APPEX Seeds

Understanding epidemiology of AMR bacteria in humans, animals, and the environment

Shigetoshi Eda

Description

Domestic animals, wildlife, and the environment can serve as reservoirs and sources of antimicrobial-resistant (AMR) bacteria and antimicrobial resistance genes. These resistant bacteria and resistance genes can spread among animals, humans, and the environment through multiple pathways, including the food chain, direct animal contact, water, and other environmental routes. In some cases, transmission of AMR bacteria from animals or environmental sources can contribute to human infections and outbreaks. Therefore, understanding the molecular epidemiology and transmission dynamics of AMR-associated pathogenic bacteria across humans, animals, and the environment is essential for identifying reservoirs and transmission pathways and for informing the development of effective One Health strategies to prevent and control future outbreaks.

As summarized in the document attached to this application, the project aims to generate and analyze antimicrobial resistome profiles by using samples collected around east Tennessee (UT CVM, UT Hospital, UT dairy farm, and environment). I will be leading the project having Drs. Xiang Li and Michael Mahero as collaborators. Dr. Xiang Li has expertise in NanoPore sequencing and bioinformatic analysis. Dr. Mahero and I will be responsible for the sample collection and epidemiological analysis. Dr. Mahero has access to samples from CVM. I recently talked with two entomologists (Drs. Becky Trout-Fryxell and Charity Owing) who have fly samples that could be used as samples from the dairy and environment.

The collected samples will be subjected to Nanopore sequencing to identify AMR genes, characterize mutations and other genetic determinants associated with antimicrobial resistance, and determine the bacterial hosts carrying these genes. The resulting data will then be used for molecular epidemiological analyses to investigate the spread, persistence, and dynamics of AMR genes and their bacterial hosts in the region.

Deliverables

This study will generate a preliminary cross-site profile of antimicrobial resistance (AMR) genes across human, animal, and environmental interfaces in the Knoxville area. The pilot will leverage a One Health approach, focusing on transmission-relevant environments where resistant organisms and resistance determinants are likely to move among people, animals, wastewater, soil, and produce systems.

Disciplines / expertise required

  • Math modeler who can incorporate molecular data into the model

Comments

No comments yet.

Linking Scales in Plant Disease Epidemics: From Within-Host Dynamics to Network Invasion

Sara Johnson

Description

Understanding the factors that contribute to the emergence and spread of fungal and oomycete pathogens is essential to ensuring food security worldwide.

Much like the process by which a susceptible individual becomes infected in a traditional Susceptible-Infected-Recovered model, disease occurrence in plants requires the interaction of a virulent pathogen with a susceptible host. A number of permissive conditions influence the transition of an individual plant from the susceptible state to the infected state, including environmental permissiveness (e.g., climate, temperature, and soil nutrient content), pathogen presence and virulence (e.g., genome architecture, population size, and life cycle speed), and host presence and susceptibility (e.g., abiotic stresses, plant health, and resistance genes). These factors may all change over time [Fones 2020, Singh 2023].

In this work we aim to examine how heterogeneous mathematical models and data across molecular, individual-plant, local-population, and regional-scales can be integrated to identify the mechanisms and tipping points through which an isolated infection becomes a large-scale epidemic.

Our framework has three main tiers:
-Develop a multiscale mechanistic model of within-plant infection that links pathogen recognition, stress-responsive gene expression dynamics, and the activation or suppression of plant defenses to pathogen establishment, growth, tissue damage, and the production of infectious material.
-Derive a compartmental epidemic model that describes how the disease spreads through a field, nursery, forest, or other local area.
-Treat local areas as nodes in a dynamic network, with connections representing trade, shipments, or other routes of transmission.

Please see the attached document for details of the three proposed tiers.

Deliverables

-Development of a sustained, geographically distributed research community through regular working-group meetings, webinars, and organized sessions at professional conferences.
-Development of a predictive multiscale modeling framework linking pathogen dynamics across biological and spatial scales.
-Peer-reviewed publications describing the modeling framework, methodological advances, and initial applications.
-Preliminary results that can support future collaborative grant proposals.
-Identification of new research questions and funding opportunities arising from the working group's activities.

Policy implications

The models could inform policies for plant disease surveillance, prevention, and response by identifying conditions under which outbreaks are likely to emerge and spread. This could support more effective disease management and strengthen food security.

Disciplines / expertise required

  • Plant Pathology
  • Mathematical Modeling- including sensitivity analysis, parameter identifiability and estimation / numerical methods
  • Bioinformatics and Computational Biology
  • Fluid Dynamics
  • Graph Theory/Network Science
  • Uncertainty Quantification
  • SIR Modeling
  • SIR Modeling
  • Fungal Pathogens
  • Gene Modeling
  • Math Modeling

Comments

  • https://docs.google.com/document/d/1vuTKNeRQhag6G9j2ygsxJUG9oH_rZ2mnfoA50ah5s4o/edit?usp=sharing Here is a link to the details for the proposed framework
    Sara Johnson

The Surveillance Paradox: When and How the Collection of Personal Information Creates Danger

Sheila Miller Edwards

Description

Public-health surveillance work to detect, track, and respond to the spread of disease is a state responsibility. During times of crisis, emergency measures are taken that frequently extend the authority of the state. Those measures frequently remain in place, either actively or as a legal option for future scenarios, after the crisis has passed. The purpose of this project is to better understand the interrelationship between pandemic expansion and state and corporate surveillance of individuals and groups.

The goal of the first branch of the proposed research is an improved understanding of Covid-19 pandemic containment outcomes as consequences of specific mixes of surveillance, testing, quarantine, and other strategies. How can we predict the outcome of state interventions based on native state surveillance behavior and consequent citizen trust (or lack thereof)? How can a given state adapt their behavior to improve pandemic containment?

Second: Corporate data meets state action. How was corporate data collection used by state agencies? Which corporations participated, what information did they collect and from whom? To what extent is that data still being collected and analyzed, and how is in control of that data? How did the use of non-auditable, proprietary datasets collected by corporations influence public policy, health outcomes, and disparity in access to care? Which groups are most imperiled by these practices, and how can they be protected? How did for-profit corporate actions impact the spread of Covid-19, how do they continue to spread ideologies, and what implications does this have for the expansion of future pandemics?

Finally, contact tracing via digital signatures such as Bluetooth and wifi signals has the potential to distort and misrepresent reality. How were digital signals translated into presumed contacts? What impacts do changes in those assumptions produce? What systemic distortions are introduced by those assumptions?

