=Paper= {{Paper |id=Vol-1327/8 |storemode=property |title=A Novel Representation of Terms Related to Infectious Disease Epidemiology for Epidemic Modeling: The Apollo Structured Vocabulary and Pre-existing Representations |pdfUrl=https://ceur-ws.org/Vol-1327/icbo2014_paper_30.pdf |volume=Vol-1327 |dblpUrl=https://dblp.org/rec/conf/icbo/BrochhausenHLBM14 }} ==A Novel Representation of Terms Related to Infectious Disease Epidemiology for Epidemic Modeling: The Apollo Structured Vocabulary and Pre-existing Representations== https://ceur-ws.org/Vol-1327/icbo2014_paper_30.pdf
                                                          ICBO 2014 Proceedings


     A novel representation of terms related to infectious
        disease epidemiology for epidemic modeling
                     The Apollo Structured Vocabulary and pre-existing representations

             Mathias Brochhausen, Josh Hanna                                                     Shawn T. Brown
                                                                                        Pittsburgh Supercomputing Center
             Division of Biomedical Informatics
                                                                                            Carnegie Mellon University
         University of Arkansas for Medical Sciences                                             Pittsburgh, USA
                       Little Rock, USA
                  mbrochhausen@uams.edu
                                                                               Michael M. Wagner, John D. Levander, Nicholas E.
                      William R. Hogan                                                             Millett
                                                                                      Department of Biomedical Informatics
          Department of Health Outcomes and Policy
                                                                                            University of Pittsburgh
                   University of Florida
                                                                                               Pittsburgh, USA
                      Gainesville, USA

    Abstract—The Apollo Structured Vocabulary (Apollo-SV) is a             infection transmission, populations of hosts, interventions, and
Web Ontology Language 2 (OWL 2) representation of terms                    the outcomes of infections. Using this input information—
related to epidemic simulation. We are developing Apollo-SV by             which we refer to as an infectious disease scenario—a
ontological analysis of the information used and created by                simulator’s algorithm computes the progression of one or more
epidemic simulators and the entities this information is about.            infections in one or more populations over time, under zero or
     A key finding of our analysis is that the input of an epidemic        more interventions. The result of this computation—the output
simulator is properly understood as (1) a representation of an             of the simulator—is information on which decision makers can
ecosystem at simulator time zero, (2) information about                    base policy or decisions about disease control.
infectious diseases of interest in the ecosystem, and (3)
information about plans to control the diseases. This insight is                At present, each simulator uses its own representation of
reflected in the scope of Apollo-SV, which includes terms from             its input and output information. For example, the FRED
the domains of both infectious disease epidemiology and                    simulator, version 2.0.1 [1] refers to the duration of school
population biology.                                                        closure 2 as ‘school_closure_period’, whereas FluTE version
    We also found that some definitions in the Infectious Disease          1.15 [2] refers to it as ‘schoolclosuredays’. The differences
Ontology (IDO), including ‘infection’, ‘infection acquisition’,            make it difficult to compare simulators and re-use machine
‘infectious disease’, ‘pathogen’, and ‘host’, were not compatible          readable information. For example, Halloran et al. spent 6
with the meanings of the terms as used in epidemic simulation;
                                                                           months creating a comparative study of three simulators [3].
thus, we created new definitions of these terms.
    Our analysis of epidemic simulators—which are                               To address this problem, we are developing machine-
mathematical models of phenomena studied by infectious disease             interpretable representations for the input and outputs of DTMs
epidemiology—afforded several advantages that likely explain               and promulgating their adoption as de facto standards. The key
why we discovered limitations of IDO.             As a result, we          goal of the standards is to enable an analyst to specify the same
recommend that development of biomedical ontologies intended               infectious disease scenario exactly once, and run the scenario
for reuse consider the perspective of the overlapping biological           on multiple simulators with no additional effort.
science(s) involved.
    Apollo-SV is freely available at:                                          In this paper, we describe one element of our proposed
http://purl.obolibrary.org/obo/apollo_sv.owl.                              standards—the Apollo Structured Vocabulary (Apollo-SV).
                                                                           Apollo-SV is an OWL 2 representation of terms related to
   Keywords—disease transmission models, epidemic simulators,              epidemic simulation. The other two elements are an XML
biomedical ontology, infectious disease epidemiology                       Schema Document (XSD), which defines the syntax for
                                                                           simulator input, and a database schema that defines the
                         I.    INTRODUCTION
                                                                           representation of simulator output. Apollo-SV defines the
The science and practice of infectious disease epidemiology,               terminology used in the XSD and database schema. These
like climate science, is increasingly reliant on computational             elements are described in Wagner et al. [4]
simulation. The simulators—known as epidemic simulators or
more generally disease transmission models (DTMs)1—require
machine-interpretable information about pathogens, rates of                2
                                                                             Closing schools is one infectious disease control strategy that
                                                                           simulators study for the control of influenza epidemics. The duration
1
    DTMs also model endemic infections such as malaria.                    of the closure is the length of time during which schools are closed.




