in Soconusco, Chiapas, México. VII. Quantitative variations in the transmission of Onchocerca volvulus (Nematoda: Filaroiidea) according to human activity space].

    PubMed

    Ortega Gutiérrez, M; Ramírez, A; Miranda, R

    1991-01-01

    In this research we tried to demonstrate differences in transmission intensities of onchocerciasis by Simulium ochraceum in the community of Golondrinas, Municipality of Acacoyagua in the Soconusco area of the state of Chiapas. Adult females of this species were captured in the center of the villages, the coffee plantation, and the corn bean planted plots, during 7 to 10 consecutive days of the months of June, August, November and December of 1983, and January, March, and May of 1984. Captures were made from 7:00 to 11:00 h, by two persons (a human bait and a collector) in each of the mentioned areas. Variations in densities of S. ochraceum were not statistically significant among the different areas, although there was a predominance in the center of the villages during all the time periods. There was not a statistical significance in the number of oviparous females, although again the center of 50 villages showed the highest percentages (43.5%), as compared to the coffee plantation (37.8%), and the corn-bean plots (33.8%). Regarding the ratio infection: infectivity, only the infective mosquitoes with L3 showed a statistical significance in the three types of areas, being highest in the center of the villages. Transmission potentials were: center of the village 28.5 L3/human/period; coffee plantation, 73 L3/human/period; corn-bean plot, 5.8 L3/human/period. We discuss the possibility that the differences in densities among the various areas might depend on the variations of the breeding sites, mobility or permanence of the individuals during the hours of greater activity of S. ochraceum, and the wind and light local conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. 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

  17. 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

  18. Impact of combined large-scale ivermectin distribution and vector control on transmission of Onchocerca volvulus in the Niger basin, Guinea.

    PubMed Central

    Guillet, P.; Sékétéli, A.; Alley, E. S.; Agoua, H.; Boatin, B. A.; Bissan, Y.; Akpoboua, L. K.; Quillévéré, D.; Samba, E. M.

    1995-01-01

    As part of the WHO Onchocerciasis Control Programme in West Africa (OCP), the attack phase of operations in the Niger basin in Guinea began in 1989 with the simultaneous use of ivermectin and vector control. Larvicide applications coupled with annual large-scale ivermectin distribution have greatly reduced blackfly infectivity (by 78.8% for the number of infective larvae per 1000 parous flies). The combination of vector control and ivermectin has permitted excellent control of transmission. In the original OCP area, it took 6-8 years of vector control alone to obtain an equivalent decrease in blackfly infectivity. For the same number of flies caught, transmission was much higher in areas where ivermectin had not been distributed. The combined use of ivermectin and vector control has opened up new prospects for carrying out OCP operations with, notably, the possibility of reducing larviciding operations. PMID:7743591

  19. 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

  20. 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

  1. Malrotation and Midgut Volvulus associated with Asymptomatic Duplication Cyst of Jejunum.

    PubMed

    Rahul, Sandip Kumar; Upadhyaya, Vijai Datta; Kumar, Basant

    2016-01-01

    Gastrointestinal duplications can affect any part of the alimentary tract and are notorious for their variable presentation. Their association with malrotation and midgut volvulus is rare. We describe an 8-year old boy presented with episodes of abdominal pain. Radiological workup showed whirlpool sign and abnormal relationship of mesenteric vessels. At operation, malrotation with chronic volvulus was found. Incidentally, a jejunal communicating duplication cyst was also noted. PMID:27672583

  2. Malrotation and Midgut Volvulus associated with Asymptomatic Duplication Cyst of Jejunum

    PubMed Central

    Upadhyaya, Vijai Datta; Kumar, Basant

    2016-01-01

    Gastrointestinal duplications can affect any part of the alimentary tract and are notorious for their variable presentation. Their association with malrotation and midgut volvulus is rare. We describe an 8-year old boy presented with episodes of abdominal pain. Radiological workup showed whirlpool sign and abnormal relationship of mesenteric vessels. At operation, malrotation with chronic volvulus was found. Incidentally, a jejunal communicating duplication cyst was also noted. PMID:27672583

  3. Sigmoid volvulus: is it a possible complication after stapled transanal rectal resection (STARR)?

    PubMed Central

    RESTA, G.; SCAGLIARINI, L.; BANDI, M.; VEDANA, L.; MARZETTI, A.; FERROCCI, G.; SANTINI, M.; ANANIA, G.; CAVALLESCO, G.; BACCARINI, M.

    2013-01-01

    Summary We report a case of sigmoid volvulus post-stapled transanal rectal resection (STARR) for obstructed defecation. The patient, a 68-year-old woman with chronic constipation and dolichosigma, two days post-STARR presented severe abdominal pain. CT revealed sigmoid ischemia. The patient underwent resection of the sigmoid colon with end colostomy (Hartmann’s procedure). Can STARR procedure produce a serious complication as sigmoid volvulus in patient with dolichosigma and obstructed defecation syndrome? PMID:24091179

  4. Sigmoid volvulus: is it a possible complication after stapled transanal rectal resection (STARR)?

    PubMed

    Resta, G; Scagliarini, L; Bandi, M; Vedana, L; Marzetti, A; Ferrocci, G; Santini, M; Anania, G; Cavallesco, G; Baccarini, M

    2013-01-01

    We report a case of sigmoid volvulus post-stapled transanal rectal resection (STARR) for obstructed defecation. The patient, a 68-yearold woman with chronic constipation and dolichosigma, two days post-STARR presented severe abdominal pain. CT revealed sigmoid ischemia. The patient underwent resection of the sigmoid colon with end colostomy (Hartmann's procedure). Can STARR procedure produce a serious complication as sigmoid volvulus in patient with dolichosigma and obstructed defecation syndrome?

  5. Gastric dilitation-volvulus in a Red Panda (Ailurus fulgens).

    PubMed

    Schlanser, Justin R; Agnew, Dalen; Paperd, Deborah W; Harrison, Tara M

    2014-06-01

    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.

  6. Gastric dilitation-volvulus in a Red Panda (Ailurus fulgens).

    PubMed

    Schlanser, Justin R; Agnew, Dalen; Paperd, Deborah W; Harrison, Tara M

    2014-06-01

    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

  7. Bochdalek Hernia With Gastric Volvulus in an Adult

    PubMed Central

    Atef, Mejri; Emna, Trigui

    2015-01-01

    Abstract Bochdalek hernias in adulthood are rare. Symptomatic Bochdalek hernias in adults are rarer, but may lead to fatal complications. Patients with acute gastric volvulus on diaphragmatic hernia are a diagnostic and therapeutic emergency. Here, we report a case of a 56-year-old woman diagnosed with epigastric pain, cough, vomiting since 2 weeks and shortness of breath. Complicated Bochdalek hernia was an incidental finding, diagnosed by chest radiograph, computed tomography (CT), and barium swallow study. Stomach was within the thorax in the left side due to left diaphragmatic hernia of a nontraumatic cause. The patient was prepared for the laparoscopic surgical repair, to close the defect. The patient recovered with accepted general condition and was discharged 9 days later. Diagnoses of Bochdalek hernias in adulthood are challenging. However, although rare, this possibility should be kept in mind to avoid fatal complications. PMID:26705205

  8. 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

  9. 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

  10. A mesenteric hernia complicated with a triple necrotic volvulus.

    PubMed

    Tassinari, Davide; Santoro, Stefano; Bernardi, Filippo; Lima, Mario

    2012-09-24

    A 6-year-old girl was admitted to the paediatric emergency department with colicky abdominal pain. She had a significant medical history, with four previous admissions due to recurrent abdominal pain in the past year. On examination the abdomen was soft, there was no rebound tenderness and Rovsing's sign was negative. Her blood tests revealed a raised white cells count, although her C reactive protein was within the normal range. Abdominal x-ray revealed small bowel obstruction. During her assessment the patient rapidly deteriorated and seemed to go into shock. Her clinical state in addition to the radiological findings meant that she was taken to theatre for surgical exploration. This showed a triple volvulus with necrotic bowel loops that had herniated through a mesenteric defect. The necrotic bowel was subsequently resected.

  11. 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

  12. 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

  13. 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

  14. Reverse intestinal rotation: a rare case of volvulus around a vitelline duct remnant

    PubMed Central

    Dreyer, Stephan; Kaczynski, Jakub; Hrobar, Petr; Collins, Patrick

    2014-01-01

    We present a rare case of reverse intestinal rotation with volvulus around a Meckel's diverticulum attached to a vitelline duct remnant. The diagnosis was established by CT. The patient was treated with exploratory laparotomy and small bowel resection. The patient made a full recovery and was discharged home on the seventh postoperative day. PMID:25246458

  15. Volvulus of an ileal conduit with retroperitoneal urinoma in a child: first reported case.

    PubMed

    Harold, D L; Kass, E J

    1978-02-01

    Ileal loop urinary diversion requires long-term followup. A case of an ileal conduit volvulus with a retroperitoneal urinoma 14 years after the initial procedure is reported. A brief discussion of long and short-term complications of ileal loops is presented.

  16. Wandering Spleen and Organoaxial Gastric Volvulus after Morgagni Hernia Repair: A Case Report and Review of the Literature

    PubMed Central

    Gulia, Caterina; Miele, Vittorio; Trinci, Margherita; Briganti, Vito

    2016-01-01

    Wandering spleen and gastric volvulus are two rare entities that have been described in association with congenital diaphragmatic hernia. The diagnosis is difficult and any delay can result in ischemia and necrosis of both organs. We present a case of a 13-year-old girl, previously operated on for anterior diaphragmatic hernia and intrathoracic gastric volvulus, that presented to our service for a subdiaphragmatic gastric volvulus recurrence associated with a wandering spleen. In this report we reviewed the literature, analyzing the clinical presentation, diagnostic assessment, and treatment options of both conditions, in particular in the case associated with diaphragmatic hernia. PMID:27703832

  17. 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.

  18. 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

  19. 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.

  20. Small bowel volvulus as a complication of von Recklinghausen’s disease: A case report

    PubMed Central

    Werner, Thomas Artur; Kröpil, Feride; Schoppe, Martin Olaf; Kröpil, Patric; Knoefel, Wolfram Trudo; Krieg, Andreas

    2014-01-01

    We report the case of a 25-year-old male with Neurofibromatosis type I (NF-1), who presented at the time of admission with clinical findings of an acute abdomen caused by a mechanical obstruction. Computerized tomography showed a volvulus of the terminal ileum with mesenteric swirling as the cause of the patient’s symptoms. Consecutive exploratory laparotomy confirmed the diagnosis and 70 cm of the small intestine was resected due to an affection of the mesentery by multiple neurofibromas. The gastrointestinal tract is affected in approximately 10% of patients with NF-1, however the mesentery is almost always spared. Here we describe the unique case of a patient with a volvulus caused by mesenteric manifestation of von Recklinghausen’s disease, emphasizing the role of surgery in a team of multidisciplinary specialists to treat this multiorganic disease. PMID:24976735

  1. 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

  2. [Predisposing factors, clinical picture and mortality in volvulus of the small intestine].

    PubMed

    Díaz Plasencia, J; Huaynalaya, E; Rodríguez, F; Rebaza, H

    1992-01-01

    This retrospective study evaluated predisposing factors, clinical picture and the methods of treatment related to morbidity and mortality of 19 small bowel volvulus (SBV) who underwent operation at Belen Hospital (Trujillo-Peru) during the last 26 years (1966-1992). The SBV was 1.6% of all cases of intestinal obstruction in this period and 10.8% of all intestinal volvulus. The median age was of 43 +/- 20.5 years (range, 6 to 78 years) and the majority of them were between 41 and 60 years. Sixteen cases (84.2%) were men from Indian and Spanish extraction and most of them were farmers and came from the Sierra of the Department of La Libertad. Two cases (10.5%) had non-related antecedents previous surgery. In six patients (31.6%) the volvulus was less than seven day's duration and in thirty (68.4%) it was more eight day's duration with previous attacks of obstruction (median: 19.3 days, range: 17 hours to 94 days). Pain, vomiting and distention were present in almost all of these cases. The most frequent abdominal finding was distention. The location of the volvulus was: ileum, 12 cases (63.2%), root of mesentery, 4 cases (21%) and jejunum, 3 cases (15.8%). Gangrenous bowel was present in six patients (31.5) and gangrenous intestine with perforation in two cases (10.5%) who underwent resection of the involved segment with primary anastomosis. In this group one patient (5.2%) died of sepsis and the wound infection rate was of 37.5%. There was no statistically significant correlation with the duration of illness and the presence of gangrenous loops or the mortality rate (p > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

  3. 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

  4. Volvulus of the Sigmoid Colon Associated With Rectal Cancer: A Case Report

    PubMed Central

    Lee, Seung-Hyun; Ahn, Byung-Kwon; Baek, Sung-Uhn

    2015-01-01

    Sigmoid volvulus is one of the three most common causes of acute colonic obstruction. Predisposing factors include chronic constipation, adhesion from a prior abdominal surgery, and megacolon. However, concomitant presentation of volvulus of the sigmoid colon and rectal cancer is extremely rare. We report a case of a 50-year-old woman with coexisting volvulus of the sigmoid colon and rectal cancer. The patient presented with abdominal distension and pain for 2 days. On computed tomography, the whole colon was dilated with gas and feces. A whirl sign with rotation of the inferior mesenteric vessel was identified. The rectum had irregular wall thickening. Colonoscopy showed a circumscribed, ulcerofungating mass approximately 6 cm from the anal verge. The sigmoid colon was obstructed at a point approximately 25 cm from the anal verge. The mucosa was hyperemic and edematous with the pathognomonic spiral pattern. Endoscopic reduction was not successful. On laparotomy, the sigmoid colon was rotated around its mesentery. It was severely distended with edematous, hyperemic serosa. A tumor of the rectum was identified in the mid-rectum. The patient underwent low anterior resection and protective ileostomy. Pathologic findings confirmed adenocarcinoma of the rectum. The postoperative course was complicated by an ileus, which was managed with conservative treatment.

  5. 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

  6. Outcome of Jejuno-Ileal Atresia Associated with Intraoperative Finding of Volvulus of Small Bowel

    PubMed Central

    Sinha, Shalini; Sarin, Yogesh Kumar

    2012-01-01

    Aim: To compare the outcome of patients with jeuno-ileal atresia (JIA) associated with the intraoperative finding of volvulus of small bowel (group A) with that of JIA without volvulus (group B). Materials and Methods: It is a retrospective observational study conducted at one of the two units of Pediatric Surgery, in a tertiary care public hospital of India, from January 2001 to December 2010. Hospital records were retrieved and analyzed. During this time period, 65 patients with JIA were operated of which 40 (61.5%) had ileal atresia (IA) and 25 (38.5%) had jejunal atresia (JA). Eleven (16.9%) patients had associated intraoperative finding of volvulus of small bowel (Group A) and were studied and compared with group B- not associated with intraoperative findings of volvulus of small bowel (n=54). The demography, clinical features, operative findings, associated anomalies, anastomotic leakage, and outcome were compared. Results: Group A comprising of 6 boys and 5 girls, had 8 IA and 3 JA; one case each of Type 3b and Type 4 JIA was seen. Associated anomalies included meconium ileus (n=2), Down’s syndrome (n=1) and malrotation (n=1). Anastomotic leak rate was 75% for IA and 66.7% for JA. The mortality was 91% in Group A, 100% for IA and 67% for JA. Group B comprising of 37 boys and 17 girls, had 32 IA and 22 JA; 2 cases of Type 4 and 1 case of Type 3b JIA was seen. Associated anomalies were malrotation (n=2), meconium ileus (n=1), exomphalos (n=1), gastroschisis (n=1) and ileal duplication cyst (n=1). The anastomotic leak rate for JA was 8/21 (38.1%) and IA was 3/28 (10.7%); persistent obstruction was seen in 3/21(14.3%) JA and 1/28 (3.6%) IA patients. In group B, overall mortality rate was 8/22 (36.4%) for JA and 9/32 (28%) for IA. The morbidity and mortality was significantly higher in group A when compared to group B. Conclusions: JIA associated with volvulus (without malrotation) is a sinister entity with a dismal outcome in our experience. PMID:26023396

  7. Sigmoid volvulus in an adolescent girl: staged management with emergency colonoscopic reduction and decompression followed by elective sigmoid colectomy.

