Answer:
The battle against sexually transmitted illnesses, except for the relatively recent HIV/AIDS, has been one that has been present in humanity almost from its beginning. Infections caused by syphilis, ghonorrea, clamydia, among others, have been a part of humans since sexual activity has been around us. However, since the appearance of antibiotics, and other chemical agents to combat them, the scenario changes for mankind, as now, a diagnosis of such diseases was not basically a death sentence, or, a reason to be socially isolated. Another thing that changed, was the pattern and incidence of transmission, as now, with treatment, the pathogens could be stopped.
However, during the 19th century, with the appearance of medically more advanced technologies, better antibiotic treatments, and other public health measures, many of these STI´s, especially those that were most frequent, like syphilis, were no longer taken as certain death. However, it also became a reason for people to act more rashly and not think about transmission.
But in the 20th century, and especially since the appearance of the most deadly HIV virus, particularly in homosexual populations, things began to look bad for humans again. People died, and the only measure that could be taken as science learned about the pathogen, was isolation of those infected. Just as in the middle ages those infected with plague, were left aside, HIV-infected people became isolated. But during the 20th century, virology, the science that studies viruses and the possible treatments to it, and the adventure of DNA discoveries, led to a huge change. It was seen that there were a series of chemical components, that were able to completely detain, and in some cases eliminate, those viruses and bacteria that caused deadly STIs. But probably one of the biggest advances in the 20th century was the realization of the importance of education of people, campaigns to educate the people about contagion, ways of prevention and possible treatments.
