Browsing by Author "Hungerford, Laura L."

Now showing 1 - 13 of 13
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    Applying Time-Valued Knowledge for Public Health Outbreak Response
    Schlitt, James Thomas (Virginia Tech, 2019-06-21)
    During the early stages of any epidemic, simple interventions such as quarantine and isolation may be sufficient to halt the spread of a novel pathogen. However, should this opportunity be missed, substantially more resource-intensive, complex, and societally intrusive interventions may be required to achieve an acceptable outcome. These disparities place a differential on the value of a given unit of knowledge across the time-domains of an epidemic. Within this dissertation we explore these value-differentials via extension of the business concept of the time-value of knowledge and propose the C4 Response Model for organizing the research response to novel pathogenic outbreaks. First, we define the C4 Response Model as a progression from an initial data-hungry collect stage, iteration between open-science-centric connect stages and machine-learning centric calibrate stages, and a final visualization-centric convey stage. Secondly we analyze the trends in knowledge-building across the stages of epidemics with regard to open and closed access article publication, referencing, and citation. Thirdly, we demonstrate a Twitter message mapping application to assess the virality of tweets as a function of their source-profile category, message category, timing, urban context, tone, and use of bots. Finally, we apply an agent-based model of influenza transmission to explore the efficacy of combined antiviral, sequestration, and vaccination interventions in mitigating an outbreak of an influenza-like-illness (ILI) within a simulated military base population. We find that while closed access outbreak response articles use more recent citations and see higher mean citation counts, open access articles are published and referenced in significantly greater numbers and are growing in proportion. We observe that tweet viralities showed distinct heterogeneities across message and profile type pairing, that tweets dissipated rapidly across time and space, and that tweets published before high-tweet-volume time periods showed higher virality. Finally, we saw that while timely responses and strong pharmaceutical interventions showed the greatest impact in mitigating ILI transmission within a military base, even optimistic scenarios failed to prevent the majority of new cases. This body of work offers significant methodological contributions for the practice of computational epidemiology as well as a theoretical grounding for the further use of the C4 Response Model.
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    Distribution of Theileria orientalis in Virginia Market Cattle, 2018-2020
    Telionis, Alex; Lahmers, Kevin K.; Todd, Michelle; Carbonello, Amanda; Broaddus, Charles C.; Bissett, Carolynn J.; Hungerford, Laura L. (MDPI, 2022-11-15)
    Theileria orientalis, genotype Ikeda, was recently detected in North America. Determining the emerging distribution of this pathogen is critical for understanding spread and developing management strategies. Whole blood samples were collected from cattle at Virginia livestock markets from September 2018 through December 2020. Animals were tested for T. orientalis using a universal and then genotype specific real-time PCR based on the MPSP gene. Prevalence for each genotype was analyzed for temporal trends and mapped by county. Spatial patterns were compared between genotypes and assessed for associations with habitat features, cattle movements through cattle markets and county proximity. Overall, 212 of 1980 samples tested positive for T. orientalis with an overall prevalence of 8.7% (172/1980) for genotype Ikeda, 1.8% (36/1980) for genotype Chitose, 0.2% (3/1980) for genotype Buffeli. The Ikeda genotype increased over time in northern and southwestern Virginia markets. The Ikeda and Chitose genotypes occurred in different regions, with little overlap, but for each genotype, spatial distribution was associated with a combination of cattle movements and environmental factors. Genotype specific qPCR testing and surveillance of cattle from across a wide area of Virginia are providing information on temporal, spatial, and other patterns for this emerging disease.