    PubMed

    Patel, Ramnik V; Njere, Ike; Campbell, Alison; Daniel, Rejoo; Azaz, Amer; Fleet, Mahmud

    2014-08-20

    A case of acute sigmoid volvulus in a 14-year-old adolescent girl presenting with acute low large bowel obstruction with a background of chronic constipation has been presented. Abdominal radiograph and CT scan helped in diagnosis. She underwent emergency colonoscopic detorsion and decompression uneventfully. Lower gastrointestinal contrast study showed very redundant sigmoid colonic loop without any transition zone and she subsequently underwent elective sigmoid colectomy with good outcome. The sigmoid volvulus should be considered in the differential diagnosis of paediatric acute abdomen presenting with marked abdominal distention, absolute constipation and pain but without vomiting. Plain abdominal radiograph and the CT scan are helpful to confirm the diagnosis. Early colonoscopic detorsion and decompression allows direct visualisation of the vascular compromise, assessment of band width of the volvulus and can reduce complications and mortality. Associated Hirschsprung's disease should be suspected if clinical and radiological features are suggestive in which case a rectal biopsy before definitive surgery should be considered.

  8. 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

  9. 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

  10. Total management of short gut secondary to midgut volvulus without prolonged total parenteral alimentation.

    PubMed

    Tepas, J J; MacLean, W C; Kolbach, S; Shermeta, D W

    1978-12-01

    Absorption studies in rats have shown that intestinal adaptation after catastrophic injury can be stimulated by early enteral feeding. Using this concept, we have devised a technique of early initiation and advancement of oral feedings that begins with Cho-Free and Polycose and gradually adds sucrose and MCT in increasing proportions. The increasing complexity and caloric density of this diet provide sufficient nutrition to allow weaning from total parenteral alimentation within 2--3 wk. Our preliminary experience in babies with midgut volvulus, necrotizing enterocolitis, and gastroschisis has been successful and uncomplicated. These patients have demonstrated consistent weight gain and have been spared the complications associated with prolonged parenteral alimentation.

  11. 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

  12. Onchocerca lupi infection in Turkey: a unique case of a rare human parasite.

    PubMed

    Ilhan, Hatice Deniz; Yaman, Aylin; Morishima, Yasuyuki; Sugiyama, Hiromu; Muto, Maki; Yamasaki, Hiroshi; Hasegawa, Hideo; Lebe, Banu; Bajin, Meltem Soylev

    2013-09-01

    Onchocerpa lupi was first isolated from a wolf in Russia. Since then, canine ocular onchocercosis has been increasingly reported, particularly in Europe and the United States. It is thought that blackflies and midges are the vectors of transmission, and it is possible that these vectors could transmit the parasite to humans. The first human case of O. lupi in Turkey was reported in 2011. In this report we present the third human case of O. lupi infection in Turkey. Our patient was a 28-year-old male who displayed a painless, immobile mass under the conjunctiva. The mass measured 10 × 12 mm in size. Pathological examination of the surgically excised tissue was suggestive of infection by a filarial nematode. Subsequently, the parasite was identified as O. lupi through molecular analysis. All of the previously reported cases of O. lupi in both humans and dogs were more symptomatic than in our patient, Onchocerca infection should not be ruled out during the differential diagnosis of the subconjunctival and orbital cystic mass in instances where there is little to no inflammation. It is important to consider biopsy and carry out molecular analysis to identify the parasite. PMID:23990437

  13. Onchocerciasis caused by Onchocerca lupi: an emerging zoonotic infection. Systematic review.

    PubMed

    Grácio, António J Santos; Richter, Joachim; Komnenou, Anastasia Th; Grácio, Maria Amélia

    2015-07-01

    Globalization has increased circulation of people, their food, livestock and pets in the world, and changes in the environment, climate and human behaviour have led to the rapid expansion of emerging infections throughout the world. One of the reasons of a new pathogen affecting humans is the passage from an animal to a human being. Onchocerca (O.) lupi, a filarial worm first described in a wolf in 1967, is an emerging pathogen which has been incriminated as the etiological agent for 205 canine, 2 feline and 18 human infections in Europe, Tunisia, Turkey, Iran and the USA. Most frequent findings in animals and humans are monolateral or asymmetrical variably painful subconjunctival swellings and nodules containing immature or mature worms affecting the eye and/or adjacent tissues accompanied by conjunctival hyperemia. Occasionally, subcutaneous nodules and masses affecting the spinal cord have been observed in humans. Diagnosis of O. lupi is achieved by microscopy of excised adult female worms which exhibit a particular cuticular structure and molecular analysis. Treatment consists in worm removal accompanied by antihelminthic, antibiotic and anti-inflammatory therapy.

  14. Protective responses against skin-dwelling microfilariae of Onchocerca lienalis in severe combined immunodeficient mice.

    PubMed Central

    Folkard, S G; Taylor, M J; Butcher, G A; Bianco, A E

    1997-01-01

    Inoculation of severe combined immunodeficient (SCID) mice with microfilariae of Onchocerca lienalis results in a sustained infection of the skin, extending for months beyond the point at which the parasites are eliminated from immunocompetent BALB/c controls. Reconstitution of SCID mice with spleen cells, thymocytes, or CD4+-cell-enriched splenocytes from naive BALB/c donors confers the ability to mount a protective immune response, leading to the rapid elimination of microfilariae. High levels of interleukin-5 and low levels of gamma interferon in the sera of reconstituted SCID mice during the destruction of microfilariae suggest that this protective immune response is directed by Th2 lymphocytes, mirroring that observed in immunocompetent controls. Unexpectedly, abbreviation of primary infections of unreconstituted SCID mice with the drug ivermectin induces resistance to reinfection with microfilariae at a level equivalent to that induced in secondarily infected, immunocompetent controls. In contrast to protection mediated by adoptive reconstitution, resistance induced by ivermectin-abbreviated infection occurs in the absence of T cells and in association with negligible levels of serum interleukin-5 and gamma interferon. This points to the activation of some alternative host defense mechanism that operates after the clearance of therapeutic levels of drug. Such a response could have important implications for the treatment of human onchocerciasis and may go some way in explaining the long-term suppression of microfilariae observed in patients after treatment with ivermectin. PMID:9199458

  15. Case report of an epidural cervical Onchocerca lupi infection in a 13-year-old boy.

    PubMed

    Chen, Tsinsue; Moon, Karam; deMello, Daphne E; Feiz-Erfan, Iman; Theodore, Nicholas; Bhardwaj, Ratan D

    2015-08-01

    A 13-year-old boy presented with fever and neck pain and stiffness, which was initially misdiagnosed as culture-negative meningitis. Magnetic resonance images of the brain and cervical spine demonstrated what appeared to be an intradural extramedullary mass at the C1-3 level, resulting in moderate cord compression, and a Chiari Type I malformation. The patient underwent a suboccipital craniectomy and a C1-3 laminectomy with intradural exploration for excisional biopsy and resection. The lesion containing the parasite was extradural, extending laterally through the C2-3 foramina. Inflammatory tissue secondary to Onchocerca lupi infection was identified, and treatment with steroids and doxycycline was initiated. At the 6-month follow-up, the patient remained asymptomatic, with MR images demonstrating a significant reduction in lesional size. However, 10 weeks postoperatively, the infection recurred, necessitating a second operation. The patient was treated with an additional course of doxycycline and is currently maintained on ivermectin therapy. This is the second reported case of cervical O. lupi infection in a human. In the authors' experience, oral doxycycline alone was insufficient in controlling the disease, and the addition of ivermectin therapy was necessary.

  16. 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

  17. Volvulus du grêle sur paquet d’ascaris: à propos d’un cas

    PubMed Central

    Diouf, Cheikh; Kane, Ahmed; Ndoye, Ndeye Aby; Ndour, Oumar; Faye-Fall, Aimé Lakh; Fall, Mbaye; Alumeti, Désiré Munyali; Ngom, Gabriel

    2016-01-01

    Nous rapportons un cas exceptionnel de volvulus nécrosé de l'intestin grêle dû à des ascaris adultes chez un enfant de 7 ans. A l'admission, l'enfant présentait le tableau d'occlusion intestinale qui évoluait depuis deux jours avec altération de l'état général. La radiographie de l'abdomen sans préparation retrouvait des niveaux hydroaériques de type grêlique et un aspect tigré évoquant le diagnostic d'une occlusion intestinale haute sur masse abdominale. Après la réanimation, le traitement chirurgical consistait en une laparotomie qui avait retrouvé un volvulus nécrosé de l'iléon terminale contenant des ascaris adultes. Une résection du grêle sur environ un mètre emportant le segment nécrosé suivie d'une iléostomie était réalisée. L'évolution a été favorable, l'anastomose iléo-colique fut réalisée quatre semaines plus tard. Au recul de deux ans l'enfant est indemne de tout symptôme. PMID:27795803

  18. Gallbladder Volvulus in a Patient with Type I Choledochal Cyst: A Case Report and Review of the Literature

    PubMed Central

    Younan, George; Schumm, Max

    2016-01-01

    Introduction. Gallbladder volvulus is a rare, potentially fatal condition unless diagnosed and treated early. Choledochal cysts are rare congenital malformations of the biliary tree predisposing to different pathologies and posing the risk of degradation into cholangiocarcinoma and gallbladder cancer. Dealing with both diseases at once has not been published yet in the literature. Presentation of Case. We report a case of gallbladder volvulus in an elderly female who happened to have a concomitant type I choledochal cyst. Treatment was achieved with a cholecystectomy and observation and follow-up of the choledochal cyst. Discussion. Prompt diagnosis and surgical management of gallbladder volvulus is important to avoid the morbidity and mortality of gangrenous cholecystitis and biliary peritonitis in a frail old population of patients. Precise clinical diagnosis, supplemented with specific imaging clues, helps in the diagnosis. Management of choledochal cysts is also surgical; however the timing of surgery is still a matter of debate. Conclusion. We describe in this report the first case of gallbladder volvulus in a patient with a choledochal cyst and propose a management algorithm of a very rare biliary tree pathology combination. PMID:27747125

  19. 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

  20. Onchocerca eberhardi n. sp. (Nematoda: Filarioidea) from sika deer in Japan; relationships between species parasitic in cervids and bovids in the Holarctic region.

    PubMed

    Uni, S; Bain, O; Agatsuma, T; Harada, M; Torii, H; Fukuda, M; Takaoka, H

    2007-09-01

    Onchocerca eberhardi n. sp. from the sika deer, Cervus nippon, in Japan is described. Adult worms lived in the carpal ligament; infection reached high levels (up to 25 female and 16 male worms in a single carpal limb). Skin dwelling microfilariae were mainly found in the ears. Prevalence of infection was 81% at the type locality, Mt. Sobo, in Kyushu. The new material was compared to the 31 species of Onchocerca presently known. Onchocerca eberhardi n. sp. females were characterized by a long slender anterior end and a thin esophagus < or =1 mm long with no or only a slight glandular region. The vulva was located near the level of the mid-esophagus and the cuticle had transverse external ridges and internal striae (two striae between adjoining ridges). The most similar species were O. stilesi (re-examined), O. lienalis, and to a lesser extent O. gutturosa, all from bovids (cattle). Two main lineages of Onchocerca are recognized in cervids with either primitive or with derived characteristics (as exemplified by the new species). The species in both lineages are not restricted to cervids but are also found in bovids in the Holarctic region, suggesting that the species diversified in the two host groups simultaneously, when these host groups lived in the some geographic area.

  1. 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...

  2. Small volume resuscitation with hypertonic sodium chloride solution in cattle undergoing surgical correction of abomasal volvulus.

    PubMed

    Sickinger, M; Doll, K; Roloff, N C; Halekoh, U

    2014-09-01

    A randomized clinical trial was conducted to compare the efficacy of rapid intravenous (IV) infusion of a 7.2% hypertonic saline solution with that of continuous application of an isotonic solution in stabilizing the circulation of cows with abomasal volvulus. Cattle treated with hypertonic saline had a significantly greater reduction in volume deficit within the first 10 min of therapy than cows treated with isotonic saline (from 5.9 ± 4.8 to 2.1 ± 4.4 L/100 kg vs. 7.0 ± 4.5 to 4.9 ± 3.8 L/100 kg, respectively). The central venous pressure (CVP) of the cows given the hypertonic saline rose within the first 10 min of therapy from 7.3 ± 3.5 to 10.8 ± 3.4 cm H2O, while the CVP of the cattle treated with isotonic saline did not increase significantly during this time. Sixty minutes after the start of the infusion, the CVP of the isotonic group was still significantly lower than that of the hypertonic group (9.5 ± 2.1 vs. 10.3 ± 3.3 cm H2O, respectively). Within the first 60 min, the base excess decreased from 5.5 ± 6.9 to 4.7 ± 6.2 mmol/L in the hypertonic group whereas it increased from 5.6 ± 5.7 to 6.8 ± 5.4 mmol/L in the isotonic group. These results suggest that for cows with abomasal volvulus, IV therapy with hypertonic saline may improve the haemodynamic and circulatory situation considerably faster and more effectively than continuous infusion with isotonic saline.

  3. The relationship between gastrointestinal motility and gastric dilatation-volvulus in dogs.

    PubMed

    Gazzola, Krista M; Nelson, Laura L

    2014-09-01

    Gastric dilatation-volvulus (GDV) is a devastating disease that most commonly affects large and giant-breed dogs. Though a number of risk factors have been associated with the development of GDV, the etiology of GDV remains unclear. Abnormal gastric motility patterns and delayed gastric emptying have been previously described in dogs following GDV. Work evaluating the effects of gastropexy procedures and changes to gastric motility after experimental GDV has not found the same changes as those found in dogs with naturally occurring GDV. Although the role of abnormal gastric motility in dogs with GDV will need to be clarified with additional research, such study is likely to be facilitated by improved access to and development of noninvasive measurement techniques for the evaluation of gastric emptying and other motility parameters. In particular, the availability of Food and Drug Administration-approved wireless motility devices for the evaluation of gastrointestinal motility is particularly promising in the study of GDV and other functional gastrointestinal diseases of large and giant-breed dogs.

  4. 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.

  5. 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

  6. Black flies (Diptera: Simuliidae) attracted to humans and water buffalos and natural infections with filarial larvae, probably Onchocerca sp., in northern Thailand.

    PubMed

    Takaoka, H; Choochote, W; Aoki, C; Fukuda, M; Bain, O

    2003-03-01

    Several Simulium species were investigated as to their biting habits and natural infections with filarial larvae at Ban Pan Fan, Chiang Mai Province, in northern Thailand. Female adults flies landing on or flighting around a human and a water buffalo were collected during the daytime from 06.00 to 19.00 hours on 22 June 2001. As a result, 217 S. nodosum, 86 S. asakoae and two S. nigrogilvum were obtained from a human attractant, and 416 S. nodosum, 25 S. nakhonense, 16 S. asakoae, four S. fenestratum and two S. nigrogilvum, from a water buffalo. The blood-feeding was confirmed only for S. nodosum and S. nigrogilvum on humans, and for S. nodosum and S. nakhonense on water buffalos. Dissections of these simuliids showed that S. nodosum was naturally infected with developing filarial larvae. Two types of microfilariae were distinguished but only one type of infective larvae. These larvae resembled Onchocerca suzukii, a parasite from a wild Japanese bovid, suggesting that an unknown Onchocerca species from ruminants was transmitted in Thailand. Infection rates with all stages of larvae and third-stage larvae were 2.3% (14/608) and 1.0% (6/608), respectively. This is the first report of natural infections of black flies with Onchocerca larvae in Southeast Asia, and the involved black fly species is shown to be not only anthropophilic but also zoophilic in this region.

