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Search Results: 1 - 10 of 9834 matches for " Patrick Lammie "
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Lack of Evidence for the Direct Activation of Endothelial Cells by Adult Female and Microfilarial Excretory-Secretory Products
Tiffany Weinkopff, Patrick Lammie
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0022282
Abstract: Lymphangiectasia (dilation of the lymphatic vessel (LV)) is pathognomonic for lymphatic filariasis. In both infected humans and animal models of infection, lymphangiectasia is not restricted to the site of the worm nest, but is found along the infected vessel. These observations argue that soluble products secreted by the worm could be mediating this effect by activating the lymphatic endothelial cells (LEC) lining the vessel. We tested the ability of filarial Excretory-Secretory products to activate LECs, but were unable to detect a direct effect of the Excretory-Secretory products on the activation of LEC as assessed by a variety of approaches including cellular proliferation, cell surface molecule expression and cytokine and growth factor production (although other mediators used as positive controls did induce these effects). Collectively, these results do not support the hypothesis that Excretory-Secretory products directly activate LECs.
Unfulfilled potential: using diethylcarbamazine-fortified salt to eliminate lymphatic filariasis
Lammie,Patrick; Milner,Trevor; Houston,Robin;
Bulletin of the World Health Organization , 2007, DOI: 10.1590/S0042-96862007000700012
Abstract: fortifying salt with diethylcarbamazine (dec) is a safe, low-cost and effective strategy to eliminate transmission of lymphatic filariasis. dec-fortified salt has been used successfully in pilot projects in several countries and has been used operationally by china to eliminate lymphatic filariasis. the successful use of iodized salt to eliminate iodine-deficiency disorders is encouraging; similarly, fortified salt could be used as a vehicle to eliminate lymphatic filariasis. despite the potential programmatic advantages of fortifying salt with dec instead of undertaking mass administration of tablets, dec-fortified salt remains an underutilized intervention. we discuss the reasons for this and suggest settings in which the use of dec-fortified salt should be considered.
Lymphatic filariasis in the Caribbean region: the opportunity for its elimination and certification
Rawlins Samuel C.,Lammie Patrick,Tiwari Tejpratap,Pons Pedro
Revista Panamericana de Salud Pública , 2000,
Abstract: In order to support the case for a certification of elimination of lymphatic filariasis (LF) in some Caribbean countries, we compared the prevalence of circulating Wuchereria bancrofti antigen in communities in Guyana, Suriname, and Trinidad. For the study, we assayed school children in six communities in Guyana, five communities in Suriname, and three communities in Trinidad for the prevalence of circulating W. bancrofti antigen, using a new immunochromatographic test for LF. We also assayed adults in these three countries, with a special focus on Blanchisseuse, Trinidad, where mass treatment for LF elimination had been carried out in 1981. The prevalences of W. bancrofti circulating antigen found in the school children populations ranged from 1.7% to 33.2% in Guyana and were 0.22% overall in Suriname and 0.0% in Trinidad. Among adults in two Guyana communities the prevalences were 16.7% and 32.1%. The results were all negative from 211 adults in communities in the north, center, and south of Trinidad, as well as from 29 adults in Suriname. The data suggest that contrary to reports of LF endemicity from the World Health Organization, LF may no longer be present in Trinidad and may be of very low prevalence in Suriname. Trinidad and Tobago and other Caribbean nations proven negative could seek to be awarded a certificate of LF elimination. In Suriname the small localized pocket of infected persons who may serve as a reservoir of LF infection could be tested and appropriately treated to achieve LF elimination. Such LF-positive countries as Guyana should access new international resources being made available for LF elimination efforts. An adequate certification program would help identify which countries should seek the new LF elimination resources.