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    Incidence of Health and Behavior Problems in Service Dog Candidates Neutered at Various Ages
    Zlotnick, Marta G.; Corrigan, Virginia Kiefer; Griffin, Erin; Alayon, Megan; Hungerford, Laura L. (2019-10-08)
    Saint Francis Service Dogs (SFSD) trains dogs to aid people with multiple sclerosis, brain injury, and many other conditions. Organizations like SFSD must carefully consider when to neuter dogs to give them the best chance at successfully completing lengthy and expensive training. The objective of this retrospective cohort study was to assess differences in the incidence of health or behavior problems leading to dismissal between dogs neutered at different ages. Data on 245 dogs-including birth date, sex, neuter date, dismissal or successful completion of training, and (where applicable) reason for dismissal-were collected from SFSD records. Age-at-neuter was grouped (<7 months; 7-11 months; >11 months) and compared for dogs who successfully completed training and dogs who were dismissed. Dogs neutered from 7 to 11 months of age were dismissed at a significantly lower overall rate than dogs neutered at an older or younger age. There were no differences between males and females. Labrador and golden retrievers were less likely to be dismissed than other breeds. This pattern was the same for dismissals for behavioral reasons. Dogs neutered at <7 months had more than twice the risk for health-related dismissals as dogs neutered at any older age and this pattern held for orthopedic dismissals. Labradors were at higher risk for orthopedic-related dismissal than golden retrievers and all other breeds. This study suggests that there is a relationship between dogs' age at neuter and the incidence of health and behavioral problems that can lead to dismissal from service dog training.
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    Integrative Analyses of Environmental Factors Impacting Animal and Human Health Through Perturbations of Microbial Communities
    Caswell, Clayton C.; Ahmed, S. Ansar; Sriranganathan, Nammalwar; Allen, Irving C.; Luo, Xin; Meng, Xiang-Jin; Theus, Michelle H.; Yuan, Lijuan; Hungerford, Laura L.; Pierson, Bill; Rist, Cassidy (Virginia Tech, 2017-05-15)
    The term ‘microbiome’ defines the vast microscopic communities collectively composed of bacteria, viruses, fungi, and eukaryotic protozoans that inhabit myriad niches, including environmental locales, as well as the surfaces and organ systems of animals and humans. Recent empirical evidence clearly demonstrates the substantial role that microbiomes play in facilitating the homeostasis of complex biological systems, and as such, perturbation of these microbial communities can lead to dysregulation of environmental ecosystems, significant declines in animal and human health, and the emergence of detrimental conditions, such as infectious diseases, inflammatory disorders, and neurodegenerative aliments. A variety of factors are involved in shifting the composition and complexity (i.e., the functionality) of microbiomes, including the contamination of soil, water, and food sources with toxicants, pharmaceuticals, and antimicrobial compounds...
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    Microbiology at the Nexus of Food, Energy, Water and Health
    Badgley, Brian D.; Boyer, Renee R.; Dufour, Monique; He, Zhen (Jason); Hungerford, Laura L.; Kiechle, Melanie A.; Kuhn, David D.; Lawrence, Christopher B.; Marr, Linsey C.; Melville, Stephen B.; Pierson, F. William; Popham, David L.; Senger, Ryan S.; Sumner, Susan S.; Vinatzer, Boris A.; Schmale, David G. III; Stevens, Ann M. (Virginia Tech, 2017-05-15)
    Microorganisms are absolutely critical to myriad aspects of the human existence. As a field of study, microbiology could and should serve a greater role on our campus, as it has key connections with many of the Destination and Strategic Growth Areas. We propose the development of a broad concept area in microbiology that will serve as a nexus, as it is applied to solve critical global challenges related to food, energy, water and health, by bridging across multiple disciplines at Virginia Tech (VT). There is increasing recognition of microbes as a driving force in natural and managed environments, biological processes, and ecological structure. Conversely, the importance of culture and individual behavior in affecting microbial communities has also become apparent....