Deliverables

1. A comparative analysis of various government responses that includes states with varying degrees of native surveillance capacity and state authority (for example, South Korea, Taiwan, Israel, the U.K., China, and the U.S.), how they were received by citizens, and what impact they had on pandemic expansion.
2. Based on the above, a policy tool for projecting the likely outcome of surveillance actions on future outbreaks.
3. An analysis of the data collected and information created by corporations, especially technology companies. To what extent was public health intelligence privatized?
4. A public database of pandemic surveillance measures taken across nations, including their legal status and whether they were continued and/or renewed.

Policy implications

Within the U.S.: By creating better understanding of corporate-to-state data pipelines created during the pandemic and other crises, we will be in a position to evaluate their legal standing and make recommendations for regulation. Internationally: A tool for projecting outcomes of pandemic responses based on the type of surveillance and other measures used by states.
I expect the public database, and work journalists and other scholars would do using it, would also have policy implications.

Disciplines / expertise required

  • Mathematical Modeling
  • Network Science
  • Political Science/Political Theory
  • Philosophy (Privacy, Surveillance)
  • Data Science/Machine Learning/Neural Nets
  • Law (Consitutional, International, Data Privacy)
  • Sociologist/ Science and Technology Scholar
  • Public Health Epidemiologist
  • Hardware Experts (Internet of Things, Wearables)

Comments

No comments yet.

How do waning immunity and waning awareness together determine whether a new outbreak dies out or expands?

Preeti Dubey

Description

Whether a newly introduced pathogen fades out or expands depends partly on how protected the population is when the outbreak happens. That protection can arise from both biological immunity, acquired through infection or vaccination, and behavioral protection driven by awareness and risk perception. Both can wane over time, potentially creating periods when a population becomes increasingly vulnerable to outbreak expansion.
This seed builds on recent APPEX-related work examining how outbreak information, lived experience, individual concern, and protective behavior shape responses to infectious-disease threats (Silk et al. 2021, Pritchard et al., 2022, 2023; Roosa & Fefferman, 2022). These studies demonstrate that behavioral protection is dynamic and can change as individuals receive information and experience disease threats. This complements our earlier mathematical work showing that awareness, behavioral responses, intervention capacity, and stochasticity can substantially alter epidemic dynamics (Dubey et al., 2016; Laskowski et al., 2014). Building on these complementary foundations, we will investigate how waning biological immunity and changing behavioral protection jointly influence the probability that a pathogen introduction dies out or becomes established.
We propose to build on these results by coupling dynamic behavioral protection with waning biological immunity and asking how their joint decline changes the probability that a pathogen introduction becomes established. Using stochastic models, we will identify whether combinations of declining immunity and awareness create a window of vulnerability during which introductions that would previously have died out become more likely to expand. Empirical data, potentially including vaccination histories and measures of public awareness/behavioral data, can be used to evaluate and refine the framework/predictions.

Deliverables

A modeling framework and open-source code linking biological and behavioral protection; a peer-reviewed study identifying conditions under which their joint decline facilitates outbreak establishment; and a brief translating results into questions about the coordinated timing of immunization and risk communication.

Policy implications

Understanding when biological and behavioral protection decline together could help public health agencies anticipate periods of increased vulnerability and assess whether immunization and risk-communication strategies should be coordinated rather than planned independently.

Disciplines / expertise required

  • Behavioral and social science To characterize awareness, risk perception, fatigue, and their relationship with protective behavior.
  • Immunology / infectious-disease epidemiology To characterize how protection against infection and onward transmission changes over time.
  • Mathematical and stochastic modeling To formulate and analyze outbreak-establishment probabilities under changing immune and behavioral states.
  • Data science / statistics To connect the framework with vaccination, epidemiological, search, media, or other behavioral data while accounting for uncertainty and measurement limitations.
  • Public health practice and risk communication To identify decision-relevant questions and translate results into realistic intervention strategies.

Comments

  • This is an interesting idea. I'm wondering if you have specific applications in mind that you will use data from?
    Sara Johnson
  • I really like the idea of developing a general framework that jointly considers the dynamics of biological immunity and human behavioral protection. I have previously worked on behavioral responses in disease models, but I did not explicitly consider the vaccination/waning-immunity process, so I think integrating these two dynamic forms of protection could be very useful. One possible future extension would be to make the behavioral component more flexible. Behavioral protection may not simply decline as disease prevalence declines. Human responses can also change with risk perception, previous experience, public-health messaging, or policy interventions, and these responses may differ across communities. Policy and behavior could themselves form a feedback process—for example, an intervention or risk-communication campaign may increase protective behavior, while changing epidemic conditions may in turn influence policy responses. Some of these relationships might also be informed by empirical behavioral or policy data. Overall, I think the general framework is very useful, and incorporating different forms of behavioral feedback could make it applicable to a broader range of realistic scenarios.
    Jing Jiao

Can Hybrid Mechanistic–Machine Learning Models Detect Outbreak Expansion Earlier?

Preeti Dubey

Description

Detecting when localized transmission is beginning to transition into sustained outbreak expansion remains difficult because these transitions often occur precisely when transmission conditions and model performance are changing.

Recent work by Azad, Candan and collaborators provides a foundation for addressing this problem. Their broader spatio-causal framework emphasizes integration of data, causal relationships, simulations, forecasting, and decision support across complex dynamic systems (Azad et al. 2024). More recently, Karami et al. showed that adaptive ensemble approaches can improve probabilistic epidemic forecasts by dynamically changing model weights as relative model performance changes across epidemic phases, while also finding that simpler ensemble approaches can remain competitive in some settings (Karami et al. 2026).

We propose to build on these results by moving from adaptive combination of existing forecasts toward deeper integration of mechanistic and machine-learning models, with particular emphasis on outbreak turning points. We will investigate approaches in which machine learning estimates time-varying mechanistic parameters, learns structured discrepancies between mechanistic predictions and observations, or augments ordinary and partial differential-equation models directly. Mechanistic, machine-learning, ensemble, and hybrid approaches will be compared specifically on their ability to detect transitions to outbreak expansion. Rather than optimizing only average forecast error, we will evaluate lead time, transition-detection sensitivity, false alarms, and uncertainty near inflection points (see attached conceptual approach figure). The central question is whether mechanistic structure combined with data-driven adaptation provides meaningful early-warning information beyond either approach alone.

