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Medicine and Health Sciences Commons

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2008

Selected Works

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Articles 1 - 30 of 348

Full-Text Articles in Medicine and Health Sciences

Evaluations Of The Effectiveness Of A Web-Based Graduate Epidemiology Course, Molly A. Rose, Anthony J. Frisby, Michael D. Hamlin, Susan S. Jones Dec 2008

Evaluations Of The Effectiveness Of A Web-Based Graduate Epidemiology Course, Molly A. Rose, Anthony J. Frisby, Michael D. Hamlin, Susan S. Jones

Anthony J Frisby, PhD

An online epidemiology course was developed, implemented, and evaluated for graduate nursing students through the collaborative efforts of nursing faculty and information, education, and instructional design staff of the library at a health sciences university. This epidemiology course is a core curriculum course for graduate nursing students. The course was piloted with 14 students (one student in Romania); the initial online offering ran concurrently with a traditional classroom section. Extensive evaluation data were collected and analyzed to compare the effectiveness of the classroom and distance-learning formats. Areas of evaluation included objective measures, such as midterm and final examination scores and …


Health Policy Newsletter Goes On-Line!, Anthony J. Frisby Dec 2008

Health Policy Newsletter Goes On-Line!, Anthony J. Frisby

Anthony J Frisby, PhD

No abstract available.


Incentives For Orphan Drug Research And Development In The United States, Rosa Rodriguez-Monguio, Enrique Seoane-Vazquez, Sheryl Szeinbach, Jay Visaria Dec 2008

Incentives For Orphan Drug Research And Development In The United States, Rosa Rodriguez-Monguio, Enrique Seoane-Vazquez, Sheryl Szeinbach, Jay Visaria

Rosa Rodriguez-Monguio

Background The Orphan Drug Act (1983) established several incentives to encourage the development of orphan drugs (ODs) to treat rare diseases and conditions. This study analyzed the characteristics of OD designations, approvals, sponsors, and evaluated the effective patent and market exclusivity life of orphan new molecular entities (NMEs) approved in the US between 1983 and 2007. Methods Primary data sources were the FDA Orange Book, the FDA Office of Orphan Drugs Development, and the US Patent and Trademark Office. Data included all orphan designations and approvals listed by the FDA and all NMEs approved by the FDA during the study …


Physicians' Experiences With Brca1/2 Testing In Community Settings., Nancy L. Keating, Kathryn A. Stoeckert, Meredith M. Regan, Lisa Digianni, Judy E. Garber Dec 2008

Physicians' Experiences With Brca1/2 Testing In Community Settings., Nancy L. Keating, Kathryn A. Stoeckert, Meredith M. Regan, Lisa Digianni, Judy E. Garber

Kathryn Sabella

PURPOSE: We surveyed a national sample of nonacademic physicians who ordered BRCA1/2 testing to understand their implementation of genetic testing and to assess recommendations for surveillance and cancer risk management of women with positive test results.

PATIENTS AND METHODS: We surveyed physicians (N = 611 of 1,050; response rate, 58.2%) practicing in nonacademic settings who ordered BRCA1/2 testing during 2004 to 2005. We described physicians' experiences with testing and used multivariable regression models to identify factors associated with more complete counseling and with recommendations for cancer risk management for a BRCA1 mutation carrier.

RESULTS: Most physicians (68.2%) usually or always …


Gender Specific Differences In The Pros And Cons Of Smoking Among Current Smokers In Eastern Kentucky: Implications For Future Smoking Cessation Interventions, Dana A. Hazen, David M. Mannino, Richard Clayton Dec 2008

Gender Specific Differences In The Pros And Cons Of Smoking Among Current Smokers In Eastern Kentucky: Implications For Future Smoking Cessation Interventions, Dana A. Hazen, David M. Mannino, Richard Clayton