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    Modeling the Potential for Vaccination to Diminish the Burden of Invasive Nontyphoidal Salmonella Disease in Young Children in Mali, West Africa
    Bornstein, Kristin; Hungerford, Laura L.; Hartley, David; Sorkin, John D.; Tapia, Milagritos D.; Sow, Samba O.; Onwuchekwa, Uma; Simon, Raphael; Tennant, Sharon M.; Levine, Myron M. (PLOS, 2017-02-09)
    A surveillance program at Gabriel Touré Hospital in Mali observed a high burden of invasive disease caused by non-typhoidal Salmonella (iNTS). This surveillance program was originally instituted to measure the amount of invasive disease (e.g., septicemia, meningitis) caused by two bacteria that invade the respiratory tract: Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae (pneumococcus). While documenting the burden of these pathogens, the surveillance program also found that serotypes of iNTS, mainly Salmonella Typhimurium and Salmonella Enteritidis, were common causes of severe invasive disease. As the number of cases of Hib and pneumococcus markedly decreased following the introduction of relevant vaccines, the relative threat of iNTS increased. Little is known about the reservoir of iNTS, whether it resides in humans, animals, or the environment, or how it is spread to susceptible children. Without this knowledge, it is not possible to employ certain disease control methods useful in interrupting the transmission of other pathogens. Therefore, vaccination remains the one promising control strategy for this disease. Our research modeled the potential effects of introducing an iNTS vaccine. The findings are of great importance to Mali and other developing countries where young children are at a high risk of developing iNTS disease.
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    One Health Approach to Emerging Viral and Vector-borne Diseases
    Bertke, Andrea S.; Paulson, Sally L.; Rist, Cassidy; Kolivras, Korine N.; Hungerford, Laura L.; Alexander, Kathleen A.; Ragan, Valerie; Gohlke, Julia M. (Virginia Tech, 2017-05-15)
    Understanding the spatial and temporal distribution of novel infectious diseases is among the most important and challenging tasks for the coming century. Emerging viral and vector-borne diseases are a significant threat to humans, animals, and plants across the globe. In the previous 40 years, the number of new emergent pathogens affecting humans have increased more than 300%. Approximately 60% of these organisms are zoonotic, transferred to humans from animals, and the number of vector-borne pathogens have increased more than 300% in the same time frame. Viruses affecting plants impact agricultural food sources, as well as regional and global economies. Understanding how these pathogens emerge and evolve, transmit from animals to humans and adapt to new hosts to increase morbidity and mortality, spread geospatially and temporally through regions or the global community, and how human behavior and beliefs impact these processes are of critical importance...
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    Optimizing Pooled Testing for Estimating the Prevalence of Multiple Diseases
    Warasi, Md S.; Hungerford, Laura L.; Lahmers, Kevin K. (Springer, 2022-08-12)
    Pooled testing can enhance the efficiency of diagnosing individuals with diseases of low prevalence. Often, pooling is implemented using standard groupings (2, 5, 10, etc.). On the other hand, optimization theory can provide specific guidelines in finding the ideal pool size and pooling strategy. This article focuses on optimizing the precision of disease prevalence estimators calculated from multiplex pooled testing data. In the context of a surveillance application of animal diseases, we study the estimation efficiency (i.e., precision) and cost efficiency of the estimators with adjustments for the number of expended tests. This enables us to determine the pooling strategies that offer the highest benefits when jointly estimating the prevalence of multiple diseases, such as theileriosis and anaplasmosis. The outcomes of our work can be used in designing pooled testing protocols, not only in simple pooling scenarios but also in more complex scenarios where individual retesting is performed in order to identify positive cases. A software application using the shiny package in R is provided with this article to facilitate implementation of our methods. Supplementary materials accompanying this paper appear online.
