The symptoms of syphilis have become less severe over the 19th and 20th century in part due to widespread availability of effective treatment and partly due to decreasing virulence of the spirochete.
Simptomi sifilisa su tijekom 19. i 20. stoljeća postali blaži, djelomice zbog široke dostupnosti učinkovitog liječenja, a djelomice zbog manje virulencije spiroheta.