David M. Mannino

This study investigated gender differences in the perceived “pros” and “cons” of smoking using the constructs of decisional balance (DB) and stage of change from the Transtheoretical Model. The population distribution for stage of change among a population-based, cross-sectional survey of 155 current smokers over 40 years was: precontemplation (22.6%), contemplation (41.9%), preparation (35.5%). Results of stepwise regression models indicated significant gender differences in DB were in the preparation stage of change; scores on the DB measure increased 3.94 points (95% CI: 1.94, 5.93) for male smokers. Interventions targeting the “pros” and “cons” of smoking may need to be gender …


Career Development For Transition-Aged Youth With Emotional Disturbances: Exemplary Practices Of Florida Mental Health And Substance Abuse Agencies, Mason G. Haber, Troy Loker, Nicole Deschenes, Hewitt B. Clark Dec 2008

Career Development For Transition-Aged Youth With Emotional Disturbances: Exemplary Practices Of Florida Mental Health And Substance Abuse Agencies, Mason G. Haber, Troy Loker, Nicole Deschenes, Hewitt B. Clark

Mason G. Haber

Though an emerging literature on career development practices for transition-age youth with emotional disturbances (TAY w/ED) exists, this literature has not been systematically reviewed. In addition, efforts by publicly-funded sites in Florida to implement such programs have not been comprehensively described. The current project is designed to advance these aims to provide a basis for expanded implementation of career development programs for TAY w/ED in the state.


Challenges, Benefits And Weaknesses Of Intermediate Care: Results From Five Uk Case Study Sites, Emma Regan, Graham Martin, Jon Glasby, Graham Hewitt, Susan Nancarrow, Hilda Parker Dec 2008

Challenges, Benefits And Weaknesses Of Intermediate Care: Results From Five Uk Case Study Sites, Emma Regan, Graham Martin, Jon Glasby, Graham Hewitt, Susan Nancarrow, Hilda Parker

Susan Nancarrow

The authors explore the views of practitioners and managers on the implementation of intermediate care for elderly people across England, including their perceptions of the challenges involved in its implementation, and their assessment of the main benefits and weaknesses of provision. Qualitative data were collected in five case study sites (English primary care trusts) via semistructured interviews (n = 61) and focus group discussions (n = 21) during 2003 to 2004. Interviewees included senior managers, intermediate care service managers, clinicians and health and social care staff involved in the delivery of intermediate care. The data were analysed thematically …


Improved Feed Protein Fractionation Schemes For Formulating Rations With The Cornell Net Carbohydrate And Protein System, Cristina Lanzas, G A. Broderick, D G. Fox Dec 2008

Improved Feed Protein Fractionation Schemes For Formulating Rations With The Cornell Net Carbohydrate And Protein System, Cristina Lanzas, G A. Broderick, D G. Fox

Cristina Lanzas

Adequate predictions of rumen-degradable protein (RDP) and rumen-undegradable protein (RUP) supplies are necessary to optimize performance while minimizing losses of excess nitrogen (N). The objectives of this study were to evaluate the original Cornell Net Carbohydrate Protein System (CNCPS) protein fractionation scheme and to develop and evaluate alternatives designed to improve its adequacy in predicting RDP and RUP. The CNCPS version 5 fractionates CP into 5 fractions based on solubility in protein precipitant agents, buffers, and detergent solutions: A represents the soluble nonprotein N, B1 is the soluble true protein, B2 represents protein with intermediate rates of degradation, B3 is …


Obstructive Lung Disease Models: What Is Valid, Jill M. Ferdinands, David M. Mannino Dec 2008

Obstructive Lung Disease Models: What Is Valid, Jill M. Ferdinands, David M. Mannino

David M. Mannino

Use of disease simulation models has led to scrutiny of model methods and demand for evidence that models credibly simulate health outcomes. We sought to describe recent obstructive lung disease simulation models and their validation. Medline and EMBASE were used to identify obstructive lung disease simulation models published from January 2000 to June 2006. Publications were reviewed to assess model attributes and four types of validation: first-order (verification/debugging), second-order (comparison with studies used in model development), third-order (comparison with studies not used in model development), and predictive validity. Six asthma and seven chronic obstructive pulmonary disease models were identified. Seven …


