Chlamydia

102,175 cases in 2024 — near the 5-year baseline of ~367,630.

What is it?

Chlamydia is caused by Chlamydia trachomatis and is the most frequently reported infectious disease in New York State, with 102,175 cases in 2024. Because the majority of infections cause no symptoms, routine screening is critical — undetected chlamydia can cause serious long-term reproductive harm.

How it spreads

Spreads through vaginal, anal, or oral sex. Can infect the genitals, rectum, and throat. Can be passed from a pregnant person to a newborn during delivery, potentially causing eye infections or pneumonia in the infant.

Symptoms

Most people have no symptoms. When symptoms occur: unusual genital discharge, burning during urination, rectal pain or discharge, or painful swollen testicles. In women, untreated chlamydia can cause pelvic inflammatory disease (PID) and damage to the fallopian tubes, potentially causing infertility or ectopic pregnancy.

Who is at risk?

Sexually active people of all ages. Annual screening is recommended for all sexually active women under 25, and for older women and men with new or multiple partners. Men who have sex with men should be tested at all exposed sites.

What you can do

Based on NYSDOH annual communicable disease report. Threat level reflects 2024 case counts compared to the 5-year baseline.