Infections caused by microorganisms are discussed in this session,are harmful to the health and some are not dangerous. can occur in humans as well as animals. Currently research and advancements have been involved to diagnose and treat the diseases caused by microorganism. Changes in the surroundings like climate have made certain humans to contact with the newly identified . The most deadly Sexually Transmitted Diseases are caused by harmful bacteria. Viruses causes emerging like flu, common cold and warts.