Deliverables

An open and reproducible benchmarking framework for evaluating models at outbreak turning points; implementations of promising hybrid mechanistic–ML approaches; and a peer-reviewed study identifying when hybridization improves early detection of outbreak expansion.

Policy implications

Improved detection of outbreak expansion could help public health agencies determine when changing transmission patterns warrant increased surveillance, testing, healthcare preparedness, or risk communication, while quantifying the uncertainty and realistic lead time associated with those warnings.

Disciplines / expertise required

  • Mathematical epidemiology and dynamical systems Mechanistic transmission models and interpretation of changing transmission dynamics.
  • Machine learning and statistical forecasting Hybrid architectures, time-varying parameter estimation, residual learning, and model evaluation.
  • Epidemiology and surveillance science Selection and interpretation of epidemiological, wastewater, genomic, mobility, or other surveillance signals.
  • Public health practice and decision science Defining what constitutes useful warning and how uncertainty should inform decisions.
  • Research software/data science Reproducible integration of heterogeneous surveillance data and model-comparison pipelines.

Comments

  • Hi! I'm wondering what machine learning methods you plan to use here and I'm wondering if the SINDy algorithm would be helpful here for figuring out the governing equations of this system. https://doi.org/10.1073/pnas.1517384113
    Sara Johnson

An unexplored mechanism of antimicrobial resistance: gut microbial modification of antibiotics by sulfation

Dhara Shah

Description

The gut microbiome is known to play an important role in drug metabolism, yet its potential to chemically modify antibiotics and thereby alter their antimicrobial activity remains poorly understood. We propose to investigate whether gut microbial sulfotransferases can sulfate antibiotics and alter their potency, bioavailability, or susceptibility to bacterial resistance mechanisms.

Gut microbes encode aryl-sulfate sulfotransferases (ASSTs), that can transfer sulfo groups to structurally diverse phenolic molecules. Our recent work demonstrates broad substrate promiscuity of a gut microbial ASST toward host, dietary, and pharmaceutical derived compounds. Interestingly, earlier studies showed that some bacterial sulfotransferases can sulfate certain antibiotics, but the broader significance of this chemistry for antibiotic activity and antimicrobial resistance have not been investigated.

We hypothesize that gut microbial sulfotransferases can potentially modify susceptible antibiotics and alter their antimicrobial activity. We will identify antibiotic substrates of representative gut microbial sulfotransferases, characterize antibiotic sulfation using biochemical and mass-spectrometric approaches, and determine whether sulfation changes antibiotic activity using bacterial growth and susceptibility assays. In addition, we will investigate if sulfotransferase expressing gut bacteria alter antibiotic efficacy within microbial communities. To understand the broader metabolic impact of ASSTs, we will develop an AI-assisted structure-function approach to predict their substrate specificity and identify potential substrates.

This work could uncover a previously unknown mechanism through which the gut microbiome influences antibiotic exposure and activity, establishing a mechanistic connection between microbial drug metabolism and antimicrobial resistance.

Deliverables

Identification of antibiotics that are substrates for gut microbial sulfotransferases, determination of how sulfation affects antimicrobial activity, identification of sulfotransferase genes or microbial taxa with the potential to influence antibiotic efficacy, preliminary data supporting external grant applications, and a manuscript describing gut microbial sulfation as a potential mechanism influencing antibiotic activity and antimicrobial resistance.

Policy implications

Understanding whether gut microbial metabolism alters antibiotic efficacy could inform strategies for optimizing antimicrobial use and help explain interindividual variation in antibiotic response. In the longer term, microbial drug-metabolism markers could potentially contribute to more personalized selection or dosing of antimicrobial therapies.

Disciplines / expertise required

  • Biostatistics/Bioinformatics For statistical analysis and integration of high-dimensional datasets
  • Microbial ecology Help with microbial community dynamics due to antibiotic modification
  • Evolutionary biology To help understand evolution and distribution of microbial sulfotransferases and antimicrobial resistance
  • Mathematical modeling To help develop quantitative models to predict gut microbial sulfotransferases mediated antibiotic modification and resistance at a community level
  • Data Science / Machine Learning Expertise in developing machine-learning approaches to predict ASST substrate specificity and potential antibiotic-enzyme interactions

Comments

  • Hi! Great idea! I'm wondering what type of data is available for this type of application?
    Sara Johnson

Space to Earth: Modeling Pandemic Expansion in the Commercial Space Economy

Nilesh Dixit

Description

Classical epidemiology models pandemic expansion through three foundational pillars: virus fitness, network topologies, and population susceptibility. Historically, these models have operated within the boundary conditions of Earth's biosphere and human society. However, the rapid expansion of the commercial space economy, encompassing Low Earth Orbit to cislunar habitats, space tourism, and orbital manufacturing, introduces unprecedented environmental vectors to viral evolution and transmission.

Space environments expose microbial populations to microgravity, altered fluid dynamics, fluctuating radiation levels, and operational stress. These variables alter mutation rates, viral replication mechanics, latent virus reactivation (e.g., herpesviruses), and drug-resistance profiles. Concurrently, human crews experience spaceflight-induced immune dysregulation. Despite these known phenomena, a critical research gap remains in modeling how space-passaged pathogens spread and behave upon re-entry into Earth’s biosphere. This shift translates foundational astrobiological concepts such as panspermia and virolithopanspermia (the interplanetary transport of viral agents protected within mineral, rock, or spacecraft material matrices) from theoretical origin hypotheses into immediate, anthropogenic biosafety considerations.

The question would be: “How are pandemic expansion dynamics altered when pathogen fitness, host susceptibility, and transmission networks operate across Earth-space environments?”

This research would aim to bridge space biology and terrestrial epidemiology to build predictive models, risk-assessment tools, and policy frameworks necessary to prevent space-linked disease outbreaks from escalating into global public health threats.

Deliverables

An integrated SEIR (Susceptible-Exposed-Infectious-Recovered)-Space model that adapts traditional terrestrial infection modeling to the unique physics, physiology, and logistics of human spaceflights.
Establishing a Space Viral Risk Benchmark- a comparative matrix ranking viral families by their sensitivity to microgravity, radiation, altered fluid dynamics, and spaceflight-associated host conditions
Whitepaper & Legislative Brief: A policy-oriented analysis for space regulatory bodies and public health agencies identifying gaps in current Earth–space biosafety governance and developing evidence-based recommendations for international standards governing pathogen monitoring, containment, reporting, and re-entry associated with human spaceflights.

