transmission tree William R. Hogan A data structure that represents, for a particular infection in ecosystem, a subset of infected organisms and for each infected organism in the subset except the first one infected temporally, its infection acquisition from an infected host as a machine-readable link to that infected host. Matthew Diller TransmissionTree A data structure that represents, for a particular infection in ecosystem, a subset of infected organisms and for each infected organism in the subset except the first one infected temporally, its infection acquisition from an infected host as a machine-readable link to that infected host. Because a set A is a subset of itself, we capture the possibility that all infected organisms in the epidemic are represented in the tree. This definition allows for multiple trees in an epidemic because we did not require that the first case infected temporally be the index case, although the ideal situation is that there is one tree for the epidemic that includes the index case. data representational model