  7. 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

  8. 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

  9. Levels of infection, pathology and nodule size of Onchocerca flexuosa (Nematoda: Onchocercidae) in red deer (Cervus elaphus) from northern Spain.

    PubMed

    Hidalgo, M R; Martínez, A; Carreño, R A; González, S; Ferreras, M C; Díez, N

    2015-05-01

    Between 2005 and 2007, the presence of Onchocerca flexuosa (Wedl, 1856) was discovered and investigated in 110 red deer (Cervus elaphus) shot in the Riaño Regional Hunting Reserve, in the province of León (north-western Spain). Nodules containing O. flexuosa were located in the dorsal region and flanks of the deer. These were collected and measured, and some adult parasites were extracted from the nodules and identified by morphology and by obtaining mitochondrial 12S rDNA sequences, which were identical to those of previously published sequences for O. flexuosa. Some nodules were prepared for histology, embedded in paraffin, sectioned and stained with haematoxylin-eosin. Histologically, the worms were found in several compartments separated by an infiltrated fibrous tissue. These compartments were inhabited by several females and males, surrounded by a fibrous capsule. A total of 85.45% (95% confidence interval (CI): 78.86-92.04%) of red deer were parasitized, with a mean intensity of 9.53 ± 12.27 nodules/host, ranging between 1 and 74 nodules/deer. Significant differences in prevalence and intensity of infection were found between young and adult red deer, and also between seasons. However, no significant differences between males and females were observed. Five hundred and ninety-seven nodules were measured (15.81 ± 3.94 mm) and classified by sizes into small ( < 10 mm), medium (10-20 mm) and large (>20 mm). No relation was found between the size of the nodules and the time of infection. The high values found in the studied parameters show that northern Spain is an area of high-intensity infection for deer.

  10. Volvulus grêlique sur hydatidose péritonéale: une cause rare d'occlusion

    PubMed Central

    Bouassria, Abdesslam; Mazine, Khalid; Elbouhaddouti, Hicham; Mouaqit, Ouadii; Ousadden, Abdelmalek; Mazaz, Khalid; Benjelloun, Elbachir; Taleb, Khalid Ait

    2014-01-01

    L'hydatidose péritonéale peut être primitive, hématogène ou hétérotopique, comme elle peut être secondaire et résulte de la fissuration d'un kyste hydatique, le plus souvent hépatique. Cliniquement polymorphe, elle peut se révéler par des douleurs abdominales ou par la palpation d'une masse abdominale. Nous rapportons le cas d'une patiente chez qui l'hydatidose péritonéale était révélée par un accident occlusif: un volvulus grêlique dû à un volumineux kyste hydatique mésentérique. Le traitement de l'hydatidose péritonéale est chirurgical, couplé à un traitement médical à base d'albendazole. PMID:25400846

  11. Multiple risk factors for the gastric dilatation-volvulus syndrome in dogs: a practitioner/owner case-control study.

    PubMed

    Glickman, L T; Glickman, N W; Schellenberg, D B; Simpson, K; Lantz, G C

    1997-01-01

    A study was conducted of 101 dogs (i.e., case dogs) that had acute episodes of gastric dilatation-volvulus (GDV) and 101 dogs (i.e., control dogs) with nonGDV-related problems. The control dogs were matched individually to case dogs by breed or size, and age. Predisposing factors that significantly (p less than 0.10) increased a dog's risk of GDV were male gender, being underweight, eating one meal daily, eating rapidly, and a fearful temperament. Predisposing factors that decreased the risk of GDV significantly were a "happy" temperament and inclusion of table foods in a usual diet consisting primarily of dry dog food. The only factor that appeared to precipitate an acute episode of GDV was stress.

  12. Sigmoid colon morphology in the population groups of Durban, South Africa, with special reference to sigmoid volvulus.

    PubMed

    Madiba, T E; Haffajee, M R

    2011-05-01

    Sigmoid volvulus demonstrates geographical, racial, and gender variation. This autopsy study was undertaken to establish morphological differences of the sigmoid colon and its mesocolon in which the length and other characteristics were assessed. A total of 590 cadavers were examined (403 African, 91 Indian, and 96 White). Length and height of the sigmoid colon and mesocolon were significantly longer in Africans, and mesocolon root was significantly narrower in Africans. Mesocolic ratio for Africans, Indians, and Whites was 1.1 ± 0.8, 1.8 ± 0.7, and 1.9 ± 1.0, respectively. Africans had a significantly high incidence of redundant sigmoid colon with the long-narrow type and suprapelvic position predominating (P = 0.003); the opposite applied to the classic type. There was no difference in sigmoid colon length, mesocolon height, and width between males and females in all population groups. Among Africans, the long-narrow type was more common in males, and the classic and long-broad types were more common in females. Splaying of teniae coli and thickening of the mesentery were more common in Africans. Tethering of the sigmoid colon to the posterior abdominal wall was less common in Africans compared with other population groups. In conclusion, the sigmoid colon was longer, and the sigmoid mesocolon root was narrower in Africans compared with the other population groups, and the sigmoid colon had a suprapelvic disposition among Africans. In Africans, the sigmoid colon was longer in males with a long-narrow shape. These differences may explain geographical and racial differences in sigmoid volvulus.

  13. 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

  14. Volvulus gastrique aigu sur éventration diaphragmatique de l'adulte: à propos d'un cas et revue de la littérature

    PubMed Central

    Guèye, Mohamadou Lamine; Touré, Alpha Oumar; Thiam, Ousmane; Seck, Mamadou; Cissé, Mamadou; Kâ, Ousmane; Dieng, Madieng; Touré, Cheikh Tidiane

    2015-01-01

    Le volvulus gastrique aigu sur éventration diaphragmatique est une affection rare et une urgence diagnostique et thérapeutique. Sa présentation clinique est peu spécifique et la tomodensitométrie abdominale permet de confirmer le diagnostic. Nous rapportons le cas d'un patient de 22 ans qui présentaitun syndrome occlusif et une voussure épigastrique. A la radiographie de l'Abdomen Sans Préparation, on notait 2 niveaux hydro-aériques sous la coupole diaphragmatique gauche qui était surélevée. Une dévolvulation et une gastrectomie atypique ont été réalisées devant un volvulus gastrique aigu avec nécrose du fundus mis en évidence à la laparotomie. Les suites opératoires ont été simples. PMID:26161223

  15. A Peterson's hernia and subsequent small bowel volvulus: surgical reconstruction utilizing transverse colon as a new Roux-en-Y limb - 1 case.

    PubMed

    Jang, Jae Seong; Shin, Dong Gue

    2013-12-01

    Peterson's hernia is an internal hernia that can occur after Roux-en-Y anastomosis. It often accompanies small bowel volvulus and is prone to strangulation. Reconstruction of intestinal continuity after massive small bowel resection in a patient who undergoes near total gastrectomy and Roux-en-Y anastomosis can be difficult. A 74-year-old man who had undergone a near total gastrectomy and Roux-en-Y gastrojejunostomy for stomach cancer presented with abdominal pain. The preoperative computed tomography showed strangulated small bowel volvulus. During the emergent laparotomy, we found a strangulated Peterson's hernia with small bowel volvulus. After resection of the necrotized intestine, we made a new Roux-en-Y anastomosis connecting the remnant stomach and the jejunum with a transverse colon segment. We were safely able to connect the remnant stomach and the jejunum by making a new Roux-en-Y anastomosis utilizing a transverse colon segment as a new Roux-limb by two stage operation.

  16. 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...

  17. 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

  18. 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 Central

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

    2013-01-01

    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

  19. 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

  20. Small bowel volvulus after transabdominal preperitoneal hernia repair due to improper use of V-Loc™ barbed absorbable wire – do we always “read the instructions first”?

    PubMed Central

    Filser, Joerg; Reibetanz, Joachim; Krajinovic, Katica; Germer, Christoph-Thomas; Dietz, Ulrich Andreas; Seyfried, Florian

    2015-01-01

    Introduction Transabdominal preperitoneal endoscopic hernia repair (TAPP) is part of primary surgical health care. While both, the reported recurrence rate and procedure specific morbidity are consistently low, rare serious complications occur. Presentiation of case A 36-year-old male patient developed bowel obstruction three days after both-sided TAPP for inguinal hernia repair. A computer tomography scan of the abdomen revealed a small bowel volvulus in the right lower quadrant of the abdomen requiring urgent revisional surgery. Intraoperatively, the small bowel and its mesenterial vessels were found to be twisted around a 5 cm long V-Loc™ barbed absorbable suturing wire. After successful laparoscopic adhesiolysis, removal of the wire and detorquing of the bowel conglomerate, resection of small intestine was not necessary. The patient's further postoperative recovery was uneventful. Discussion Due to the barbed configuration of the V-Loc™ wire, a gapless continuous suturing of the peritoneum without laparoscopic knotting is easily and fast to accomplish. In this case the recommendation of the manufacturer to shorten the wire was not strictly followed and neither had the suture stump been extraperitonealized in order to avoid such rare complications. Conclusion Surgeons need to be aware of relevant “tricks and traps” of routinely performed procedures and have to know all tools and material they use very well. This case may therefore increase our attention when it comes to little things which actually do matter. PMID:25704567

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. Risk comparison

    SciTech Connect

    Coppola, A.; Hall, R.E.

    1981-02-01

    This report presents data for the comparison of societal risk from natural and man-made hazards. Only fatalities resulting from the hazards are used in the comparison, with the data and the comparative analysis taken from current literature. In comparing societal risks for most of the hazards, both expected values and frequency vs consequence curves are presented. For a subset of hazards, notably the power generation technologies (nuclear, coal, oil, and gas), which have not exhibited high consequence events (catastrophes), the comparisons are based on estimated expected values only. Individual risk data are presented in two ways, a probability of death within a year and the amount of life shortening of an average life span. 27 refs., 21 figs., 25 tabs.

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  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 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%.

  14. In a bovine model of onchocerciasis, protective immunity exists naturally, is absent in drug-cured hosts, and is induced by vaccination

    PubMed Central

    Tchakouté, Virginia L.; Graham, Simon P.; Jensen, Siv Aina; Makepeace, Benjamin L.; Nfon, Charles K.; Njongmeta, Leo M.; Lustigman, Sara; Enyong, Peter A.; Tanya, Vincent N.; Bianco, Albert E.; Trees, Alexander J.

    2006-01-01

    Onchocerciasis (river blindness) is a major parasitic disease of humans in sub-Saharan Africa caused by the microfilarial stage of the nematode Onchocerca volvulus. Using Onchocerca ochengi, a closely related species which infects cattle and is transmitted by the same black fly vector (Simulium damnosum sensu lato) as O. volvulus, we have conducted longitudinal studies after either natural field exposure or experimental infection to determine whether, and under what circumstances, protective immunity exists in onchocerciasis. On the basis of the adult worm burdens (nodules) observed, we determined that cattle reared in endemic areas without detectable parasites (putatively immune) were significantly less susceptible to heavy field challenge than age-matched, naïve controls (P = 0.002), whereas patently infected cattle, cured of infection by adulticide treatment with melarsomine, were fully susceptible. Cattle immunized with irradiated third-stage larvae were significantly protected against experimental challenge (100% reduction in median nodule load, P = 0.003), and vaccination also conferred resistance to severe and prolonged field challenge (64% reduction in median nodule load, P = 0.053; and a significant reduction in microfilarial positivity rates and density, P < 0.05). These results constitute evidence of protective immunity in a naturally evolved host–Onchocerca sp. relationship and provide proof-of-principle for immunoprophylaxis under experimental and field conditions. PMID:16585501

  15. Antibiotic chemotherapy of onchocerciasis: in a bovine model, killing of adult parasites requires a sustained depletion of endosymbiotic bacteria (Wolbachia species).

    PubMed

    Gilbert, Jeffrey; Nfon, Charles K; Makepeace, Benjamin L; Njongmeta, Leo M; Hastings, Ian M; Pfarr, Kenneth M; Renz, Alfons; Tanya, Vincent N; Trees, Alexander J

    2005-10-15

    Development of a drug lethal to adult Onchocerca volvulus (i.e., macrofilaricide) is a research priority for the control of human onchocerciasis. Using bovine O. ochengi infections, we investigated the effects of oxytetracycline administered in a short intensive regimen (SIR; 10 mg/kg daily for 14 days), compared with a prolonged intermittent regimen (PIR; 20 mg/kg monthly for 6 months) or a combination of both (COM), on the viability of adult worms and their endosymbiotic bacteria (Wolbachia species). The long-term treatments eliminated >80% (COM) or >60% (PIR) of adult female worms (P<.001), and the COM regimen effected a sustained depletion of Wolbachia organisms. Conversely, SIR was not macrofilaricidal and only transiently depleted Wolbachia densities, which repopulated worm tissues by 24 weeks after treatment. These results unequivocally demonstrate the macrofilaricidal potential of tetracyclines against Onchocerca infection and suggest that intermittent, protracted administration will be more effective than continuous shorter term treatment.

  16. Parasites of urological importance.

    PubMed

    Kehinde, Elijah O; Anim, Jehoram T; Hira, Parsotam R

    2008-01-01

    With the world increasingly becoming a global village, transnational and transcontinental migration has become the order of the day. It is expected that migrants will take with them some diseases (including parasites) which are normally endemic in their countries of origin, to their host countries. Similarly, environmental changes that result from development of water resources, global warming, growth and migration of population can facilitate the spread of parasites. In this review we describe the epidemiology, presentation, diagnosis and treatment options of parasites that urologists may encounter. Notably among these parasites are Schistosoma haematobium, Echinococcus granulosus, Wuchereria bancrofti and Onchocerca volvulus.

  17. 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

  18. 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.

  19. 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

  20. An atypical microfilaria in blood samples from inhabitants of Brazilian Amazon.

    PubMed

    Adami, Y L; Moraes, M A P; Lanfredi, R M; Maia-Herzog, M

    2008-12-01

    An unidentified microfilaria sharing characteristics with Mansonella ozzardi and Onchocerca volvulus was detected in blood samples from seven human volunteers, inhabitants of a community in the border of Amazonas and Acre State. They were detected during epidemiological studies carried out in some communities along Antimary, Acre, and Purus Rivers in the Brazilian Amazon. The most striking difference was presented in the shape of the cephalic space from this microfilaria which was different from those of M. ozzardi and with similarities to O. volvulus in this region, but no remarkable differences were observed at the caudal region. More accurate studies are being carried out in order to provide additional data and supporting evidences before establishment of a new species can be done. PMID:18779979

  1. 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…

  2. 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

  3. A temporary focus of savanna species of the Simulium damnosum complex in the forest zone of Liberia.

    PubMed

    Garms, R; Cheke, R A; Sachs, R

    1991-09-01

    Savanna species of the Simulium damnosum complex, the major vectors of the blinding savanna type of onchocerciasis, were considered to be rare in Liberia, until the dry season of 1988. In 1988 they became a serious nuisance, biting people at the Bong iron ore mine within the rain forest zone. S. damnosum s.str. and S. sirbanum were found breeding, in association with S. adersi a non man-biting savanna species, in a stream emerging from the mine's tailings pond. The local forest species were extremely rare in this stream. The water of the stream was characterized by an increased hardness and higher temperatures in comparison with those of natural watercourses in the area. The mass occurrence of flies was probably related to expansions of the tailings ponds, when rich nutrition was provided for the blackfly larvae by the decaying forests submerged by the rising water levels. The phenomenon did not recur in 1989 when only a few savanna flies were caught, and none were seen in the dry season of 1990. Although it is not known why the artificial environment of the tailings ponds was so attractive for the savanna species the events clearly demonstrated that savanna flies seasonally invading the area, possibly aided by the northeasterly harmattan winds, can become established in the rain forest zone if suitable conditions are met. No infections with Onchocerca volvulus were found in more than 1000 flies caught by vector collectors but, after experimental infection with the local forest strain, a few parasites developed to the infective stage. As yet there is no evidence that the occurrence of savanna flies in the rain forest zone of Liberia was of epidemiological significance.

