Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-11 (of 11 Records) |
Query Trace: Hamlin K[original query] |
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Large community outbreak of legionnaires disease potentially associated with a cooling tower - Napa County, California, 2022
Grossmann NV , Milne C , Martinez MR , Relucio K , Sadeghi B , Wiley EN , Holland SN , Rutschmann S , Vugia DJ , Kimura A , Crain C , Akter F , Mukhopadhyay R , Crandall J , Shorrock M , Smith JC , Prasad N , Kahn R , Barskey AE , Lee S , Willby MJ , Kozak-Muiznieks NA , Lucas CE , Henderson KC , Hamlin JAP , Yang E , Clemmons NS , Ritter T , Henn J . MMWR Morb Mortal Wkly Rep 2023 72 (49) 1315-1320 Legionnaires disease is a serious infection acquired by inhalation of water droplets from human-made building water systems that contain Legionella bacteria. On July 11 and 12, 2022, Napa County Public Health (NCPH) in California received reports of three positive urinary antigen tests for Legionella pneumophila serogroup 1 in the town of Napa. By July 21, six Legionnaires disease cases had been confirmed among Napa County residents, compared with a baseline of one or two cases per year. NCPH requested assistance from the California Department of Public Health (CDPH) and CDC to aid in the investigations. Close temporal and geospatial clustering permitted a focused environmental sampling strategy of high-risk facilities which, coupled with whole genome sequencing results from samples and investigation of water system maintenance, facilitated potential linking of the outbreak with an environmental source. NCPH, with technical support from CDC and CDPH, instructed and monitored remediation practices for all environmental locations that tested positive for Legionella. The investigation response to this community outbreak illustrates the importance of interdisciplinary collaboration by public health agencies, laboratory support, timely communication with the public, and cooperation of managers of potentially implicated water systems. Timely identification of possible sources, sampling, and remediation of any facility testing positive for Legionella is crucial to interrupting further transmission. |
tinselR-an R Shiny Application for Annotating Phylogenetic Trees
Hamlin JAP , Nakov T , Williams-Newkirk A . Microbiol Resour Announc 2021 10 (27) e0022721 Public health laboratories obtain whole-genome sequences of pathogens to confirm outbreaks and identify transmission routes. Here, we present tinselR, an open-source and user-friendly application for visualization and annotation of relatedness among pathogens with phylogenetic trees. By combining annotation and phylogenetics, we simplify one critical step in the pathogen analysis workflow. |
Is it time for a patient-centered quality measure of asthma control
Herman E , Beavers S , Hamlin B , Thaker K . J Allergy Clin Immunol Pract 2019 7 (6) 1771-1777 Quality measures play a prominent role in the US health care system. They are used to monitor and report performance across health plans, providers, and health systems and are a foundational element of value-based payment. Measuring the quality of asthma care has been challenging because of a lack of reliable data to assess clinical processes and track patient-specific outcomes. Existing asthma Healthcare Effectiveness Data and Information Set measures rely on administrative claims-derived data on dispensed medications. These are proxy measures of appropriate prescribing but are not reflective of comprehensive asthma care. The increase in the volume and specificity of longitudinal clinical data in electronic health records, movement toward electronic quality measures, and advances in electronic clinical data systems enable the development of more meaningful measures. A patient-reported measure of asthma control would incorporate key clinical indicators such as a validated age- and culturally appropriate test, and would reflect the combined outcome of medical management, self-management education, reduction of environmental exposures, and appropriate support services. Although there is a current quality measure that includes a test of asthma control (the Optimal Asthma Control Measure), work is needed to address questions about usability, patient literacy, and the influence of setting on self-reported scores. Comprehensive reliability and validity testing of both clinical data and stratification across risk groups will be needed to determine whether a measure based on standardized assessments of asthma control indeed promote improved clinical outcomes. |
Comparison of antigen and antibody responses in repeat lymphatic filariasis transmission assessment surveys in American Samoa
