Influenza Posted on 1st December 20153rd October 2020 by ThePD (The Project Definition) Influenza is a highly infectious viral disease that is the inflammation of the respiratory tract. Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window) Related Posted in HSE and tagged health, hse. ThePD (The Project Definition) ThePD has been developing the Preferred Project Definitions based on the actual project execution and operation experiences and knowledge with the Project Language, and sharing with you daily basis.