contact definition ContactDefinition An information content entity that specifies which kinds of processes involving an interaction between a given organism and either (1) another, potentially infectious organism or (2) a contaminated environment have a sufficiently high probability of resultling in an infection acquisition by the organism to be of interest to an outbreak investigation. An information content entity that specifies which kinds of processes involving an interaction between a given organism and either (1) another, potentially infectious organism or (2) a contaminated environment have a sufficiently high probability of resultling in an infection acquisition by the organism to be of interest to an outbreak investigation. William R. Hogan potentially infectious contact definition information content entity