  4. 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

  5. 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.

  6. 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.

  7. 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

  8. 1997 MWD comparison tables

    SciTech Connect

    Wiseman, K.

    1997-05-01

    This year`s MWD Comparison Tables include a Quick Reference Guide listing MWD sensors by collar size for each manufacturer. Following the Quick Reference Guide are the comparison tables, which list general, directional, gamma ray, resistivity, density and neutron data for each tool. The MWD Tables should only be used as a reference source. System specifications frequently change as tools are refined and developed. Consult MWD marketing representatives prior to making final tool selections. A contact key for all the companies listed in the tables appears on the last page.

  9. 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.…

  10. 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…

  11. Motives for Social Comparison.

    ERIC Educational Resources Information Center

    Helgeson, Vicki S.; Mickelson, Kristin D.

    1995-01-01

    A set of motive statements for social comparison was elicited from one group of subjects and then rated in terms of usefulness by a second group of subjects. Analysis of these statements revealed six motives in response to two different hypothetical scenarios: self-evaluation, common bond, self-improvement, self-enhancement, altruism, and…

  12. Comparison of five benchmarks

    SciTech Connect

    Huss, J. E.; Pennline, J. A.

    1987-02-01

    Five benchmark programs were obtained and run on the NASA Lewis CRAY X-MP/24. A comparison was made between the programs codes and between the methods for calculating performance figures. Several multitasking jobs were run to gain experience in how parallel performance is measured.

  13. 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

  14. 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.

  15. 1996 MWD comparison tables

    SciTech Connect

    Gastineau, J.

    1996-05-01

    Petroleum Engineer International`s ninth annual Measurement While Drilling Tables compare the different operating capabilities of survey and logging tools from 13 MWD vendors. This year`s MWD Comparison Tables include a Quick Reference Guide listing MWD sensors by collar size for each manufacturer. Following the Quick Reference Guide are the comparison tables, listing general, directional, gamma ray, resistivity, density and neutron data for each tool. The MWD Tables should serve only as a reference source. System specifications can change rapidly as tools are refined and developed. Consultation with MWD marketing representatives before making a final tool selection is recommended. A contact key for all of the companies listed in the tables is provided.

  16. 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.

  17. 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.

  18. NTP comparison process

    NASA Astrophysics Data System (ADS)

    Corban, Robert

    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.

  19. 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.

  20. Notes on the Comparison Class

    NASA Astrophysics Data System (ADS)

    Solt, Stephanie

    This paper investigates the role of comparison classes in the semantics of gradable adjectives in the positive form, focusing on the case where the comparison class is expressed overtly via a for-phrase (e.g. John is tall for a jockey). Two central questions are addressed: what information does the comparison class provide, and how is this information integrated compositionally? It is shown that the standard of comparison invoked by the positive form can be analyzed as a range of values whose width is based on the degree of dispersion in the comparison class. Compositionally, the comparison class can be analyzed as an argument of a null positive morpheme (contra Kennedy [13]), in parallel to recent proposals for the superlative (e.g. Heim [9]). The implications of the analysis for the choice between degree- and delineation-based analyses of gradable adjectives are discussed.

  1. 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

  2. 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.

  3. 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

  4. Filariasis in the Igwun River Basin, Nigeria: an epidemiological and clinical study with a note on the vectors.

    PubMed

    Udonsi, J K

    1988-02-01

    In a cross-sectional, epidemiological and parasitological study of human filariasis, 845 individuals were examined in settlements along the Igwun Basin, Imo State, Nigeria. Four different filarial nematode species were identified. Two hundred and fifty-six (30.3%) of the individuals examined were positive for Onchocerca volvulus, 113 (13.4%) for Mansonella perstans, 76 (9.6%) for Wuchereria bancrofti and 77 (9.1%) for Loa loa. Microfilarial rates increased with age of individuals and showed a tendency towards higher prevalence rates in males than in females. The intensity of O. volvulus infection was high, with the highest microfilarial density of 44 mf mg-1 snip which occurred in the 40-49-year-old individuals. In W. bancrofti and L. loa infections, infections of over 1000 mf 20 ml-1 blood were recorded in 15.8% and 19.5% of individuals, respectively. Observed clinical signs were associated with inflammatory, lympho-obstructive and ocular manifestations. In M. perstans infections all clinical cases were inflammatory. In W. bancrofti, 44.4% of clinical cases were inflammatory, and lympho-obstructive manifestations consisted of 23.8% chyluria, 12.7% hydrocele and 19.1% elephantiasis. In L. loa infections all clinical cases were inflammatory with indications of Calabar swellings. In O. volvulus infections 23.5% of clinical cases were inflammatory, while 76.5% showed ocular manifestations. The absence of blindness despite high O. volvulus infection rates was remarkable. The presence of potential insect vectors and the occurrence of clinical signs are indications of active transmissions.

  5. Repositioning of an existing drug for the neglected tropical disease Onchocerciasis

    PubMed Central

    Gloeckner, Christian; Garner, Amanda L.; Mersha, Fana; Oksov, Yelena; Tricoche, Nancy; Eubanks, Lisa M.; Lustigman, Sara; Kaufmann, Gunnar F.; Janda, Kim D.

    2010-01-01

    Onchocerciasis, or river blindness, is a neglected tropical disease caused by the filarial nematode Onchocerca volvulus that affects more than 37 million people, mainly in third world countries. Currently, the only approved drug available for mass treatment is ivermectin, however, drug resistance is beginning to emerge, thus, new therapeutic targets and agents are desperately needed to treat and cure this devastating disease. Chitin metabolism plays a central role in invertebrate biology due to the critical structural function of chitin for the organism. Taken together with its absence in mammals, targeting chitin is an appealing therapeutic avenue. Importantly, the chitinase OvCHT1 from O. volvulus was recently discovered, however, its exact role in the worm’s metabolism remains unknown. A screening effort against OvCHT1 was conducted using the Johns Hopkins Clinical Compound Library that contains over 1,500 existing drugs. Closantel, a veterinary anthelmintic with known proton ionophore activities, was identified as a potent and specific inhibitor of filarial chitinases, an activity not previously reported for this compound. Notably, closantel was found also to completely inhibit molting of O. volvulus infective L3 stage larvae. Closantel appears to target two important biochemical processes essential to filarial parasites. To begin to unravel closantel’s effects, a retro-fragment-based study was used to define structural elements critical for closantel’s chitinase inhibitor function. As resources towards the development of new agents that target neglected tropical diseases are scant, the finding of an existing drug with impact against O. volvulus provides promise in the hunt for new therapies against river blindness. PMID:20142509

  6. 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.

  7. 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.

  8. 1994 MWD comparison tables

    SciTech Connect

    Not Available

    1994-05-01

    Twenty-eight measurement while drilling tools are listed in this year's MWD Comparison Tables. Updated data on tools listed last year and data on five new tools provide a convenient guide for choosing MWD systems. Future MWD technologies include sonic tools and tools that make measurements ahead of the bit. For the seventh year, Petroleum Engineer International presents the Measurement While Drilling (MWD) Tables comparing a variety of available tools from many different vendors. The 1994 Tables include two additional companies and five new MWD tools not found in last year's Tables. However, the tables should serve only as a reference source. System specifications can change rapidly as tools are refined and new technologies develop. Operators and contractors should consult designated MWD marketing representatives before making a final tool selection.

  9. 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,…

  10. 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…

  11. 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

  12. 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

  13. Data storage technology comparisons

    NASA Technical Reports Server (NTRS)

    Katti, Romney R.

    1990-01-01

    The role of data storage and data storage technology is an integral, though conceptually often underestimated, portion of data processing technology. Data storage is important in the mass storage mode in which generated data is buffered for later use. But data storage technology is also important in the data flow mode when data are manipulated and hence required to flow between databases, datasets and processors. This latter mode is commonly associated with memory hierarchies which support computation. VLSI devices can reasonably be defined as electronic circuit devices such as channel and control electronics as well as highly integrated, solid-state devices that are fabricated using thin film deposition technology. VLSI devices in both capacities play an important role in data storage technology. In addition to random access memories (RAM), read-only memories (ROM), and other silicon-based variations such as PROM's, EPROM's, and EEPROM's, integrated devices find their way into a variety of memory technologies which offer significant performance advantages. These memory technologies include magnetic tape, magnetic disk, magneto-optic disk, and vertical Bloch line memory. In this paper, some comparison between selected technologies will be made to demonstrate why more than one memory technology exists today, based for example on access time and storage density at the active bit and system levels.

  14. {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.

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. Ocular changes with oral and transepidermal diethylcarbamazine therapy of onchocerciasis.

    PubMed

    Taylor, H R; Greene, B M

    1981-07-01

    Twenty men with moderate infection of Onchocerca volvulus were studied in a double-masked, controlled clinical trial to compare the safety and efficacy of oral diethylcarbamazine (DEC) with topical DEC lotion. Visual acuity and colour vision did not alter during the 6 months of observation, although 2 patients receiving DEC lotion and 3 patients receiving oral DEC developed either visual field constriction or optic atrophy. Fluffy corneal opacities were common in both groups. Intraocular microfilariae also appeared in both groups but to a greater extent in those receiving DEC lotion. New chorioretinal changes developed in 4 men receiving lotion and in only 1 receiving tablets. It is concluded that DEC lotion offers no advantage over tablets in the treatment of ocular onchocerciasis and in fact may be associated with more ocular complications than the conventional oral treatment.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. Filariasis in Gongola State Nigeria. I: Clinical and parasitological studies in Mutum-Biyu District.

    PubMed

    Akogun, O B

    1992-08-01

    A total of 2,552 persons living in 9 villages along the Benue river valley, Mutum Biyu district of Gongola State, Nigeria were examined between October and December 1989 for filariasis. It is the first time a filariasis survey will be carried out in this state. 276 (10.8%) had Wuchereria bancrofti, 50 (2.0%) had Loa loa, 281 (11.0%) were positive for Mansonella perstans while 12 (0.5%) were positive for Onchocerca volvulus. Villages located near the Benue river had higher prevalence rates than those further away. Dermatitis and hydrocoele were common and clinical manifestations were associated with parasite types. Clinical symptoms without microfilaremia and microfilaremia without clinical symptoms were also observed.

  11. Filariasis in Gongola State Nigeria. I: Clinical and parasitological studies in Mutum-Biyu district.

    PubMed

    Akogun, O B

    1991-01-01

    A total of 2552 persons living in 9 villages along the Benue river valley, Mutum-Biyu district of Gongola State, Nigeria were examined between October and December 1989 for filariasis. It is the first time a filariasis survey will be carried out in this State. 276 (10.8%) had Wuchereria bancrofti, 50 (2.0%) had Loa loa, 281 (11.0%) were positive for Mansonella perstans while 12 (0.5%) were positive for Onchocerca volvulus. Villages located near the Benue river had higher prevalence rates than those further away. Dermatitis and hydrocoele were common and clinical manifestations were associated with parasite types. Clinical symptoms without microfilaremia and microfilaremia without clinical symptoms were also observed. The study will fill the gap in our knowledge of filariasis in this part of Nigeria.

  12. [Apropos of 5 new cases of onchocerciasis edema].

    PubMed

    Nozais, J P; Caumes, E; Datry, A; Bricaire, F; Danis, M; Gentilini, M

    1997-01-01

    We report 5 cases of onchocerciasis presenting as limb's swelling collected in the tropical disease unit of a parisian hospital between 1982 and 1993. They are 5 men which have lived between 3 weeks and 4 years in forested areas of Cameroon in four cases and Côte d'Ivoire in one case. The incubation period varied from 5 months to 2 years. The limb oedema was always located to one arm. It was associated with a blood eosinophilia above 2000/mm3 in 4 of 5 patients. The skin detection of microfilaria of Onchocerca volvulus was positive in every case. The serodiagnostic tests were negative for indirect immunoflurescent assay and immunoelectrophoresis with exception of one patient. These patients were cured with ivermectine and/or diethylcarbamazine. In addition, 26 other cases described in the literature are discussed. PMID:9507765

  13. On the Benefit of Dimensional Comparisons

    ERIC Educational Resources Information Center

    Pohlmann, Britta; Moller, Jens

    2009-01-01

    People not only use social comparisons to evaluate their abilities, they also engage in dimensional comparisons, comparing their own achievement in different domains. Processes of dimensional comparison have contrasting effects on subject-specific self-concepts: downward dimensional comparisons result in higher self-concept in the…

  14. Do ants make direct comparisons?

    PubMed

    Robinson, Elva J H; Smith, Faith D; Sullivan, Kathryn M E; Franks, Nigel R

    2009-07-22

    Many individual decisions are informed by direct comparison of the alternatives. In collective decisions, however, only certain group members may have the opportunity to compare options. Emigrating ant colonies (Temnothorax albipennis) show sophisticated nest-site choice, selecting superior sites even when they are nine times further away than the alternative. How do they do this? We used radio-frequency identification-tagged ants to monitor individual behaviour. Here we show for the first time that switching between nests during the decision process can influence nest choice without requiring direct comparison of nests. Ants finding the poor nest were likely to switch and find the good nest, whereas ants finding the good nest were more likely to stay committed to that nest. When ants switched quickly between the two nests, colonies chose the good nest. Switching by ants that had the opportunity to compare nests had little effect on nest choice. We suggest a new mechanism of collective nest choice: individuals respond to nest quality by the decision either to commit or to seek alternatives. Previously proposed mechanisms, recruitment latency and nest comparison, can be explained as side effects of this simple rule. Colony-level comparison and choice can emerge, without direct comparison by individuals.

  15. Do ants make direct comparisons?

    PubMed Central

    Robinson, Elva J.H.; Smith, Faith D.; Sullivan, Kathryn M.E.; Franks, Nigel R.

    2009-01-01

    Many individual decisions are informed by direct comparison of the alternatives. In collective decisions, however, only certain group members may have the opportunity to compare options. Emigrating ant colonies (Temnothorax albipennis) show sophisticated nest-site choice, selecting superior sites even when they are nine times further away than the alternative. How do they do this? We used radio-frequency identification-tagged ants to monitor individual behaviour. Here we show for the first time that switching between nests during the decision process can influence nest choice without requiring direct comparison of nests. Ants finding the poor nest were likely to switch and find the good nest, whereas ants finding the good nest were more likely to stay committed to that nest. When ants switched quickly between the two nests, colonies chose the good nest. Switching by ants that had the opportunity to compare nests had little effect on nest choice. We suggest a new mechanism of collective nest choice: individuals respond to nest quality by the decision either to commit or to seek alternatives. Previously proposed mechanisms, recruitment latency and nest comparison, can be explained as side effects of this simple rule. Colony-level comparison and choice can emerge, without direct comparison by individuals. PMID:19386652

  16. Deforestation and the spatio-temporal distribution of savannah and forest members of the Simulium damnosum complex in southern Ghana and south-western Togo.

    PubMed

    Wilson, M D; Cheke, R A; Flasse, S P J; Grist, S; Osei-Ateweneboana, M Y; Tetteh-Kumah, A; Fiasorgbor, G K; Jolliffe, F R; Boakye, D A; Hougard, J M; Yameogo, L; Post, R J

    2002-01-01

    Spatio-temporal data on cytotaxonomic identifications of larvae of different members of the Simulium damnosum complex collected from rivers in southern Ghana and south-western Togo from 1975 until 1997 were analysed. When the data were combined, the percentages of savannah blackflies (S. damnosum sensu stricto and S. sirbanum) in the samples were shown to have been progressively increasing since 1975. The increases were statistically significant (P < 0.001), but the rates of increase were not linear. Further analyses were conducted according to the collection seasons and locations of the samples, to account for possible biases such as savannah flies occurring further south in the dry season or a preponderance of later samples from northern rivers having more savannah flies. These analyses showed that the increasing trend was statistically significant (P < 0.0001) only during the periods April to June and October to December. The presence of adult savannah flies carrying infective larvae (L3) indistinguishable from those of Onchocerca volvulus in the study zone was confirmed by examinations of captured flies. The percentages of savannah flies amongst the human-biting populations and the percentages with L3s in the head were higher during dry seasons than wet seasons and the savannah species were found furthest south (5 degrees 25'N) in the dry season. Comparisons of satellite images taken in 1973 and 1990 over a study area in south-western Ghana encompassing stretches of the Tano and Bia rivers demonstrated that there have been substantial increases in urban and savannah areas, at the expense of forest. This was so not only for the whole images but also for subsamples of the images taken at 1, 2, 4, 8 and 16 km distant from sites alongside the River Tano. At every distance from the river, the percentages of pixels classified as urban or savannah have increased in 1990 compared with 1973, while those classified as degraded or dense forest have decreased. The

  17. 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.