Won KY , Robinson K , Hamlin KL , Tufa J , Seespesara M , Wiegand RE , Gass K , Kubofcik J , Nutman TB , Lammie PJ , Fuimaono S . PLoS Negl Trop Dis 2018 12 (3) e0006347 BACKGROUND: Current WHO recommendations for lymphatic filariasis (LF) surveillance advise programs to implement activities to monitor for new foci of transmission after stopping mass drug administration (MDA). A current need in the global effort to eliminate LF is to standardize diagnostic tools and surveillance activities beyond the recommended transmission assessment survey (TAS). METHODOLOGY: TAS was first conducted in American Samoa in 2011 (TAS 1) and a repeat TAS was carried out in 2015 (TAS 2). Circulating filarial antigen (CFA) and serologic results from both surveys were analyzed to determine whether interruption of LF transmission has been achieved in American Samoa. PRINCIPAL FINDINGS: A total of 1,134 and 864 children (5-10 years old) were enrolled in TAS 1 and TAS 2, respectively. Two CFA-positive children were identified in TAS 1, and one CFA-positive child was identified in TAS 2. Results of both surveys were below the threshold for which MDA was warranted. Additionally, 1,112 and 836 dried blood spots from TAS 1 and TAS 2, respectively were tested for antibodies to Wb123, Bm14 and Bm33 by luciferase immunoprecipitation system (LIPS) assay and multiplex bead assay. In 2011, overall prevalence of responses to Wb123, Bm14, and Bm33 was 1.0%, 6.8% and 12.0%, respectively. In 2015, overall prevalence of positive Bm14 and Bm33 responses declined significantly to 3.0% (p<0.001) and 7.8% (p = 0.013), respectively. CONCLUSIONS/SIGNIFICANCE: Although passing TAS 1 and TAS 2 and an overall decline in the prevalence of antibodies to Bm14 and Bm33 between these surveys suggests decreased exposure and infection among young children, there were persistent responses in some schools. Clustering and persistence of positive antibody responses in schools may be an indication of ongoing transmission. There is a need to better understand the limitations of current antibody tests, but our results suggest that serologic tools can have a role in guiding programmatic decision making. |
Measuring changes in transmission of neglected tropical diseases, malaria, and enteric pathogens from quantitative antibody levels.
Arnold BF , van der Laan MJ , Hubbard AE , Steel C , Kubofcik J , Hamlin KL , Moss DM , Nutman TB , Priest JW , Lammie PJ . PLoS Negl Trop Dis 2017 11 (5) e0005616 BACKGROUND: Serological antibody levels are a sensitive marker of pathogen exposure, and advances in multiplex assays have created enormous potential for large-scale, integrated infectious disease surveillance. Most methods to analyze antibody measurements reduce quantitative antibody levels to seropositive and seronegative groups, but this can be difficult for many pathogens and may provide lower resolution information than quantitative levels. Analysis methods have predominantly maintained a single disease focus, yet integrated surveillance platforms would benefit from methodologies that work across diverse pathogens included in multiplex assays. METHODS/PRINCIPAL FINDINGS: We developed an approach to measure changes in transmission from quantitative antibody levels that can be applied to diverse pathogens of global importance. We compared age-dependent immunoglobulin G curves in repeated cross-sectional surveys between populations with differences in transmission for multiple pathogens, including: lymphatic filariasis (Wuchereria bancrofti) measured before and after mass drug administration on Mauke, Cook Islands, malaria (Plasmodium falciparum) before and after a combined insecticide and mass drug administration intervention in the Garki project, Nigeria, and enteric protozoans (Cryptosporidium parvum, Giardia intestinalis, Entamoeba histolytica), bacteria (enterotoxigenic Escherichia coli, Salmonella spp.), and viruses (norovirus groups I and II) in children living in Haiti and the USA. Age-dependent antibody curves fit with ensemble machine learning followed a characteristic shape across pathogens that aligned with predictions from basic mechanisms of humoral immunity. Differences in pathogen transmission led to shifts in fitted antibody curves that were remarkably consistent across pathogens, assays, and populations. Mean antibody levels correlated strongly with traditional measures of transmission intensity, such as the entomological inoculation rate for P. falciparum (Spearman's rho = 0.75). In both high- and low transmission settings, mean antibody curves revealed changes in population mean antibody levels that were masked by seroprevalence measures because changes took place above or below the seropositivity cutoff. CONCLUSIONS/SIGNIFICANCE: Age-dependent antibody curves and summary means provided a robust and sensitive measure of changes in transmission, with greatest sensitivity among young children. The method generalizes to pathogens that can be measured in high-throughput, multiplex serological assays, and scales to surveillance activities that require high spatiotemporal resolution. Our results suggest quantitative antibody levels will be particularly useful to measure differences in exposure for pathogens that elicit a transient antibody response or for monitoring populations with very high- or very low transmission, when seroprevalence is less informative. The approach represents a new opportunity to conduct integrated serological surveillance for neglected tropical diseases, malaria, and other infectious diseases with well-defined antigen targets. |
Diagnostic and prognostic value of human prion detection in cerebrospinal fluid.
Foutz A , Appleby BS , Hamlin C , Liu X , Yang S , Cohen Y , Chen W , Blevins J , Fausett C , Wang H , Gambetti P , Zhang S , Hughson A , Tatsuoka C , Schonberger LB , Cohen ML , Caughey B , Safar JG . Ann Neurol 2016 81 (1) 79-92 Objective-Several prion amplification systems have been proposed for detection of prions in cerebrospinal fluid (CSF), most recently, the measurements of prion seeding activity with second-generation real-time quaking-induced conversion (RT-QuIC). The objective of this study was to investigate the diagnostic performance of the RT-QuIC prion test in the broad phenotypic spectrum of prion diseases. Methods- We performed CSF RT-QuIC testing in 2,141 patients who had rapidly progressive neurological disorders, determined diagnostic sensitivity and specificity in 272 cases which were autopsied, and evaluated the impact of mutations and polymorphisms in the PRNP gene, and Type 1 or Type 2 of human prions on diagnostic performance. Results-The 98.5% diagnostic specificity and 92% sensitivity of CSF RT-QuIC in a blinded retrospective analysis matched the 100% specificity and 95% sensitivity of a blind prospective study. The CSF RT-QuIC differentiated 94% of cases of sporadic Creutzfeldt-Jakob disease (sCJD) MM1 from the sCJD MM2 phenotype, and 80% of sCJD VV2 from sCJD VV1. The mixed prion type 1-2 and cases heterozygous for codon 129 generated intermediate CSF RT-QuIC patterns, while genetic prion diseases revealed distinct profiles for each PRNP gene mutation. Interpretation-The diagnostic performance of the improved CSF RT-QuIC is superior to surrogate marker tests for prion diseases such as 14-3-3 and Tau proteins and together with PRNP gene sequencing, the test allows the major prion subtypes to be differentiated in vivo. This differentiation facilitates prediction of the clinicopathological phenotype and duration of the disease-two important considerations for envisioned therapeutic interventions. |
Seroepidemiology of Toxoplasma in a coastal region of Haiti: multiplex bead assay detection of immunoglobulin G antibodies that recognize the SAG2A antigen
Priest JW , Moss DM , Arnold BF , Hamlin K , Jones CC , Lammie PJ . Epidemiol Infect 2015 143 (3) 618-30 Toxoplasma gondii is a globally distributed parasitic protozoan that infects most warm-blooded animals. We incorporated a bead coupled with recombinant SAG2A protein into our Neglected Tropical Disease (NTD) multiplex bead assay (MBA) panel and used it to determine Toxoplasma infection rates in two studies in Haiti. In a longitudinal cohort study of children aged 0-11 years, the infection rate varied with age reaching a maximum of 0.131 infections/year in children aged 3 years [95% confidence interval (CI) 0.065-0.204]. The median time to seroconversion was estimated to be 9.7 years (95% CI 7.6-infinity). In a cross-sectional, community-wide survey of residents of all ages, we determined an overall seroprevalence of 28.2%. The seroprevalence age curve from the cross-sectional study also suggested that the force of infection varied with age and peaked at 0.057 infections/year (95% CI 0.033-0.080) at age 2.6 years. Integration of the Toxoplasma MBA into NTD surveys may allow for better estimates of the potential burden of congenital toxoplasmosis in underserved regions. |
Serological measures of malaria transmission in Haiti: comparison of longitudinal and cross-sectional methods
Arnold BF , Priest JW , Hamlin KL , Moss DM , Colford JM Jr , Lammie PJ . PLoS One 2014 9 (4) e93684 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. |
Longitudinal evaluation of enteric protozoa in Haitian children by stool exam and multiplex serologic assay
Moss DM , Priest JW , Hamlin K , Derado G , Herbein J , Petri WA Jr , Lammie PJ . Am J Trop Med Hyg 2014 90 (4) 653-60 Haitian children were monitored longitudinally in a filariasis study. Included were stool samples examined for Giardia intestinalis and Entamoeba histolytica cysts, and serum specimens analyzed for immunoglobulin G (IgG) responses to eight recombinant antigens from G. intestinalis (variant-specific surface protein [VSP1-VSP5]), E. histolytica (lectin adhesion molecule [LecA]), and Cryptosporidium parvum (17- and 27-kDa) using a multiplex bead assay. The IgG responses to VSP antigens peaked at 2 years of age and then diminished and were significantly lower (P < 0.002) in children > 4.5 years than in children < 4.5 years. The IgG responses to Cryptosporidium tended to increase with age. The IgG responses to LecA and VSP antigens and the prevalence of stools positive for cysts were significantly higher (P < 0.037 and P < 0.035, respectively) in the rainy season than in the dry season. The multiplex bead assay provides a powerful tool for analyzing serologic responses to multiple pathogens. |
Longitudinal monitoring of the development of antifilarial antibodies and acquisition of Wuchereria bancrofti in a highly endemic area of Haiti
Hamlin KL , Moss DM , Priest JW , Roberts J , Kubofcik J , Gass K , Streit TG , Nutman TB , Eberhard ML , Lammie PJ . PLoS Negl Trop Dis 2012 6 (12) e1941 Antifilarial antibody testing has been established as a sensitive and specific method of diagnosing lymphatic filariasis. However, the development of serological responses to specific filarial antigens and their relationship to acquisition of infection is poorly understood. In order to evaluate whether the development of antigen specific antifilarial antibodies precedes microfilaremia and antigenemia, we compared the antibody responses of serum samples collected between 1990 and 1999 from a cohort of 142 Haitian children followed longitudinally. Antigen status was determined using the Og4C3 ELISA and the presence of microfilaremia was detected using microscopy. Antibody responses to Wb123, a Wuchereria bancrofti L3 antigen, were measured using a Luciferase Immunoprecipitation System (LIPS) assay. Antibody responses to Bm14 and Bm33, Brugia malayi antigens and to a major surface protein (WSP) from Wolbachia were analyzed using a multiplex bead assay. Over follow-up, 80 (56%) of the children became antigen-positive and 30 (21%) developed microfilaremia. Detectable antibody responses to Bm14, Bm33, Wb123, and WSP developed in 95%, 100%, 92%, and 29% of children, respectively. With the exception of WSP, the development of antibody responses generally preceded detection of filarial antigen. Our results show that antifilarial antibody responses can serve as an important epidemiological indicator in a sentinel population of young children and thus, may be valuable as tool for surveillance in the context of lymphatic filariasis elimination programs. |
Development of a new platform for neglected tropical disease surveillance
Lammie PJ , Moss DM , Brook Goodhew E , Hamlin K , Krolewiecki A , West SK , Priest JW . Int J Parasitol 2012 42 (9) 797-800 An expanded global focus on the control and elimination of neglected tropical diseases (NTDs) has called attention to the need to develop and validate surveillance strategies that are cost effective and can be integrated across diseases. Here, we describe a multiplex tool for the sensitive detection of antibody responses to NTDs as well as vaccine preventable diseases, malaria, and waterborne and zoonotic infections. The assay platform is robust, can be performed with either serum or dried blood spots and can be adapted to local epidemiological conditions and public health priorities. Multiplex assays open the door to conducting routine serosurveillance for NTDs through demographic health surveillance or malaria indicator surveys. |
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