Policy implications

This research has potential to develop an evidence-based Earth–Space Biosafety Governance Framework addressing five emerging policy domains:
Planetary protection and human-mediated back-contamination,
Biological risk assessment within commercial-space licensing,
Spaceports as potential future international points of entry,
Emergency reentry and isolation protocols, and
Pathogen surveillance, data sharing, and outbreak reporting.

Disciplines / expertise required

  • Space Economy & Market Intelligence
  • Space/Astrobiology
  • Virology and Immunology
  • Mathematical Epidemiology
  • Network Science & Data Science
  • Space Systems Engineering
  • Public Health, Space Law & Policy
  • Mathematical and Computational Modeling To formulate and analyze modeling framework under changing environments and difference spaces.

Comments

  • Thank you for sharing this fascinating idea. I was really intrigued by the connection between space biology and terrestrial epidemic dynamics. Looking at the figure, I was also wondering if Earth, LEO, and cislunar environments could be considered as connected environments with different pathogen fitness, host susceptibility, and transmission patterns. I also wonder how differences in gravity, radiation, and spatial/environmental scales across these settings could be incorporated into the model, since these may influence both pathogen and host dynamics. It would be interesting to explore how these changes ultimately affect the probability that a pathogen becomes established after re-entry to Earth.
    Preeti Dubey
  • An intriguing research question! Have you considered including the host microbiome as part of host susceptibility? Spaceflight could change the microbiome and its metabolic functions, which might affect susceptibility to infection and pathogen behavior. I also wonder how persistent these changes are after reentry. If a space associated phenotype disappears once the organism or host returns to terrestrial conditions, wouldn't its epidemiological significance be very different from a stable change that persists after reentry?
    Dhara Shah

Ecology-Informed Microbiome Modeling for Microbial Dispersal and Persistence in Indoor Environments

Rui Li

Description

Indoor environments, occupants, and microbiomes constitute a system of ecosystems with extensive interactions that impact one another. Understanding the interactions between these systems is essential to develop strategies for effective management of the indoor environment and its inhabitants to enhance public health and well-being.

Microorganisms introduced into buildings may disappear rapidly, persist locally, or disperse across connected spaces. However, the ecological and environmental processes governing these different outcomes remain poorly understood. Microbial communities are shaped by deterministic selection, dispersal-related processes, and stochastic events, while indoor factors such as ventilation, temperature, humidity, spatial connectivity, and human occupancy may further influence their persistence and distribution.

This working group proposes to integrate existing long-term building microbiome monitoring datasets with ecological community-assembly modeling, including the Normalized Stochasticity Ratio (NST) and iCAMP, to characterize the relative roles of deterministic and stochastic processes and identify ecological signatures associated with microbial persistence and spatial distribution.

We will further explore machine-learning approaches that integrate microbial community profiles, ecological-process estimates, spatial information, and indoor environmental variables to identify conditions associated with microbial persistence and dispersal across indoor spaces. A central goal will be to determine when the inclusion of ecological processes improves prediction

beyond environmental modeling alone and whether identified relationships are transferable across buildings, occupancy patterns, and microbial systems.

By linking microbial ecology, building science, and predictive modeling, this project seeks to develop a mechanistic and predictive framework for understanding how localized microbial populations may become persistent and spatially distri

Deliverables

Expected outcomes include a reproducible computational framework integrating microbial community data, ecological assembly models, environmental metadata, and predictive modeling; identification of ecological and environmental factors associated with microbial persistence and spatial distribution; and evaluation of whether ecological-process modeling improves prediction across indoor environments.

The working group will also aim to develop transferable hypotheses for how indoor conditions influence microbial dispersal, produce at least one peer-reviewed publication, and provide recommendations for future indoor microbial and epidemiological surveillance studies.

Policy implications

The project could help identify indoor environmental conditions that warrant enhanced microbial or pathogen surveillance and provide evidence for evaluating ventilation and building-management strategies during infectious-disease outbreaks.

Disciplines / expertise required

  • Environmental Microbiology and Microbial Ecology To characterize microbial communities and apply community-assembly models such as NST and iCAMP to evaluate deterministic, stochastic, and dispersal-related ecological processes.
  • Building Science and Indoor Environmental Engineering To characterize ventilation, temperature, humidity, spatial connectivity, and occupancy and determine how these factors influence microbial persistence and movement across indoor spaces.
  • Machine Learning and Computational Modeling To develop and evaluate models integrating microbial, ecological, spatial, and environmental information and assess model transferability across buildings and datasets.
  • Bioinformatics and Microbiome Data Science To harmonize microbiome sequencing datasets and environmental metadata and develop reproducible analytical workflows across heterogeneous studies.
  • Infectious Disease Epidemiology and Environmental Surveillance To determine when microbial dispersal patterns are relevant to pathogen exposure and transmission and connect ecological findings with outbreak surveillance and public-health applications.

Comments

  • From an environmental microbiologist’s perspective, this proposal addresses an important question: why do some microorganisms persist and spread within buildings while others disappear? Linking microbial community assembly with building conditions could help explain the ecological processes behind these outcomes. I particularly value the effort to test whether ecological information improves predictions across different buildings. This work could strengthen the scientific basis for indoor microbial monitoring and help guide building-management strategies that support healthier indoor environments.
    Dr. Liu Cao
  • From an environmental microbiologist’s perspective, this proposal addresses an important question: why do some microorganisms persist and spread within buildings while others disappear? Linking microbial community assembly with building conditions could help explain the ecological processes behind these outcomes. I particularly value the effort to test whether ecological information improves predictions across different buildings. This work could strengthen the scientific basis for indoor microbial monitoring and help guide building-management strategies that support healthier indoor environments.
    Dr. Liu Cao
  • This is a very interesting framework. One issue that may be important to consider is how to distinguish true microbial persistence within an indoor environment from repeated reintroduction from occupants, outdoor air, or other connected spaces. Similar temporal patterns could arise from these different processes, but they would have very different ecological interpretations. Incorporating temporal source information, spatial connectivity, or source-tracking approaches where available could help strengthen the inference of persistence and dispersal and provide an additional way to validate the ecological modeling results.
    Xinghan Zhao
  • Are historical contingency and priority effects important in these systems? It could be interesting to ask when knowing the order of microbial arrival improves understanding of community composition or persistence within a building.
    Kelsey Lyberger
  • One potentially useful extension would be to frame the building as a dynamic metapopulation network and ask whether there is a measurable threshold separating microbial fade-out from sustained persistence and spatial expansion. Could the temporal and spatial data be used to estimate an “environmental expansion” metric analogous to a reproduction number? For example, the expected number of newly colonized spaces generated from an occupied space before local clearance? Integrating such a threshold with NST/iCAMP and building-connectivity data could help translate community-assembly results into a mechanistic early-warning framework. This could provide a basis for testing how ventilation, humidity, filtration, or other building interventions shift the system from expansion toward fade-out.
    Benti Deresa Gelalcha
  • I really love the direction of your proposal and its focus on the actual mechanics of why microbes persist indoors. Beyond building structures and ecological parameters, I wonder how crucial it is to factor in the human element. Specifically, how can this predictive framework account for host susceptibility and socio-cultural proxies like standard of living, lifestyle choices, and cultural preferences? Is it possible that these human-centric factors actually exert a more significant deterministic pressure on microbial communities than the ecological or physical building parameters alone?
    Nilesh Dixit
  • Seems like a framework that could lead to a better understanding for how microorganisms persist and transmit within the built environment. It is significant that this would translate results of one building into another. I wonder how this may look as an applied approach to microorganism management
    Clifford Swanson
  • Interesting idea. One dimension that could also be added over here is to understand connections between persistence driven by dormant microbes vs actively growing microbes. Sequencing would generally show the presence of both. However, could dormant microbes show different patterns of persistence from actively growing microbes?
    Dhara Shah

