An STD is an infecious disease caused by bacteria or virus. There are many different types of STD's but I've decided to talk about the most common 3 worldwide.
STD have been known to mankind for centuries. Before the advent of modern medicine, people's lack of awareness and understanding of STDs contributed to the widespread transmission of the infections while few or no treatments were available to treat the conditions. In medieval times, syphilis and gonorrhoea were two of the most prevalent STDs in Europe. One theory suggest that syphilis was spread by crew members who picked up the disease on the voyages led by Christopher Columbus. They are thought to have contracted syphilis while in the Americas and to have then spread it on their return when docking at ports in Europe. Sailors are also thought to be responsible for the spread of gonorrhoea from Tahiti to New Zealand during the Cook voyages.