The incidence of chlamydia, gonorrhea and syphilis is increasing, according to a new report from the Centers for Disease Control and Prevention. At any given time, there are an estimated 110 million sexually transmitted infections in the United States.

While HPV is the most common sexually transmitted disease, according to the C.D.C., chlamydia is the most common type that can be easily cured, yet 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.