How do competing biological clocks shape epidemic expansion at thermal limits?

Kelsey Lyberger

Description

Temperature accelerates many biological processes involved in transmission, including parasite replication, pathogen development, vector activity, and host contact rates. Hotter temperatures can also shorten host or vector lifespan, reduce fecundity, and disrupt transmission. Epidemic expansion into hotter environments may depend on whether the parasite completes the steps required for onward transmission before the host, vector, or infectious stage dies.

Expansion limits may therefore be shaped by temperature-dependent biological clocks. For vector-borne diseases, this may mean comparing pathogen incubation time with vector lifespan. For other parasites or environmentally transmitted pathogens, the relevant race may involve parasite replication versus host survival, environmental persistence versus infectious-stage mortality, immune clearance versus replication, or development of infectious stages versus exposure to a susceptible host. Possible systems include dengue, malaria, West Nile virus, leishmaniasis, tick-borne pathogens, and helminths.

Deliverables

This working group would develop a comparative framework for identifying biological clocks that constrain epidemic expansion at thermal limits. We would define metrics that compare the time required for parasite or pathogen development with the expected lifespan of the host, vector, or infectious stage across temperatures. We would apply these metrics to selected case studies, such as dengue, malaria, West Nile virus, or leishmaniasis, to evaluate whether competing biological clocks help explain observed or projected limits of expansion.

Policy implications

This framework could improve expansion risk maps by identifying where thermal conditions permit transmission, where heat constrains expansion, and where small temperature changes may shift the balance between parasite replication and host or vector survival.

Disciplines / expertise required

  • Thermal physiology to define the relevant clocks and how they scale with temperature.
  • Vector biology to connect pathogen development, vector survival, biting behavior, and competence to transmission.
  • Parasitology to compare how parasite life cycles create different timing constraints across systems.
  • Mathematical modeling to formalize the competing-clocks idea.
  • Disease ecology to link within-host, vector, and environmental processes to population-level expansion.

Comments

  • This is a very interesting framework, especially the idea of comparing competing temperature-dependent biological clocks across different transmission systems. One point that may be worth clarifying is how the clocks would be normalized or compared across systems, since incubation, survival, environmental persistence, and exposure operate at different biological scales. A common dimensionless metric, such as the ratio between time required for onward transmission and the expected duration of the relevant host, vector, or infectious stage, could make the framework more transferable across diseases and strengthen the comparative analysis.
    Xinghan Zhao
  • The competing biological clocks framework is compelling. It would be helpful to clarify how these clocks will be selected and standardized across different disease systems, and whether the framework will distinguish constraints on geographic expansion from changes in transmission intensity within already suitable areas.
    Rui Li
  • I really like the competing biological clocks idea. One possible extension would be to incorporate the temperature-dependent clocks directly into an epidemiological model to examine how they jointly shape R0 or another transmission threshold. This could then be combined with spatial and seasonal temperature data in a GIS framework to map where disease expansion is possible versus thermally constrained.
    Jing Jiao

LIQUID-M (Leveraging Insights from Qualitative data for Infectious Disease Models)

Rachel Gur-Arie

Description

Emerging Infectious Disease (EID) outbreaks and pandemics cost lives, cause a substantial burden of disease and severely disrupt economies and societies. The constant evolution of pathogens in host networks pose challenges for effective mitigation strategies. Mathematical models can optimise decision-making to prevent such health threats and support decision-making by predicting outcomes (e.g. number of cases, hospitalisations and deaths) and the utility of possible interventions (e.g. lockdowns, masks and vaccines). However, existing disease transmission models fail to fully capture the complexity of individual decision-making. An individual’s experience, socioeconomic status, sources of health information, and peer interactions all influence behaviour. Mathematical models fail to incorporate attitudinal and behavioural factors (captured by qualitative research), leading to over-simplistic, unverifiable, and unrealistic assumptions that in turn create models with limited precision, accuracy and public health utility. To address this, US, UK, and Israeli experts in social sciences, clinical research, public health, epidemiology and mathematical modelling, with input from decision makers and community members, will co-develop a unique mathematical model – US-UK-Israel Collab: LIQUID-M (Leveraging Insights from Qualitative data for Infectious Disease Models) – that integrates qualitative data and encompasses various population strata, their social norms, and their interactions. To ensure real-world utility and impact, a tool based on the model will be developed, piloted, and evaluated. The tool will support decision makers in prioritising optimal intervention strategies, including timing to prevent transmission, protect vulnerable populations and improve outbreak outcomes. The model will predict the spread of diseases and the likely impact and success of public health interventions with a new level of accuracy and precision.

Deliverables

The mathematical model will use a new methodology that transforms qualitative insights into quantitative variables, advancing the field of modelling. It will be adaptable to different pathogens and contexts and relevant to decision makers. It will provide a new level of precision, accuracy and confidence with regards to the spread of pathogens in subpopulations and factors impacting on transmission, as well as impact of public health interventions. We aim to produce at least one peer-reviewed publication from this seed grant opportunity, which will serve as the background and foundation for a larger grant proposal. To do this, we will use the seed funding to facilitate an in-person working meeting that will be hosted at Arizona State University.

