We know, for example, that gonorrhea passed from cattle to humans. Syphilis also came to humans from cattle or sheep many centuries ago, possibly sexually. There were sheep that originated in the United States. But sheep were in Asia, Africa and Europe for centuries before Columbus.
It is not realistic to think that a disease has occurred all over Europe and Asia in only 30 or 40 people. Some STDs can have serious, life-changing consequences; syphilis, for example, can cause progressive destruction of the brain and spinal cord, leading to mental dysfunction and hallucinations, speech problems, and general paresis. In the 20th century, the advent of penicillin and other antibiotics led to an effective cure for bacterial STDs. At the end of the 20th century, the transmission of viral sexually transmitted diseases such as HIV and herpes emerged, infections that are not curable and that in some cases can be fatal.
You may not realize that you have certain STDs until you have no damage to your reproductive organs (making you infertile), vision, heart, or other organs. Soon, sexual health clinics were created to identify and treat people with sexually transmitted diseases and their partners, in order to prevent their spread in the general population. It was in the late 19th and early 20th centuries that the importance of tracking the sexual partners of a person infected with an STD was recognized. Sexually transmitted infections (STIs), also known as sexually transmitted diseases (STDs) and the older term venereal diseases, are infections that are transmitted through sexual activity, especially vaginal intercourse, anal sex and oral sex.
HIV, chlamydia, genital herpes, genital warts, gonorrhea, some forms of hepatitis, syphilis and trichomoniasis are sexually transmitted diseases. Before the advent of modern medicine, people's lack of knowledge and understanding of STDs contributed to the widespread transmission of infections, while there were few or no treatments available to treat diseases.