Filarial Excretory-Secretory Products Induce Human Monocytes to Produce Lymphangiogenic Mediators
Tiffany Weinkopff ,Charles Mackenzie,Rob Eversole,Patrick J. Lammie
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0002893
Abstract: The nematodes Wuchereria bancrofti and Brugia spp. infect over 120 million people worldwide, causing lymphedema, elephantiasis and hydrocele, collectively known as lymphatic filariasis. Most infected individuals appear to be asymptomatic, but many exhibit sub-clinical manifestations including the lymphangiectasia that likely contributes to the development of lymphedema and elephantiasis. As adult worm excretory-secretory products (ES) do not directly activate lymphatic endothelial cells (LEC), we investigated the role of monocyte/macrophage-derived soluble factors in the development of filarial lymphatic pathology. We analyzed the production of IL-8, IL-6 and VEGF-A by peripheral blood mononuclear cells (PBMC) from na?ve donors following stimulation with filarial ES products. ES-stimulated PBMCs produced significantly more IL-8, IL-6 and VEGF-A compared to cells cultured in medium alone; CD14+ monocytes appear to be the primary producers of IL-8 and VEGF-A, but not IL-6. Furthermore, IL-8, IL-6 and VEGF-A induced in vitro tubule formation in LEC Matrigel cultures. Matrigel plugs supplemented with IL-8, IL-6, VEGF-A, or with supernatants from ES-stimulated PBMCs and implanted in vivo stimulated lymphangiogenesis. Collectively, these data support the hypothesis that monocytes/macrophages exposed to filarial ES products may modulate lymphatic function through the secretion of soluble factors that stimulate the vessel growth associated with the pathogenesis of filarial disease.
Assessing the Impact of a Missed Mass Drug Administration in Haiti
Kimberly Y. Won,Madsen Beau de Rochars,Dominique Kyelem,Thomas G. Streit,Patrick J. Lammie
PLOS Neglected Tropical Diseases , 2009, DOI: 10.1371/journal.pntd.0000443
Abstract:
Secondary Mapping of Lymphatic Filariasis in Haiti-Definition of Transmission Foci in Low-Prevalence Settings
Naomi Drexler ,Charles H. Washington,Maribeth Lovegrove,Caroline Grady,Marie Denise Milord,Thomas Streit,Patrick Lammie
PLOS Neglected Tropical Diseases , 2012, DOI: 10.1371/journal.pntd.0001807
Abstract: To eliminate Lymphatic filariasis (LF) as a public health problem, the World Health Organization (WHO) recommends that any area with infection prevalence greater than or equal to 1% (denoted by presence of microfilaremia or antigenemia) should receive mass drug administration (MDA) of antifilarial drugs for at least five consecutive rounds. Areas of low-antigen prevalence (<1%) are thought to pose little risk for continued transmission of LF. Five low-antigen prevalence communes in Haiti, characterized as part of a national survey, were further assessed for transmission in this study. An initial evaluation of schoolchildren was performed in each commune to identify antigen-positive children who served as index cases for subsequent community surveys conducted among households neighboring the index cases. Global positioning system (GPS) coordinates and immunochromatographic tests (ICT) for filarial antigenemia were collected on approximately 1,600 persons of all ages in the five communes. The relationship between antigen-positive cases in the community and distance from index cases was evaluated using multivariate regression techniques and analyses of spatial clustering. Community surveys demonstrated higher antigen prevalence in three of the five communes than was observed in the original mapping survey; autochthonous cases were found in the same three communes. Regression techniques identified a significantly increased likelihood of being antigen-positive when living within 20 meters of index cases when controlling for age, gender, and commune. Spatial clustering of antigen-positive cases was observed in some, but not all communes. Our results suggest that localized transmission was present even in low-prevalence settings and suggest that better surveillance methods may be needed to detect microfoci of LF transmission.