Policy implications

The unique model, and the decision-making tool derived from it, will enable health ministries, public health institutes, and other decision makers to make better decisions about outbreak and pandemic management. The model will create the possibility of prioritising interventions for populations, optimising the protection of individuals, communities and society, improving health outcomes and mitigating wider socio-economic costs.

Disciplines / expertise required

  • Mathematical modelling
  • Policy translation
  • Project management
  • Global Infectious Diseases
  • Ethics
  • Infectious Disease Control
  • Computer Science
  • Artificial Intelligence

Comments

  • Dear Rachel, Your idea is really exciting! I do mathematical and physical modeling of the spread of epidemics, employing both pde modeling and stochastic Monte Carlo simulations (https://sites.google.com/oakland.edu/khain/). I also feel that individual social and behavioral factors must be incorporated into the modeling to make it more realistic and predictive. I would be happy to discuss possible collaboration on this project.
    Evgeniy Khain
  • Dear Rachel: I see great value in this idea. Team 1 has been using qualitative (historical) data to model processes in one epidemic and working with Selcuk on some promising AI interventions. I would be happy to talk more about this. One question I have is why the data you describe are necessarily qualitative. The individual-level variables you suggest are available from many population-representative surveys. I suspect you have something very specific in mind (like geo-coded social media data), and I would love to hear what that is.
    Stephanie Bohon
  • I think this is a highly relevant and potentially impactful idea, although the proposed integration of qualitative and epidemiological data is ambitious. I would be particularly interested in seeing a conceptual framework or flowchart illustrating which qualitative/behavioral variables may map onto specific parameters in existing epidemiological models. For an initial proof of concept, it may be useful to take a building-block approach—starting with a baseline epidemiological model, incorporating one or a small number of well-defined behavioral factors, and evaluating their incremental contribution before adding further complexity. AI/ML could potentially play a useful role in extracting or structuring variables from qualitative data, while retaining an interpretable link between those variables and epidemiological parameters. This staged approach might also provide a feasible foundation for the first publication and subsequent expansion of the model.
    Jing Jiao
  • Dear Rachel: This is a fantastic idea. Working alongside a robust network of collaborators, we are in the foundational stages of developing an integrated machine learning framework that leverages both qualitative and quantitative data streams to inform the development of tailored biosecurity interventions for the swine industry. What makes this work distinctive—and what we believe positions it for broader pandemic preparedness impact—is our intentional infusion of behavioral science frameworks at every stage: during study design, model development, and data integration. Our preliminary swine-focused work has taught us that predictive accuracy is necessary but insufficient; without understanding the behavioral drivers of biosecurity adoption (and non-adoption), interventions fail in the field. We are making behavioral theory the connective tissue between data and action. Which leads me to the question I had which is basically Stephanie’s question :) -nature of the qualitative data you are targeting or have in mind... Very cool work-excited to see it take shape. Happy to talk more.
    Michael Mahero

Can Synthetic Data Help Us Understand and Predict Pandemic Expansion Without Waiting for the Next Pandemic?

Jonathon Gass

Description

How can synthetic data be generated, validated, and used to study the transition from sporadic infections to outbreaks when real-world data are sparse, biased, delayed, incomplete, or inaccessible?

Deliverables

Paper outlining synthetic dataset development, implementation, validation

Disciplines / expertise required

  • Epidemiology
  • AI scientist
  • Modeler
  • graph machine learning

Comments

  • This is a timely question. I wonder whether the project could make “realism” more explicit: matching marginal distributions may not be sufficient if the synthetic data fail to preserve joint dependencies, temporal dynamics, network structure, or responses to interventions. Could validation include mechanistic constraints, comparison with held-out outbreaks, and sensitivity analyses across multiple plausible data-generating processes? It would also be useful to identify which scientific conclusions remain stable when the generator changes. One possible behavioral component is MatrAIx, a population-scale simulated-user platform we recently developed. Diverse persona agents could help stress-test how heterogeneous risk perception, care-seeking, adherence, mobility decisions, or responses to public-health communication affect simulated outbreak trajectories. I would view this as a behavioral layer coupled to an epidemiological model, rather than a replacement for biological or real-world validation. Comparing multiple agent models and calibrating relevant behaviors against observed data would be important. A useful additional deliverable might be a benchmark or checklist specifying levels of synthetic-data validity, appropriate uses, and known failure modes.
    Yixuan He
  • One application could be synthetic surveillance data for the early phase of emergence, when a few detected infections could represent repeated importations, a self-limiting transmission chain, or the beginning of sustained local spread. Could the group develop and test methods for distinguishing those three possibilities?
    Kelsey Lyberger
  • Really interesting idea. I’m curious what types of information would be included in the synthetic data, such as case numbers, contact networks, mobility, demographics, or environmental factors, and how these different data types would be used to represent outbreak expansion.
    Rui Li
  • This is a great question! I'm wondering if you're planning to use mathematical modeling such as compartmental models, agent-based models, network-based models, etc and how you envision the synthetic data needed for each case would change in response to the approach.
    Sara Johnson
  • I really like the insight behind this idea. I think it would be helpful to first identify a specific study system and clarify what the synthetic data would look like. For example, would the synthetic data represent the underlying infection dynamics, the observed surveillance/reporting process, or both? Defining this more clearly could help connect the synthetic-data framework to the transition from sporadic observations to outbreak establishment.
    Jing Jiao
  • Fabulous Idea Jon; I agree with Jing, in addition to the system level clarity perhaps further defining the geographic and ecological context within which your simulations will be grounded may help increase the robustness and real-world applicability of your simulation. Perhaps you could define a range of ecosystem profiles and allow this to contribute to the stochastisty of your models...? Food for thought...:)
    Michael Mahero

Can Population Immunity Predict When Seasonal Disease Will Become Epidemic?

Jonathon Gass

Description

Can changes in population-level and spatially clustered immunity be used to develop an early-warning signal for the transition from predictable seasonal disease dynamics to explosive outbreaks?

