The incidence of chlamydia, gonorrhea, and syphilis is increasing, according to a new report from the Centers for Disease Control and Prevention. An estimated 110 million Americans now are infected with a sexually transmitted disease. Chlamydia is the most common S.T.D., and the number of cases rose 4.7 percent from 2015 to 2016. The increases occurred nationwide; rates were highest in the South and lowest in the Northeast. Chlamydia is usually asymptomatic, and the number of reported cases may have

grown in part because of newer, more sensitive screening techniques. Adolescents and young adult women have the highest rates of chlamydia: one survey found that 9.2 percent of girls aged 15 to 19 were infected, as were 8.0 percent of women aged 20 to 24. Rates declined 3.5 percent among African-Americans and 6.4 percent among Native Americans and Alaska Natives, but chlamydia still is most common in these groups. Rates rose among all other races and ethnicities. READ MORE