Chlamydia trachomatis infection most commonly affects the urogenital tract. In men, the infection usually is symptomatic, with dysuria and a discharge from the penis. Untreated chlamydial infection in men can spread to the epididymis. Most women with chlamydial infection have minimal or no symptoms, but some develop pelvic inflammatory disease. Chlamydial infection in newborns can cause ophthalmia neonatorum. Chlamydial pneumonia can occur at one to three months of age, manifesting as a protracted onset of staccato cough, usually without wheezing or fever. Treatment options for uncomplicated urogenital infections include a single 1-g dose of azithromycin orally, or doxycycline at a dosage of 100 mg orally twice per day for seven days. The recommended treatment during pregnancy is erythromycin base or amoxicillin. The Centers for Disease Control and Prevention and the U.S. Preventive Services Task Force recommend screening for chlamydial infection in women at increased risk of infection and in all women younger than 25 years.