Deliverables

Report or model

Disciplines / expertise required

  • Epidemiology
  • Computational biology
  • Modeling
  • graph machine learning

Comments

  • This question seems closely connected to network-based early warning. Population-average immunity may conceal spatial clustering: two populations with the same overall immunity level could have very different outbreak risks if susceptible individuals are concentrated in highly connected communities or bridge locations. Could immunity be represented as a time-varying signal on a mobility or contact network, and could graph-aware measures of susceptible connectivity be compared with aggregate seroprevalence as early-warning indicators? It would be especially informative to test whether these signals transfer across pathogens, regions, and seasons using a prospective-style evaluation in which each alert is based only on information available at that time.
    Yixuan He
  • I would be curious to learn more about the translation and policy implications/directions of this work. While this project is focused on modeling and computational methods, I could envision a more social science/policy/decision-making oriented crowed write a project with the same title, but completely different methods. I think that together the impact would be stronger! But, I do not know at what stage this proposal is - if this is the first step in the work, or if it builds off of previous collaboration, and if policy implications have been thought through yet. I recognize it might be very early! Thank you, Rachel
    Rachel Gur-Arie
  • This is a very interesting question. One aspect that may be important is how the transition from “seasonal” to “epidemic” behavior is formally defined, since the early-warning signal will depend strongly on that threshold. It may also be useful to consider uncertainty in immunity estimates, including waning immunity, incomplete serological sampling, and spatial heterogeneity. Testing how robust the warning signal is to these uncertainties could help determine whether population immunity can provide a reliable and transferable indicator across pathogens and seasons.
    Xinghan Zhao
  • Hi, Jonathan: This idea makes my population scientist heart skip a beat. I don't think the approach has to be different for the different audiences you envision. I think the social science/policy angle is probably more applied: once you figure out the representation, how can policy makers use it effectively?
    Stephanie Bohon
  • Hey there, What an awesome proposed topic! A few APPEX researchers have been modeling some very similar questions already and I'd love to connect you. Some links to some of the papers some of us have already published on this (or basically the same question just switching from endemic to epidemic rather than having to be seasonal) are: https://www.sciencedirect.com/science/article/am/pii/S2468042723000623 (this one is being continued in a Working Group now for Rotavirus!); https://www.nature.com/articles/s41598-022-07962-2.pdf; https://journals.plos.org/plosbiology/article/file?id=10.1371/journal.pbio.3001770&type=printable; and https://www.mdpi.com/2414-6366/5/4/184.
    Nina Fefferman
  • Hi! Interesting question! Disclaimer that I'm a student, but I can at least toss you a few thoughts/questions I have about the way you plan to conceptualize population immunity. ^^ By "seasonal," are you trying to point to IAV, coronaviruses, etc? Or are you thinking about pathogens for which vaccination can induce lifelong immunity? For influenza at least, population immunity both protects hosts and causes the virus to evolve to evade said immunity. I imagine this would make the problem harder (but possibly cooler)...? You also may also want to ask questions like, "What is the effect of age-stratefied immune imprinting/original antigenic sin? Is it helping prevent transmission or causing inefficient immune responses?" If you hope to avoid data, somebody has almost certainly asked about optimal memory cell allocation given antigenic change as "perceived" by the degree of cross-reactivity with existing antibodies, but I wouldn't know the paper... (Point being that "original antigenic sin" is maybe not a sin if you consider that treating every flu strain like measles would be an inefficient use of B cell memory.) Not sure that is useful, but it's where my brain went. Best of luck thinking about this! ^^
    Caitlin Cox

Transferable Early-Warning Signals of Pandemic Expansion in Dynamic Networks

Yixuan He

Description

An outbreak usually begins with sparse, delayed, and incomplete observations from a small number of locations. By the time conventional time-series indicators clearly show sustained growth, opportunities for early intervention may already be disappearing. Could changes in the structure and activity of the underlying transmission network provide earlier warning that an outbreak is shifting from localized transmission toward regional or wider expansion?

We propose studying outbreaks as dynamic, directed, multiscale graphs. Nodes could represent geographic areas, populations, healthcare systems, or host groups. Time-varying edges could represent mobility, contact, transportation, inferred transmission, or genetic relatedness. Signals observed on the nodes could include cases, hospitalizations, wastewater measurements, syndromic surveillance, and genomic indicators.

The working group would identify structural-temporal warning signals—such as changes in connectivity, directionality, community boundaries, or bridge populations—that precede expansion. A central question would be whether these signals transfer across pathogens, locations, spatial resolutions, and surveillance systems. Retrospective studies would simulate real-time emergence by restricting the information available at each point in an outbreak.

Graph-based approaches would be evaluated against time-series-only methods, static-network approaches, established epidemiological models, and ensemble forecasts. The group would explicitly study missingness, reporting delays, changes in surveillance, uncertainty, and negative transfer: situations in which a pattern learned from one outbreak produces misleading conclusions in another.

We seek interpretable principles for when network structure adds actionable information, when evidence from previous outbreaks can be reused, what additional observations would reduce uncertainty, and when a model should abstain from issuing an alert.

Deliverables

A multidisciplinary definition and taxonomy of network-based pandemic-expansion warning signals.

An open benchmark spanning multiple pathogens, locations, outbreak phases, and surveillance modalities.

An evaluation protocol that prevents future information from leaking into retrospective analyses.

Statistical and graph-learning methods for early warning, transferability assessment, uncertainty quantification, and detection of negative transfer.

An open-source diagnostic toolkit for outbreak analysts.

Academic publications and novel hypotheses about how network changes precede geographic expansion.

A policy and technical brief for public-health forecasting and surveillance teams.

A foundation for a larger interdisciplinary grant proposal.

Policy implications

The project could help public-health agencies determine when changes in mobility, transmission, or surveillance networks warrant heightened monitoring or intervention. It could also provide evidence-based criteria for deciding whether an early-warning model developed for one outbreak is safe to reuse in another setting.