                                                                      21
                                                              ICBO 2014 Proceedings

                              II.    METHODS                                              In accordance with the Foundry principle of orthogonality,
We developed Apollo-SV for use in a set of Web services                               which stipulates that a given term is defined only once across
designed to improve access to epidemic simulators. We begin                           all ontologies, we search for and import pre-existing
this section with an overview of these services, then detail our                      ontological representations into Apollo-SV. Besides importing
methods to develop Apollo-SV, including conformance to                                entire ontologies, we import selected classes, individuals, and
OBO Foundry Principles, methods to ensure validity for its                            properties using the Minimum Information to Reference an
intended use, and multi-disciplinary development.                                     External Ontology Term (MIREOT) [9] Protégé plugin that we
                                                                                      developed [10].
The Apollo Web Services: Briefly, the Apollo Web Services are
a set of Web services designed to allow a publicly available,                             We also adhere to Foundry naming conventions [11]. We
Web-based, end-user application to access multiple epidemic                           edit our terms to (1) avoid connectives ('and', 'or'), (2) prefer
simulators through requests to a single Broker service (Fig. 1).                      singular nouns, (3) avoid the use of negations, and (4) avoid
                                                                                      catch-all terms such as "Unknown x".
    In Figure 1, the Simple End User Application (SEUA)
creates an infectious disease scenario for simulation, encoded                            To help link the OWL file with the XSD, we create a
in an XML document that conforms to the Apollo XSD, which                             Unique Apollo Label (UAL) for classes in Apollo-SV. The
uses terminology defined by Apollo-SV. The SEUA invokes                               UAL is the exact XSD type or attribute name to which the
the runSimulation() method of the Broker service with the                             class    in    Apollo-SV     corresponds,  for  example,
infectious disease scenario. The Broker service invokes the                           InfectiousDisease and basicReproductionNumber.
Translator service, which translates the infectious disease                           Analysis of simulators’ input and output files, and
scenario into the native terminology and syntax of the                                documentation: We analyzed the input and output files of four
requested simulator(s).                                                               epidemic simulators. We also analyzed documentation, such as
                                                                                      user guides and published papers. We reviewed terms that we
                                                                                      extracted from these resources with the developers of the
                                                                                      simulators to identify relevant but missing terms, to discover
                                                                                      synonymy among terms, and to detect and resolve ambiguity.
                                                                                      Validation by representation in XSD message syntax: We
                                                                                      further refine our OWL DL representations by using the terms
                                                                                      in the XSD representation as it progressively expands to be
                                                                                      able to represent the input of four simulators.