  18. 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

  19. 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

  20. 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

  1. 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.

  2. International Comparisons and Educational Reform.

    ERIC Educational Resources Information Center

    Purves, Alan C., Ed.

    Increasingly over the past decade there have appeared in the press bar graphs comparing the performance of U.S. students with their counterparts in other countries. Usually these graphs have been accompanied by dire warnings and pointing fingers. The main source of the data on international comparisons has been the International Association for…

  3. 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…

  4. A comparison of five benchmarks

    NASA Technical Reports Server (NTRS)

    Huss, Janice E.; Pennline, James A.

    1987-01-01

    Five benchmark programs were obtained and run on the NASA Lewis CRAY X-MP/24. A comparison was made between the programs codes and between the methods for calculating performance figures. Several multitasking jobs were run to gain experience in how parallel performance is measured.

  5. 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.

  6. Metric-Free Distributional Comparisons.

    ERIC Educational Resources Information Center

    Haertel, Edward H.; And Others

    Two methods are presented for comparing distributions, such as achievement test score distributions, for distinctly different groups of persons in such a way that the comparison will not be influenced by the particular metric of the test being used. Both methods use percentile scores. One method, attributed to Flanagan, fits a straight line to the…

  7. Comparison of Air Temperature Calibrations

    NASA Astrophysics Data System (ADS)

    Heinonen, M.; Anagnostou, M.; Bartolo, J.; Bell, S.; Benyon, R.; Bergerud, R. A.; Bojkovski, J.; Böse, N.; Dinu, C.; Smorgon, D.; Flakiewicz, K.; Martin, M. J.; Nedialkov, S.; Nielsen, M. B.; Oğuz Aytekin, S.; Otych, J.; Pedersen, M.; Rujan, M.; Testa, N.; Turzó-András, E.; Vilbaste, M.; White, M.

    2014-07-01

    European national metrology institutes use calibration systems of various types for calibrating thermometers in air. These were compared to each other for the first time in a project organized by the European Association of National Metrology Institutes (EURAMET). This EURAMET P1061 comparison project had two main objectives: (1) to study the equivalence of calibrations performed by different laboratories and (2) to investigate correlations between calibration methods and achievable uncertainties. The comparison was realized using a pair of 100 platinum resistance thermometer probes connected to a digital thermometer bridge as the transfer standard. The probes had different dimensions and surface properties. The measurements covered the temperature range between and , but each laboratory chose a subrange most relevant to its scope and performed measurements at five nominal temperature points covering the subrange. To enable comparison between the laboratories, comparison reference functions were determined using weighted least-squares fitting. Various effects related to variations in heat transfer conditions were demonstrated but clear correlations to specific characteristics of calibration system were not identified. Calibrations in air and liquid agreed typically within at and . Expanded uncertainties determined by the participants ranged from to and they were shown to be realistic in most cases.

  8. 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…

  9. The cosmic code comparison project

    NASA Astrophysics Data System (ADS)

    Heitmann, Katrin; Lukić, Zarija; Fasel, Patricia; Habib, Salman; Warren, Michael S.; White, Martin; Ahrens, James; Ankeny, Lee; Armstrong, Ryan; O'Shea, Brian; Ricker, Paul M.; Springel, Volker; Stadel, Joachim; Trac, Hy

    2008-10-01

    Current and upcoming cosmological observations allow us to probe structures on smaller and smaller scales, entering highly nonlinear regimes. In order to obtain theoretical predictions in these regimes, large cosmological simulations have to be carried out. The promised high accuracy from observations makes the simulation task very demanding: the simulations have to be at least as accurate as the observations. This requirement can only be fulfilled by carrying out an extensive code verification program. The first step of such a program is the comparison of different cosmology codes including gravitational interactions only. In this paper, we extend a recently carried out code comparison project to include five more simulation codes. We restrict our analysis to a small cosmological volume which allows us to investigate properties of halos. For the matter power spectrum and the mass function, the previous results hold, with the codes agreeing at the 10% level over wide dynamic ranges. We extend our analysis to the comparison of halo profiles and investigate the halo count as a function of local density. We introduce and discuss ParaView as a flexible analysis tool for cosmological simulations, the use of which immensely simplifies the code comparison task.

  10. 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

  11. 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

  12. 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

  13. 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

  14. Chitinase is stored and secreted from the inner body of microfilariae and has a role in exsheathment in the parasitic nematode Brugia malayi

    PubMed Central

    Wu, Yang; Preston, Gillian; Bianco, Albert E.

    2008-01-01

    Chitinase expression in microfilariae of the parasitic nematode Brugia malayi (B. malayi, Bm) is coincidental with the onset of their infectivity to mosquitoes. An antibody raised to Onchocerca volvulus (O. volvulus, Ov) infective-stage larval chitinase (Ov-CHI-1) was specifically reactive against B. malayi microfilarial chitinase and was used to study the localization of chitinase in B. malayi during microfilarial development and transmission to the insect vector. Immuno-electron microscopy (IEM) was used to demonstrate that the chitinase was confined to the inner body of the microfilariae and furthermore that chitinase was only present in sheathed microfilarial species, although the inner body is present in all species. Observation using the IEM implicates two distinct routes of chitinase secretion from the inner body, via either the pharyngeal thread, or during transmission of the microfilariae to the vector, contained in vesicle-like structures. Many morphological studies have described the structure of the inner body, but no function has been assigned to it as of yet. Although it has been commented that the cells surrounding the inner body and pharyngeal thread are those destined to become the intestine and pharynx and that the inner body represents a store of material. Our studies suggest that chitinase is one such product stored in the inner body and that it is secreted during the exsheathment of the microfilaria in the mosquito. PMID:18611418

  15. Wolbachia endosymbionts induce neutrophil extracellular trap formation in human onchocerciasis

    PubMed Central

    Tamarozzi, Francesca; Turner, Joseph D.; Pionnier, Nicolas; Midgley, Angela; Guimaraes, Ana F.; Johnston, Kelly L.; Edwards, Steven W.; Taylor, Mark J.

    2016-01-01

    The endosymbiotic bacteria, Wolbachia, induce neutrophilic responses to the human helminth pathogen Onchocerca volvulus. The formation of Neutrophil Extracellular Traps (NETs), has been implicated in anti-microbial defence, but has not been identified in human helminth infection. Here, we demonstrate NETs formation in human onchocerciasis. Extracellular NETs and neutrophils were visualised around O. volvulus in nodules excised from untreated patients but not in nodules from patients treated with the anti-Wolbachia drug, doxycycline. Whole Wolbachia or microspheres coated with a synthetic Wolbachia lipopeptide (WoLP) of the major nematode Wolbachia TLR2/6 ligand, peptidoglycan associated lipoprotein, induced NETosis in human neutrophils in vitro. TLR6 dependency of Wolbachia and WoLP NETosis was demonstrated using purified neutrophils from TLR6 deficient mice. Thus, we demonstrate for the first time that NETosis occurs during natural human helminth infection and demonstrate a mechanism of NETosis induction via Wolbachia endobacteria and direct ligation of Wolbachia lipoprotein by neutrophil TLR2/6. PMID:27752109

  16. Molecular and biochemical characterization of nematode cofactor independent phosphoglycerate mutases.

    PubMed

    Raverdy, Sylvine; Zhang, Yinhua; Foster, Jeremy; Carlow, Clotilde K S

    2007-12-01

    Phosphoglycerate mutase (PGM, EC 5.4.2.1) catalyzes the isomerization of 3-phosphoglycerate and 2-phosphoglycerate in glycolysis and gluconeogenesis. Two distinct types of PGM exist in nature, one that requires 2,3-bisphosphoglycerate as a cofactor (dPGM) and another that does not (iPGM). The two enzymes are structurally distinct and possess different mechanisms of action. In any particular organism, one form may exist or both. Nematodes possess the iPGM form whereas mammals have dPGM. In the present study, we have cloned and expressed iPGM from Onchocerca volvulus and described the catalytic properties of O. volvulus, Brugia malayi and Caenorhabditis elegans iPGM enzymes. Temperature and pH optima were determined for each enzyme. Like other iPGM enzymes, the activities of the nematode iPGM enzymes were dependent on the presence of divalent ions. Inactivation by EDTA could be restored most effectively by magnesium and manganese ions. Kinetic parameters and specific activities of the various recombinant enzymes were determined. The high similarity in catalytic properties among the enzymes indicates that a single enzyme inhibitor would likely be effective against all nematode enzymes. Inhibition of iPGM activity in vivo may lead to lethality as indicated by RNAi studies in C. elegans. Our results support the development of iPGM as a promising drug target in parasitic nematodes.

  17. 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

  18. 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.

  19. Development of a Novel Trap for the Collection of Black Flies of the Simulium ochraceum Complex

    PubMed Central

    Rodríguez-Pérez, Mario A.; Adeleke, Monsuru A.; Burkett-Cadena, Nathan D.; Garza-Hernández, Javier A.; Reyes-Villanueva, Filiberto; Cupp, Eddie W.; Toé, Laurent; Salinas-Carmona, Mario C.; Rodríguez-Ramírez, Américo D.; Katholi, Charles R.; Unnasch, Thomas R.

    2013-01-01

    Background Human landing collections are currently the standard method for collecting onchocerciasis vectors in Africa and Latin America. As part of the efforts to develop a trap to replace human landing collections for the monitoring and surveillance of onchocerciasis transmission, comprehensive evaluations of several trap types were conducted to assess their ability to collect Simulium ochraceum sensu lato, one of the principal vectors of Onchocerca volvulus in Latin America. Methodology/Principal Findings Diverse trap designs with numerous modifications and bait variations were evaluated for their abilities to collect S. Ochraceum s.l. females. These traps targeted mostly host seeking flies. A novel trap dubbed the “Esperanza window trap” showed particular promise over other designs. When baited with CO2 and BG-lure (a synthetic blend of human odor components) a pair of Esperanza window traps collected numbers of S. Ochraceum s.l. females similar to those collected by a team of vector collectors. Conclusions/Significance The Esperanza window trap, when baited with chemical lures and CO2 can be used to collect epidemiologically significant numbers of Simulium ochraceum s.l., potentially serving as a replacement for human landing collections for evaluation of the transmission of O. volvulus. PMID:24116169

  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. Impact of long-term treatment of onchocerciasis with ivermectin in Ecuador: potential for elimination of infection

    PubMed Central

    Vieira, Juan Carlos; Cooper, Philip J; Lovato, Raquel; Mancero, Tamara; Rivera, Jorge; Proaño, Roberto; López, Andrea A; Guderian, Ronald H; Guzmán, José Rumbea

    2007-01-01

    Background Onchocerciasis is a leading cause of blindness worldwide, hence elimination of the infection is an important health priority. Community-based treatment programs with ivermectin form the basis of control programs for the disease in Latin America. The long-term administration of ivermectin could eliminate Onchocerca volvulus infection from endemic areas in Latin America. Methods A strategy of annual to twice-annual treatments with ivermectin has been used for onchocerciasis in endemic communities in Ecuador for up to 14 years. The impact of ivermectin treatment on ocular morbidity, and O. volvulus infection and transmission was monitored in seven sentinel communities. Results Over the period 1990–2003, high rates of treatment coverage of the eligible population were maintained in endemic communities (mean 85.2% per treatment round). Ivermectin reduced the prevalence of anterior segment disease of the eye to 0% in sentinel communities and had a major impact on the prevalence and transmission of infection, with possible elimination of infection in some foci. Conclusion The distribution of ivermectin in endemic communities in Ecuador might have eliminated ocular morbidity and significant progress has been made towards elimination of the infection. A strategy of more frequent treatments with ivermectin may be required in communities where the infection persists to achieve the objective of elimination of the infection from Ecuador. The elimination of the infection from an endemic country in Latin America would be a major public health achievement and could stimulate the implementation of elimination strategies in other endemic countries. PMID:17521449

  2. Group membership and everyday social comparison experiences

    PubMed Central

    SMITH, HEATHER J.; LEACH, COLIN W.

    2006-01-01

    In two everyday experience studies, we examined the degree to which everyday social comparisons are framed by group membership. In the first study, 30 undergraduates attending a public university in the United States completed short questionnaires about their social comparison experiences whenever they were signalled. In the second study, 34 ethnic minority undergraduates from the same university completed similar questionnaires about their social comparison experiences. Across both studies, comparisons in which participants viewed themselves as an ingroup member in comparison to an outgroup comprised less than 10% of the comparison experiences reported by participants. However, minorities in the second study who reported closer identification with their ethnic group reported more comparison experiences in which they mentioned their own or the comparison target's ethnicity. PMID:16691290

  3. 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

  4. 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

  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. 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

  7. 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.

  8. 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

  9. Interleukin 4 and T helper type 2 cells are required for development of experimental onchocercal keratitis (river blindness)

    PubMed Central

    1995-01-01

    Inflammation of the corneal stroma (stromal keratitis) is a serious complication of infection with the nematode parasite Onchocerca volvulus. Because stromal keratitis is believed to be immunologically mediated in humans, we used a murine model to examine the role of T cells and T helper cell cytokines in the immunopathogenesis of these eye lesions. BALB/c mice immunized subcutaneously and injected intrastromally with soluble O. volvulus antigens (OvAg) developed pronounced corneal opacification and neovascularization. The corneal stroma was edematous and contained numerous eosinophils and mononuclear cells. Stromal keratitis in immunized mice was determined to be T cell dependent based on the following observations: (a) T cell-deficient nude mice immunized and injected intrastromally with OvAg fail to develop corneal pathology; and (b) adoptive transfer of spleen cells from OvAg-immunized BALB/c mice to naive nude mice before intrastromal injection of OvAg results in development of keratitis. OvAg-stimulated lymph node and spleen cell cytokine production was dependent on CD4 cells and included interleukin (IL)-4 and IL-5, but not interferon gamma, indicating a predominant T helper type 2 cell-like response. Inflamed corneas from immunized BALB/c mice and from reconstituted nude mice had greatly elevated CD4 and IL-4 gene expression compared with interferon gamma. Mice in which the IL-4 gene was disrupted failed to develop corneal disease, demonstrating that IL-4 is essential in the immunopathogenesis of O. volvulus-mediated stromal keratitis. PMID:7561696

  10. 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

  11. Rapid, novel, specific, high-throughput assay for diagnosis of Loa loa infection.

    PubMed

    Burbelo, Peter D; Ramanathan, Roshan; Klion, Amy D; Iadarola, Michael J; Nutman, Thomas B

    2008-07-01

    The ability to diagnose Loa loa infection readily and accurately remains a demanding task. Among the available diagnostic methods, many are impractical for point-of-care field testing. To investigate whether luciferase immunoprecipitation systems (LIPS) can be used for rapid and specific diagnosis of L. loa infection, a LIPS assay was developed based on immunoglobulin G (IgG) and IgG4 subclass antibodies to a recombinant L. loa SXP-1 (designated LlSXP-1) antigen and tested with sera from healthy controls or patients with proven infection with L. loa, Mansonella perstans, Onchocerca volvulus, Strongyloides stercoralis, or Wuchereria bancrofti. A LIPS test measuring IgG antibody against LlSXP-1 readily differentiated L. loa-infected from uninfected patients and demonstrated markedly improved sensitivity and specificity compared with an LlSXP-1 IgG4-based enzyme-linked immunosorbent assay (67% sensitivity and 99% specificity). No significant immunoreactivity was observed with S. stercoralis-infected sera, but a small number of patients infected with O. volvulus, M. perstans, or W. bancrofti showed positive immunoreactivity. Measuring anti-IgG4-specific antibodies to LlSXP-1 showed a significant correlation (r approximately 0.85; P < 0.00001) with the anti-IgG results but showed no advantage over measuring the total IgG response alone. In contrast, a rapid LIPS format (called QLIPS) in which the tests are performed in less than 15 minutes under nonequilibrium conditions significantly improved the specificity for cross-reactive O. volvulus patient sera (100% sensitivity and 100% specificity). These results suggest that LIPS (and the even more rapid test QLIPS) represents a major advance in the ability to diagnose L. loa infection and may have future applications for point-of-care diagnostics. PMID:18508942

  12. 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

  13. 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.