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    A retrospective analysis of bull:cow ratio effects on pregnancy rates of beef cows previously enrolled in fixed-time artificial insemination protocols
    Timlin, Claire L.; Dias, Nicholas W.; Hungerford, Laura L.; Redifer, Tracey; Currin, John F.; Mercadante, Vitor R. G. (2021-07)
    This retrospective study aimed to determine if the number of cows exposed per bull affects pregnancy rates of cows returning to estrus after fixed-time artificial insemination (FTAI). Data were compiled over the course of 13 breeding seasons (six fall and seven spring seasons) between 2010 and 2017 from the Virginia Department of Corrections herd. Available records contained data from 17 farms and 324 groups of cows (average 47 cows/group). Multiparous cows and heifers (average age per group: 5.11 +/- 0.14 yr; n = 14,868) were exposed to FTAI. After FTAI, animals were placed on pasture with bulls diagnosed as fertile by a breeding soundness exam for natural service of cows who did not become pregnant to FTAI (n = 7,248; average 22 cows/group). Animals were classified as pregnant to FTAI, to natural service on first return to estrus, or to natural service on second or subsequent estrus determined by fetal aging at pregnancy diagnosis. The bull:cow ratio for the total number of cows exposed ranged from 1:9 to 1:73 with an average of 1:31. The bull:cow ratio considering only open cows exposed after FTAI ranged from 1:2 to 1:44 with an average of 1:14. There was significant negative, small correlation between the bull:cow ratio for total number of cows exposed and return to estrus pregnancy rate in fall breeding seasons (P = 0.01, r(2) = 0.04) but not in spring (P = 0.90). There was a significant negative, small correlation between bull:cow ratio of open cows exposed and pregnancy rates to first return to estrus in fall herds with a single sire (P < 0.001, r(2) = 0.11). There was no correlation in fall herds using multiple sires or spring herds (P = 0.12). Bull:cow ratio accounted for only 1-11% of variation in the pregnancy rates, thus we conclude that a decreased bull:cow ratio (up to 1:73) did not affect natural service return to estrus pregnancy rate. Cattlemen may consider a reduced number of bulls needed for natural service breeding after FTAI, which can decrease bull related costs and increase the economic feasibility of adopting FTAI protocols.
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    Social network analysis and whole-genome sequencing to evaluate disease transmission in a large, dynamic population: A study of avian mycobacteriosis in zoo birds
    Witte, Carmel; Fowler, James H.; Pfeiffer, Wayne; Hungerford, Laura L.; Braun, Josephine; Burchell, Jennifer; Papendick, Rebecca; Rideout, Bruce A. (PLoS, 2021-06-09)
    This study combined a social network analysis and whole-genome sequencing (WGS) to test for general patterns of contagious spread of a mycobacterial infection for which pathways of disease acquisition are not well understood. Our population included 275 cases diagnosed with avian mycobacteriosis that were nested in a source population of 16,430 birds at San Diego Zoo Wildlife Alliance facilities from 1992 through mid-2014. Mycobacteria species were determined using conventional methods and whole genome sequencing (WGS). Mycobacterium avium avium (MAA) and Mycobacterium genavense were the most common species of mycobacteria identified and were present in different proportions across bird taxa. A social network for the birds was constructed from the source population to identify directly and indirectly connected cases during time periods relevant to disease transmission. Associations between network connectivity and genetic similarity of mycobacteria (as determined by clusters of genotypes separated by few single nucleotide polymorphisms, or SNPs) were then evaluated in observed and randomly generated network permutations. Findings showed that some genotypes clustered along pathways of bird connectivity, while others were dispersed throughout the network. The proportion of directly connected birds having a similar mycobacterial genotype was 0.36 and significant (p<0.05). This proportion was higher (0.58) and significant for MAA but not for M. genavense. Evaluations of SNP distributions also showed genotypes of MAA were more related in connected birds than expected by chance; however, no significant patterns of genetic relatedness were identified for M. genavense, although data were sparse. Integrating the WGS analysis of mycobacteria with a social network analysis of their host birds revealed significant genetic clustering along pathways of connectivity, namely for MAA. These findings are consistent with a contagious process occurring in some, but not all, case clusters.
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    Spatiotemporal network structure among "friends of friends" reveals contagious disease process
    Witte, Carmel; Hungerford, Laura L.; Rideout, Bruce A.; Papendick, Rebecca; Fowler, James H. (PLOS, 2020-08-06)
    Disease transmission can be identified in a social network from the structural patterns of contact. However, it is difficult to separate contagious processes from those driven by homophily, and multiple pathways of transmission or inexact information on the timing of infection can obscure the detection of true transmission events. Here, we analyze the dynamic social network of a large, and near-complete population of 16,430 zoo birds tracked daily over 22 years to test a novel "friends-of-friends"strategy for detecting contagion in a social network. The results show that cases of avian mycobacteriosis were significantly clustered among pairs of birds that had been in direct contact. However, since these clusters might result due to correlated traits or a shared environment, we also analyzed pairs of birds that had never been in direct contact but were indirectly connected in the network via other birds. The disease was also significantly clustered among these friends of friends and a reverse-time placebo test shows that homophily could not be causing the clustering. These results provide empirical evidence that at least some avian mycobacteriosis infections are transmitted between birds, and provide new methods for detecting contagious processes in large-scale global network structures with indirect contacts, even when transmission pathways, timing of cases, or etiologic agents are unknown.