                                                                                      Validation by automatic translation:        The process of
                                                                                      developing the mappings from the XSD and Apollo-SV terms
                                                                                      to the native language of the simulators identifies additional
                                                                                      issues with Apollo-SV that we feed back into our analysis.
                                                                                      Validation by implementation in a user application: The SEUA
                                                                                      exposes Apollo-SV definitions and elucidations in tool tips that
                                                                                      appear when the mouse hovers over a term. This view
Fig. 1. The relationships of Apollo components and epidemic simulators.
Apollo-SV defines the terminology used in Apollo XSD, which specifies the             identifies problems with elucidations by placing them into the
message syntax for the Web services [1]. The SEUA calls the Broker service            context of an end-user configuring a simulator, and wanting to
to configure simulators (messages passed along blue arrows) and to access             understand what is meant by a term.
simulator output (messages passed along red arrows). The Translator service
translates Apollo messages to/from native simulator input/output. The SEUA            Public release: To encourage adoption of Apollo-SV and to
is available at http://research.rods.pitt.edu; the XSD is available at:               allow external scientific review, comments, and requests for
http://research.rods.pitt.edu/apollo-types_2.0.2.xsd. Purple ovals represent          additions, we make Apollo-SV publicly available at
Apollo standards; blue ovals represent Apollo-developed software that use the         http://purl.obolibrary.org/obo/apollo_sv.owl, a permanent URL
Apollo Web services; and red ovals represent entities interacting with Apollo.
                                                                                      (PURL). We also ensure that Apollo-SV is easily accessible for
Upper ontology: We import Basic Formal Ontology                                       browsing and download at the Web-based Ontobee portal:
(http://www.ifomis.org/bfo/1.1) into Apollo-SV as its upper                           http://www.ontobee.org/browser/index.php?o=APOLLO_SV.
ontology [5].                                                                         The issue tracker and under-development version of Apollo-
                                                                                      SV are located at our Google Code site. The PURL to the
Conformance with OBO Foundry principles: We followed the                              development          version       of       Apollo-SV       is
principles of the OBO Foundry in implementing Apollo-SV [6,                           http://purl.obolibrary.org/obo/apollo_sv/dev/apollo_sv.owl.
7]. Thus we release it in a common format, OWL 2 [8].
                                                                                      Multi-disciplinary development: The team developing Apollo-
    In accordance with Foundry principles, we write a textual                         SV comprises personnel with backgrounds in simulator
definition for every term that we create. Because formal                              development, disease surveillance, medicine, biomedical
ontological textual definitions often use the technical language                      informatics, medical terminologies, ontological engineering,
of ontologists, we created an elucidation annotation for classes                      artificial intelligence, and formal logic. All these individuals,
in Apollo-SV. The elucidation restates the definition in                              including a simulator developer (author SB), have been
language more familiar to subject matter experts. We also
axiomatize Apollo-SV terms wherever possible (e.g., Fig. 2-5).