  14. 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.

  15. Comparison of ASGARD and UFOCapture

    NASA Astrophysics Data System (ADS)

    Blaauw, R.; Cruse, K. S.

    2012-01-01

    The Meteoroid Environment Office is undertaking a comparison between UFOCapture/Analyzer and Asgard (All Sky and Guided Automatic Realtime Detection), both software used to detect meteors. To accomplish this, video output from a Watec video camera on a 17 mm Schneider lens (25degrees field of view) was split and input into two computers, one running UFOCapture and the other running Asgard. The purpose of this study is to compare the sensitivity of the two systems, false alarm rates, and ease of use.

  16. 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.

  17. Selected Theoretical Comparisons for Bosons

    NASA Astrophysics Data System (ADS)

    Proukakis, Nick P.; Davis, Matthew J.; Gardiner, Simon A.

    2013-02-01

    One of the aims of the organisers of the FINESS conferences, and of the editors of this book, has been to encourage dialogue between researchers working in the general area of non-equilibrium superfluids. The researchers come from widely different backgrounds, and come with a broad array of favourite theoretical techniques. In this chapter we present an incomplete survey of figures from previously published papers that make a comparison between selected subsets of different theoretical methods. The goal is that this compilation of figures, when placed in a broader context, will provide some background for the reader to understand the physical conditions that determine when various theories are useful.

  18. 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.

  19. 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.

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

    PubMed

    Toliczenko-Bernatowicz, Dorota; Dębek, Wojciech; Matuszczak, Ewa

    2016-06-01

    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. PMID:27516794

  1. 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. PMID:27516794

  2. 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.

  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

    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.

  5. 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.

  6. 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

  7. Visual Color Comparisons in Forensic Science.

    PubMed

    Thornton, J I

    1997-06-01

    Color is used extensively in forensic science for the characterization and comparison of physical evidence, and should thus be well understood. Fundamental elements of color perception and color comparison systems are first reviewed. The second portion of this article discusses instances in which defects in color perception may occur, and the recognition of opportunities by means of which color perception and color discrimination may be expressed and enhanced. Application and limitations of color comparisons in forensic science, including soil, paint, and fibers comparisons and color tests, are reviewed.

  8. Comparison of Holdup Measurement Techniques

    SciTech Connect

    Lousteau, Angela L; Stooksbury, John C; Cleveland, Steven L

    2012-01-01

    The measurement of uranium holdup, the residual material left in process equipment such as pipes or ducts, is an integral element of material control and accountability. Not only are the measurements important for accountability, they are also important for criticality safety. The goal in measuring holdup is to quantify the amount of material in the pipes to verify that all material is accounted for (inventory in [inventory out + holdup] = 0) and to ensure that the amount of material heldup is not a criticality risk. There are a number of ways to measure holdup in process equipment; however, this paper will evaluate only two methods (i.e., Holdup Measurement System 4 (HMS-4) and In Situ Object Counting Software (ISOCS)) for specific measurement scenarios. The comparison will use measurements of well-known reference materials in various configurations and will examine the results, uncertainties, repeatability, time required, portability, and cost of each system.

  9. Comparison of energy calculation procedures

    SciTech Connect

    Kusuda, T.

    1981-08-01

    ASHRAE has developed a simplified energy-calculation procedure suitable for small calculators that applied to nonresidential buildings and includes all the essential calculation elements - climatic data, buildings construction, operational characteristics, utility system and equipment performance, and internal heat gain due to lighting, occupancy, cooking, etc. A comparison of the results predicted by the proposed method for four typical HVAC (heating, ventilation, and air conditioning) systems in an office building in Washington, DC, against the predictions of seven detailed computer-simulation programs - AXCESS, BLAST, BLDSIM, DOE-2, E-CUBE, ESAS, and TRACE - revealed that the similarity of the results depended more on which analyst employed the methods than on which methods were used.

  10. 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.

  11. Commentary: Problematic issues in cultural comparisons.

    PubMed

    Campesino, Maureen

    2002-01-01

    This commentary offers a critique of cross-cultural comparisons of health care systems between the United States and less economically developed nations. Two main issues are discussed: the abuse of power in such comparisons and the reluctance of nurses from the United States to address conditions of suffering in their own country. Recommendations are given to increase sensitivity of nurses. PMID:12486641

  12. 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

  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. What Is Social Comparison and How Should We Study It?

    ERIC Educational Resources Information Center

    Wood, Joanne V.

    1996-01-01

    Examines frequently used measures and procedures in social comparison research. The question of whether a method truly captures social comparison requires a clear understanding of what social comparison is; hence a definition of social comparison is proposed, multiple ancillary processes in social comparison are identified, and definitional…

  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. Comparison of microarray preprocessing methods.

    PubMed

    Shakya, K; Ruskin, H J; Kerr, G; Crane, M; Becker, J

    2010-01-01

    Data preprocessing in microarray technology is a crucial initial step before data analysis is performed. Many preprocessing methods have been proposed but none has proved to be ideal to date. Frequently, datasets are limited by laboratory constraints so that the need is for guidelines on quality and robustness, to inform further experimentation while data are yet restricted. In this paper, we compared the performance of four popular methods, namely MAS5, Li & Wong pmonly (LWPM), Li & Wong subtractMM (LWMM), and Robust Multichip Average (RMA). The comparison is based on the analysis carried out on sets of laboratory-generated data from the Bioinformatics Lab, National Institute of Cellular Biotechnology (NICB), Dublin City University, Ireland. These experiments were designed to examine the effect of Bromodeoxyuridine (5-bromo-2-deoxyuridine, BrdU) treatment in deep lamellar keratoplasty (DLKP) cells. The methodology employed is to assess dispersion across the replicates and analyze the false discovery rate. From the dispersion analysis, we found that variability is reduced more effectively by LWPM and RMA methods. From the false positive analysis, and for both parametric and nonparametric approaches, LWMM is found to perform best. Based on a complementary q-value analysis, LWMM approach again is the strongest candidate. The indications are that, while LWMM is marginally less effective than LWPM and RMA in terms of variance reduction, it has considerably improved discrimination overall.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  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. 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.

  6. 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 ...

  7. 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.

  8. 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…

  9. 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…

  10. Comparison of Tritium Component Failure Rate Data

    SciTech Connect

    Lee C. Cadwallader

    2004-09-01

    Published failure rate values from the US Tritium Systems Test Assembly, the Japanese Tritium Process Laboratory, the German Tritium Laboratory Karlsruhe, and the Joint European Torus Active Gas Handling System have been compared. This comparison is on a limited set of components, but there is a good variety of data sets in the comparison. The data compared reasonably well. The most reasonable failure rate values are recommended for use on next generation tritium handling system components, such as those in the tritium plant systems for the International Thermonuclear Experimental Reactor and the tritium fuel systems of inertial fusion facilities, such as the US National Ignition Facility. These data and the comparison results are also shared with the International Energy Agency cooperative task on fusion component failure rate data.

  11. 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.

  12. 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

  13. 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.

  14. 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).

  15. Comparison of IR and Visible Cloud Imagers

    NASA Astrophysics Data System (ADS)

    Mandeville, W.; McLaughlin, T.; Bygren, S.; Randell, C.

    This paper presents a comparison between the Infrared Cloud Imager (IRCI) used at Ground-based Electro-Optical Deep Space Surveillance (GEODSS) sites and the Visible Cloud Imager (VCI) developed using a COTS all-sky camera. The cloud imagers are used to create exclusion maps for GEODSS observations based on detected cloud locations. Excluding observation attempts in obscured areas of the sky is done to improve the allocation of sensor resources. Estimates are made for atmospheric extinction across the entire sky by comparing known star brightness to measured brightness. Data for the comparison were collected at the GEODSS test site located in Yoder, Colorado for a variety of cloud conditions.

  16. 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.

  17. Comparison of MMW ground vehicle signatures

    NASA Astrophysics Data System (ADS)

    Saylor, Ph. D., Annie V.; Kissell, Ann

    2006-05-01

    A continuing question asked of MMW target signature and model providers is the applicability of data from one frequency band to another. Recent monopulse Ka-band ground target signature measurements made by US Army programs provide an opportunity to do an in-depth comparison of signatures of several ground vehicles. The vehicles measured correspond to those measured at W-band by another Army program. This paper provides a comparison of vehicle signatures produced by models derived by AMRDEC from the measurements. The results have implications for missile programs that do not have an extensive measurement budget but require target signatures and models for algorithm development.

  18. IASON-FREE: theory and experimental comparisons.

    PubMed

    Felsberger, E; O'Brien, K; Kindl, P

    2009-10-01

    A sophisticated flight code named FREE (acronym for Flight Route Effective Dose Estimation) was built for professional commercial usage. During its creation special precautions have been taken to take correctly into account all existing dependencies and details, so that the best possible result is achieved. Some of these factors are presented in detail and their effect on doses or dose rates is estimated. Detailed comparisons to more recent measurements for both quiescent as well as disturbed conditions are presented. The agreement at undisturbed conditions turns out to be excellent and also the comparisons to measured transient effects are very satisfactory.

  19. 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.

  20. 1998 MWD/LWD comparison tables

    SciTech Connect

    1998-05-01

    This year`s comparison tables feature an updated Quick Reference Guide listing MWD sensors by collar size for each manufacturer. Following the Quick Reference Guide are the comparison tables, which list general, directional, gamma ray, resistivity, density and neutron data for each tool. The MWD Tables should only be used as a reference source. System specifications frequently change as tools are refined and developed. Please consult representatives for each company prior to making final tool selections. A contact key for all the companies is included.

  1. 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.

  2. Parallel mergs sort using comparison matrices. I

    SciTech Connect

    Romm, Y.E.

    1995-05-01

    The topics discussed in this paper are connected with internal merge sorting by a key (in short, M-sorting or M-sort). Originally developed by von Neumann, this is one of the first sorting methods. It still remains one of the fastest, involving Nlog{sub 2}N comparisons. The purpose of our article is to demonstrate the use of comparison matrices (CMs) for merging in M-sort. While preserving the known advantages of the sequential implementation of M-sort. CMs ensure more efficient use of main memory (one of the known weaknesses of M-sort is its large memory requirements) and effective parallelizability.

  3. 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

  4. Consistent Comparisons between Monopoly and Perfect Competition.

    ERIC Educational Resources Information Center

    Skeath, Susan E.; And Others

    1992-01-01

    Identifies inconsistencies in treatments of the perfect competition, monopoly welfare comparison in textbooks for economics instruction. Argues for explanation of how experiments are being conducted and explicit identification of all underlying assumptions. Suggests straightforward analysis of the social cost of monopoly based on a comparison…

  5. 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...

  6. Comparison Between Different Notions of Resonances

    NASA Astrophysics Data System (ADS)

    Helffer, Bernard

    Introduction A Brief Review on the Analytic Distortion or Dilation Techniques From the Second Definition From the First Definition Case a. The Analytic Dilation (or Complex Scaling) Case b. The Exterior Scaling Case c. The "Regularized" Exterior Scaling (Hislop and Sigal) Case d. A "Linearized" Analytic Distortion Comparison to the Definition of Resonances by Helffer and Sjöstrand Final Remarks

  7. 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…

  8. "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…

  9. Photographic catalog of selected planetary size comparisons

    NASA Technical Reports Server (NTRS)

    Meszaros, S. P.

    1985-01-01

    Photographs taken by NASA spacecraft, and cartographic products based on these photos, are used to illustrate size comparisons of the planets and moons of the solar system. Global views and prominent geographical features are depicted at the same scale, allowing size relationships to be studied visually.

  10. 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.

  11. 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…

  12. 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

  13. 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.

  14. 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.

  15. ABL and BAM Friction Analysis Comparison

    DOE PAGES

    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.

  16. 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…

  17. 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…

  18. 78 FR 38075 - International Labor Comparisons

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-25

    ... Comparisons (ILC) program adjusted foreign data to a common framework of concepts, definitions, and... Productivity and Technology, Bureau of Labor Statistics, Room 2120, 2 Massachusetts Avenue NE., Washington, DC... Productivity and Technology, Bureau of Labor Statistics, telephone number 202-691-6304 (this is not a toll...

  19. Benefits of State-by-State Comparisons.

    ERIC Educational Resources Information Center

    Phillips, Gary W.

    1991-01-01

    Suggests that the National Assessment of Educational Progress's (NAEP) Trial State Assessment (TSA) will provide reliable and valid state-by-state comparisons of what students have learned and will assess their progress over time. The TSA will also provide information on home learning environments, instructional practices, educational resources,…

  20. What's Wrong with Media Comparison Studies?

    ERIC Educational Resources Information Center

    Surry, Daniel W.; Ensminger, David

    2001-01-01

    Reviews the use of media comparison studies in the field of educational technology, argues that they are weak and inappropriate, and recommends a new focus on the issues of instructional methods and learner characteristics. Discusses intra-medium studies and aptitude treatment interaction studies as better alternatives. (LRW)

  1. Analysis of Paired Comparison Data Using Mx

    ERIC Educational Resources Information Center

    Tsai, Rung-Ching; Wu, Tsung-Lin

    2004-01-01

    By postulating that the random utilities associated with the choice options follow a multivariate normal distribution, Thurstonian models (Thurstone, 1927) provide a straightforward representation of paired comparison data. The use of Monte Carlo Expectation-Maximization (MCEM) algorithms and limited information approaches have been proposed to…

  2. 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)

  3. 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)

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. 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

  12. The intervals between the blood-meals of man-biting Simulium damnosum (Diptera: Simuliidae).

    PubMed

    Thompson, B H

    1976-09-01

    Six marking-recapture experiments were carried out with Simulium damnosum in the Cameroon Republic, five in the rain-forest and one in the Sudan-savanna zone. Adult flies were marked by applying a small spot of oil paint to the mesonotum while they were engorging with blood on the legs of volunteers infected with Onchocerca volvulus microfilariae. Catches of wild flies were carried out for 12-13 days after the first day of marking, and all marked flies recaptured were examined. Some of the flies recaptured on days 0, 1 and 2 were nulliparous and had probably been disturbed by the application of the paint before they had completed their blood-meal. The frequency distribution of recaptured marked parous flies returning for their "second" blood-meal rose to a peak early on day 4, but more flies returned earlier,three days after taking a blood-meal, than later on day 5. After day 5, the numbers of recaptured flies were too low to demonstrate any peaks corresponding to "third" and later blood-meals. The longest surviving fly was recaptured 10 days after marking. Twenty-six percent of the flies recaptured on days 3 and 4 contained developing O. volvulus larvae three-five days old, which had presumably been ingested as microfilariae during the blood-meal taken on day 0. Infective larvae first appeared in flies returning late on day 6, and the highest percentage of infective flies occurred on day 7. Infective larvae were found in recaptured flies until day 10, the last day on which marked flies were recovered. Of 929 flies marked on the Sudan-savanna experiment, three (0-32%) flies were recaptured. Two returned on day 4 and one on day 6. PMID:971002

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  18. Tropomyosin implicated in host protective responses to microfilariae in onchocerciasis.

