Chimeric molecules that contain at least one pathogen-detection domain and at least one effector domain, and their methods of use in preventing or treating a pathogen infection in a cell or organism are described. The pathogen-detection domain and effector domain of the chimeric molecules are domains not typically found in nature to be associated together. Agents are also described herein having at least one pathogen-interacting molecular structure and at least one effector-mediating molecular structure, the agent being one that is non-naturally-occurring in a cell. The methods of prevention and treatment described herein are effective for a broad spectrum of pathogens and exhibit little or no toxic side-effects. Assays for the detection of a pathogen, pathogen component, or product produced or induced by a pathogen, are also provided.