                                                                                 22
                                                        ICBO 2014 Proceedings

actively engaged in review of Apollo-SV, and their feedback                           TABLE II.   CLASSES IN APOLLO-SV BY SUBDOMAIN

guides design decisions.
                                                                             Domain                 Classes in Apollo-SV
                             III.   RESULTS                                  Infectious disease     Infection            Infection acquisition
                                                                             epidemiology           Pathogen             Host
   Overall, Apollo-SV has 594 classes: 287 that we created
                                                                                                    Latent period        Infectious period
new in Apollo-SV and 307 that we imported: 57 via MIREOT                                            Contaminated thing   Contamination acquisition
(Table I) and 250 from entire ontologies. The number of                                             Contamination
imported classes is artificially high because the import of entire                                  Infectious disease   Basic reproduction
ontologies brings classes into Apollo-SV we do not require.                                         scenario             number
                                                                                                    Transmission         Transmission probability
  TABLE I.         RE-USE OF CLASSES AND OBJECT PROPERTIES FROM PRE-                                coefficient
             EXISTING ONTOLOGIES IN APOLLO-SV VIA MIREOT.
                                                                                                    Disease              Infectious disease control
 Ontology (by      Classes           Object            Total                                        transmission model   strategy
 OBO Foundry                         Properties                                                     Susceptible          Exposed population
 namespace)                                                                                         population
                                                                                                    Infectious           Resistant population
 UBERON            7                 1                 8                                            population
 OMRSE             26                7                 33
                                                                             Population biology     Ecosystem            Biotic ecosystem
 GO                1                 0                 1
 OGMS              11                0                 11                                           Abiotic ecosystem    Community
 OBI               9                 5                 14                                           Population           Population census
 IDO               3                 7                 10                                           Population           Abiotic ecosystem census
 Totals            57                20                77                                           infection and
                                                                                                    immunity census
    The core classes in Apollo-SV represent key entities of
interest to infectious disease epidemiology and population                  abnormality to immunocompetent organisms of the same
biology (Table II). Throughout the course of developing the                 Species as the host (the organism corresponding to the
Apollo standard, we reached the conclusion that the input to an             extended organism) through transmission of a member or
epidemic simulator is properly understood as a representation               offspring of a member of the infectious agent population.
of an ecosystem at simulator time zero, with additional                         However, epidemic simulators represent infection as a
information about infectious diseases and planned or ongoing                process, because that is how ‘infection’ is defined in infectious
interventions to control them. This conclusion motivates the
                                                                            disease epidemiology. For example, [13, 14] define ‘infection’
inclusion in Apollo-SV of terms from population biology. In
                                                                            as the invasion of a host organism's tissue by pathogens, the
turn, the ecosystem viewpoint heavily influenced our
definitions of key terms in infectious disease epidemiology.                multiplication of those pathogens, and the reaction of the
                                                                            host’s tissue(s) to the pathogens and the toxins they produce.
    At present, Apollo-SV and the XSD enable configuration
of three epidemic simulators with the same infectious disease                   Also, the IDO definition requires that an infection cause
scenario in the SEUA. We are piloting a fourth simulator. They              clinical abnormality in an individual of a particular species.
are (1) a compartmental model developed by authors MMW,                     However, infectious disease epidemiology recognizes the
NEM, and JDL (disease agnostic); (2) the FRED model                         existence of species that do not experience clinical
developed by the University of Pittsburgh Public Health                     abnormalities when infected with a particular pathogen. The
Dynamics Laboratory in collaboration with the Pittsburgh                    importance in epidemic simulation is that members of species
Supercomputing Center and the School of Computer Science at                 that can experience clinical abnormalities when infected can
Carnegie Mellon University, University of Pittsburgh and                    acquire infection with the pathogen from a ‘carrier’ species.
Imperial College (influenza A in humans); and (3) the FluTE
model developed by the University of Washington and Fred                       Apollo-SV defines ‘infection’ as: A reproduction of a
Hutchinson Cancer Research Center in Seattle and the Los                    pathogen in (a part of) the tissue of an organism from another
Alamos National Laboratories (influenza A in humans).                       species (Fig. 2).

   With respect to Foundry orthogonality, we attempted to                       This biologically-grounded definition recognizes that two
reuse IDO’s definitions of ‘infection’, ‘pathogen’, ‘host’, but             species are interacting and—from the pathogen species point of
had to create new definitions (and thus new representations) for            view—infection is a process of reproduction. The definition
them in Apollo-SV as discussed in the following sections.                   only requires reproduction of one species within the tissues of
                                                                            an individual (organism) from another species.
A. Infection
                                                                            B. Infection Acquisition (reformulation of Transmission
   IDO defines infection as a material entity that is:                          Process)
A part of an extended organism that itself has as part a                        IDO imports two definitions of ‘transmission process’ from
population of one or more infectious agents and that is (1)                 the Transmission Ontology:
clinically abnormal in virtue of the presence of this infectious
agent population, or (2) has a disposition to bring clinical                  1. A process that is the means during which the pathogen is
                                                                                 transmitted directly or indirectly from its natural
                                                                                 reservoir, a susceptible host or source to a new host.