    PubMed

    Jenkins, R E; Taylor, M J; Gilvary, N J; Bianco, A E

    1998-06-23

    A cDNA from adult female Onchocerca volvulus encoding the C-terminal portion of a tropomyosin isoform (termed MOv-14) has been shown previously to confer protective immunity in rodent models of onchocerciasis. The full-length sequence (designated Ov-tmy-1) obtained by PCR amplification, codes for a protein of 33 kDa and shares 91% identity with tropomyosins from other nematodes, falling to 57% identity with human alpha-tropomyosin. Ov-TMY-1 migrates with an apparent molecular mass of 42 kDa on SDS/PAGE and is present in all life-cycle stages, as determined by immunoblotting. Immunogold electron microscopy identified antigenic sites within muscle blocks and the cuticle of microfilariae and infective larvae. Anti-MOv14 antibodies were abundant in mice exhibiting serum-transferable protection against microfilariae conferred by vaccination with a PBS-soluble parasite extract. In contrast, little or no MOv14-specific antibody was present in mice inoculated with live microfilariae, in which resistance is mediated by antibody-independent mechanisms. In human infections, there was an inverse correlation between anti-tropomyosin IgG levels and densities of microfilariae in the skin. Seropositivity varied with the relative endemicity of infection. An immunodominant B cell epitope within Ov-TMY-1 (AQLLAEEADRKYD) was mapped to the N terminus of the MOv14 protein by using sera from protectively vaccinated mice. Intriguingly, the sequence coincides with an IgE-binding epitope within shrimp tropomyosin, believed to be responsible for hypersensitivity in individuals exhibiting allergy to shellfish. IgG and IgE antibodies reacting with the O. volvulus epitope were detected in human infections. It is concluded that antibody responses to tropomyosin may be important in limiting microfilarial densities in a proportion of individuals with onchocerciasis and have the potential to mediate hypersensitivity reactions to dead microfilariae, raising the possibility of a link with the

  19. An Analysis of Comparison Questions in the Context of Auditing.

    ERIC Educational Resources Information Center

    Lauer, Thomas W.; Peacock, Eileen

    1990-01-01

    Provides a definition of comparison questions and shows how they relate to the semantic categories of two taxonomies for classifying questions, both of which omit comparison questions. Examines the comparison questions that auditors generate when they diagnose problems in a company. (SR)

  20. 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…

  1. 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…

  2. 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...

  3. 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

  4. 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.

  5. 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

  6. Comparison of stereoscopic technologies in various configurations

    NASA Astrophysics Data System (ADS)

    Fliegel, Karel; Vítek, Stanislav; Jindra, Tomáš; Páta, Petr; Klíma, Miloš

    2012-10-01

    The aim of this paper is twofold. In the first part of the paper we present results of subjective quality assessment based comparison of stereoscopic technologies in various configurations. Subjective assessment has been done on a limited set of observers while using a database of stereoscopic test videos of various source types. There is also comparison of results obtained with the same stereoscopic content from the two cooperating test laboratories. The results can be used to address different aspects of viewing experience, especially comparing passive and active stereoscopic display technologies. The second part of the paper is focused on preliminary experimental results analyzing the vergence-accommodation conflict present in current stereoscopic systems. Simultaneous measurement of the vergence and accommodation has been done with observers viewing a real scene and its stereoscopic reproduction.

  7. Comparison of fugitive coal dust sizing techniques

    SciTech Connect

    Meyer, J.H.; Lenkevich, M.J.; Davis, E.A.

    1984-10-01

    In conjunction with a field-test program to measure fugitive dust emissions from a rotary railcar dumper, several techniques for particle sizing were compared. The comparison experiments were done at Potomac Electric Power Company's coal-fired generating station at Morgantown, Maryland with support of the Maryland Power Plant Siting Program. Three cascade impactor instruments were compared, including a quartz-crystal microbalance. In addition, two other methods, a 40mm millipore filter operated isokinetically and a rotary arm impactor, were used to obtain particulate samples for optical sizing from calibrated microphotographs. The microphotographs also provided information on coal-particle shape, aggregation, and friability. An aerodynamic particle sizer based on laser velocimetry was also used during one of three comparison tests. Two particle resuspension and sizing methods were attempted but abandoned due to experimental difficulties. Coal particle size and cumulative mass-fraction size distributions for the various sampling techniques were compared.

  8. Metrics for comparison of crystallographic maps

    DOE PAGES

    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

  9. 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.

  10. 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.

  11. 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.

  12. Rocket/Nimbus Sounder Comparison (RNSC)

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The experimental results for radiance and temperature differences in the Wallops Island comparisons indicate that the differences between satellite and rocket systems are of the same order of magnitude as the differences among the various satellite and rocket sounders. The Arcasondes produced usable data to about 50 km, while the Datasondes require design modification. The SIRS and IRIS soundings provided usable data to 30 mb; extension of these soundings was also investigated.

  13. Comparison of STIS and SNAP spectrograph throughputs

    SciTech Connect

    Aldering, Greg

    2002-06-30

    This is a comparison of the measured throughput of STIS on HST versus what we might expect from the spectrograph on SNAP. The principle reference is Woodgate et al. (1998) PASP, 110, 1183. Additional material was taken from the STIS Handbook, available on-line at www.stsci.edu. The goal is to demonstrate that there are sound reasons to expect better performance for a SNAP spectrograph (even one with a grating) than would be expected by scaling from HST+STIS.

  14. Supercomputers and biological sequence comparison algorithms.

    PubMed

    Core, N G; Edmiston, E W; Saltz, J H; Smith, R M

    1989-12-01

    Comparison of biological (DNA or protein) sequences provides insight into molecular structure, function, and homology and is increasingly important as the available databases become larger and more numerous. One method of increasing the speed of the calculations is to perform them in parallel. We present the results of initial investigations using two dynamic programming algorithms on the Intel iPSC hypercube and the Connection Machine as well as an inexpensive, heuristically-based algorithm on the Encore Multimax.

  15. 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.

  16. 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.

  17. Sequence comparisons via algorithmic mutual information.

    PubMed

    Milosavljević, A

    1994-01-01

    One of the main problems in DNA and protein sequence comparisons is to decide whether observed similarity of two sequences should be explained by their relatedness or by mere presence of some shared internal structure, e.g., shared internal tandem repeats. The standard methods that are based on statistics or classical information theory can be used to discover either internal structure or mutual sequence similarity, but cannot take into account both. Consequently, currently used methods for sequence comparison employ "masking" techniques that simply eliminate sequences that exhibit internal repetitive structure prior to sequence comparisons. The "masking" approach precludes discovery of homologous sequences of moderate or low complexity, which abound at both DNA and protein levels. As a solution to this problem, we propose a general method that is based on algorithmic information theory and minimal length encoding. We show that algorithmic mutual information factors out the sequence similarity that is due to shared internal structure and thus enables discovery of truly related sequences. We extend that recently developed algorithmic significance method (Milosavljević & Jurka 1993) to show that significance depends exponentially on algorithmic mutual information.

  18. 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.

  19. Overview of Recent Radiation Transport Code Comparisons for Space Applications

    NASA Astrophysics Data System (ADS)

    Townsend, Lawrence

    Recent advances in radiation transport code development for space applications have resulted in various comparisons of code predictions for a variety of scenarios and codes. Comparisons among both Monte Carlo and deterministic codes have been made and published by vari-ous groups and collaborations, including comparisons involving, but not limited to HZETRN, HETC-HEDS, FLUKA, GEANT, PHITS, and MCNPX. In this work, an overview of recent code prediction inter-comparisons, including comparisons to available experimental data, is presented and discussed, with emphases on those areas of agreement and disagreement among the various code predictions and published data.

  20. KEY COMPARISON: Key comparison CCQM-K29: Anion calibration solutions: final report

    NASA Astrophysics Data System (ADS)

    Weber, Michael; Wüthrich, Jürg

    2006-01-01

    In this key comparison anion calibration solutions of chloride and phosphate were investigated. The contents of both solutions were about 1 g/kg relative to the anion mass. For the chloride comparison 10 participants provided results by the following three analytical techniques: coulometry, titrimetry and ion chromatography. The phosphate amount content was determined by 10 NMIs whereby the following 6 techniques were applied: ion chromatography, titrimetry, ICP-OES, gravimetry, UV-Vis and ion-exchange followed by coulometry. The following institutes participated in this key comparison: BAM and PTB (Germany) BNM-LNE (France) CENAM (Mexico) EMPA (Switzerland) GUM (Poland) INTEC (Chile) KRISS (Korea) NMIJ (Japan) NRCCRM (China) SMU (Slovakia) With one exception all results were found within the range of +/-0.25% with respect to the gravimetric value. The variability (RSD) of the results is below 0.1% for both the chloride and the phosphate solution (chloride without CENAM result). Compared to the pilot study CCQM-P32 the results of CCQM-K29 were significantly better. This is especially true for the phosphate comparison. 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. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. Comparison of properties of digital spectrometer systems.

    PubMed

    Mazanova, Monika; Dryak, Pavel; Kovar, Petr; Auerbach, Pavel

    2014-05-01

    We have tested two digital spectrometer systems, the DSP 9660 and Lynx(®) modules, connected to a HPGe detector. Lynx(®) is a fully integrated 32K channel signal analyzer based on digital signal processing techniques, which offers advanced digital stabilization. The model DSP 9660 digitalizes the signal directly at a very high sampling rate. The evaluated properties were integral nonlinearity, differential linearity, channel profiles, resolution and throughput. We found that the DSP system has slightly inferior resolution and throughput in comparison with the Lynx(®) system.

  7. 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.

  8. 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.

  9. 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.

  10. Cross comparison of four DPRK events

    NASA Astrophysics Data System (ADS)

    Bobrov, Dmitry; Kitov, Ivan; Rozhkov, Mikhail

    2016-04-01

    Seismic signals were detected by the IMS seismic network from four announced underground test conducted by the DPRK in 2006, 2009, 2013, and 2016. These data allow thorough comparison of relative locations, including depth estimates, and magnitudes using several techniques based on waveforms cross correlation. Seismic signals from these events also provide waveform templates for detection of possible aftershocks with magnitudes by two-to-three units lower than the events themselves. We have processed one month of continuous data after each of four events and detected no aftershocks. Independent Component Analysis based Blind Source Separation was conducted for all events at different stations to compare the robustness of the source function recovery.

  11. Technoeconomic comparisons of leading hydrogen storage options

    NASA Astrophysics Data System (ADS)

    Carpetis, C.

    The purpose of this paper is to discuss the main features of the leading options for hydrogen storage and to deliver a basic framework for technoeconomic comparisons. From the utilization point of view, several major areas of hydrogen storage (e.g., for large-scale stationary storage, transient storage, onboard storage for vehicular applications) must be considered separately. In each area, more than one storage option (gaseous, liquid, adsorbed, or adsorbed in solid materials) may be economically beneficial. Typical areas of beneficial use and restrictive features will be shown for each of the different storage options.

  12. Multivariate Lipschitz optimization: Survey and computational comparison

    SciTech Connect

    Hansen, P.; Gourdin, E.; Jaumard, B.

    1994-12-31

    Many methods have been proposed to minimize a multivariate Lipschitz function on a box. They pertain the three approaches: (i) reduction to the univariate case by projection (Pijavskii) or by using a space-filling curve (Strongin); (ii) construction and refinement of a single upper bounding function (Pijavskii, Mladineo, Mayne and Polak, Jaumard Hermann and Ribault, Wood...); (iii) branch and bound with local upper bounding functions (Galperin, Pint{acute e}r, Meewella and Mayne, the present authors). A survey is made, stressing similarities of algorithms, expressed when possible within a unified framework. Moreover, an extensive computational comparison is reported on.

  13. Planetary size comparisons: A photographic study

    NASA Technical Reports Server (NTRS)

    Meszaros, S. P.

    1983-01-01

    Over the past two decades NASA spacecraft missions obtained photographs permitting accurate size measurements of the planets and moons, and their surface features. Planetary global views are displayed at the same scale, in each picture to allow visual size comparisons. Additionally, special geographical features on some of the planets are compared with selected Earth areas, again at the same scale. Artist renderings and estimated sizes are used for worlds not yet reached by spacecraft. Included with each picture is number designation for use in ordering copies of the photos.

  14. 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.

  15. Smythii basin topography and comparisons with Orientale

    NASA Technical Reports Server (NTRS)

    Strain, P. L.; El-Baz, F.

    1979-01-01

    The Smythii basin has the most extensive topographic coverage of any lunar multi-ringed basin. Topographic data are used to study the morphology and morphometry of Smythii and to make comparisons with similar basins. The depth of the basin is shown to be over 8 km, which is comparable to that of Orientale. The inner ring reaches heights of 3.4 km, while the intermediate ring exhibits little relief. Lowest points in the basin are related to mare ridges. Basin volume is estimated to be 21 million cubic kilometers. Evidence suggests that significant differences in substrate characteristics may have existed for the Smythii and Orientale impacts.

  16. Digital signal processing methods for biosequence comparison.

    PubMed Central

    Benson, D C

    1990-01-01

    A method is discussed for DNA or protein sequence comparison using a finite field fast Fourier transform, a digital signal processing technique; and statistical methods are discussed for analyzing the output of this algorithm. This method compares two sequences of length N in computing time proportional to N log N compared to N2 for methods currently used. This method makes it feasible to compare very long sequences. An example is given to show that the method correctly identifies sites of known homology. PMID:2349096

  17. 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.

  18. On using the bootstrap for multiple comparisons.

    PubMed

    Westfall, Peter H

    2011-11-01

    There are many ways to bootstrap data for multiple comparisons procedures. Methods described here include (i) bootstrap (parametric and nonparametric) as a generalization of classical normal-based MaxT methods, (ii) bootstrap as an approximation to exact permutation methods, (iii) bootstrap as a generator of realistic null data sets, and (iv) bootstrap as a generator of realistic non-null data sets. Resampling of MinP versus MaxT is discussed, and the use of the bootstrap for closed testing is also presented. Applications to biopharmaceutical statistics are given.

  19. 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.

  20. Interior structure of neptune: comparison with uranus.

    PubMed

    Hubbard, W B; Nellis, W J; Mitchell, A C; Holmes, N C; Limaye, S S; McCandless, P C

    1991-08-01

    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-calied 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.

  1. 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.

  2. 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).

  3. A comparison of two ozone sampling methods

    SciTech Connect

    Downey, E.B.; Buchan, R.M.; Blehm, K.D.; Gunter, B.J.

    1983-05-01

    A study was conducted to compare the alkaline potassium iodide (AKI) impinger method versus a direct-reading chemiluminescent monitor for determining ozone concentrations. Comparisons were made in both a controlled laboratory situation and in the field during MIG welding. Laboratoy results indicated that the accuracy of the AKI procedure is affected by sample size. In the field, AKI impinger samples seemed to give very low estimations of the true ozone concentration. The direct-reading chemiluminescent monitor performed excellently in both the laboratory and field, and exhibited its merit as an industrial hygiene field instrument.

  4. 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.

  5. Local and Global Comparison of Continuous Functions

    SciTech Connect

    Edelsbrunner, H; Harer, J; Natarajan, V; Pascucci, V

    2004-12-16

    We introduce local and global comparison measures for a collection of k {<=} d real-valued smooth functions on a common d-dimensional Riemannian manifold. For k = d = 2 we relate the measures to the set of critical points of one function restricted to the level sets of the other. The definition of the measures extends to piecewise linear functions for which they are easy to compute. The computation of the measures forms the centerpiece of a software tool which we use to study scientific datasets.

