The multi-agency Ecology and Evolution of Infectious Diseases program supports research on the ecological, evolutionary, organismal, and social drivers that influence the transmission dynamics of infectious diseases. The central theme of submitted projects must be the quantitative, mathematical, or computational understanding of pathogen transmission dynamics. The intent is discovery of principles of infectious disease (re)emergence and transmission and testing mathematical or computational models that elucidate infectious disease systems. Projects should be broad, interdisciplinary efforts that go beyond the scope of typical studies. They should focus on the determinants and interactions of (re)emergence and transmission among any host species, including but not limited to humans, non-human animals, and/or plants. This includes, for example, the spread of pathogens; the influence of environmental factors such as climate; the population dynamics and genetics of vectors and reservoir species or hosts; how the physiology or behavior of the pathogen, vector, or host species biology affects transmission dynamics; the feedback between ecological transmission and evolutionary dynamics; and the cultural, social, behavioral, and economic dimensions of pathogen transmission and disease. Research may be on zoonotic, environmentally-borne, vector-borne, enteric, or respiratory pathogens of either terrestrial, aquatic, or marine systems and organisms, including diseases of animals and plants, at any scale from specific pathogens to inclusive environmental systems. Proposals for research on disease systems of public health concern toLow- or Middle-Income Countries (LMICs) are strongly encouraged, as are disease systems of concern in agricultural systems. Investigators are encouraged to develop the appropriate multidisciplinary team, including for example, anthropologists, modelers, ecologists, bioinformaticians, genomics researchers, social scientists, economists, oceanographers, mathematical scientists, behaviorists, epidemiologists, evolutionary biologists, entomologists, immunologists, parasitologists, microbiologists, bacteriologists, virologists, pathologists or veterinarians, with the goal of integrating knowledge across disciplines to enhance our ability to predict and control infectious diseases.