Preschool Parent-Pediatrician Consultations And Predictive Referral Patterns For Problematic Behaviors, John Fanton, Brittany Macdonald, Elizabeth Harvey Dec 2008

Preschool Parent-Pediatrician Consultations And Predictive Referral Patterns For Problematic Behaviors, John Fanton, Brittany Macdonald, Elizabeth Harvey

Elizabeth (Lisa) Harvey

Objective—The present study examined parents’ reports of the frequency, nature, and outcome of pediatrician consultation and interventions about significant preschool behavior problems. Method—Parents were asked whether they consulted or not with their pediatric providers about disruptive behavioral problems during a longitudinal study of preschool children. Results—Eighty 4-year-old children had parents who had consulted with their pediatricians versus 90 children whose parents did not. Children who eventually met criteria for Attention Deficit/ Hyperactivity Disorder (ADHD) or Oppositional Defiant Disorder (ODD) two years later, received different pediatric interventions at age 4 than children who did not have a diagnosis, χ2 (2) = …


Fluoranthene, But Not Benzo[A]Pyrene, Interacts With Hypoxia Resulting In Pericardial Effusion And Lordosis In Developing Zebrafish, Cole W. Matson, Alicia R. Timme-Laragy, Richard T. Di Giulio Nov 2008

Fluoranthene, But Not Benzo[A]Pyrene, Interacts With Hypoxia Resulting In Pericardial Effusion And Lordosis In Developing Zebrafish, Cole W. Matson, Alicia R. Timme-Laragy, Richard T. Di Giulio

Alicia R. Timme-Laragy

Previous research has documented several PAHs that interact synergistically, causing severe teratogenicity in developing fish embryos. The coexposure of CYP1A inhibitors (e.g. FL or ANF) with AHR agonists (e.g. BaP or BNF) results in a synergistic increase in toxicity. As with chemical CYP1A inhibitors, it has also been shown that CYP1A morpholinos exacerbate BNF-induced embryotoxicity. We hypothesized that a hypoxia-induced reduction in CYP1A activity in BNF or BaP-exposed zebrafish embryos would similarly enhance pericardial effusion and other developmental abnormalities. BaP, BNF, ANF, and FL exposures, both individually and as BaP+FL or BNF+ANF combinations, were performed under hypoxia and normoxia. CYP1A …


Social Policy, Imperiled Communities, And Hiv/Aids Transmission In Prisons: A Call For Zero Tolerance, Louis F. Graham, Henrie Treadwell, Kisha Braithwaite Nov 2008

Social Policy, Imperiled Communities, And Hiv/Aids Transmission In Prisons: A Call For Zero Tolerance, Louis F. Graham, Henrie Treadwell, Kisha Braithwaite

Louis F Graham

HIV/AIDS and African-American male imprisonment contribute to the destruction of African-American communities. African-American men and HIV/AIDS are disproportionately represented throughout all sectors of the criminal justice industry, including the juvenile justice system. The criminal justice system contributes to unacceptably high African-American male imprisonment rates and HIV prevalence directly via the ‘war on drugs’ and lax enforcement of institutional policy among other things, and indirectly through perpetuation of economic hardship which further exacerbates imprisonment rates, thus closing the loop of a vicious cycle of revolving prison doors and HIV contraction. This article briefly introduces surrounding socio-political issues that contextualizes the ensuing …


Technical Analysis: The Interface Of Rational And Irrational Decision Making, William Marty Martin Nov 2008

Technical Analysis: The Interface Of Rational And Irrational Decision Making, William Marty Martin

William Marty Martin

No abstract provided.