  6. 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

  7. Quantum Private Comparison Protocol with Linear Optics

    NASA Astrophysics Data System (ADS)

    Luo, Qing-bin; Yang, Guo-wu; She, Kun; Li, Xiaoyu

    2016-09-01

    In this paper, we propose an innovative quantum private comparison(QPC) protocol based on partial Bell-state measurement from the view of linear optics, which enabling two parties to compare the equality of their private information with the help of a semi-honest third party. Partial Bell-state measurement has been realized by using only linear optical elements in experimental measurement-device-independent quantum key distribution(MDI-QKD) schemes, which makes us believe that our protocol can be realized in the near future. The security analysis shows that the participants will not leak their private information.

  8. 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

  9. KEY COMPARISON: Final report on the key comparison CCQM-K48: Assay of potassium chloride

    NASA Astrophysics Data System (ADS)

    Liandi, Ma; Mariassy, Michal; Pratt, Kenneth W.

    2010-01-01

    The CCQM-K48 key comparison for determination of the purity of potassium chloride was organized jointly by the inorganic analysis and electrochemical analysis working groups of CCQM to test the abilities of the metrology institutes to measure the amount content of chloride in KCl. National Institute of Metrology P.R.China (NIM) acted as the coordinating laboratory of this comparison with SMU and NIST as co-coordinating laboratories. Seven NMIs participated in this key comparison. All participants used coulometry (except NMIJ which used gravimetry) and all of them analyzed the impurity bromine in the sample and made corrections. In general very good agreement of the results was observed. Some possible problems were highlighted. 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).

  10. 16 CFR 233.2 - Retail price comparisons; comparable value comparisons.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... comparisons. 233.2 Section 233.2 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES... charged by others for the same merchandise in the advertiser's trade area (the area in which he does... advertiser or by others in the advertiser's trade area for other merchandise of like grade and...

  11. 16 CFR 233.2 - Retail price comparisons; comparable value comparisons.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... comparisons. 233.2 Section 233.2 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES... charged by others for the same merchandise in the advertiser's trade area (the area in which he does... advertiser or by others in the advertiser's trade area for other merchandise of like grade and...

  12. 16 CFR 233.2 - Retail price comparisons; comparable value comparisons.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... comparisons. 233.2 Section 233.2 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES... charged by others for the same merchandise in the advertiser's trade area (the area in which he does... advertiser or by others in the advertiser's trade area for other merchandise of like grade and...

  13. 16 CFR 233.2 - Retail price comparisons; comparable value comparisons.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... comparisons. 233.2 Section 233.2 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES... charged by others for the same merchandise in the advertiser's trade area (the area in which he does... advertiser or by others in the advertiser's trade area for other merchandise of like grade and...

  14. 16 CFR 233.2 - Retail price comparisons; comparable value comparisons.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... comparisons. 233.2 Section 233.2 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES... charged by others for the same merchandise in the advertiser's trade area (the area in which he does... advertiser or by others in the advertiser's trade area for other merchandise of like grade and...

  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. 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…

  17. 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

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. Multiple comparison analysis testing in ANOVA.

    PubMed

    McHugh, Mary L

    2011-01-01

    The Analysis of Variance (ANOVA) test has long been an important tool for researchers conducting studies on multiple experimental groups and one or more control groups. However, ANOVA cannot provide detailed information on differences among the various study groups, or on complex combinations of study groups. To fully understand group differences in an ANOVA, researchers must conduct tests of the differences between particular pairs of experimental and control groups. Tests conducted on subsets of data tested previously in another analysis are called post hoc tests. A class of post hoc tests that provide this type of detailed information for ANOVA results are called "multiple comparison analysis" tests. The most commonly used multiple comparison analysis statistics include the following tests: Tukey, Newman-Keuls, Scheffee, Bonferroni and Dunnett. These statistical tools each have specific uses, advantages and disadvantages. Some are best used for testing theory while others are useful in generating new theory. Selection of the appropriate post hoc test will provide researchers with the most detailed information while limiting Type 1 errors due to alpha inflation.

  4. Storage as a Metric of Catchment Comparison

    USGS Publications Warehouse

    McNamara, J.P.; Tetzlaff, D.; Bishop, K.; Soulsby, C.; Seyfried, M.; Peters, N.E.; Aulenbach, Brent T.; Hooper, R.

    2011-01-01

    The volume of water stored within a catchment, and its partitioning among groundwater, soil moisture, snowpack, vegetation, and surface water are the variables that ultimately characterize the state of the hydrologic system. Accordingly, storage may provide useful metrics for catchment comparison. Unfortunately, measuring and predicting the amount of water present in a catchment is seldom done; tracking the dynamics of these stores is even rarer. Storage moderates fluxes and exerts critical controls on a wide range of hydrologic and biologic functions of a catchment. While understanding runoff generation and other processes by which catchments release water will always be central to hydrologic science, it is equally essential to understand how catchments retain water. We have initiated a catchment comparison exercise to begin assessing the value of viewing catchments from the storage perspective. The exercise is based on existing data from five watersheds, no common experimental design, and no integrated modelling efforts. Rather, storage was estimated independently for each site. This briefing presents some initial results of the exercise, poses questions about the definitions and importance of storage and the storage perspective, and suggests future directions for ongoing activities. ?? 2011 John Wiley & Sons, Ltd.

  5. 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

  6. 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

  7. Topology based methods for vector field comparisons

    NASA Astrophysics Data System (ADS)

    Batra, Rajesh Kumar

    Vector fields are commonly found in almost all branches of the physical sciences. Aerodynamics, dynamical systems, electromagnetism, and global climate modeling are a few examples. These multivariate data fields are often large, and no general, automated method exists for comparing these fields. Existing methods require either subjective visual judgments, or data interface compatibility, or domain specific knowledge. A topology based method intrinsically eliminates all of the above limitations and has the additional advantage of significantly compressing the vector field by representing only key features of the flow. Therefore, large databases are compactly represented and quickly searched. Topology is a natural framework for the study of many vector fields. It provides rules of an organizing principle, a flow grammar, that can describe and connect together the properties common to flows. Helman and Hesselink first introduced automated methods to extract and visualize this grammar. This work extends their method by introducing automated methods for vector topology comparison. Basic two-dimensional flows are first compared. The theory is extended to compare three-dimensional flow fields and the topology on no-slip surfaces. Concepts from graph theory and linear programming are utilized to solve these problems. Finally, the first automated method for higher order singularity comparisons is introduced using mathematical theories from geometric (Clifford) algebra.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. [Acute gastric volvulus: late complication of Nissen fundoplication. Report of two cases and review of the literature].

    PubMed

    Reyes-Zamorano, Jesús

    2014-01-01

    Antecedentes: el vólvulo gástrico puede clasificarse por su etiología en primario o secundario, por su anatomía en órgano axial o mesentérico axial y por su presentación en crónico o agudo. El tratamiento del vólvulo gástrico secundario agudo siempre debe ser quirúrgico y la elección del procedimiento basarse en la etiología y en los casos asociados con cirugía previa será importante la lisis de adherencias y el retiro de cuerpos extraños (material de sutura, mallas, banda gástrica). La funduplicatura Nissen es un procedimiento seguro y efectivo que rara vez puede tener complicaciones tardías severas entre las que se encuentran el vólvulo gástrico. Objetivo: comunicar 2 casos y revisar la bibliografía médica. Casos clínicos: se describen 2 casos de vólvulo gástrico agudo secundarios a funduplicatura tipo Nissen laparoscópica, con síntomas de dolor epigástrico y vómito no productivo, ambos tratados por laparoscopia. Se revisan los síntomas de presentación, incidencia, diagnóstico, tratamiento y los factores predisponentes de vólvulo gástrico postfunduplicatura. Conclusión: el vólvulo gástrico rara vez puede ser una complicación de una funduplicatura Nissen con incidencia similar a la de otras de sus complicaciones tardías. Los mecanismos descritos que lo originan se relacionan con adherencias postquirúrgicas, material de sutura (poliéster), mallas, tubos de gastrostomía, gastropexia y por herniación gástrica interna a través del túnel "transfunduplicatura." En pacientes con síntomas de obstrucción gástrica dentro del primer año posterior a una funduplicatura Nissen laparoscópica se requiere un alto índice de sospecha. El tratamiento quirúrgico laparoscópico es seguro con o sin gastropexia para corregir los mecanismos que lo originan.

  13. How social neuroscience can inform theories of social comparison.

    PubMed

    Swencionis, Jillian K; Fiske, Susan T

    2014-04-01

    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.

  14. 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

  15. A comparison of packaged piezoactuators for industrial applications

    NASA Astrophysics Data System (ADS)

    Pretorius, Jaco; Hugo, Marius; Spangler, Ronald L., Jr.

    2004-07-01

    A comparison of different commercially available packaged piezoelectric actuators is presented. The comparisons are based on force, stress and strain performance at similar field densities. A new metric of comparison, based on energy efficiency, is introduced. This paper provides designers with useful information on actuators and actuator performance for industrial applications. The QuickPack and PowerAct actuators remain the only packaged piezoelectric actuators to be produced in high volume and to feature in commercial applications.

  16. PR Personnel and Print Journalists: A Comparison of Professionalism

    ERIC Educational Resources Information Center

    Nayman, Oguz; And Others

    1977-01-01

    Reports on a comparison of Colorado public relations personnel and newspaper journalists, which focused on demographic characteristics, professional orientation, job satisfaction, and attitude toward professional improvement. (GW)

  17. 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

  18. Remote and Ground Truth Spectral Measurement Comparisons

    NASA Astrophysics Data System (ADS)

    Abercromby, K.; Hamada, K.; Guyote, M.; Okada, J.; Barker, E.

    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. Laboratory spectral measurements were taken of outer surface materials on FORMOSAT III. From those measurements, a computer model was built to predict the spectral reflectance accounting for both solar 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" is characterized by an increase in slope of the reflectance as the wavelength increases. Therefore, the model of pre-flight materials was augmented to include the presumed causative agent: space weathering effects. Remote data were collected on two of the six FORMOSAT satellites using the 1.6 meter telescope at the AMOS (Air Force Maui Optical and Supercomputing) site with the Spica spectrometer. Due to the separation in ascending node, observations were acquired of 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 five nights of data were collected using the blue (3200 -6600 angstroms) filter. A comparison of the data showed a good match to the pre-flight models 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 all satellites observed. The features in the red filter regime agreed with the pre-flight model up through 7000 angstroms where the reddening begins and the slope of the remote sample increases. A comparison of the satellites showed similar features in the red and blue filter regions, i.e. the satellite surfaces were aging at the same rate. A comparison of the pre

  19. Comparison of metagenomic samples using sequence signatures

    PubMed Central

    2012-01-01

    Background Sequence signatures, as defined by the frequencies of k-tuples (or k-mers, k-grams), have been used extensively to compare genomic sequences of individual organisms, to identify cis-regulatory modules, and to study the evolution of regulatory sequences. Recently many next-generation sequencing (NGS) read data sets of metagenomic samples from a variety of different environments have been generated. The assembly of these reads can be difficult and analysis methods based on mapping reads to genes or pathways are also restricted by the availability and completeness of existing databases. Sequence-signature-based methods, however, do not need the complete genomes or existing databases and thus, can potentially be very useful for the comparison of metagenomic samples using NGS read data. Still, the applications of sequence signature methods for the comparison of metagenomic samples have not been well studied. Results We studied several dissimilarity measures, including d2, d2* and d2S recently developed from our group, a measure (hereinafter noted as Hao) used in CVTree developed from Hao’s group (Qi et al., 2004), measures based on relative di-, tri-, and tetra-nucleotide frequencies as in Willner et al. (2009), as well as standard lp measures between the frequency vectors, for the comparison of metagenomic samples using sequence signatures. We compared their performance using a series of extensive simulations and three real next-generation sequencing (NGS) metagenomic datasets: 39 fecal samples from 33 mammalian host species, 56 marine samples across the world, and 13 fecal samples from human individuals. Results showed that the dissimilarity measure d2S can achieve superior performance when comparing metagenomic samples by clustering them into different groups as well as recovering environmental gradients affecting microbial samples. New insights into the environmental factors affecting microbial compositions in metagenomic samples are obtained through

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  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. 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

  9. 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

  10. 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

  11. O-Crystallin, arginine kinase and ferritin from the octopus lens.

    PubMed

    Zinovieva, R D; Piatigorsky, J; Tomarev, S I

    1999-05-18

    Three proteins have been identified in the eye lens of the octopus, Octopus dofleini. A 22 kDa protein comprising 3-5% of the soluble protein of the lens is 35-43% identical to a family of phosphatidylethanolamine-binding proteins of vertebrates. Other members of this family include the immunodominant antigen of the filarial parasite, Onchocerca volvulus, putative odorant-binding proteins of Drosophila and a protein with unknown function of Caenorhabditis elegans. We have called this protein O-crystallin on the basis of its abundance in the transparent lens. O-Crystallin mRNA was detected only in the lens. Two tryptic peptides of another octopus lens protein, less abundant than O-crystallin, showed 80% identity to arginine kinase of invertebrates, a relative of creatine kinase of vertebrates. Finally, ferritin cDNA was isolated as an abundant cDNA from the octopus lens library. Northern blots showed that ferritin mRNA is not lens-specific. PMID:10350626

  12. The predicted and observed decline in onchocerciasis infection during 14 years of successful control of Simulium spp. in west Africa.

    PubMed Central

    Remme, J.; De Sole, G.; van Oortmarssen, G. J.

    1990-01-01

    In 55 villages from the well-protected central area of the Onchocerciasis Control Programme in West Africa (OCP), skin snip surveys have been carried out at regular intervals since the programme started, and the latest round of surveys was undertaken after 12-14 years of successful vector control. The observed trends in the prevalence and intensity of onchocerciasis infection in cohorts of adults were compared with the trends predicted using a host-parasite model. After 12-14 years of control the community microfilarial load (CMFL) was close to zero in all villages. During the last few years of control, the prevalence of infection declined at an accelerated rate, and this was predicted by the model. There was generally good agreement between observed and predicted trends. The predictions were based on an estimated average duration of infection of 10.4 years, which corresponds to a mean reproductive lifespan for Onchocerca volvulus of 9-9.5 years, and an upper limit of 15 years for 95% of the infections. Differences between the observed and predicted data included the trend in CMFL between the first and second surveys, which in 18 villages did not show the predicted decline. Furthermore, the observed final decline in prevalence was faster than predicted in the north-eastern part of the central OCP area. After 14 years of vector control, the level of onchocerciasis has fallen to such a low level that consideration is being given to ending larviciding. PMID:2393979

  13. Trehalose metabolism genes in Caenorhabditis elegans and filarial nematodes.

    PubMed

    Pellerone, F I; Archer, S K; Behm, C A; Grant, W N; Lacey, M J; Somerville, A C

    2003-09-30

    The sugar trehalose is claimed to be important in the physiology of nematodes where it may function in sugar transport, energy storage and protection against environmental stresses. In this study we investigated the role of trehalose metabolism in nematodes, using Caenorhabditis elegans as a model, and also identified complementary DNA clones putatively encoding genes involved in trehalose pathways in filarial nematodes. In C. elegans two putative trehalose-6-phosphate synthase (tps) genes encode the enzymes that catalyse trehalose synthesis and five putative trehalase (tre) genes encode enzymes catalysing hydrolysis of the sugar. We showed by RT-PCR or Northern analysis that each of these genes is expressed as mRNA at all stages of the C. elegans life cycle. Database searches and sequencing of expressed sequence tag clones revealed that at least one tps gene and two tre genes are expressed in the filarial nematode Brugia malayi, while one tps gene and at least one tre gene were identified for Onchocerca volvulus. We used the feeding method of RNA interference in C. elegans to knock down temporarily the expression of each of the tps and tre genes. Semiquantitative RT-PCR analysis confirmed that expression of each gene was silenced by RNA interference. We did not observe an obvious phenotype for any of the genes silenced individually but gas-chromatographic analysis showed >90% decline in trehalose levels when both tps genes were targeted simultaneously. This decline in trehalose content did not affect viability or development of the nematodes.

  14. 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.

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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

  20. 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