In the United States, the incidence of the disease dropped from 66.4 cases per 100,000 in 1947 to 3.9 per 100,000 in 1956 as a result of the discovery of penicillin, but in the late 1980s, as a result of increased drug abuse and intravenous cocaine, sex exchange versus drugs, People with more than one sexual partner increased by 53.8 per 100,000 in 1990 and then dropped significantly. In the last 2007 study, the incidence of the disease rose from 3.3 to 3.7 per 100,000 with 11466 cases. The same year, most of this rise was in men and especially those who had sex with Men .
Worldwide, the incidence of syphilis varies from region to region. The highest is in South and Southeast Asia, followed by sub-Saharan Africa, Latin America and the Caribbean are third. In Siberia, the infection rate is 1300 per 100,000. In 1999.
As for the age at which the disease starts, most cases in men and women start at the age of 15 – 40 years and are the years of sexual activity for both sexes.
Men are more likely to be infected with the disease than women. The percentage of males to females infected with primary and secondary levels is 1: 6 in the United States.
Among them, 65% of the new cases were in this category, in addition to the spread of the disease
(AIDS) among themselves as well.
The disease is also more prevalent among dark-skinned people compared with light-skinned people. The incidence of blacks is 3-5 times higher than in whites.