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    Subsewershed SARS-CoV-2 Wastewater Surveillance and COVID-19 Epidemiology Using Building-Specific Occupancy and Case Data
    Cohen, Alasdair; Maile-Moskowitz, Ayella; Grubb, Christopher; Gonzalez, Raul A.; Ceci, Alessandro; Darling, Amanda; Hungerford, Laura L.; Fricker, Ronald D. Jr.; Finkielstein, Carla V.; Pruden, Amy; Vikesland, Peter J. (American Chemical Society, 2022-05-01)
    To evaluate the use of wastewater-based surveillance and epidemiology to monitor and predict SARS-CoV-2 virus trends, over the 2020-2021 academic year we collected wastewater samples twice weekly from 17 manholes across Virginia Tech's main campus. We used data from external door swipe card readers and student isolation/quarantine status to estimate building-specific occupancy and COVID-19 case counts at a daily resolution. After analyzing 673 wastewater samples using reverse transcription quantitative polymerase chain reaction (RT-qPCR), we reanalyzed 329 samples from isolation and nonisolation dormitories and the campus sewage outflow using reverse transcription digital droplet polymerase chain reaction (RT-ddPCR). Population-adjusted viral copy means from isolation dormitory wastewater were 48% and 66% higher than unadjusted viral copy means for N and E genes (1846/100 mL to 2733/100 mL/100 people and 2312/100 mL to 3828/100 mL/100 people, respectively; n = 46). Prespecified analyses with random-effects Poisson regression and dormitory/cluster-robust standard errors showed that the detection of N and E genes were associated with increases of 85% and 99% in the likelihood of COVID-19 cases 8 days later (incident-rate ratio (IRR) = 1.845, p = 0.013 and IRR = 1.994, p = 0.007, respectively; n = 215), and one-log increases in swipe card normalized viral copies (copies/100 mL/100 people) for N and E were associated with increases of 21% and 27% in the likelihood of observing COVID-19 cases 8 days following sample collection (IRR = 1.206, p < 0.001, n = 211 for N; IRR = 1.265, p < 0.001, n = 211 for E). One-log increases in swipe normalized copies were also associated with 40% and 43% increases in the likelihood of observing COVID-19 cases 5 days after sample collection (IRR = 1.403, p = 0.002, n = 212 for N; IRR = 1.426, p < 0.001, n = 212 for E). Our findings highlight the use of building-specific occupancy data and add to the evidence for the potential of wastewater-based epidemiology to predict COVID-19 trends at subsewershed scales.
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    Theileria orientalis Ikeda Genotype: Implications for Cattle Health in Virginia
    Oakes, Vanessa Jacqueline (Virginia Tech, 2022-06-30)
    Of the four most economically important tickborne diseases of cattle in the world, two have been identified in Virginia, occasionally as co-infections: anaplasmosis and theileriosis. The latter is caused by the emerging infectious agent, the Theileria orientalis complex, in particular the Ikeda and Chitose genotypes. These organisms are carried by the ixodid tick, Haemaphysalis longicornis, recently identified in the United States. Our work has been focused on initially identifying the protozoal organisms, crafting assays to aid in the identification of these organisms in clinically affected animals, and briefly examining the rate of co-occurrence of theileriosis and anaplasmosis. This is important, as Anaplasma marginale - the most common etiologic agent of anaplasmosis in cattle in Virginia - is treatable with a safe, effective, FDA-approved compound, whereas there is no currently approved treatment for theileriosis. Finally, we seek to contextualize theilerosis as a cause of infectious bovine anemia (IBA) and its expected economic impact on the cattle industry in Virginia.