                                                                       23
                                                              ICBO 2014 Proceedings

  2. Suggested definition: A process by which a pathogen                                  Apollo-SV defines ‘infection acquisition’ as: The
     passes from one host organism to a second host organism                          biological process of pathogen organism(s) entering (the body
     of the same Species.                                                             of) a host organism from a contagious host or a contaminated
                                                                                      thing and reproducing using host resources.
                                                                                          As with our definition of ‘infection’, this definition is
                                                                                      biologically grounded and recognizes that from the pathogen
                                                                                      species’ point of view, infection acquisition is the entry into a
                                                                                      host and the beginning of reproduction there. Note that Apollo-
                                                                                      SV’s definition of ‘contaminated thing’ is general and includes
                                                                                      natural reservoirs, vector organisms that are not infected (a.k.a.
                                                                                      mechanical vectors), and fomites like contaminated pencils.
                                                                                      C. Host
                                                                                         IDO defines ‘host’ as: An organism bearing a host role
                                                                                          This definition is not sufficient in and of itself to
                                                                                      understand what IDO refers to by ‘host’. It is also necessary to
                                                                                      review its definitions of ‘host role’ and ‘extended organism’:
                                                                                        1.   ‘Host role’: A role borne by an organism in virtue of the
                                                                                             fact that its extended organism contains a material
                                                                                             entity other than the organism.
                                                                                        2.   ‘Extended organism’: An object aggregate consisting of
                                                                                             an organism and all material entities located within the
Fig. 2. Representation of the equivalent class axiom for ‘infection’ in                      organism, overlapping the organism, or occupying sites
Apollo-SV. Boxes represent named classes, boxes with curved bases represent
anonymous classes, arrows represent object properties. In the boxes is the
                                                                                             formed in part by the organism.
rdfs:label and the namespace of the source ontology, if different from Apollo-            Under these definitions, any organism that has an artificial
SV. Each arrow is labeled with the rdfs:label of the property it represents.
                                                                                      joint, a penny in its gut, or an arrow through its chest is a host.
    The second, “suggested definition” erroneously restricts                          The fact that a person with a prosthetic knee is a “host” is
transmission to occur only between two hosts of the same                              counterintuitive. This definition is too admissive for our use
species. It is thus not usable in infectious disease epidemiology                     cases (and for clinical medicine, too): any foreign material
or any other science that deals with cross-species transmission.                      entity inside the organism’s body renders the organism a host.

    The first definition of ‘transmission process’ has two major                          In addition, from the ontological perspective, we doubt
problems. The first problem is that it is circular, defining                          there is any such entity as host role. First, according to BFO, a
‘transmission process’ in terms of a pathogen being                                   role is manifested or realized in one or more processes.
transmitted, with no definition of ‘transmitted.’                                     However, because there is no representation of the infection
                                                                                      process in IDO, infection cannot be the realization. No other
    The second problem is an ontological one. It attributes to                        process in IDO suffices, either. If there is no process that
one process the property of being the means by which                                  realizes a role, then by definition of ‘role’, there is no role.
something else happens. For example, assume droplet spread
of infection from one host to another by a sneeze. This                                  Apollo-SV defines host as: An organism that has as part
definition equates the sneeze with the transmission process.                          some tissue that is the location of an infection (Fig. 3).
That is, it says that only the sneeze exists, but it also has the                         We therefore distinguish pathogen and host based on which
property of “having transmitted the pathogen”. However,                               one is reproducing inside tissue (pathogen) and which one is
equating the sneeze to the transmission process is nonsensical                        the location of the reproduction (host).
because for transmission to be complete, the second host must
have an infection. But this infection will not begin for minutes                      D. Pathogen
to hours after the sneeze is over. The sneeze cannot somehow
                                                                                         IDO defines ‘pathogen’ as: A material entity with a
extend itself in time until an infection is established, but
                                                                                      pathogenic disposition.
conversely not extend in time when no infection results. There
exist two distinct processes: the sneeze and the transmission.                        Again, this definition requires the definitions of other terms to
                                                                                      understand its meaning:
    We also had the insight that it is only the second host who
acquires the infection that undergoes a change during the                               1.   ‘Pathogenic disposition’: A disposition to initiate
process.     Therefore, we chose to rename it ‘infection                                     processes that result in a disorder.
acquisition’. We recognize that we are diverging from
standard terminology in the field, but anyone wishing to add an                         2.   ‘Disorder’: A material entity which is clinically
alternative label to the infection acquisition class in Apollo-SV                            abnormal and part of an extended organism. Disorders
could do so without changing the meaning of the class.                                       are the physical basis of disease.