A Hybrid Model For Prediction Of Peptide Binding To Mhc Molecules, P. Zhang, V. Brusic, K. Basford Nov 2008

A Hybrid Model For Prediction Of Peptide Binding To Mhc Molecules, P. Zhang, V. Brusic, K. Basford

Ping Zhang

We propose a hybrid classification system for predicting peptide binding to major histocompatibility complex (MHC) molecules. This system combines Support Vector Machine (SVM) and Stabilized Matrix Method (SMM). Its performance was assessed using ROC analysis, and compared with the individual component methods using statistical tests. The preliminary test on four HLA alleles provided encouraging evidence for the hybrid model. The datasets used for the experiments are publicly accessible and have been benchmarked by other researchers.

© Copyright Springer-Verlag Berlin Heidelberg, 2009

Access the published version at www.springerlink.com/.


Finding Recurrent Regions Of Copy Number Variation: A Review, Oscar M. Rueda, Ramon Diaz-Uriarte Nov 2008

Finding Recurrent Regions Of Copy Number Variation: A Review, Oscar M. Rueda, Ramon Diaz-Uriarte

Ramon Diaz-Uriarte

Copy number alterations (CNA) in genomic DNA are linked to a variety of human diseases. Although many methods have been developed to analyze data from a single subject, disease-critical genes are more likely to be found in regions that are common or recurrent among diseased subjects. Unfortunately, finding recurrent CNA regions remains a challenge. We review existing methods for the identification of recurrent CNA regions. Methods differ in their working definition of ``recurrent region'', the type of input data, the statistical and computational methods used to identify recurrence, and the biological considerations they incorporate (which play a role in the …


Regressing Scalar Outcomes On Image Predictors Via Functional Principal Component Regression, Philip T. Reiss Nov 2008

Regressing Scalar Outcomes On Image Predictors Via Functional Principal Component Regression, Philip T. Reiss

Philip T. Reiss

No abstract provided.


Application Of Two Machine Learning Algorithms To Genetic Association Studies In The Presence Of Covariates, Bareng As Nonyane, Andrea S. Foulkes Nov 2008

Application Of Two Machine Learning Algorithms To Genetic Association Studies In The Presence Of Covariates, Bareng As Nonyane, Andrea S. Foulkes

Andrea S Foulkes

Background - Population-based investigations aimed at uncovering genotype-trait associations often involve high-dimensional genetic polymorphism data as well as information on multiple environmental and clinical parameters. Machine learning (ML) algorithms offer a straightforward analytic approach for selecting subsets of these inputs that are most predictive of a pre-defined trait. The performance of these algorithms, however, in the presence of covariates is not well characterized. Methods and Results - In this manuscript, we investigate two approaches: Random Forests (RFs) and Multivariate Adaptive Regression Splines (MARS). Through multiple simulation studies, the performance under several underlying models is evaluated. An application to a cohort …


Gene Set Enrichment Analysis For Non-Monotone Association And Multiple Experimental Categories, Rongheng Lin, Shuangshuang Dai, Richard D. Irwin, Alexandra N. Heinloth, Gary A. Boorman, Leping Li Nov 2008

Gene Set Enrichment Analysis For Non-Monotone Association And Multiple Experimental Categories, Rongheng Lin, Shuangshuang Dai, Richard D. Irwin, Alexandra N. Heinloth, Gary A. Boorman, Leping Li

Rongheng Lin

Background Recently, microarray data analyses using functional pathway information, e.g., gene set enrichment analysis (GSEA) and significance analysis of function and expression (SAFE), have gained recognition as a way to identify biological pathways/processes associated with a phenotypic endpoint. In these analyses, a local statistic is used to assess the association between the expression level of a gene and the value of a phenotypic endpoint. Then these gene-specific local statistics are combined to evaluate association for pre-selected sets of genes. Commonly used local statistics include t-statistics for binary phenotypes and correlation coefficients that assume a linear or monotone relationship between a …


Facing The Challenge Of Data Transfer From Animal Models To Humans: The Case Of Persistent Organohalogens, Alexander Suvorov, Larissa Takser Nov 2008

Facing The Challenge Of Data Transfer From Animal Models To Humans: The Case Of Persistent Organohalogens, Alexander Suvorov, Larissa Takser

Alexander Suvorov

A well-documented fact for a group of persistent, bioaccumulating organohalogens contaminants, namely polychlorinated biphenyls (PCBs), is that appropriate regulation was delayed, on average, up to 50 years. Some of the delay may be attributed to the fact that the science of toxicology was in its infancy when PCBs were introduced in 1920's. Nevertheless, even following the development of modern toxicology this story repeats itself 45 years later with polybrominated diphenyl ethers (PBDEs) another compound of concern for public health. The question is why? One possible explanation may be the low coherence between experimental studies of toxic effects in animal models …


New Episodes And New Onsets Of Major Depression In Borderline And Other Personality Disorders, John G. Gunderson, Robert L. Stout, Charles A. Sanislow, M. Tracie Shea, Thomas H. Mcglashan, Mary C. Zanarini, Maria T. Daversa, Carlos M. Grilo, Shirley Yen, Andrew E. Skodol Nov 2008

New Episodes And New Onsets Of Major Depression In Borderline And Other Personality Disorders, John G. Gunderson, Robert L. Stout, Charles A. Sanislow, M. Tracie Shea, Thomas H. Mcglashan, Mary C. Zanarini, Maria T. Daversa, Carlos M. Grilo, Shirley Yen, Andrew E. Skodol

Charles A. Sanislow, Ph.D.

Background: In the context of much literature and conjecture about the relationship of personality disorders (PD) and major depressive disorder (MDD), this paper uses longitudinal data to assess the frequency with which PD patients, and especially those with borderline personality disorder (BPD), have recurrences (for patients with lifetime histories), or new onsets (for patients without lifetime histories) of MDD. Methods: A sample of 478 PD patients received reliable repeated follow-up assessments over a period of 6 years. The rates of new onsets and recurrences of MDD in all PD patients, and in BPD patients compared to OPD patients were analyzed. …


Incorporating Home Demands Into Models Of Job Strain: Findings From The Work, Family & Health Network, Karen Ertel, K. Koenen, L. Berkman Nov 2008

Incorporating Home Demands Into Models Of Job Strain: Findings From The Work, Family & Health Network, Karen Ertel, K. Koenen, L. Berkman

Karen A. Ertel

Objective—To integrate home demands with the Demand-Control-Support model to test if home demands interact with job strain to increase depressive symptoms. Methods—Data were from 431 employees in four extended care facilities. Presence of a child under age 18 in the household signified home demands. The outcome was depressive symptoms based on a shortened version of the Center for Epidemiologic Studies Depression Scale. Results—The association between job strain and depressive symptoms was moderated by social support (SS) and presence of a child in the household (child). There was no association among participants with high SS and no child, but a positive …


Chronic Disease And Risk Factor Surveillance Using The Sa Monitoring And Surveillance System (Samss) – History, Results And Future Challenges, Anne Taylor, Eleonora Dal Grande Nov 2008

Chronic Disease And Risk Factor Surveillance Using The Sa Monitoring And Surveillance System (Samss) – History, Results And Future Challenges, Anne Taylor, Eleonora Dal Grande

Anne Taylor

Discussion of how chronic disease and risk factor surveillance systems can deliver data-driven evidence to assist in the prevention and slowing of the progression of chronic diseases such as diabetes, asthma, heart disease, arthritis, chronic obstructive pulmonary disease (COPD) and osteoporosis.


Survival Unchanged Five Months After Implementing The 2005 Aha Cpr And Ecc Guidelines For Out-Of-Hospital Cardiac Arrest., Blair L. Bigham, Kent M. Koprowicz, John Stouffer, Tom P. Aufderheide, Stuart Donn, Judy Powell, Dan Davis, Sarah Nafziger, Brian Suffoletto, Ahamed Idris, Mike Helbock, Laurie J. Morrison Nov 2008

Survival Unchanged Five Months After Implementing The 2005 Aha Cpr And Ecc Guidelines For Out-Of-Hospital Cardiac Arrest., Blair L. Bigham, Kent M. Koprowicz, John Stouffer, Tom P. Aufderheide, Stuart Donn, Judy Powell, Dan Davis, Sarah Nafziger, Brian Suffoletto, Ahamed Idris, Mike Helbock, Laurie J. Morrison

Kent M Koprowicz

Introduction: To improve survival from out of hospital cardiac arrest (OHCA), the American Heart Association released guidelines in 2005. We examined the effect of these guidelines on survival in the Resuscitation Outcomes Consortium (ROC) Epistry – Cardiac Arrest. We hypothesized that survival would increase after guideline implementation. Methods: 174 EMS agencies from 8 of the 10 ROC sites were surveyed to determine 2005 AHA guideline implementation, or crossover, date. Two sites with 2005 compatible treatment algorithms prior to guideline release were not included. Patients with OHCA secondary to a non cardiac cause, EMS witnessed events, patients <18 years>old, and patients with …


Antibacterial Activity Of Indium Curcumin And Indium Diacetylcurcumin, Keivan Zandi Nov 2008

Antibacterial Activity Of Indium Curcumin And Indium Diacetylcurcumin, Keivan Zandi

Keivan Zandi

Studies on curcumin, the principal element of turmeric powder, have demonstrated several biological actions such as antibacterial activity. Evaluation of new analogs or new compounds of curcumin for their antibacterial effect is interesting for researchers. In this in vitro study, we attempted to test the antibacterial activity of indium curcumin (In(CUR)(3)), indium diacetylcurcumin (In(DAC)(3)), and diacetylcurcumin (DAC) in comparison with curcumin. The action of these agents were examined on Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 14990), Pseudomonas aeruginosa (ATCC 27853), and Escerichia coli (ATCC 25922). Curcumin was effective against S. aureus and S. epidermidis, whereas In(DAC)(3) showed activity against …


A New Application Of Spatiotemporal Analysis For Detecting Demographic Variations In Aids Mortality: An Example From Florida, Yuwen Chiu, Chiehwen Ed Hsu Nov 2008

A New Application Of Spatiotemporal Analysis For Detecting Demographic Variations In Aids Mortality: An Example From Florida, Yuwen Chiu, Chiehwen Ed Hsu

Chiehwen Ed Hsu

The purpose of the present study was to characterize, geographically and temporally, the patterns of acquired immune deficiency syndrome (AIDS) death disparity in 67 Florida jurisdictions, and to determine if the detected trends varied according to age, race, and sex. The space-time scan statistic proposed by Kulldorff et al was used to examine the excess AIDS deaths that occurred between 1987 and 2004. Results were geographically referenced in maps using EpiInfo and EpiMap made available by the Centers for Disease Control. Miami-Dade and the nearby counties including Broward, Martin, and Palm Beach are the most likely clusters (observed/expected: 1505.16) with …


The ‘Yin And Yang’ Of Epidemiology — The North West Adelaide Health Study As An Example Of The Successful Merging Of Quantitative And Qualitative Ways Of Thinking, Kay Price, Anne Taylor Nov 2008

The ‘Yin And Yang’ Of Epidemiology — The North West Adelaide Health Study As An Example Of The Successful Merging Of Quantitative And Qualitative Ways Of Thinking, Kay Price, Anne Taylor

Anne Taylor

The North West Adelaide Health Study (NWAHS) is used as an example to show how quantitative and qualitative research contribute to producing an innovative knowledge network.


Lexical And Indexical Cues In Masking By Competing Speech, Karen S. Helfer, Richard L. Freyman Nov 2008

Lexical And Indexical Cues In Masking By Competing Speech, Karen S. Helfer, Richard L. Freyman

Karen S Helfer

Three experiments were conducted using the TVM sentences, a new set of stimuli for competing speech research. These open-set sentences incorporate a cue name that allows the experimenter to direct the listener's attention to a target sentence. The first experiment compared the relative efficacy of directing the listener's attention to the cue name versus instructing the subject to listen for a particular talker's voice. Results demonstrated that listeners could use either cue about equally well to find the target sentence. Experiment 2 was designed to determine whether differences in intelligibility among talkers' voices that were noted when three utterances were …


The Effects Of Lactation And Negative Energy Balance On Kisspeptin-Stimulated Luteinizing Hormone And Growth Hormone In Dairy Cows, Brian K. Whitlock, Joseph A. Daniel, Robyn R. Wilborn, Herris S. Maxwell, Barbara P. Steele, James L. Sartin Nov 2008

The Effects Of Lactation And Negative Energy Balance On Kisspeptin-Stimulated Luteinizing Hormone And Growth Hormone In Dairy Cows, Brian K. Whitlock, Joseph A. Daniel, Robyn R. Wilborn, Herris S. Maxwell, Barbara P. Steele, James L. Sartin

Brian K Whitlock, PhD, DVM, DACT

Kisspeptin, a neuroendocrine regulator of gonadotropin releasing hormone, is hypothesized to integrate nutrition and hormones critical to metabolism and the regulation of reproduction. Since the negative energy balance of early lactation is associated with reduced fertility via suppression of gonadotropin secretion and enhanced growth hormone (GH) responsiveness, this experiment was designed to determine the effects of stage of lactation and negative energy balance on kisspeptin-10 (Kp-10) stimulated luteinizing hormone (LH) and GH concentrations. Five nonlactating [5.1 ± 0.8 (SEM) years; 577 ± 19 kg body weight (BW)] and five lactating [4.1 ± 0.6 years; 608 ± 11 kg BW] multiparous …


The Effect Of Heterogeneous Infectious Period And Contagiousness On The Dynamics Of Salmonella Transmission In Dairy Cattle, Cristina Lanzas, S Brien, R Ivanek, Y Lo, P P. Chapagain, K A. Ray, P Ayscue, L D. Warnick, Y T. Grohn Nov 2008

The Effect Of Heterogeneous Infectious Period And Contagiousness On The Dynamics Of Salmonella Transmission In Dairy Cattle, Cristina Lanzas, S Brien, R Ivanek, Y Lo, P P. Chapagain, K A. Ray, P Ayscue, L D. Warnick, Y T. Grohn

Cristina Lanzas

The objective of this study was to address the impact of heterogeneity of infectious period and contagiousness on Salmonella transmission dynamics in dairy cattle populations. We developed three deterministic SIR-type models with two basic infected stages (clinically and subclinically infected). In addition, model 2 included long-term shedders, which were defined as individuals with low contagiousness but long infectious period, and model 3 included super-shedders (individuals with high contagiousness and long infectious period). The simulated dynamics, basic reproduction number (R0) and critical vaccination threshold were studied. Clinically infected individuals were the main force of infection transmission for models 1 and 2. …


The Risk And Control Of Salmonella Outbreaks In Calf-Raising Operations: A Mathematical Modeling Approach, Cristina Lanzas, L D. Warnick, R Ivanek, P Ayscue, D V. Nydam, Y T. Grohn Nov 2008

The Risk And Control Of Salmonella Outbreaks In Calf-Raising Operations: A Mathematical Modeling Approach, Cristina Lanzas, L D. Warnick, R Ivanek, P Ayscue, D V. Nydam, Y T. Grohn

Cristina Lanzas

Salmonellosis in calves has economic and welfare implications, and serves as a potential source of human infections. Our objectives were to assess the risk of Salmonella spread following its introduction into a herd of pre-weaned calves and to evaluate the efficacy of control strategies to prevent and control outbreaks. To meet these objectives, we developed a model of Salmonella transmission within a pre-weaned group of calves based on a well documented outbreak of salmonellosis in a calf-raising operation and other literature. Intervention scenarios were evaluated in both deterministic and stochastic versions of the model. While the basic reproduction number (R0) …