Global Programme to Eliminate Lymphatic Filariasis: The Processes Underlying Programme Success
Kazuyo Ichimori,Jonathan D. King ,Dirk Engels,Aya Yajima,Alexei Mikhailov,Patrick Lammie,Eric A. Ottesen
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0003328
Abstract:
Eliminating Lymphatic Filariasis, Onchocerciasis, and Schistosomiasis from the Americas: Breaking a Historical Legacy of Slavery
Patrick J. Lammie ,John F. Lindo,W. Evan Secor,Javier Vasquez,Steven K. Ault,Mark L. Eberhard
PLOS Neglected Tropical Diseases , 2007, DOI: 10.1371/journal.pntd.0000071
Abstract:
Lymphatic filariasis in the Caribbean region: the opportunity for its elimination and certification
Rawlins,Samuel C.; Lammie,Patrick; Tiwari,Tejpratap; Pons,Pedro; Chadee,Dave D.; Oostburg,Baltus F. J.; Baboolal,Shiremattee;
Revista Panamericana de Salud Pública , 2000, DOI: 10.1590/S1020-49892000000500005
Abstract: in order to support the case for a certification of elimination of lymphatic filariasis (lf) in some caribbean countries, we compared the prevalence of circulating wuchereria bancrofti antigen in communities in guyana, suriname, and trinidad. for the study, we assayed school children in six communities in guyana, five communities in suriname, and three communities in trinidad for the prevalence of circulating w. bancrofti antigen, using a new immunochromatographic test for lf. we also assayed adults in these three countries, with a special focus on blanchisseuse, trinidad, where mass treatment for lf elimination had been carried out in 1981. the prevalences of w. bancrofti circulating antigen found in the school children populations ranged from 1.7% to 33.2% in guyana and were 0.22% overall in suriname and 0.0% in trinidad. among adults in two guyana communities the prevalences were 16.7% and 32.1%. the results were all negative from 211 adults in communities in the north, center, and south of trinidad, as well as from 29 adults in suriname. the data suggest that contrary to reports of lf endemicity from the world health organization, lf may no longer be present in trinidad and may be of very low prevalence in suriname. trinidad and tobago and other caribbean nations proven negative could seek to be awarded a certificate of lf elimination. in suriname the small localized pocket of infected persons who may serve as a reservoir of lf infection could be tested and appropriately treated to achieve lf elimination. such lf-positive countries as guyana should access new international resources being made available for lf elimination efforts. an adequate certification program would help identify which countries should seek the new lf elimination resources.
Serological Measures of Malaria Transmission in Haiti: Comparison of Longitudinal and Cross-Sectional Methods
Benjamin F. Arnold, Jeffrey W. Priest, Katy L. Hamlin, Delynn M. Moss, John M. Colford Jr, Patrick J. Lammie
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0093684
Abstract: Background Efforts to monitor malaria transmission increasingly use cross-sectional surveys to estimate transmission intensity from seroprevalence data using malarial antibodies. To date, seroconversion rates estimated from cross-sectional surveys have not been compared to rates estimated in prospective cohorts. Our objective was to compare seroconversion rates estimated in a prospective cohort with those from a cross-sectional survey in a low-transmission population. Methods and Findings The analysis included two studies from Haiti: a prospective cohort of 142 children ages ≤11 years followed for up to 9 years, and a concurrent cross-sectional survey of 383 individuals ages 0–90 years old. From all individuals, we analyzed 1,154 blood spot specimens for the malaria antibody MSP-119 using a multiplex bead antigen assay. We classified individuals as positive for malaria using a cutoff derived from the mean plus 3 standard deviations in antibody responses from a negative control set of unexposed individuals. We estimated prospective seroconversion rates from the longitudinal cohort based on 13 incident seroconversions among 646 person-years at risk. We also estimated seroconversion rates from the cross-sectional survey using a reversible catalytic model fit with maximum likelihood. We found the two approaches provided consistent results: the seroconversion rate for ages ≤11 years was 0.020 (0.010, 0.032) estimated prospectively versus 0.023 (0.001, 0.052) in the cross-sectional survey. Conclusions The estimation of seroconversion rates using cross-sectional data is a widespread and generalizable problem for many infectious diseases that can be measured using antibody titers. The consistency between these two estimates lends credibility to model-based estimates of malaria seroconversion rates using cross-sectional surveys. This study also demonstrates the utility of including malaria antibody measures in multiplex assays alongside targets for vaccine coverage and other neglected tropical diseases, which together could comprise an integrated, large-scale serological surveillance platform.
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