                                                                                 24
                                                             ICBO 2014 Proceedings




Fig. 3. Representation of the equivalent class axiom for "host" in Apollo-SV.        Fig. 4. Representation of the equivalent class axiom for "pathogen" in
The graphical representation is analogous to Fig. 1.                                 Apollo-SV. The graphical representation is analogous to Fig. 1.

    Thus per IDO any material that causes injury is a pathogen,                          We set a high priority on implementing Apollo-SV in a
including the endotoxin of Clostridium difficile or an overdose                      Web service for three reasons. First, we wanted to demonstrate
of acetaminophen. IDO does have an infectious agent class as a                       the capability to initialize multiple simulators with one
subtype to pathogen that refers specifically to organisms that                       infectious disease scenario to motivate the adoption of Apollo.
enter into a host cause injury. But this definition is not how                       In addition, we wanted to lower barriers to adoption by making
infectious disease epidemiology uses the term ‘pathogen’.                            available a reference implementation. Lastly, implementation
                                                                                     is the basis of our iterative development and refinement
    IDO also asserts pathogens must typically cause disease.                         process that ensures Apollo is production ready and flexible,
However, attenuated poliovirus used in oral polio vaccines                           which also lowers the barriers to adoption.
infects the gut mucosa of humans and thus is a pathogen (or
infectious agent per IDO), but it causes disease in only one per                        A key insight from our iterative development of Apollo-SV
2.7 million first doses of vaccine.                                                  and XSD is that a simulator configuration is properly
                                                                                     understood as a representation of an ecosystem at a particular
    Apollo-SV defines ‘pathogen’ as: A material entity that is                       time. This insight led us to include in Apollo-SV key terms
the bearer of a disposition that, when realized, is realized as an                   from population biology, such as ‘ecosystem’ and ‘census’.
infection (Fig. 4).                                                                  Furthermore, it led us to our redefinition of ‘infection’, which
E. Infectious disease                                                                was central to redefining other IDO terms.
   IDO defines ‘infectious disease’ as:
    A disease whose physical basis is an infectious disorder.
    Per IDO, infectious disorder is a subytpe of infection.
However, we require a representation of infectious disease that
is consistent with our definition of ‘infection’ as a process. But
because IDO defines ‘infection’ and thus by inheritance
‘infectious disorder’ as a material entity, we could not reuse
this definition of ‘infectious disease’.
    Apollo-SV defines ‘infectious disease’ as: A disease that
inheres in a host and, when realized, is realized as a disease
course that is causally preceded by an infection (Fig. 5). This
definition is compatible with the OBO Foundry definition of
disease, which is in the Ontology of General Medical Science
(OGMS) [15]. We thus were able to reuse the OGMS
definition of disease, in keeping with the Foundry principle of
orthogonality.
                                                                                     Fig. 5. Representation of the equivalent class axiom for "infectious disease"
    Note that the disease inheres only in the host. From the                         in Apollo-SV. The graphical representation is analogous to Fig. 1.
pathogen’s perspective, there is no clinical abnormality (which
is a necessary condition to meet the definition of disease in                            A key result of our development of Apollo-SV was that we
OGMS). For the pathogen, infection is perfectly normal.                              could not reuse IDO definitions of ‘infection’, ‘host’,
                                                                                     ‘pathogen’, and ‘infectious disease’, and thus we created the
                           IV.     DISCUSSION                                        definitions presented here. This result was surprising because
Apollo-SV version 2.0.1 is an ontology for use in representing                       we had anticipated reuse of IDO at the outset of Apollo-SV
DTM input and output. It includes core terms from infectious                         development. Given that we did not expect this result, it is
disease epidemiology and population biology. Apollo-SV                               worth considering the possible reasons behind it.
currently supports the representation of infectious disease                             A key reason is that our concentration on how terms are
scenarios that can be run on three epidemic simulators and the                       used in biological sciences—especially population biology—
results of the simulations.                                                          exposed many issues. This focus differed fundamentally from




                                                                                25
                                                          ICBO 2014 Proceedings

IDO’s concentration on how the terms are used in clinical               potential to generate the XSD from the ontology, a successful
medicine. In particular, our focus led us to a requirement to           strategy in other projects [18].
represent the process of infection as opposed to the steady-
state, material-entity view of IDO.                                                               ACKNOWLEDGMENTS
    So what then led us to the perspective of population                This work was funded by award R01GM101151 from the
biology? We believe the reason we reached this perspective, as          National Institute for General Medical Sciences (NIGMS).
well as ontological clarity elsewhere in Apollo-SV, is that             This paper does not represent the view of NIGMS. This work
working with epidemic simulators quickly brought into view              used the Protégé resource, which is supported by grant
the key phenomena studied (that are also of relevance to                GM10331601 from NIGMS.
epidemic simulation) and their fundamental nature. These                                               REFERENCES
simulators are mathematical models in the field of infectious
                                                                        [1]  J. J. Grefenstette, S. T. Brown, R. Rosenfeld, et al. FRED (A
disease epidemiology. They have explicit ontological                         Framework for Reconstructing Epidemic Dynamics): an open-source
commitments that have been rigorously vetted through peer                    software system for modeling infectious diseases and control strategies
review of research using the models (as well as the models                   using census-based populations. BMC Public Health, 2013;13:940.
themselves). In addition, these ontological commitments                 [2] D. L. Chao, M. E. Halloran, V. J. Obenchain, and I. M. Longini, Jr.,
comprise the core entities involved in infections and their                  “FluTE, a publicly available stochastic influenza epidemic simulation
acquisition, leading us to confront the issues involved in                   model.” PLoS Computational Biology. 2010 Jan;6(1):e1000656.
representing them from the outset. It is likely that IDO, by            [3] M. E. Halloran, N. M. Ferguson, S. Eubank, et al. Modeling targeted
contrast, started with a disease focus and worked from there                 layered containment of an influenza pandemic in the United States. Proc
                                                                             Natl Acad Sci USA. 2008 Mar 25;105(12):4639-44.
towards the nature of infection. Finally, because these
                                                                        [4] M. M. Wagner et al. Apollo: giving application developers a single point
simulators make a relatively small number of ontological                     of access to public health models using structured vocabularies and Web
commitments, we had the ability to to devote sufficient time to              services. AMIA Annu Symp Proc. 2013 Nov 16;2013:1415-24.
ontological analysis while still achieving demonstrable                 [5] P. Grenon, B. Smith, and L. Goldberg, “Biodynamic Ontology:
progress in implementing the SEUA. Because implementing                      Applying BFO in the Biomedical Domain”, in D. M. Pisanelli
the SEUA is central to validating Apollo standards, we thus                  (ed.), Ontologies in Medicine: Proceedings of the Workshop on Medical
also achieved rapid validation.                                              Ontologies, Rome October 2003 (Studies in Health and Technology
                                                                             Informatics, 102 (2004)), Amsterdam: IOS Press, 2004, 20–38.
    We conclude that biomedical ontology developers should              [6] B. Smith, M. Ashburner, C. Rosse, J. Bard, W. Bug, W. Ceusters, et al,
incorporate the perspective of the basic sciences that study the             “The OBO Foundry: Coordinated evolution of ontologies to support
phenomena underlying clinical practice, such as medicine and                 biomedical data integration.” Nat Biotechnol 2007, 25(11):1251–5.
public health practice, when developing ontologies of clinical          [7] The Open Biological and Biomedical Ontologies, “OBO Foundry
                                                                             Principles.” http://www.obofoundry.org/crit.shtml. Last accessed:
phenomena. When mathematical models of such phenomena                        05/13/2014
exist, they are potentially useful starting points for analysis.        [8] W3C, “OWL 2 Web Ontology Language Primer (Second Edition.”
    We also could not reuse prior work on other ontologies that              http://www.w3.org/TR/owl2-primer. Last accessed 05/12/2014
have overlap with Apollo-SV. This work includes the                     [9] M. Courtot et al. “MIREOT: the Minimum Information to Reference an
                                                                             External                Ontology                 Term”                2009.
Epidemiology Ontology (EO) [16] and the Ontology for                         http://dx.doi.org/10.1038/npre.2009.3576.1.
Simulation Modeling of Population Health (SimPHO) [17].
                                                                        [10] J. Hanna et al. “Simplifying MIREOT; a MIREOT Protege Plugin.”
EO (like Apollo-SV) strives to meet Foundry principles [16].                 Proceedings of the ISWC 2012 Posters & Demonstrations Track;
However it, like IDO, also defines ‘infection’ as a material                 2012:11–15. http://ceur-ws.org/Vol-914/paper_48.pdf.
entity. It erroneously defines infection acquisition as occuring        [11] D. Schober et al. “Survey-based naming conventions for use in OBO
only in humans. It does not axiomatize its classes.                          Foundry ontology development. BMC Bioinformatics 2009, 10:125.
Okhmatovskaia et al. do not define for SimPHO [17] any of the           [12] L. G. Cowell, B. Smith. Infectious Disease Ontology. In: V Sintchenko,
terms in Table I. Further comparison is not possible because                 ed. Infectious Disease Informatics: Springer New York; 2010. p. 373-95.
SimPHO is not publicly available for review/reuse3.                     [13] J. M. Last (ed.), A Dictionary of Epidemiology. 4th Edition. Oxford,
                                                                             Oxford University Press, 2001.
   Note that Apollo-SV is still a significant work in progress.         [14] M. T. O’Toole (ed.), Mosby’s Disctionary of Medicine, Nursing, and
We represented entities sufficient to cover the input and output             Health Profession. 9th Edition. St. Louis: Elsevier, 2013.
of just three simulators and did pilot work on a fourth                 [15] R. H. Scheuermann, W. Ceusters, B. Smith, “Toward an Ontological
simulator. We have also done preliminary work to represent                   Treatment of Disease and Diagnosis”, Proceedings of the 2009 AMIA
other types of information in infectious disease epidemiology.               Summit on Translational Bioinformatics, 2009, 116-120.
                                                                        [16] C. Pesquita, J. D. Ferreira, F. M. Couto, M. J. Silva. The epidemiology
    Our future plans include harmonizing Apollo-SV                           ontology: an ontology for the semantic annotation of epidemiological
definitions with IDO (we plan to submit the issues described                 resources. J Biomed Sem, 2014;5:4.
here to the IDO issue tracker) and expanding Apollo-SV to               [17] A. Okhmatovskaia, P. Finès, D. L. Buckeridge, et al. SimPHO: An
cover additional simulators and types of information used in                 Ontology for Simulation Modeling of Public Health. In C. Laroque et
                                                                             al., eds. Proceedings of the 2012 Winter Simulation Conference: 883-94.
infectious disease epidemiology. We also plan to study the
                                                                        [18] I. Sim et al. “The Ontology of Clinical Research (OCRe): An
                                                                             informatics foundation for the science of clinical research. J. Biomed.
                                                                             Inf.           2013.           http://dx.doi.org/10.1016/j.jbi.2013.11.002.
3
 The link provided at http://surveillance.mcgill.ca/trac/star/
wiki/StarComponents/Ontology is broken as of this writing.




                                                                   26