With the advent of genomics, we have learned that microdiversity among strains of the vast majority of pathogens is extensive; each genotype infecting a host can present significant differences in virulence, immunogenicity, and antigenic variation. Thus, pathogens in circulation are not uniform; instead, they are comprised of sub-groups that can be defined by the expression of different genetic, pathogenic and population dynamic traits. The circulation of these parasites depends heavily on human movement dynamics, and, in some situations, vector availability and competence. Together, these anthropological, ecological, molecular, and immunological factors are fundamental drivers in the transmission of infectious disease, and their correct characterization requires a comprehensive interdisciplinary multi-scale modeling approach.
The traditional epidemiological approach to characterize transmission of infectious disease consists of compartmentalizing hosts into susceptible, exposed, infected, recovered (SEIR), and vectors into susceptible, exposed and infected (SEI), and variations of this paradigm (e.g. SIR, SIR/SI, etc.). This paradigm is challenged when trying to capture essential aspects of infectious disease such as: (i) Simultaneous Infection: An infection can include the simultaneous presence of several distinct pathogen genomes, from the same or multiple species, thus the rates of transition between epidemiological compartments is not constant; rather, it is function of the ecological competition between multiple strains and the immune system response. (ii) Antigenic diversity and variation: Antigenic diversity, defined as antigenic differences between pathogens in a population, and antigenic variation, defined as the ability of a pathogen to change antigens presented to the immune system during an infection, are central to the pathogen's ability to 1) infect previously exposed hosts, and 2) maintain a long-term infection in the face of the host immune response. Immune evasion facilitated by this variability is a critical factor in the dynamics of pathogen growth, and therefore, transmission.
The goal of this workshop is to bring together scientists from multiple disciplines to exchange ideas about new perspectives for the quantification of within-host dynamics and between-host transmission of infectious disease. Attendants will have the opportunity to discuss novel molecular and ecological data that has become available at an unprecedented level of detail ('omic, clinical, entomological, and epidemiological data through efforts currently funded by NIH), and will set the stage to discuss the novel application of mathematical perspectives that go beyond the traditional epidemiological models of transmission.