Disciplines / expertise required

  • Infectious-disease epidemiology define plausible transmission mechanisms and meaningful outcomes
  • Public-health surveillance and outbreak analytics characterize reporting delays, missingness, and operational constraints
  • Mathematical epidemiology connect learned patterns to mechanistic models of outbreak expansion
  • Network science and human mobility construct and interpret dynamic, directed, and multiscale networks
  • Time-series analysis and change-point detection identify temporal warning signals and suitable baselines
  • Machine learning on graphs develop transferable models and structural diagnostics
  • Genomic epidemiology and phylogeography incorporate evolutionary and inferred-transmission relationships
  • Uncertainty quantification produce calibrated alerts and criteria for abstention
  • Public-health decision science and policy translate predictions into actionable thresholds
  • Data governance and health equity examine representativeness, privacy, and uneven surveillance coverage

Comments

  • Hello! This project sounds fascinating. I am wondering that qualitative and/or social science and/or engagement expertise you have on your team. The quantitative methods are clearly strong but I'd love to see more detail on the qualitative and translational methods and/or applications. Given the listed desired expertise of public health decision science, policymaking, and health equity, I know the study team is not overlooking it. I look forward to learning more. Thank you!
    Rachel Gur-Arie
  • Great research direction, Yixuan. Would it be of interest to look at the reconstruction of the time-varying transmission network from sparse and delayed observations as a regularized optimization problem? I believe there is some related work that could provide a starting point: Prasse & Van Mieghem (2020), "Network Reconstruction and Prediction of Epidemic Outbreaks for General Group-Based Compartmental Epidemic Models"; Hallac et al, "Network Inference via the Time-Varying Graphical Lasso".; Ditzler et al. (2019), "Approximate k ximate kernel r ernel reconstruction for time-v econstruction for time-varying networks ying networks ".
    Bogdan Gavrea
  • Hi! This sounds very interesting. I'm wondering about data availability for this application. What type of data do you expect to be using? At what level could the data be used? How will you fit models to data?
    Sara Johnson
  • Hi! This sounds very interesting. I'm wondering about data availability for this application. What type of data do you expect to be using? At what level could the data be used? How will you fit models to data?
    Sara Johnson
  • Yixuan, this is an interesting proposal. I am curious, though, about how the dynamic multiscale graph framework might incorporate some of the more nuanced biological complexities, such as asymptomatic transmission and environmentally driven viral mutations. For example, I wonder how the graph could specifically account for asymptomatic hosts who might silently construct hidden transmission edges before any syndromic signals are triggered. I am also interested in learning more about how the multiscale graph might represent a virus mutating at different rates depending on distinct environmental or population pressures.
    Nilesh Dixit
  • Yixuan, this is an interesting proposal. I am curious, though, about how the dynamic multiscale graph framework might incorporate some of the more nuanced biological complexities, such as asymptomatic transmission and environmentally driven viral mutations. For example, I wonder how the graph could specifically account for asymptomatic hosts who might silently construct hidden transmission edges before any syndromic signals are triggered. I am also interested in learning more about how the multiscale graph might represent a virus mutating at different rates depending on distinct environmental or population pressures.
    Nilesh Dixit

How can mechanistic theory guide the detection and interpretation of nonlinear coinfection relationships across diverse disease ecology systems?

Jing Jiao

Description

Coinfection is widespread across disease ecology systems, yet empirical studies report highly variable and often inconsistent relationships among coinfecting parasites. Beyond genuine biological variation among systems, this inconsistency may also reflect substantial heterogeneity in how coinfection is observed and analyzed. Existing datasets vary widely in sampling design and resolution, ranging from presence–absence records to quantitative measures of infection intensity, while analytical approaches often rely on relatively standard statistical assumptions that may not reflect the underlying biological processes. As a result, potentially important coinfection relationships may be overlooked or difficult to interpret.

Mechanistic theory offers an opportunity to distinguish biological variation from methodological limitations by identifying plausible relationships that may otherwise be missed in empirical analyses. Our recent work provides a proof of concept, showing that theory can guide the detection of nonlinear coinfection relationships that become obscured under reduced data resolution or conventional analytical assumptions. Building from this foundation, we propose to systematically examine how coinfection data are structured and analyzed across disease ecology systems, determine how these differences affect what biological relationships can be detected, and develop a flexible, theory-informed framework for extracting greater biological insight from existing data.

Ultimately, we aim to translate these insights into a computational framework in which mechanistic knowledge prioritizes biologically plausible hypotheses while empirical data determine which relationships are supported, making data-driven and machine-learning analyses more efficient and interpretable.

Deliverables

A systematic synthesis of coinfection data structures and analytical approaches across disease ecology systems; a theory-informed framework for evaluating what biological relationships can be detected from different types of existing data; and a prototype computational approach for integrating mechanistic knowledge into data-driven analyses. These products will provide practical guidance for extracting greater biological insight from existing coinfection datasets and identify priorities for future empirical and theoretical studies.

Policy implications

By improving our ability to detect and interpret coinfection interactions across disease ecology systems, this framework could provide important insights for future disease control and management. Understanding when coinfecting pathogens facilitate or inhibit one another, and how these relationships change across ecological contexts, could inform whether and how targeting one pathogen may affect another. Translating these insights into specific management actions will require further collaboration with disease managers and other stakeholders.

Disciplines / expertise required

  • Empirical parasite and coinfection ecology across diverse systems To provide biological perspectives and experience with diverse coinfection systems and existing empirical datasets.
  • Theory-data integration and quantitative disease ecology To help translate mechanistic insights into analytical approaches that work across heterogeneous empirical data structures
  • Machine learning and computational biology To help develop scalable, interpretable computational approaches that incorporate mechanistic knowledge into data-driven analyses

Comments

  • One possible computational perspective would be to represent coinfection relationships as a signed, potentially directed and context-dependent network. Nodes could represent pathogens or host–pathogen states, while edges encode theoretically plausible facilitation or inhibition. Directionality could be important when the effect of pathogen A on pathogen B differs from the reverse effect.
    Yixuan He
  • This is a very interesting idea. A thought came to mind that might complement this approach. Simulation-based “virtual experiments” might be useful here. Mechanistic within-host or population coinfection models could generate synthetic data where the true interactions are known. The data could then be reduced from detailed infection intensities to presence–absence or coarser measurements to test which statistical or machine-learning approaches can still recover those relationships. It might also be interesting to combine this with identifiability analysis to understand which biological relationships can actually be distinguished at different levels of data resolution.
    Preeti Dubey
  • Hi all, thank you for these helpful insights. My previous theoretical and empirical work has focused primarily on nonlinear coinfection interactions within hosts. Considering the spatial/network dimension of coinfection would be an interesting extension that I would like to explore in the future. The simulation idea actually connects closely with work I already have underway. I have a manuscript currently under review in which I used a high-resolution empirical dataset from a damselfly–parasite system and transformed the infection data to represent three common empirical data structures: (1) both parasites measured as intensity; (2) the focal parasite measured as intensity while the coinfecting parasite is represented as presence/absence; and (3) both parasites represented as presence/absence. Our current statistical tools can identify nonlinear coinfection effects under scenarios (1) and (2), but not under scenario (3). I think a more systematic simulation framework could therefore be very helpful.
    Jing Jiao

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This material is based upon work supported by the National Science Foundation under Award No. 2412115 and 2622265. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation